Sky Commander User`s Manual - Charlotte Amateur Astronomers Club
Contents
1. 39 Appendix C Encoder Jack zeen 43 Appendix D Pointing Accuracy 44 Appendix E Installing Dob Kit 46 Warranty 51 1 Introduction Thank you for buying the Sky CommanderXP4 telescope computer system You have made an excellent choice If you have not already used a computer equipped telescope you are in for a pleasant experience that may change forever the way you observe XP4 was designed especially for those amateurs who would like to be able to locate and observe celestial objects fast and easily With the aid of Sky Commander XP4 more time can be spent at the eyepiece and less time at the finder scope and sky atlas Objects are located by entering their catalog number using push buttons A liquid crystal display shows you the scope s position and lets you zero in to objects With a little practice you can locate even the hardest to find objects in seconds You will find that operating the unit is next to intuitive This and other exciting features described in this manual will help make your nights out under the stars more enjoyable than ever 1 1 XP4 New Features XP4 builds on the tradition of the original Sky Commander and adds new capability e New custom ABS plastic enclosure for dura2. Nylon Thumb Screw 6 X 1 Wood Screw 0 gd UIT HI 3 EP N GE EE EG N Encoder Shaft 0 Black Delrin Elevation Encoder Coupler Figure 8 Elevation Encoder Mounting 49 3 17 2009 3 Install the elevation encoder tangent arm assembly by sliding the slotted end over the anchor pin and then inserting the 1 4 shaft of the encoder into the hole in the coupler Tighten the nylon thumb screw 4 Find the end of the elevation encoder cable shorter of the two cables Plug it into the RJ11 jack on the elevation tangent arm This completes the installation of the elevation encoder OTA EL Bearing Tangent Arm Rocker Box EL Encoder Cable Anchor Pin Figure 9 Mounting of Elevation Encoder Arm 50 3 17 2009 1 Year Warranty The Sky Commander KP4 is warranted for a period of 1 year from date of purchase If the unit or encoders or associated parts fail due to defective material or workmanship the unit or parts will be repaired or replaced free of charge The unit or parts will be shipped free of charge one way Damage done by incorrect installation or abuse is not covered by this warranty 51 3 17 2009
3. SKY Engineering Inc Sky Commander XP4 User s Manual Rev 4 1 1991 1995 2007 2009 Sky Engineering Inc All Rights Reserved Table of Contents dee e TE ee AAA 1 ES APAMew Fil AA 1 1 2 About this Manual 1 1 37 FamiliarizatOf sis Me Aa Wi Od ee ee ed tec ee ee ee bose tate 2 14 Batiery Replacement us iss ER EERS EENS EER EE EER ee N EE ee Ee 3 1 5 External 12 Volt Operation DEE 4 Unit Setup sesse EER se ee R ee EK dee EWE KA EE Ged ee ek GE N ER Ge Ge eN ee EA EE be N EE 5 21 SG MENU Re GE ee DE AA 5 2 2 Determining Encoder Parameierg 7 2 2 1 EineoderHesolitiofis ss ake she hh ee tte tee 7 2 2 2 Encoder Direction Dobsonian Alt AZ w 7 2 2 3 Encoder Direction Fork Mount 8 2 2 4 Encoder Direction German Eguatorial 9 Star eu E 10 3 1 Polar le Ee uwiii awa 10 3 2 Dobsonian Alt Azimuth Scopes ssessessssennnneessserrrrrnnnrrneerrrrnrnnnnneeeee 10 3 3 Fork 2 Star Alidrimelilss KAREN AR a Aaa a aaa sta ie 11 34 German Equatorial 2 Star Alignment ss ee ee ee Re ee ee ee 12 Sky Commander Operatioft is ies sieki insek lu de ie ke bw de ki ie ke eko nne 13 SEL Selina Dae ER EE EE Ee SE AAA RE ED Ee Ee 13 4 2 Basics of Object EGO EE RD AG AG Ge al 14 4 Catalog Selaellod EK ED SR DE N hee ae oN 16 44 Catalog Tvpes eee 17 4 4 1 Numbered Catalogs win 17 4 4 2 Named Gatalpde EE 18 4 4 3 Named with Constellation Catalogs
4. To delete the entire favorite list see operating menu item Purge Favorite List Menu 27 3 17 2009 6 5 Special Object List You may wish to reference object coordinates other than those included in the catalogs The Special Object list provides an easy way to do just that You can enter up to 59 coordinates by Right Ascension and declination This can be done either through the keypad on the Sky Commander or through a PC program via the RS232 port See Load Special Object Coordinates Command in Appendix B To see the Special Object list move the cursor under the catalog name and use A or VY to get to the catalog named with a single S as shown below The two digits following S are object index Put the cursor under the first digit and use A or CV to scroll the list The index range is 00 to 58 There is also a 99 index which is explained below Return to index 00 and then move the cursor under the first digit of RA hours Use a or CV to change this digit then move to the next digit changing it as well Continue to move the cursor to the right changing digits as desired When you are done entering the special object coordinates press to save it in EEPROM memory The information will be retained even after turning the Sky Commander off Special objects are located just as other catalog objects i e with the cursor in home position the A button toggles on and off the F so you can zer
5. Slide the cover to the closed position ON OFF P Button Use small screwdriver to Long Tab This End help slide open if needed aas JIE attery Cover r2 5 Slide to Open Slide to Close gt Bottom View Figure 2 Battery Installation 3 3 17 2009 1 5 External 12 Volt Operation The unit will operate on external 12 volt DC power The power jack is on the left side It is a standard 2 1mm ID 5 5mm OD type The center contact is positive polarity WARNING Use only regulated 12 volt DC power supply or 12 volt battery for external power A regulated AC to DC adapter for this purpose is available as part number PWR AC 1210 Use of unregulated adapters will void warrantee External power must be used in cold weather 10 degrees C and below It powers a heater to keep the liquid crystal display operating normally Without the heater the display response can be very slow making it difficult to use External power is also very useful when using the Fast track feature When Fast Track is on the unit will draw an extra 50 to 100 mA depending on the encoder type and resolution This will run down an internal 9 volt battery 300 to 400 mAH quickly It is not necessary to use an internal 9 volt battery when operating from external power You can leave the internal 9 volt battery installed however It will not damage the unit 4 3 17 2009 2 Unit Setup This chapter deals with getting the uni
6. computed position may not match the true position hence a pointing error Besides the problem of orthogonality between the two main axes there is the question of orthogonality between the declination or elevation axis and the scope s optical axis This likewise can cause pointing errors with an effect similar to that noted above The two misalignments though independent of each other can be difficult to distinguish when trying to correct Always collimate the tube assembly before trying to sguare it with the declination or elevation axis Dobsonian telescopes in particular can exhibit a wobbling of the azimuth axis caused by non flatness of the bottom of the rocker box It is not difficult to understand how this can contribute to pointing errors It can easily be checked with a straightedge If either of the two encoders is mounted off the center of rotation there will be some error for instance if the elevation encoder on a Dobsonian is not mounted in the center of the bearing disk an error due to runout is experienced The encoders themselves have a certain angular resolution This is the smallest movement that can be detected Resolution itself is a source of error when aligning and in normal use Though small it can add to other errors Always take time to center alignment stars in the eyepiece This obvious source of error should not be overlooked Remember the axiom sometimes referred to as GIGO or 44 3 17 2009 Ga
7. 8 XP4 Specifications PARAMETER CONDITIONS SPECIFICATION Operating Voltage 9 volt Internal Battery 5 5 volts Minimum External DC Supply 11 v Min 13 8v Max Supply Current Internal 9v battery Fast Track off 10 mA typical External DC Supply Fast Track on 4000 step encoders 90 mA typical External DC Supply display heater on Additional 120mA Battery Life Internal 9v battery Fast Track off 30 Hours with typical use DC Power Jack 2 1mm ID 5 5mm OD power jack center positive Encoder Type Optical Rotary US Digital type Max Rotational Speed S1 and S2 Fast Track Off 1200 steps sec Max Fast Track On 2000 steps sec Max Encoder Resolution Includes any gearing ratio 32767 2 1 Max Operating Temp Internal 9v battery no heater 10C to 50C External DC Supply with heater on 25C to 50C Displayed Resolution RA Declination mode 1 min RA 1 deg declination Alt Azimuth Mode 1 deg Azimuth 1 deg elevation 2x16 char high contrast super Display Type twist LCD yellow green backlight Adjustable intensity 300 to 9600 baud 1 start bit Serial Port 8 data bits no parity 1 stop bit 33 3 17 2009 9 Troubleshooting Your Sky Commander computer was checked out fully before shipping Should you experience difficulty please refer to the following trouble chart before c
8. degrees declination Press when you see it displayed The display should look similar to the following Move the scope up toward the zenith The numbers of declination should increase If they decrease instead just note it and proceed Now move the scope in the counter clockwise direction The numbers of RA should increase If either declination or RA directions are incorrect go into the Setup Menu and change the direction from Normal to Reverse or visa versa Repeat the steps above to verify that the changes you made took effect then return the scope mount setting to DOB 2 2 3 Encoder Direction Fork Mount Sky Commander detects motion and direction of telescope movement through the encoders but it does not know the sense of direction with respect to North South or East West You will determine that sense of direction and enter it through the Setup Menu The Sky Commander should already be setup for operation in FORK mode If not then follow directions in the section Setup Menu Identify the side of the fork that will normally be facing up during alignment and use This is the side that is up when the scope is pointing to an object on the meridian Be sure to use this side during the following test and during star alignment With the encoder cable plugged into the Sky Commander turn it on Press in response to the Set Date prompt It is not necessary to set the date at this time Wait until Calc
9. first reading This completes the azimuth test 6 Move the scope in elevation to its lowest point There should be some kind of mechanical stop Note the elevation declination number Now move to the zenith stop point and note that number The two numbers should be roughly 90 degrees apart allowing for the fact the mechanical stops may not be exactly 90 degrees apart Also allow for negative numbers at the horizontal position and overshooting 90 degree reading at the vertical position 7 Move the scope in elevation between the two stops and note that the readout returns to the recorded numbers at the stop points This completes the elevation test 35 3 17 2009 Technical Assistance Technical assistance is available to all customers free of charge Normal business hours are from 7 00 PM to 10 00 PM EST Mon Sat Leave message if necessary By Phone 954 345 8726 E Mail skycomm att net Web Site http www skyeng com Orders and other correspondence Sky Engineering Inc 4613 N University Drive 351 Coral Springs FL 33067 36 3 17 2009 Appendix A Method of Determining 90 Degree Setting for GE Mounts The advantage of the 2 star alignment is in not having to be polar align Whenever a 2 star alignment is done the user is required to orient the scope to 90 degree declination except for Dobsonians It is important to understand that this position is relative to the telescope itself and not the sky The 90 deg
10. rotation in response to the F command A single floating point number four binary bytes is returned The sign is arbitrary since the number of mirrors in the optical system will affect the direction of rotation Units are in degrees minute Floating Point Format Numbers that are returned in response to various commands are expressed in IEEE floating point format as described below Each number consists of four bytes 32 bits with the most significant byte sent first The bits are assigned the following meaning 31 sign of mantissa 1 negative 30 23 exponent biased by 128 22 0 mantissa 24 bits MSB hidden and always 1 The mantissa is normalized 24 bits with the MSB hidden The MSB is always assumed to be 1 therefore only 23 bits are needed to store the mantissa The exponent is biased by 128 i e a 128 value represents an exponent of zero A 129 value is an exponent of 1 Example if the exponent has a 131 value 13 the number is 2 3 mantissa The mantissa is always less than one and greater than or equal to 1 2 The number zero is stored as four zero bytes 42 3 17 2009 Appendix C Encoder Jack Sky Commander XP4 User s Manual 12345678 Figure 5 RJ45 Encoder Jack RJ45 Pin Function 1 Azimuth or RA Channel B Signal Azimuth Encoder 5V Power Azimuth Channel A Signal Ground Elevation or Declination Channel B Signal Elevation Encoder 5V Power Elevatio
11. tone phone If the buttons are held down for more than about a second however multiple presses of the button are generated This can be convenient for scrolling through long lists 4 1 Setting the Date The date displayed each time you turn on the Sky Commander is not driven by a real time clock as in a desktop PC You are able to change and save it as described below however Setting the date is optional it is used only for the calculation of planet positions and has no effect on alignment or location of other objects Change the date by moving the cursor with gt and scrolling the month day and year with A or Press to save the date and proceed to Star Alignment 13 3 17 2009 4 2 Basics of Object Location After performing Star Alignment Sky Commander is ready to guide you to any of thousands of database objects This section will take you through the basic steps of locating an astronomical object Note The Sky Commander database can be customized in terms of catalog selection and arrangement For the purpose of describing basic operation an example will be used It is assumed that the Messier catalog is loaded and it is the first one in the list of catalogs See Catalog Selection for details Assume the star Betelgeuse has been used for alignment second star in the case of 2 star alignment The display will look similar to the following Line 1 of the display shows the telescope position in RA and declination Li
12. 19 Epi Mehile ss ei gs AG ke n eb aaa a eg ab ol 20 5 1 Search amp Identify Menu ee ee ee 20 5 2 Limit Magnitude Menu N SE OE EE GE Ge N GE GN SE Ge NG Ee 20 5 3 EEN 21 5 4 Favorite List Menu 21 5 5 Purge Favorite List MENU sees sk HEES Ek eg Re EE Gee be Ok Ge SA Ge EE uwiii 21 5 6 Battery Monitor MENU i s RR MEE RE GE ie De ee AG De Ee EE ed 21 5 7 Realign on Object Menu sies dsE RE ee ERG de AN EE Ede Ede Rd Se Rds See RE Cen 21 5 8 Equatorial Table Reset Menu EE 22 6 Operating Fealure ss N RS Ee GAN RANG Ed NA KAN kke ER GN ee N 23 6 1 Display Object Jonn oe EERS EE ER ER ER EED ER EES 23 6 2 Search de EE EE N N ii wakaka niki aw 24 6 3 Scroll by Constellation and Catalog mwm 24 64 Favorite Objects Eegeregie GES 26 6 5 Special Object liet EE EE Ee BE EE Ge De Ee De Eg EE Ee 28 6 6 The Planet Catalog EEN 29 6 7 Standby le SES ER EE awa 29 6 8 Use with Equatorial Table 29 6 8 1 2 Star Alignment with EO Table sesse ee ese ees se ee ee ee 30 6 8 2 Equatorial Table Real REKEN R REK REKE Gesk ee ieke 30 6 9 Realignment on Database Objects AAA 31 6 10 eelere 31 7 Alignment Stars ad onde saNK Ns Vas de Rds Ne N GE GRENS A NN AN Ke Ed GE N ANENE NARE Rds kke Ne 32 8 XPA Specifications sis n ed N N N EE n N aaa 33 9 Troubleshooting E 34 Appendix A 90 Degree Setting for GE Type Mounts 37 Appendix B RS232 Serial Port
13. 6 4 Favorite Objects List Objects from the internal database can be marked as Favorite and put into a list for quick reference Another possible use is to record your evenings observations When the cursor is in the home position on the bottom line of the display pressing 2 will cause the following prompt If you wish to add the object to the favorite list move the cursor under YES and press Otherwise just press and the object will not be saved A maximum of 73 objects can be saved to the favorite list If you try to save more than the maximum an error message is displayed When you want to access an object that was stored in the favorite list the list must be turned on Go to the operating menus and index to the Favorite List menu See Favorite List Menu Turn on the list by moving the cursor under ON then press again to exit menus If you forgot to put any objects into the list the following error message is displayed The F on the top line indicates that the Favorite list is active In this example M21 is in the list Other favorites are accessed using the and gt buttons While the 26 3 17 2009 list is active these buttons are dedicated to scrolling the list While the list is in use objects may be deleted Press and the following prompt is displayed Move the cursor under YES and then press to delete it Otherwise just press and it will not be deleted
14. Equatorial 2 Star Alignment When you are prompted for 1 or 2 star alignment select 2 star with Y You will be prompted to set the scope to 90 degrees This means relative to the scope not the sky The optical tube should be oriented parallel to the polar shaft of the mount Note This setting must be accurate See the appendix describing the method for determining the 90 degree position for a German Equatorial Next you will be prompted to sight the 1st star Usel A and _ buttons to select a convenient star on the eastern side of the meridian Get the star sighted accurately in the scope and press Now you will be prompted for the 2nd star Choose one on the western side of the meridian preferably at least 90 degrees from the first Again sight the star and press This completes the alignment procedure and the Sky Commander enters operating mode 12 3 17 2009 4 Sky Commander Operation All of the Sky Commander functions are accessible through the six button keypad array on the front panel The buttons are arranged in such a way to make them easily located by feel The four arrow buttons are for navigating menus and scrolling lists The remaining two buttons are ENTER for making selections and MENU for accessing the menu controls NAVIGATION BUTTONS aje ENTER MENU BUTTON BUTTON Figure 3 Keypad Buttons In normal operation the buttons are pressed and quickly released like dialing on a touch
15. Pivot pin may be binding if not mounted perpendicular Pivot pin may be too short causing binding Try to remount Use lubricant on pin bushing if necessary Unit does not work when used with Sky Tracker Dobsonian drive system Check connection between Sky Commander and Sky Tracker box Make sure Sky Commander RS232 baud rate is set to 9600 34 3 17 2009 360 Degree Rotation Test Do this test if you cannot find any mechanical or electrical connection problems with the encoders It is not necessary to have the scope outside to do this test 1 Put the unit into FORK mode and turn OFF sidereal clock see Setup Menu These settings are only for the test Remember to restore the original settings after the test is done 2 Turn the unit on and position the Dob scope roughly horizontal When prompted for 1 or 2 star alignment select 1 star 3 Select a star near the equator like Betelgeuse 7 5 North and press 5 to align on it 4 Establish a mechanical reference point in azimuth This can be any fixed object in the room Move the scope to the reference position and note the azimuth or RA number on the display 5 Move the scope as you would normally in azimuth making several complete rotations first in clockwise direction and then counter clockwise direction If you move slightly in elevation it is OK Each time the scope comes to the reference point note the number displayed It should always be the same as the
16. again Information about double stars is different Example select the double star catalog Dbl and scroll to the constellation of Andromeda AND With the cursor under the star name scroll to second separation For other star catalogs such as Named Star NST and Bayer Star Byr the star magnitude and spectral type is displayed Example for EF HLFHER ILA the following info is displayed Alpha Andromeda Alpheratz is a 2 1 magnitude star of spectral type B8 23 3 17 2009 6 2 Search amp Identify Sky Commander has the ability to identify objects you come across while panning the scope Enable Search amp ID through the Operating Menu see Search amp Identify Menu As you move the scope any object brighter than the Limit Magnitude which is within a 5 degree circle is displayed If multiple objects qualify the closest one is displayed While Search amp ID mode is on an S is displayed in the upper left of the display as a reminder to the user All loaded catalogs except Special Objects and Planets are searched If no object is found meeting the criteria the following message is displayed Power consumption is slightly higher while in Search amp ID mode 6 3 Scroll by Constellation and Catalog You may have noticed the diamond symbol ki that appears with most catalogs Positioning the cursor under the diamond allows you to browse through objects in the current cata
17. alling for assistance TROUBLE CORRECTIVE ACTION No display indication when unit is turned on Check internal battery and connection Try external 12V power No display backlight visible Adjust intensity with keypad Light is intentionally dim for night use Either RA or dec readout does not change when scope is moved Check connections to encoder Inspect contacts of encoder jack on Sky Commander unit Look for bent or out of place pins Inspect encoder cable ends closely Damaged ends can cause bad electrical contact Try switching encoders to isolate problem i e determine if problem is encoder or cable or unit Objects cannot be found Check direction and resolution settings for each encoder Objects may be too dim Be sure to correctly identify alignment stars Position accuracy poor Check resolution setting for each encoder Check centering of encoders Check orthogonality of axes and optical collimation Center alignment stars accurately Other position accuracy problems Perform 360 degree rotation test see below Position accuracy degrades with time Check that the sidereal clock is turned on Check encoders to make sure they are not slipping Do not move scope too fast RA or Azimuth reading seems to stop counting when turning scope counter clockwise but may be OK in clockwise direction Azimuth pivot pin may not be tightly secured to ground board Retighten
18. amed e Named with Constellation 4 4 1 Numbered Catalogs A four digit number appears to the right of the catalog name The constellation name appears to the far right 17 3 17 2009 The cursor can be placed under each digit and the A and VY buttons are used to change them Pressing causes the entered object to become current If an invalid number is accidentally entered an error message is displayed and the display reverts to the previously selected object The cursor may be moved under the constellation name The constellation can be changed with the A and VY buttons Note Only constellations that contain objects within the current catalog and the object meets Limit Magnitude criteria will be selectable Having selected a constellation objects of the current catalog can be browsed by placing the cursor under the symbol As the and VY buttons are pressed first a brief object description appears then the object number The description helps the user decide whether or not it is of interest See Scroll by Constellation and Catalog 4 4 2 Named Catalogs There are two catalogs namely NDS Named Deep Sky and NST Named Star which allow the user to select in alphabetical order the common name of an object When the cursor is moved under the first letter of the object name the 4 and TY buttons let you increment or decrement to the next letter You can move quickly to the first letter of the na
19. an should be selected for any Alt Az type mount e Hemisphere Select the hemisphere where you will be operating the scope 5 3 17 2009 RA Direction This is the direction for the RA or Azimuth encoder The direction Normal or Reverse will be determined by doing a simple test with the scope The default Normal is the one that is most typical for most Dobsonian scopes See directions for determining this setting for DOB Fork or German Eq Dec Direction This is the direction for the Declination or Elevation encoder The direction Normal or Reverse will be determined by doing a simple test with the scope The default Normal is the one that is most typical for most Dobsonian scopes RA Encoder Res This is the number of counts of the encoder per revolution of the telescope RA or Azimuth axis Typical values are 4000 4096 8000 8192 10000 etc Dec Encoder Res This is the number of counts of the encoder per revolution of the telescope Declination or Elevation axis Typical values are 4000 4096 8000 8192 10000 etc Important Note The resolution numbers entered represent the counts per revolution of the telescope For instance if an 8192 step encoder is used for azimuth and 4096 step encoder is used for elevation then you must enter those numbers Any gearing or pulley ratio must be taken into account If a 2048 step encoder is geared 2 1 then enter 4096 Fast Track ON OFF The Fast Track feature
20. asier of the two procedures since it requires only one sighting The positioning accuracy of your system however will depend on the accuracy of the polar alignment After turning on select 1 Star alignment with the A J button The display will show Sight 1st Star on the top line The bottom line will show the name of one of 40 alignment stars along with its magnitude A or buttons let you select the star you are going to use If you have a German Equatorial NOT FORK mount and you want to use a star in the western sky use the lt 4 or gt buttons to change the display to Sight 2nd Star For fork mounts leave the display at Sight 1st Star for any alignment star East or West of the meridian Sight the star with your scope Get it as close to center of field as possible When the star is centered press ENTER This completes the alignment procedure and the Sky Commander enters operating mode 3 2 Dobsonian Alt Azimuth Scopes To use Sky Commander with a Dobsonian Alt Azimuth scope a 2 Star alignment must be done every time the unit is turned on The stars should not be too close to the zenith or horizon 10 to 60 degrees elevation is preferable They should be separated in azimuth at least 90 degrees the more separation the better Two star alignment begins with the Sight 1st Star prompt Use AT and 10 3 17 2009 LY buttons to select the first star The first one in the list is Polaris This is
21. bility and easier battery replacement e 4X Memory Size plenty of room for operating program and 30 000 database objects e Flash Memory Upgrade software and manage database through your PC with Windows based utility program e Four independent setups for multiple scopes e Additional Catalog Types Named object catalogs for deep sky and stars are now supported Also a Bayer Greek letter number star catalog is available e Users can select from a list of available catalogs and load only those that are of interest e Users can create their own catalogs using Microsoft Excel spreadsheet e Support for third party drive systems such as ServoCat and SiTech in addition to the Sky Engineering Sky Tracker In the original Sky Commander program and database changes were done by replacing an EPROM Electrically Programmable Read Only Memory device This required the unit to be opened and was not convenient XP4 introduces flash memory which can be updated without opening the box Simply connect it to your PC and run an upgrade utility 1 2 About this Manual This manual contains everything you need to know to start using Sky Commander XP4 Parts of the manual are written as a tutorial to help you get familiar with operating the unit Every feature is described using examples 1 3 17 2009 1 3 Familiarization Figure 1 shows the Sky Commander computer The ON OFF pushbutton switch is located on the left front of the bor A pow
22. der shaft into the end of the pivot pin At the same time slide the forked end of the tangent arm over the anchor pin Make sure that the encoder shaft is all the way into the hole of the pivot pin Tighten the nylon thumb screw lightly 7 Find the end of the azimuth encoder cable longer of the two cables Plug the cable into the RJ11 jack on the tangent arm This completes the installation of the azimuth encoder 47 3 17 2009 NOTE Minimum clearance to mirror box front corner as if swings 6 8 past center 1 1 2 Conhector Pins Az Anchor Pin Groove for Retainer Ring y Bronze Bushing is Tangent Arm X Nominal Dimensions specify when ordering Azimuth Encoder Installation SCALE none DATE 3 11 94 BY V McKe gnan Figure 7 Azimuth Encoder Mounting 48 3 17 2009 Elevation 1 Mount the elevation encoder coupler to one of the side bearings with three 6 X 1 stainless steel wood screws Use care to center the coupler An off center coupler could result in degraded pointing accuracy 2 Mount the elevation anchor pin to the side of the rocker box Drill a small pilot hole for the 4 wood screw at a point 12 from the center of the encoder coupler The hole may be straight down from the center or on an angle as required Use the 4 stainless steel washer under the screw head to prevent the slotted end of the encoder arm from slipping off the anchor pin 10 32 X 1
23. e position and makes the displayed object current With the cursor under the catalog name use A and VY buttons to see other catalogs that make up the database 16 3 17 2009 The following table is a list of catalogs available at the time of writing this manual Updated catalogs when available can be found at http www skyeng com Abbreviation Catalog Name Brief Description keen Mes Mes i r The famous catalog of Charles 110 Messier NGC New General Catalog Entire NGC Catalog 7800 NDS Named Deep Sky Various types of deep sky objects 135 by common name NST Named Star Stars by common name 142 600 best double stars provided by Di Double stars Saguaro Astronomy Club SE Byr Bayer Stars Stars by Greek letter and number 1500 Large but very faint planetary APN Abell Planetary Nebula nebula cataloged by George Abell in 86 1966 Arp Arp Peculiar Galaxies Se EE 338 Brd Barnard Dark nebula 159 Hr4 Herschel 400 Herschel 400 listed by NGC number 400 HIC Hickson Galaxy Clusters Catalog at compact salary 100 clusters IC Index Catalog Entire Index Catalog 5250 Brk Berkley Open Clusters 86 Cr Collinder Open Clusters 71 Trm Trumpler Open Clusters 34 S Special Objects User entered coordinates 74 PLN Planets All observable planets 8 Table 1 Installed Catalogs 4 4 Catalog Types The way that you access objects within a given catalog depends on the type e Numbered e N
24. elect 1 star Position the scope in declination near the equator and near the eastern horizon in RA Use A and _ to select a star also near the equator like Aldebaran which is about 16 degrees declination Press when you see it displayed The display should look similar to the following Move the scope in the northerly direction The numbers of declination should increase If they decrease instead just note it and proceed Now move the scope in the easterly down toward horizon direction The numbers of RA should increase If either declination or RA directions are incorrect go into the Setup Menu and change the direction from Normal to Reverse or visa versa 9 3 17 2009 3 Star Alignment Each time Sky Commander is turned on you must go through an alignment procedure so the computer has an orientation to the sky Sky Commander XP4 supports two alignment methods 1 Star and 2 Star The procedure you use depends on the type of mounting your scope has and the accuracy to which it is polar aligned If the scope is very well polar aligned only one alignment star is needed However if polar alignment is only rough or the scope is Dobsonian type or Alt Azimuth then two stars are needed Note that anytime polar alignment is in question a 2 Star alignment can be done 3 1 Polar Aligned Scopes This section describes the 1 Star alignment that can be used on mounts that have been well polar aligned The 1 Star alignment is the e
25. en pulses and steps there are four steps per pulse Example if the encoder is marked S2 1000 the 1000 number refers to pulses and the number of steps is 4000 Moreover if the mechanical coupling between the encoder and telescope axis includes any gearing or pulley ratio then that ratio must be taken into account when setting the resolutions in the setup menu Determine the number of steps per revolution of the telescope on each axis and enter those numbers through the Setup Menu 2 2 2 Encoder Direction Dobsonian Alt Az Sky Commander detects motion and direction of telescope movement through the encoders but it does not know the sense of direction with respect to up down or left right You will determine that sense of direction and enter it through the Setup Menu For the purpose of doing the following test put the unit into FORK mode See Setup Menu for instructions on how to do that When you are finished with the test you will return to DOB mode With the encoder cable plugged into the Sky Commander turn it on Press in response to the Set Date prompt It is not necessary to set the date at this time Wait until Calculating Planets is finished You will be prompted to select 1 or 2 star alignment Press CA to select 1 star Position the scope in elevation to just above horizontal Use A J and _ to select 7 3 17 2009 a star near the equator like Aldebaran which is about 16
26. er jack is available for powering the unit from external 12 volt DC The unit also operates from an internal 9 volt battery A six button keypad is used to make selections navigate menus etc Optical encoders for sensing scope motion attach by cable to an 8 pin modular jack RJ45 A second 6 pin modular jack is used for RS 232 communications to a host PC It is also used for installing upgrades and changes to the database RJ 45 RJ 11 RS232 Encoder Jack Flash Port SKY COMMANDER XP4 FLASH Li Lu kL Tie Mh Lie esd 12 Volt DC Jack Pushbutton Keypad ON OFF Figure 1 Sky Commander XP4 Computer The display is 32 character 2 lines of 16 characters dot matrix LCD Liquid Crystal Display It is illuminated with an adjustable yellow green LED backlight 2 3 17 2009 1 4 Battery Replacement The unit has an internal compartment for a 9 volt alkaline battery When replacement is reguired follow the steps outlined below 1 On the bottom of the unit you will find a slide cover Push in the direction shown in order to open the battery compartment If the slide is hard to move a coin or small screwdriver blade may be used at the point indicated 2 Remove the battery and attach a new one 3 When replacing the battery insert the wire lead side first wire goes under battery not next to cover 4 Replace the plastic slide cover The end of the cover with the long tab goes to the end of the opening nearest the ON OFF button
27. f See Search amp Identify for description of this feature Press to return to operating mode 5 2 Limit Magnitude Menu Use Tal and gt buttons to increment or decrement the limiting magnitude Objects dimmer than this setting will not be displayed during object scrolling operations or Search amp ID mode Press to permanently save the setting You do not necessarily need to save the setting will still be in effect until the unit is turned off even if it is not saved Press to return to operating mode Note a unique Limit Magnitude value is saved for each scope defined in the setup parameters There are four of them See Setup Menu Example you can set Limit Mag to 13 for your 16 dob and 10 for your 4 refractor When you change from one scope to the other the correct Limit Mag will used 20 3 17 2009 5 3 LCD Intensity Menu Use Tal and gt buttons to select the desired display brightness LOW MEDIUM or HIGH Press to permanently save the setting Press to return to operating mode 5 4 Favorite List Menu Use Tal and gt buttons to turn the list On or Off See Favorite Objects List for information on this special mode Press to return to operating mode 5 5 Purge Favorite List Menu If the Favorite List gets cluttered or corrupted or you just want to start over select YES using the Tal button and button The Favorite list will be erased Press to return to operating mode 5 6 Ba
28. g Min Sec Visual s Magnitude Alpha UMi Polaris 2 31 50 89 15 50 2 Alpha CAS Schedar 0 40 30 56 32 15 2 2 Beta CET Deneb Kaitos 0 43 35 17 59 12 2 Beta AND Mirach 1 9 44 35 37 14 2 1 Alpha ARI Hamal 2 7 10 23 27 45 2 Beta PER Algol 3 8 10 40 57 21 2 1 Alpha PER Mirfak 3 24 19 49 51 40 1 8 Gamma ERI Zaurak 3 58 2 13 30 31 3 Alpha TAU Albedaran 4 35 55 16 30 33 0 9 Beta ORI Rigel 5 14 32 8 12 6 0 1 Alpha AUR Capella 5 16 41 45 59 53 0 1 Alpha ORI Betelgeuse 5 55 10 7 24 26 0 5 Alpha CMa Sirius 6 45 9 16 42 58 1 5 Alpha CMi Procyon 7 39 18 5 13 30 0 4 Beta GEM Pollux 7 45 19 28 1 34 1 1 lota UMa Talitha 8 59 12 48 2 29 3 1 Alpha HYA Alphard 9 27 35 8 39 31 2 Alpha LEO Regulus 10 8 22 11 58 2 1 4 Lambda UMa Tania Borealis 10 17 6 42 54 52 3 5 Delta LEO Zosma 11 14 6 20 31 25 2 6 Gamma UMa Phecda 11 53 50 53 41 41 2 4 Alpha2 CVn Cor Caroli 12 56 2 38 19 6 2 9 Alpha VIR Spica 13 25 12 11 9 41 1 Eta UMa Alkaid 13 47 32 49 18 48 1 9 Alpha BOO Arcturus 14 15 40 19 10 57 0 Beta BOO Nekkar 15 1 57 40 23 26 3 5 Beta LIB Zubeneschamali 15 17 0 9 22 58 2 6 Alpha SCO Antares 16 29 24 26 25 55 1 Zeta HER 16 41 17 31 36 10 2 8 Alpha OPH Rasalhague 17 34 56 12 33 36 2 1 Alpha LYR Vega 18 36 56 38 47 1 0 Alpha AQL Altair 19 50 47 8 52 6 0 8 Gamma CYG Sadr 20 22 14 40 15 24 2 2 Alpha CYG Deneb 20 41 26 45 16 49 1 3 Epsilon PEG Enif 21 44 11 9 52 30 24 Eta PEG Matar 22 43 0 30 13 17 2 9 Alpha PSA Fomalhaut 22 57 39 29 37 20 1 2 32 3 17 2009
29. he drill as 46 3 17 2009 perpendicular as possible to the wood surface Exact centering is not critical 2 Press the 1 bronze bushing 1 1 4 OD into the hole from the top DO NOT hit it directly with a hammer since it will deform easily If it will not press in by hand use a piece of rough sandpaper or a rasp to enlarge the hole slightly If the bushing is loose in the hole use some quick set epoxy Be sure that the flange of the bushing is resting flat on the wood surface as the epoxy sets up 3 Mount the 1 diameter pivot pin as shown in the drawing Drill a 3 8 hole in the center of the ground board centering not very critical Use the smaller flat washer under the head of the 3 8 16 x 1 1 2 bolt Pass the bolt through the hole from the bottom Put the larger flat washer over the end of the bolt and then thread on the 1 diameter pivot pin Tighten until snug 4 Assemble the rocker box and ground board Slide the spring retainer ring into the groove of the pivot pin if you wish to always keep the rocker box and ground board together The ring can be removed later if necessary 5 Mount the azimuth anchor pin to the inside bottom of the rocker box at a place six inches from the pivot point and in the direction that you will dress the azimuth encoder cable 6 Start the 10 32 nylon thumb screw into the side of the 1 pivot pin Take the azimuth encoder tangent arm assembly the shorter of the two and insert the 1 4 dia enco
30. helps the Sky Commander keep up with fast motion when using higher resolution encoders 8192 and up By default it is OFF Setting to 12V will turn on fast track automatically when external 12 volts is detected The ON selection will force it on all the time Note having Fast Track on uses more power from the battery so if only internal battery is used the battery will not last nearly as long Sidereal Clock This selection should always be ON unless the scope is a Dobsonian on a motorized equatorial platform In this case it should be OFF RS232 Baud Rate The default is 9600 bits per second Lower values can also be selected SiTech Mode The Default is OFF It should only be turned ON when using the Sidereal Technology Alt Az drive system 6 3 17 2009 2 2 Determining Encoder Parameters In the previous section you learned how to enter and save setup parameters including those for the telescope encoders Unless the telescope manufacturer sets these for you you will need to set them yourself Failure to do this will result in very large pointing errors when you attempt to use it for the first time 2 2 1 Encoder Resolution Encoder Resolution refers to the smallest angular movement of the encoder shaft that can be detected It is normally specified as the number of steps per revolution Frequently however the number printed on the encoder itself represents the number of pulses per revolution There is a direct relationship betwe
31. inates stored in the Sky Commander use the following command 2xx where xx special object ID number 00 through 58 valid Sky Commander will respond with hh hhh dd ddd CR Object Offset Command ASCII O Azimuth and elevation offsets distance to current object can be obtained with the single character O command This is useful when the telescope is to slew automatically to the current object Sky Commander responds with eight binary bytes not ASCII The bytes represent two floating point numbers The first number is the elevation offset Go Up The second of the two numbers is the azimuth offset Go CCW Both numbers are in units of degrees See section Floating Point Format below for a full description 41 3 17 2009 Drive Rates Command ASCII R Sky Commander calculates the azimuth and elevation drive rates required to track an object The single letter R command is used Sky Commander responds with eight binary bytes representing two floating point numbers The first number is the elevation rate and the second is the azimuth rate Positive numbers indicate the telescope should move UP for elevation or go CCW for azimuth Units are in degrees minute Field Rotation Command ASCII F While tracking an object in azimuth and elevation the field will rotate slowly limiting photographic exposure times The rate of rotation depends on where the telescope is pointing Sky Commander calculates and reports field
32. it to the reset position At the same time turn the Sky Commander on These two operations should be done simultaneously or as nearly so as possible The table must be running during alignment and must not slip Perform the 2 star alignment see Alt Az Alignment You are now ready to observe 4 To assure accuracy of the setting circles leave the table running 5 At some point it will be necessary to reset the table When you are ready to do this perform the following steps Press to get to menu screens CA or VY to get to Equatorial Table Reset Bring table back to reset position The table must be running Press immediately Press to return to normal operation Important Note if you suddenly encounter poor pointing accuracy during operation the table may have slipped If this happens there is no need to do another two star alignment simply reset the table as described above Do not use the Realign to Object function until you have eliminated table slippage as the cause of pointing error 22 3 17 2009 6 Operating Features 6 1 Display Object Information While the cursor is in Home position pressing LY will display basic information about the current object For instance go to the Messier catalog Mes Change the number to 0027 and press to make it current M27 is a planetary nebula of magnitude 7 3 Press VY again and the display goes back to showing the object catalog and number
33. log that are also in the current constellation shown to right of diamond While the cursor is under the diamond use the A and VY buttons to scroll through the list The description of each object is displayed briefly before the display reverts to showing the object number This gives you the ability to quickly sort objects such as bright galaxies clusters etc Note the objects displayed while in this mode are limited to those brighter than the Limit Magnitude Example Make the NGC catalog current and move the cursor under the diamond The default constellation is Pegasus because NGC 0001 is in that constellation 24 3 17 2009 Use the A and buttons to browse the NGCs of Pegasus Notice there are many dim galaxies but also a few bright ones For instance as you scroll you may see 10 6 is the magnitude The display then reverts to showing the object number To move to a different constellation simply move the cursor under the constellation name far right bottom line and use the A and VY buttons to select a new one Note if a constellation does not contain objects of the current catalog it will not be selectable With the cursor under PEG press YT twice to get to the constellation Orion ORI Again move the cursor under the diamond and scroll with AT and Y buttons Notice there are many bright nebulas and clusters to choose from You may see something like 25 3 17 2009
34. me you are trying to locate Move the cursor once more to the right and then scroll to the exact name you want In this example press A several times to get from Acamar to Alberio 18 3 17 2009 Press to make the object current 4 4 3 Named with Constellation Catalogs The Double Star Catalog in particular is organized by name and constellation Positioning the cursor under the name lets you scroll through all the double stars in the current constellation Andromeda in this case To get to a different constellation just move the cursor under the first letter of the constellation name Scroll to the constellation with the a and gl buttons Move the cursor back under the double star name to continue with your search Press to make the object current 19 3 17 2009 5 Operating Menus More advanced control over operating features parameters and settings is accomplished through the Operating Menus To access the operating menus press the button once You will see the first menu item Use the A and F buttons to get to other menu items There are eight of them Search amp ID Limit Search Magnitude LCD Intensity Favorite List On Off Purge Favorite List Battery Monitor Realign on Object Equatorial Table Reset appears only when sidereal clock is off Exit the operating menus by pressing once more 5 1 Search amp Identify Menu Use Tal and gt buttons to turn this feature On or Of
35. ment Note this example is for Alt Azimuth Dobsonian if the scope is Fork or German Eq the top line will look like indicating hours and minutes of RA displacement and degrees of declination displacement You will now move the telescope in azimuth RA for polar type mounts and elevation declination for polar type mounts to the target object M42 The right pointing arrow indicates you should move clockwise in azimuth The down pointing arrow indicates you should move down in elevation As you move the scope the numbers change For azimuth the starting number is greater than 180 degrees so they increment toward 360 degrees same as zero as you get closer to the target For elevation the numbers decrease to zero as you get closer Move the scope until both displacements are zero The telescope is now pointing at the target object If you find that it is not repeat the alignment procedure turn power off and on to reset If there is still a problem see the section in this manual titled Troubleshooting 15 3 17 2009 4 3 Catalog Selection In the last section you learned the basics of object location The example used the Messier catalog but Sky Commander can hold many more catalogs up to 32 including Planet and Special Object catalogs which you will learn about later To select other catalogs move the cursor under the catalog name using the sd button as shown below Pressing always returns the cursor to hom
36. n Channel A Signal DE JJ ISA YN Ground 43 3 17 2009 Appendix D A Discussion of Pointing Accuracy You have purchased a sophisticated computer system with high resolution motion encoders You would hope to be able to pinpoint objects with it when you zero in Still you may find that for one reason or another there are inaccuracies in pointing Even after carefully following alignment procedures you still have to fish around a little to find the object This section is a discussion of factors that influence pointing accuracy To start with consider the telescope itself Whether it has an equatorial mount or an alt azimuth it moves on two axes Ideally these axes are orthogonal or perpendicular to each other The reason for this stems from the fact that celestial coordinates are based on a polar system that is orthogonal in itself An equatorial telescope can never be truly polar aligned unless its axes are orthogonal While alt azimuth telescopes are never physically polar aligned it is nonetheless important to have orthogonality where digital setting circles are concerned All of the calculations done in the Sky Commander computer are based on orthogonal coordinates The effect of not having orthogonality is that the computer receives slightly distorted position information Even though the encoders are installed perfectly and give the exact angular position of each shaft or axis if the axes are not orthogonal the
37. n horizontal See how close Polaris comes to center of field as you sweep on the dec axis 6 If Polaris cannot be centered it means that the optical axis is not square with the dec axis Shim the optical tube as required to correct the error Take up just half the error as seen in the eyepiece otherwise you will be off in opposite direction when you flip the scope to the other side You will have to make a small azimuth adjustment as well each time you adjust the shim Repeat steps 4 6 until Polaris is centered on both sides of the mount 7 Bring the scope to top position once more Move on the dec axis to bring Polaris to 37 3 17 2009 the center of field If it is a little high or low don t worry but make sure it is centered left to right 8 Now adjust the mechanical declination setting circle to exactly 90 degrees and lock it down well If there is no mechanical setting circle some means should be employed to locate this exact position when it is needed 38 3 17 2009 Appendix B RS 232 Serial Port The serial port is used for communications with a PC during normal use and also for the purpose of flash memory upgrade e Connector and Pin Assignment The serial port is located on the rear panel of the unit It is a 6 pin RJ11 type modular jack 12345 6 Figure 4 RS232 Serial Port Pin functions are as follows RJ11 Pin DB9 Pin Function 1 NC Used for flash upgrade do not use in n
38. ne 2 shows catalog object number and constellation The object shown is the default one i e Messier Mes is the first catalog and Messier 1 is the first object in the Messier catalog The displayed object is referred to as the current object Notice the underscore symbol on line 2 between the catalog name and number This is the cursor symbol and is used to aid in navigating catalogs menus etc The cursor may be moved using 4 and gt buttons The cursor position shown is the home position It is normally in this position unless you are in the process of making a catalog selection In this example M42 the Orion Nebula will be located The first step is to change the current object to Mes 0042 Move the cursor under the third zero and use A to change it to 4 Now move the cursor under the 1 and change it to 2 Now press to make the selection current Notice the cursor returns to home position M42 is now current and the display looks like The top line of the display is still showing telescope absolute position Change it to relative position by pressing A once The display will change to 14 3 17 2009 The asterisk 7 symbol on the top left indicates the display is showing telescope relative position i e the difference between telescope absolute position and object position Arrows on the top are an indication of which way to move the scope to get to the object Numbers indicate degrees of displace
39. o in to the target Entering of object information other than coordinates is not supported so it is a good idea to keep your own list with that type of information Special object coordinates can also be uploaded from a PC program using the RS232 port See Appendix B for information on serial protocol Special object 99 is to be used by PC software to upload coordinates On the Fly It is not saved in EEPROM so any changes to it through the keypad or PC will be lost after the Sky Commander is turned off 28 3 17 2009 6 6 The Planet Catalog The planet catalog is a bit different than the other catalogs because the positions are calculated during initialization when the Sky Commander is turned on Positions are based on the date that the user enters Since there is no time entry other than date it is best to set the date one day ahead i e if it is the evening of June 17 set the date to June 2 The reason is that the calculations assume 0 hours universal time for the given date For instance in early evening US the time is much closer to 0 hours UT of the following day than it is to O hours UT of the present day Press Tal button to move the cursor under the catalog name and then index to the PLN catalog using the a and buttons The display should look something like Now move the cursor over by the planet name with the gt button and index to a different planet with the a and VY buttons ret
40. ormal operation 2 5 Ground 3 NC Alternate 12V Power input for Sky Commander 4 2 Data from Sky Commander to PC 5 3 Data from PC to Sky Commander 6 NC Used for flash upgrade do not use in normal operation DB9 pins refer to the serial connector of a Personal Computer Note PCs that do not have serial ports can use USB to serial COM port adapter cables A number of commercially available programs for the PC will communicate with the Sky Commander These programs allow you to display a section of the sky centered on the position of the telescope This can be convenient when hopping from one object to others nearby 39 3 17 2009 Line Settings When connecting with a PC use the following line settings 1 start bit 8 data bits No parity 1 stop bit Flow Control None Available baud rate settings are 300 600 1200 2400 4800 and 9600 bits per second See section Setup Menu for information on how to set the Sky Commander baud rate This rate must match the rate selected on the PC Command Protocol Some users may wish to write their own programs to interface with Sky Commander For this you will need to understand the data format that is used This section describes the various commands Request Position Command 0X0D Whenever the program needs updated coordinates it sends a carriage return character hexadecimal OD to the Sky Commander The program will then receive a 16 character ASCII string The format i
41. rbage In Garbage Out Whenever a computer is given erroneous data input you can expect erroneous data output The computer itself contributes little if any error All calculations are done in single preci sion floating point with six or seven digit accuracy more than is required Star and deep sky object coordinates are stored in the computer s memory to the nearest 01 degree Remember that you can use the Realign on Object feature to improve pointing accuracy See Realignment on Database Objects 45 3 17 2009 Appendix E Installing the ALT AZ 1000 Kit Azimuth Bushing Bi vation Coupler K Az amp El Anchor Pins Elevation Tangent Arm Ze Chr Azimuth Pivot KA St Azimuth Tangent Arm Figure 6 Dob Kit encoders not included Important Note Before performing the following procedure make certain that there is at least 1 3 8 clearance between the inside bottom surface of the rocker box and the front bottom corner of the mirror box as it swings past the rocker box center pivot point Insufficient clearance will result in damage to the azimuth encoder Azimuth 1 Cut a 1 1 4 hole in the bottom center of the rocker box A hole saw works very well for this operation One can be obtained at almost any hardware store for about five dollars If a hole already exists it is a good idea to plug it up first with a piece of wood dowel so that the hole saw has something to keep it centered Try to keep t
42. ree position is achieved by having the optical axis of the scope parallel to the scope s polar axis The Sky Commander computer uses a unique Auto Lock method whereby the 90 degree point is found by computation based on the sighting of the two alignment stars You are only required to set the position to within about a degree or so Thus one opportunity for error is eliminated Auto Lock applies only to fork mounted scopes It does not apply to German equatorials This means that the 90 degree setting must be done with some precision for a German equatorial Fortunately there is an easy method to locate the 90 degree point on a German equatorial Perform the following steps 1 Collimate the telescope as accurately as possible 2 Position the scope with the polar axis pointed toward Polaris not the actual celestial pole Polaris is used because is relatively stationary 3 Put the scope in top position dec axis vertical as viewed from front Adjust the elevation of the mount so that Polaris passes through the center of field as the scope is moved left and right on the dec axis Use a medium power eyepiece preferably one with an illuminated reticle 4 Now put the scope in side position dec axis horizontal on the west side of the mount Adjust the mount left and right until Polaris moves through the center of field as the scope is moved up and down on the dec axis 5 Flip the scope to the opposite side of the mount dec axis agai
43. refully centering a database object in the eyepiece and then telling the Sky Commander to realign to it a poor alignment can be improved First make sure the object you are aligning to is the same one showing on the Sky Commander display Press to get to menu items then A or VY to get to Realign on Obj menu Center the object in the eyepiece Press to complete the realign function OK is displayed briefly before normal operating mode is resumed Note When selecting an object for realign use the same criteria as you do when selecting initial alignment stars i e not too close to the zenith for Dobsonian scopes or not near the celestial poles for polar aligned scopes 6 10 Sidereal Clock Sky Commander has a built in clock to keep pace with the apparent motion of the sky For most scopes and mountings the Sidereal Clock should be ON Only when using a Dobsonian scope with an equatorial table should it be turned OFF See the section Setup Menu for instructions on navigating to this menu item It appears as follows Select the desired setting using lt or gt button then press to save 31 3 17 2009 7 Alignment Stars Alignment Stars for use in Northern Hemisphere Declination RA 2000 2000 Star Name Common Name kour Min Sec De
44. rn the table on and bring it to the mechanical start position At the same time turn the Sky Commander on These two operations should be done simultaneously or as nearly so as possible Perform the 2 star alignment e During the alignment procedure the table must not slip If it does slip you must start over The equatorial table must continue to run and must not slip during the observing period If however the table stops or slips it is NOT necessary to repeat the two star alignment If this happens just perform the table reset procedure described below 6 8 2 Equatorial Table Reset When it becomes necessary to do a mechanical reset of the table or the table stops or slips do the following e Goto the operating menu item Equatorial Table Reset Menu It looks like e Before pressing the button bring the table back to the mechanical start position table running Press to coincide in time with the starting of the table from the start position Press to return to normal operation Alignment and accuracy will be restored Note Equatorial Table Reset appears in the list of menu items only when the sidereal clock is turned off as it must be for using the Sky Commander XP4 on an equatorial table 30 3 17 2009 6 9 Realignment on Database Objects For various reasons pointing accuracy may not always be as good as it should be The Realign on Object feature can help correct that condition By ca
45. s as follows 1 space 2 3 integer part of RA hours 4 fixed decimal point 5 7 fractional part of hours 8 space 9 or for declination 10 11 integer part of declination 12 fixed decimal point 13 15 fractional part of declination 16 NULL character to terminate string Example _ 12 345 67 890 underscore represents a space character 0X20 The fractional part of the number is treated as a fractional part of an hour e g 4 25 is 4 hours 15 minutes The same applies to declination Most programming languages provide an easy means to convert the string to floating point variables 40 3 17 2009 Load Special Object Coordinates Command Coordinates of special objects can be uploaded to the Sky Commander from a PC using the following command Lxx_hh hhh_ dd ddd CR o Xx special object ID number 00 through 58 and 99 valid o s space character o hh hhh RA hour and fractional part thereof O O dd ddd Declination with sign and fractional part CR carriage return character Sky Commander will respond with ASCII A for acknowledge For object IDs 00 through 58 the coordinates are stored in EEPROM Electrically Erasable Programmable Read Only Memory and are permanent until overwritten If object ID number 99 is used the data is stored in RAM Random Access Memory and is only valid until the unit is turned off Read Special Object Coordinates Command To read back special object coord
46. t setup for your particular telescope If you purchased the unit along with the telescope the dealer may already have done these steps for you 2 1 Setup Menu The purpose of the Setup Menu is to make changes to various parameters such as encoder resolution i e steps per revolution etc Enter the setup menu by starting with the unit off With both the A and _ buttons pressed at the same time turn the unit on You will see copyright and version display for two seconds then the following Four independent setups can be selected These are intended to accommodate multiple telescope i e you can configure up to four telescopes each with different encoder settings When changing the unit from one scope to another it is only necessary to select the preconfigured setup Helpful hint most users will have just one telescope so leave the setup selection to 1 Use lt 4 and gt buttons to change the selection indicated with brackets Press to make the selection current i e this is the setup that will be used when the unit is turned on for normal operation With the brackets indicating which setup you wish to view or make changes to press LY to see the first item A and CV let you navigate through the list of items that can be changed When changing an item remember to press to save it otherwise the change will not take effect e Scope Mount Select Fork Dobsonian or German Eq Dobsoni
47. ttery Monitor Menu A bar is displayed on the bottom line The farther the bar extends to the right the higher the charge of the battery Full indicates 9 volts or more Empty is about 6 volts 5 7 Realign on Object Menu While in operating mode pointing accuracy can sometimes be improved by sighting on a known database object and executing a Realign For Dobsonian Alt Az scopes avoid realigning on objects higher than about 60 degrees i e use the same criteria for selecting the realign object as you use to select the initial alignment stars Be sure the object is current on the display and center it in the eyepiece Go to the Realign on Obj menu and press 5 Sky Commander will automatically exit the menu display The offset should now be zero on each axis If the offset is not exactly zero you can execute the realign command once more See section titled Realignment on Database Objects 21 3 17 2009 5 8 Eguatorial Table Reset Menu If your scope is a Dobsonian and you are using an eguatorial table you will need to use the Table Reset menu It allows you to reestablish alignment after physically resetting the table You do not have to do another star alignment Use the following setup and alignment procedure 1 Polar align the table as accurately as possible 2 Sidereal clock must be turned off See Setup Menu 3 When you are ready to do the initial 2 star alignment turn the table on and then bring
48. ulating Planets is finished You will be prompted to select 1 or 2 star alignment Press CA to select 1 star Position the scope in declination near the equator Usel A and _ to select a star also near the equator like Aldebaran which is about 16 degrees declination Press when you see it displayed The display should look similar to the following 8 3 17 2009 Move the scope in the northerly direction The numbers of declination should increase If they decrease instead just note it and proceed Now move the scope in the easterly direction The numbers of RA should increase If either declination or RA directions are incorrect go into the Setup Menu and change the direction from Normal to Reverse or visa versa 2 2 4 Encoder Direction German Equatorial Sky Commander detects motion and direction of telescope movement through the encoders but it does not know the sense of direction with respect to North South or East West You will determine that sense of direction and enter it through the Setup Menu The Sky Commander should already be setup for operation in GERMN mode If not follow directions in the section Setup Menu With the encoder cable plugged into the Sky Commander turn it on Press in response to the Set Date prompt It is not necessary to set the date at this time Wait until Calculating Planets is finished You will be prompted to select 1 or 2 star alignment Press CA to s
49. urns the cursor to home position 6 7 Standby Mode During an observing session there will be times when you are not actively using the Sky Commander It is a good idea to put the unit into standby to save battery power and turn out the display backlight Standby is activated by a quick double press of the button The display shows and the backlight goes out While in standby encoder alignment is maintained even if the scope moves Press any button to return the unit to normal operation 6 8 Use with Equatorial Table An equatorial table is one way to give Dobsonian scopes tracking ability The scope is mounted atop the table which is driven with a clock drive When properly polar aligned the table cancels out the motion of the earth thus making all celestial objects stationary in the eyepiece 29 3 17 2009 In the normal case no table Sky Commander uses an internal sidereal clock to keep pace with the apparent motion of the sky When used with a table itis only necessary to turn the clock off See Sidereal Clock under Setup Menu Also see Eguatorial Table Reset Menu 6 8 1 2 Star Alignment with EG Table Even though the table is equatorial it is still necessary to perform a 2 star alignment since the scope is moving on axes which are not polar When doing the alignment it is necessary to follow the steps below e The table must be well polar aligned e Sky Commander sidereal clock is turned off e Tu
50. usually a good star for northern hemisphere users Sight the star with the scope Be as accurate as possible Press when you have the star sighted The display will now prompt with Sight 2nd Star Select the next star from the list Note The Sky Commander will allow you to select any of the available alignment stars It is up to you to choose ones that are suitable Suggestion Mark the stars on a planisphere for a handy reference Also choose your alignment stars ahead of time Sight this star just like the first then press ENTER You have just completed the alignment procedure The Sky Commander enters operating mode 3 3 Fork 2 Star Alignment When you are prompted for 1 or 2 star alignment select 2 star with Y You will be prompted to set the scope to 90 degrees This means relative to the scope not the sky The optical tube should be oriented parallel to the fork arms The positioning is not very critical within a degree is fine Next you will be prompted to sight the 1st star Usel A and _ buttons to select a convenient star on the eastern side of the meridian Get the star sighted accurately in the scope and press Now you will be prompted for the 2nd star Choose one on the western side of the meridian preferably at least 90 degrees from the first Again sight the star and press This completes the alignment procedure and the Sky Commander enters operating mode 11 3 17 2009 3 4 German
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