ASTRO-PHYSICS 1200 GERMAN EQUATORIAL WITH GTO SERVO
Contents
1. pointer Counterweight shaft 18 useable length Motors Zero cogging servo motors 1 875 diameter Power Consumption 0 4 amps at the sidereal rate stainless steel 2 amps both motors slewing removeable Power requirements 12 VDC range 11 5 to 15 Latitude range 20 to 68 degrees with or Weight of mount total 91 Ibs without polar scope or Dec axis 30 Ibs encoders attached if you are R A axis 47 lbs counterweight shaft 14 Ibs INTRODUCTION The 1200 German equatorial was designed to meet the needs of the advanced observer who requires a mount with maximum strength and rigidity and minimum weight The excess material in both axes has been carved out while retaining a heavily ribbed structure for internal strength and rigidity A unique dovetail was machined into the mating surfaces of the R A and Dec axes This feature allows quick and easy assembly in the field without any tools The DC servo motor drive with GTO computer system including the keypad controller with its digital display screen and DigitalSky Voice software offer extraordinary sophistication for today s observer Whether you enjoy visual astronomy exclusively or plan an aggressive astrophotography or CCD imaging program this mount will allow you to maximize your night out under the stars The advanced keypad features allow you to slew automatically to objects in a wide range of databases as well as any RA Dec coordinate A large selection of common names for stars an2. 1 2 turn the four pier knobs NOTE If you have already attached the Dec axis remove the sight hole cover and rotate the internal Dec shaft by moving the top of the Dec axis or the cradle plate if it is attached to reveal the sight hole that has been drilled into it Now you can look through the shaft to the other side Azimuth adjustments Move the entire pier or tripod east or west until the mount is oriented approximately towards the pole an imaginary line drawn through the hollow shaft Use the two fine azimuth adjustment knobs one on each side of the mount to make adjustments You must back off the opposing azimuth knob in order to move the other knob in that direction Please refer to Diagram 4 Altitude latitude adjustments Loosen the altitude locking knobs Move the polar axis up or down with the large altitude adjustment knob located in the front of the polar axis assembly The tommy bar can be positioned in any of the threaded holes located in the altitude adjustment knob Use this bar to help you turn the knob Please refer to Diagrams 3 and 4 We have found that fine altitude adjustments also can be made by using the turnbuckle on the north leg of our pier if used Continue your azimuth and altitude adjustments until you can sight Polaris in the polar alignment sight hole At this point you have achieved rough polar alignment which may be sufficient for casual visual observations if you are not planning to slew to target ob
3. ENCODERS AND ENCODER HOUSINGS 1200 MOUNT Fitting Declination Encoder Housing Fitting Right Ascension Encoder Housing Periodic Maintenance 17 17 19 19 20 20 ASTRO PHYSICS 1200 GERMAN EQUATORIAL WITH GTO SERVO MOTOR DRIVE MODEL 1200GTO PARTS LIST MODEL GTOCP2 1 Polar axis assembly right ascension R A with Servo Box 1 Declination Dec axis assembly 1 Pier top adapter with six 6 5 16 18 x 5 8 button head screws with washers these may be attached to your pier post if you ordered one Stainless counterweight shaft with washer stop and black plastic knob knob has 5 16 thread Y cable R A portion is 12 5 long and Dec portion is 37 5 long D C power cord cigarette lighter adapter on one end 8 long GTO Keypad controller with 15 coiled cable DigitalSky Voice Software CD ROM Hex key set 8 32 thumbscrews substitute these for 8 32 set screws that hold GTO Servo Control Box in place if you wish Dana In order to fully assemble your mount you will need the following items sold separately mounting plate 10 O D pier counterweights and portable rechargeable battery pack or 110 to 12V DC converter Several sizes and types are available for your selection Many of these items will be discussed throughout these instructions Several additional options are available Longer counterweight shaft 27 useable length part M12661 Santa Barbara Instrument Group CCD Imaging cameras and ST 4
4. assemble your mount Fit together the R A and Dec assemblies plus mounting plate and counterweight shaft Do not put scope and counterweights on at this stage With the above assembly with the clutch knobs firmly hand tightened as shipped you can feel the amount of force needed to move each axis by hand Grab each end of the telescope mounting plate and move it with a backward and forward movement of the Dec axis You will feel considerable resistance to this motion Perform the same operation on the R A axis by moving the counterweight shaft backward and forward With a well balanced telescope the above tightness of the clutch knobs will be sufficient for all normal conditions of use Now if you proceed to mount up and balance your telescope you can feel what this resistance in R A and Dec movement backwards and forwards is like when you make these motions from the eyepiece end of your telescope as you would during normal use when slewing pushing by hand to acquire an astronomical object within the field of view of your finder or scope How tight can the clutch be and can you do any damage by pushing against them The maximum tightness of this clutch system is 1 3 turn with a 5 32 allen key further in than the tension you can achieve with the knobs by hand You will see that each clutch knob has a 5 32 hex socket for tightening with an allen key With this extra 1 3 turn on each clutch knob the axis axes will be considered complet
5. change the position of the altitude adjuster bar 1 Use only the R A axis DO NOT attempt the make these adjustments with the declination axis in place and certainly not with an instrument fully mounted 2 Loosen both altitude locking knobs about 1 turn 3 Locate the side of the polar axis that does not have the motor gear housing box Loosen about 1 turn the polar axis pivot screw and altitude adjuster bar fixing screws on this side only With your hand push the polar axis upwards so that the altitude locking knobs are positioned at the top of the altitude slot this is the maximum altitude position Some resistance will be felt with this operation as you are pushing against the weight of the polar housing and the resistance of the remaining polar axis pivot screw which has not been Poleo EA coca f af shai Alude a los kr Eric loosened 4 Before attempting to move the altitude adjuster bar you must tighten the altitude locking knob on the motor gear housing side This will prevent any downward movement of the polar axis during positioning of the altitude adjuster bar 5 While supporting the altitude adjuster bar remove the two screws that support it on each side 4 screws in all but keep the two ends of the bar in contact with the side of the mount don t remove it completely this tip is for your convenience ie ri gt Fa HU Torres bar dl oi decrees
6. da depas a Bo 24 5 ages Altadis cdjrimart 77 AN rar palon Fa J a y las y Fa 1 Anmuth inse F i F Diagram 3 Polar axis housing Altitude adjuster Altitude adjuster bar bar fixing screws 4 Altitude adjustment knob Pier knobs 4 Azimuth adjustment block Azimuth adjustment knobs Diagram 4 6 Determine the latitude range that you need refer to Diagram 3 and position the hole that is marked A in Diagram 5 at that location Note that this hole is located at the rounded part of the altitude bar 7 Attach two of the screws one on either side of the adjuster bar but do not tighten Rotate the altitude adjuster bar around this pivot point until one of the other holes lines up Insert the remaining two screws Lightly tighten so that you still have some ability to move the bar 8 Note that the altitude adjustment knob is attached to a threaded rod that travels through the altitude adjuster bar Turn the knob so that the altitude adjuster bar is positioned approximately in the middle of the threaded rod You should see about half of the threaded rod protruding from both sides of the altitude adjuster bar This will allow you to move the mount fully within the altitude range 9 At the end of the threaded rod mentioned in the last step you will Side view see a small brass altitude adjuster thrust pad This is t
7. lt typically takes about 4 lb of unbalance to trip the overload but a very heavy load of scopes accessories and counterweights on the mount can decrease this unbalance threshold 2 The voltage of your battery has probably gone below 10 5 volts 3 current rating of your AC DC power supply is too low Additional explanation During slewing the two motors draw up to 3 amps from a 12 volt source This may increase when the temperature approaches freezing or below It is recommended that your supply be rated at 5 amps 12 volts DC minimum 18 volts max If you also power other equipment CCD cameras dew heaters etc from the same source you will need a supply capable of up to 10 amps The more equipment you have the more current capability you will need For portable applications we recommend a heavy duty marine battery designed for deep discharge applications The most common problems are due to inadequate power supply The keypad reset or locked up when plugged my CCD camera PC or other equipment into the same battery as the GTO mount was using The battery has a meter which shows 12V The meter is reading an average and will not show dips Gel cells have internal resistance which will cause voltage drop when the load changes When you connect an additional CCD camera and PC the load will drop below 9 volts and the keypad will reset or it may affect the GTO circuit itself and cause the keypad to lock up We recommend that you
8. 1 5 thick 24 long and 7 6 at its widest point The width of the plate tapers to 5 5 at each end A pair of keyhole slots that measure 3 2 between centers are provided at each end The distance between these pairs of holes is 23 Due to the ribbed structure you may not be able to drill additional holes for non Astro Physics mounting rings The plate weighs an Diagram 11 amazing 9 5 lbs for its size This is a view of the rib structure on the underside of the 24 plate Attach this plate with six 1 4 20 x1 socket head cap screws at the location indicated by the filled holes on the diagram DOVETAIL FOR LOSMANDY D SERIES PLATE DOVELM This Astro Physics plate attaches to the 400 600E 900 and 1200 mounts If you already own one of the Losmandy DAP series fits Astro Physics refractors DC series for Celestron 8 11 or 14 SCTs or DM series for Meade 8 10 and 12 SCTs plates this is the mounting plate for you Attach this plate with four 1 4 20 x 3 4 socket head cap screws and two 1 4 20x5 8 flat head socket cap screws at the locations indicated by the filled holes on the diagram Attach Mounting Rings purchased 11 Diagram 12 separately Our flat and ribbed plates are constructed with keyhole slots at the location where your mounting rings attach This feature enables you to partially loosen the screws on your rings just enough to insert them into the larger part of the keyhole then sli
9. ASTRO PHYSICS 1200 GERMAN EQUATORIAL WITH GTO SERVO MOTOR DRIVE Model GTOCP2 July 27 2001 ASTRO PHYSICS 1200 GERMAN EQUATORIAL WITH GTO SERVO MOTOR DRIVE MODEL 1200GTO PARTS LIST MODEL GTOCP2 FEATURES AND SPECIFICATIONS INTRODUCTION Why Polar Alignment is Important Compensation for the Earth s rotation ASSEMBLY INSTRUCTIONS Before You Leave Home Before You Leave Home Gross Latitude Adjustment Attach Pier Adapter to Pier Post Assemble Pier purchased separately Assemble Polar Axis Assembly to Pier or Tripod Altitude and Azimuth Adjustments Rough polar alignment Assemble Declination Axis Removing Declination Axis at the End of your Observing Session Attach Mounting Plate purchased separately Attach Mounting Rings purchased separately Fine Polar Alignment Methods for fine polar alignment Altitude and Azimuth Adjustments OPERATION OF THE MOUNTING R A and Dec Damper Knobs R A and Dec Clutch Knobs Balancing Your Telescope SERVO MOTOR DRIVE GTO Control Box Model GTOCP2 R A and Dec Cable Connections 12V Connector POWER Indicator Light KEYPAD Connector RS 232 Connectors FOCUS Connector RETICLE Connector AUTOGUIDER Connector 6V Connector N and S Switch Prevent the Cables from Tangling 1200 Motor Cables Accessory Cables Removing the GTO Control Box From 1200 Mount GTO Keypad Controller Operation OMDANND DO oan A A MOUNT MAINTENANCE AND ALIGNMENT TROUBLESHOOTING INSTALLATION OF
10. Autoguider if you plan to pursue CCD imaging or astrophotography Pier accessory trays for 10 pier and support bars handy to keep your eyepieces close at hand Polar axis telescope threads into the base of the polar axis assembly We plan to introduce a new polar scope in the near future please call for details Many users find a polar axis telescope useful for zeroing in on the pole quickly particularly with telescopes that are not orthogonal to the mount Mounted encoders you will need these if you plan to use digital setting circles Keep in mind that these 4000 step encoders which read the position of the shaft are very coarse 324 arc seconds while the encoder that is built into the servo motor itself is 0 05 arc seconds JMI Digital setting circles The go to keypad will perform most of the functions of the digital setting circles One advantage of the JMI unit is the ability to move the telescope by hand while the unit displays your position FEATURES AND SPECIFICATIONS R A worm wheel 10 3 225 tooth aluminum above 65 you will have to Dec worm wheel 7 2 225 tooth aluminum remove one pier top knob Worm gear Brass Azimuth adjustment Approximately 14 degrees R A shaft 3 35 diameter Setting circles Porter Slip Ring design R A thrust bearings 9 5 diameter engraved Dec shaft 2 36 diameter Right ascension 4 minute increments pointer Dec thrust bearings 6 5 diameter Declination 1 degree increments
11. Dec lock knobs Thread the counterweight shaft into the Dec axis Remove the hand knob and safety washer from the base of the counterweight shaft Add sufficient counterweights 10 or 18 lb counterweights are purchased separately to the declination shaft to balance the telescope you intend to use Always use two hands to attach or move them on the shaft Reattach the hand knob and safety washer to the end of the declination shaft This will help to prevent injury if someone accidentally loosens the counterweight knob NOTE Firm tightening of the counterweight knob will not damage the surface of the counterweight shaft The pin that tightens against the stainless counterweight shaft is constructed of brass Likewise the bronze sleeve that has been press fit into the center of the counterweight will prevent marring of the shaft as you move the counterweight up and down your Observing Session Unscrew the lock knobs 5 5 to 7 full turns this is still 5 16 to 3 8 out from the fully tightened position and slide tilt the Dec axis assembly in an upwards direction arrow B 1 2 pocket dovetails parallel guides altitude adjustor knob For transport storage we recommend fully tightening the lock knobs 10 Attach Mounting Plate purchased separately Several mounting plates are available for the 1200 mount If you own more than one instrument you m
12. Rods with Turnbuckles 2 Place the pier post on the base orienting the center azimuth block directly north If you choose to have one leg north then the pier adapter plate will have to be installed with the azimuth block directly over a turnbuckle If you have one leg south the pier adapter plate will have to be installed with the azimuth block over and between two of the pier post turnbuckles 3 Attach the tension rods The turnbuckles should be drawn tight until the whole assembly is stiff Diagram 6 enough to support your weight without movement Assemble Polar Axis Assembly to Pier or Tripod In order to track the motion of astronomical objects the polar axis must be positioned so that an imaginary line drawn through the center of the axis points toward the celestial pole At this stage of the assembly process you want to position the mount so that it points roughly north 1 2 Remove the four 4 hand knobs on the pier top adapter and keep them close at hand Prior to lifting the polar axis assembly into place turn the fine azimuth adjustment knobs so that the space between them is wide enough to allow the center azimuth block to fit easily between them Ensure both pier top and polar axis assembly mating surfaces are clean and free of dirt Place the polar axis assembly onto the pier top adapter so that the center azimuth block fits between the fine azimuth adjustment knobs Move the base of the polar axis as
13. axis adapter will not be removed 4 If you look into the black encoder housing you will see the encoder itself mounted at the rear of the housing When this installation procedure is complete the encoder shaft will insert into the center hole of the Dec axis adapter This allows the encoder to read the motion of the declination shaft as the declination axis moves 5 Thread the Dec encoder housing onto the Dec axis housing of the 1200 mount You may need to wiggle the encoder housing gently to engage the shaft of the encoder with the hole in the center of the Dec axis adapter When the threading is complete tighten up with firm hand pressure or insert your special tool from above and tighten firmly since normally this encoder housing will not be removed 6 The counterweight shaft may now be rethreaded into the rear of the Dec encoder housing h axi i Cable for Digital Setting Circles ousing of 1200 moun not included with encoders i Counterweight shaft Declination Declination axis adapter encoder housing Diagram 13 19 Fitting Right Ascension Encoder Housing If the encoders were purchased with the 1200 mount it is likely that the right ascension axis adapter and encoder housing have already been installed Please continue to read these directions since you may need to remove and reinstall the encoders if you use a polar alignment scope Since the polar axis telescope and axis adapter thread into the
14. ay need more than one plate Follow the appropriate directions for the plate s that you have 18 FLAT MOUNTING PLATE FP1800 This plate is 18 long and 7 5 at its widest point in the center The width of the plate tapers to 5 5 at each end Four pairs of keyhole slots that measure 3 2 between centers are provided The two inner pairs are 13 75 apart and the outer two pairs are 17 apart You can drill additional holes to suit your needs This plate also fits the 900 German Equatorial Attach this plate with six 1 4 20 x 1 flat head socket cap screws at the locations indicated by the filled holes on the diagram 15 RIBBED MOUNTING PLATE 1200RP15 This plate is 14 75 long 7 75 at its widest point 5 at each end and 1 thick The underside of the plate is carved into a ribbed pattern to maximize the strength and minimize the weight 3 lbs A pair of keyhole slots that measure 3 2 between centers are provided at each end The distance between the pairs is 13 75 Attach this plate with six 1 4 20 x 3 4 socket head cap screws at the locations indicated by the filled holes on the diagram Note that the plate is asymmetrical Attach the plate so that the long end points toward the sky 24 RIBBED MOUNTING PLATE 1200RP For larger instruments the ribbed structure of this plate provides the maximum support Our machinist begins with thick aluminum plate and carves a strong rib structure The final result is
15. balancing use of the clutches and operation of the keypad controller Zenith Why Polar Alignment is Important Compensation for the Earth s rotation If you were to take a long exposure photograph with Polaris often called the north star in the center of the field you would discover that all stars seem to revolve around Polaris This effect is due to the rotation of the earth on its axis Motor driven equatorial mounts were designed to compensate for the earth s rotation by moving the telescope at the same rate and opposite to the earth s rotation When the polar axis of the telescope is pointed at the celestial pole polar aligned as shown Horizon in Diagram 1 the mount will follow track the motions of the sun moon planets and stars As a result the object that you are observing will appear motionless as you observe through the eyepiece or take astrophotos Diagram 1 ASSEMBLY INSTRUCTIONS Please read all instructions before attempting to set up your 1200 mount The Model 1200 is very rugged however like any precision instrument it can be damaged by improper use and handling Please refer to Diagram 2 for an illustration of the mount The parts are labeled so that we can establish common terminology The following terms and abbreviations are used interchangeably in these instructions polar axis right ascension axis R A axis R A housing declination axis dec axis dec housing fhe motor gear homing
16. box gh hola cows Y chich 4 Night ascension oxi housing Servo drive box Corera e gh shat Brass pin Soo bs 12 Torr lt z Coumierweolght foptenal ae a En AGtide odpotnant kno balety washe i eeljusimerd block g Feat 4 kare 5 18 18 8 8 bulionhead screws 8 ua 4 34 5149 05 00 washer 8 Pier bon odopder Diagram 2 Before You Leave Home Since most of us must set up our instruments in the dark in the cold or while battling mosquitoes a bit of preplanning and organization is important There are few simple things that can be accomplished in the comfort of your home before heading outside Gross Latitude Adjustment The total latitude range of the 1200 mount is approximately 20 68 degrees with 4 adjustment positions Since most astronomers typically observe within one latitude range this adjustment is made just once if at all Prior to shipment we preset the mount to your latitude range for your convenience If you travel to another observing location determine the latitude of your observing site and make the appropriate adjustment The four positions for the altitude adjustments have the following approximate ranges 55 degrees to 68 degrees latitude top position 37 degrees to 59 degrees latitude third position 28 degrees to 50 degrees latitude second position 20 degrees to 37 degrees latitude bottom position How to
17. cking posts to secure the cable firmly If your serial cable does not have a 9 pin connector you can use a gender changer or adapter to convert it When you are controlling the position of the mount with a computer program such as DigitalSky Voice or TheSky the microprocessor chip located in the servo drive box will send continual RA and Dec coordinate data via the cable connections to your computer When you use the software to give instruction to slew to a new object the commands RA and Dec coordinates are sent to the mount We provide two serial port connections on the mount so that you can use two software programs simultaneously For instance you can give verbal commands in DigitalSky Voice while using TheSky as a planetarium program Since the mount will update the RA and Dec coordinates simultaneously both programs are continually updated with the data from the mount You can watch the screen display of TheSky to see where your telescope is pointing as it slews This is most effective if you have a reasonably fast computer with plenty of RAM If you try this with a 100MHz processor and only 32 MB of RAM the response time will be slow since both programs must be continuously updated with position data You must have two serial ports available on your computer to take advantage of this feature If you use a laptop you may need to purchase a PCMCIA adapter to gain an additional serial port Socket Communications offers adapters for many
18. computers Check out their web site at www socketcom com FOCUS Connector Attach the 2 5mm phono plug connector of your JMI Motofocus or Meade electric focuser optional accessories here Refer to the section regarding focus adjustment in the GTO Keypad Manual for instructions on using the keypad controller to adjust focus Alternatively you can verbally control the focus using the Focus Mode of DigitalSky Voice software RETICLE Connector If you wish to use a plug in type guiding eyepiece with an illuminated reticle available from several manufacturers insert the 2 5mm phono plug into this connector for power Reticle brightness can be adjusted with the hand control Refer to the section pertaining to reticle illuminator adjustment in the GTO Keypad Manual for further information AUTOGUIDER Connector This connector interfaces with the RJ 11 4 modular jack of an autoguider cable purchased separately or as part of a CCD Imaging Camera or Autoguider The autoguider will be functional and ready to go as soon as you plug it in Please refer to the appropriate manual from the manufacturer for operation of the autoguider We offer CABTIC Tracking Interface Cable for SBIG ST 4 and ST 6 camera and CAB7 8RC Relay cable for SBIG ST 7 8 9 and 10 cameras Please refer to our price list or call for further information 6V Connector This 6 volt output accepts 2 5mm phono plugs It is used primarily to power the Pentax 6x7 camera directly from
19. d other objects makes your selection a snap The rapid slew rate of 5 degrees per second 1200x allows you to locate objects very quickly and accurately You will be very pleased with the intuitive operation of this controller There are no complicated sequences of keystrokes to remember It is so easy to use that even it you don t use it for a few months you will feel at home with the keypad very quickly DigitalSky Voice software provides additional capabilities to control the movement of your telescope by using two way verbal communication with a microphone or by a few clicks of your computer mouse or touchpad You can remain at the eyepiece while you direct your telescope with verbal commands There is no need to put a flashlight in your mouth to see the keyboard You have total control with your voice and or mouse Voice control also allows you to retain your dark adaptation The 1200 is equally at home in a permanent observatory or as a portable mounting for remote star parties thanks to the ease with which the two axes come apart This is the perfect mount for a large refractor Newtonian Cassegrain or astrograph In order to maximize your pleasure on your first night out we recommend that you familiarize yourself with the assembly and basic operation of the mount indoors The temperature will be comfortable the mosquitoes at bay and you ll have enough light to see the illustrations and read the manual Please take particular note of counter
20. de the rings to the narrow part and tighten them with a hex key You can even accomplish this with the rings on the scope although this maneuver may be difficult to accomplish with a large heavy instrument We prefer this keyhole method to the standard way of completely removing the screws and dropping them in the grass Fine Polar Alignment For casual observation you may skip this section and move to Operation of the Mounting tighten your altitude locking knobs 2 and pier knobs first If you plan to use any of the go to functions of the 1200GTO or do astrophotography you must polar align Methods for fine polar alignment Polar Alignment Scope Our optional polar scope PASILL2 will allow you to quickly align your mount on the pole stars The reticle was designed for use in both the Northern and Southern hemispheres Even users of the GTO computerized mounts will find these polar scopes useful particularly if your telescope is not orthogonal to the mount please refer to the keypad manual for a discussion of orthogonality If you have a polar alignment scope please read the instructions sheets that come with it GTO Keypad Please refer to the instruction manual for the GTO Servo Drive and read the section describing the startup sequence DigitalSky Voice computer program Please read the corresponding manual JMI Digital Setting Circles Please read the instructions included with your JMI unit You must have the e
21. eadouts refer to the relevant operating manual from the manufacturer We provide some startup tips in our instruction sheet entitled Using JMI Setting Circles Polar alignment scope adapter R A axis housing Encoder adapter 7 included with encoders Illuminator included with polar alignment scope R A encoder housing optional Cable for digital setting circles not included with encoders Diagram 14 Periodic Maintenance If you remove the R A encoder frequently you may wish to use a very tiny amount of auto grease on the mating threads 20
22. ely locked up and you should not attempt to push your scope by hand against this locked up resistance or undue stress will be placed on the worm wheel worm and bearings However if you are undertaking a very long astrophoto exposure it is advisable to increase the pressure on each clutch knob with the 5 32 key by about 1 8 turn on Dec and 1 8th turn on R A You may safely slew the scope by hand with this tension however you will notice considerably more effort is required to achieve movement This is the absolute maximum tension that can be used for hand slewing As a general rule if you have a big scope 7 or 8 refractor with all the accessories you will need more clutch tension than a 5 or 6 scope Balancing Your Telescope For proper operation the telescope must be adequately counterbalanced Start by balancing the tube assembly 1 2 Tighten the 4 R A axis clutch knobs Loosen the 4 Dec axis clutch knobs about 3 4 to 1 turn so that the telescope moves freely about the declination axis be careful because if your telescope is significantly out of balance it may swing rapidly in the out of balance direction Position the R A axis so that the counterweights are in their lowest position i e the declination axis assembly is in the meridian this is the usual way that German equatorials are depicted as shown in diagram 2 Loosen the tube mounting rings and slide the tube up and down for balancing This is be
23. he part that of altitude will come in contact with the polar axis as you ease it back into position Loosen the altitude locking knob motor gear side adjuster bar lower the polar axis so that it rests comfortably on this pad The Diagram 5 threaded rod should be positioned at a right angle to the polar axis 9 housing Firmly tighten the altitude adjustment screws 10 Turn the altitude adjustment knob to raise or lower the polar axis to your approximate observing latitude Tighten the altitude locking knobs with finger pressure only You do not need to tighten with the hex key 11 Firmly tighten both polar axis pivot screws with the hex key Attach Pier Adapter to Pier Post If you purchased the pier from Astro Physics the pier top adapter of the 1200 may be already attached to the top of the pier If you are constructing your own pier or tripod you will need to incorporate this part The pier adapter was designed to fit into a 10 x 0 094 wall tube Use six 6 screws to attach this part Note that with the Astro Physics pier you can orient the pier adapter so that one of the pier legs faces north or south as you prefer Assemble Pier purchased separately Begin by assembling the portable pier at the desired observing location Note which direction is north 1 Slide the three legs onto the nubs of the base and rotate the assembly so that one of the legs points toward north or south if that is your preference
24. ion Dec Encoder housing black anodized R A Axis Adapter clear anodized silver colored labeled R A 1 Dec Axis Adapter clear anodized silver colored labeled Dec To install your encoders first remove the telescope from your mount Remove your declination counter weight s and declination counterweight shaft A a Fitting Declination Encoder Housing If the encoders were purchased with the 1200 mount it is likely that the declination axis adapter and encoder housing have already been installed No further action will be required as this encoder will remain in place 1 If the encoders were purchased separately the silver colored Dec axis adapter may be inside the black Dec axis encoder housing If it is remove it now 2 Locate the counterweight shaft adapter the black anodized part that the counterweight threads into on the Dec axis When we assembled the mounts we threaded this on rather tightly so you will need some extra leverage to remove it Locate the hole that was drilled into the part and find some object that you can insert We suggest that you use one of your allen head wrenches that is wrapped in masking tape so that you do not mar the finish of the part You may need to apply a good deal of force so it may be easiest to do if the mount is on the pier so that it won t move 3 Thread the Dec axis adapter into the end of your Dec axis Final tightening should be done with firm hand pressure Normally the Dec
25. jects with the keypad When the R A motor is engaged it will compensate for the rotation of the earth and keep the target object within the eyepiece field of view Your target object will slowly drift since polar alignment at this stage is only approximate However you can make corrections with your hand controller as we will discuss later Tighten the altitude locking knobs by hand Tighten the pier knobs firmly by hand Assemble Declination Axis 1 Removing Declination Axis at the End of Do not have your telescope or counterweights connected to the Dec axis assembly for either assembly or disassembly of the Dec and RA axes Position the R A axis as shown in Diagram 7 with the pocket A at the top opposite the altitude adjuster knob Firmly tighten R A clutch knobs During shipment the Dec axis assembly lock knobs will be fully screwed into the Dec axis For correct assembly these lock knobs should be unscrewed at least 7 full turns and no more then 8 5 full turns This is between 5 16 and 3 8 out from the shipped tightened position Note These lock knobs can be completely removed from the Dec axis assembly with about 9 5 full turns out Position the Dec axis above the R A axis as shown in Diagram 8 a light movement wiggle in the downward direction arrow A will help to correctly seat the principle dovetail s and parallel guides When both Dec and R A assemblies are fully seated hand tighten both
26. ncoders installed on your 900 mount part 1200ENC Refer to the section of this manual entitled Installation of Encoders and Encoder Housings 1200 Mount Star Drift method Traditionally this has been regarded as the most accurate method of polar alignment however it is also the most time consuming If you are planning long exposure astrophotos we suggest that you use the polar axis telescope then tweak the final polar alignment by star drifting Please refer to the recommended reading list at the end of this manual Altitude and Azimuth Adjustments 1 Loosen the altitude locking knobs 2 and pier knobs 4 and refer back to the section on Altitude and Azimuth Adjustments Rough polar alignment Follow one of the methods of polar alignment mentioned above When polar alignment has been achieved tighten at these locations note that the polar axis pivot screws should have been tight throughout the fine polar alignment process Altitude locking knob 2 hand tighten Pier knobs 4 hand tighten For a permanent installation all knobs in step 3 above may be firmly tightened with the assistance of a hex wrench OPERATION OF THE MOUNTING R A and Dec Damper Knobs The R A and Dec damper knobs are not intended as axis locks They should be tightened with light finger pressure so that a slight resistance can be felt when pushing an unclutched axis by hand This really adds to the feel at the end of the scope
27. ol Box as shown above When the connector is attached to the Dec motor box the cable should be positioned as shown in the photograph Accessory Cables Accessories may include Kendrick Dew Removers CCD cameras and autoguiders focus motors illuminated guiding eyepiece reticles power cords for the Pentax 6x7 camera etc As you attach each accessory carefully assess the best position to assure complete movement as your telescope slews from one side of the mount to the other If an external power source is used determine the optimum location for the battery We prefer to use tie wraps not glamorous but effective or cable ties from electronic supply store or catalog to secure our cables to the mount telescope rings or bind them together Plastic adhesive cable mounts available from electronic supply stores are an alternative choice We prefer to use ties since we cannot bear to attach adhesive cable mounts to our telescopes or mounts If we use tie wraps to secure several cables together and plan to use that same setup in our next observing session we keep the ties in place when we disassemble our equipment The setup for the next session is much quicker Removing the GTO Control Box From 1200 Mount The GTO control box can be removed easily from the RA axis It is secured by two 8 32 set screws located at the base of the GTO Servo Control Box Loosen the screws with one of the hex keys from the set included with the mount Lift the box up fr
28. om the bottom and tilt so that it frees from the dovetail connection Some people have a permanent observatory yet prefer to store their electronics in their home to keep them clean and free of cobwebs If you do you may wish to substitute the 8 32 thumbscrews included with your mount for the set screws This will allow you to remove and install your GTO control box without tools GTO Keypad Controller Operation Please refer to the manual for the GTO Keypad Controller for complete instructions 16 MOUNT MAINTENANCE AND ALIGNMENT Under normal operating conditions minimal maintenance is required Every 12 months the clutch knobs 4 for Dec and 4 for R A should be removed and 1 or 2 drops of light oil 3 in 1 household oil should be put in the exposed hole If the R A and Dec axes are attached together for a long time in outside conditions i e in a permanent observatory then the mating surfaces should be lightly oiled or greased if you expect to get them apart again after 10 years Your 1200 is a precision instrument with very accurate worm and wheel adjustments Please be careful if you place the mount on a flat surface i e the ground or trunk of your car The gear alignment may be affected if the R A and Dec motor gear box assemblies sustain undue lateral force This is true of any fine instrument We suggest that you transport and store the mount in a case or in a well padded box TROUBLESHOOTING Additional troublesh
29. ooting questions are in the GTO Keypad Controller manual Please refer to them The LED on the GTO Control Box changes from red to yellow and the motors stop or goes out completely for mounts shipped after 02 25 00 1 The motors are overloaded probably due to an unbalanced load on your mount Rebalance your telescope and then press one of the N S E W buttons to reset the keypad Re enter the last object on your keypad and the scope will slew to the correct position Even though your motors had stopped the logic in the control box retained the scope position in memory As long as you didn t change the pointing position of the scope you are still calibrated If the scope was moved during re balancing simply enter a nearby bright star on the hand controller press GOTO and allow the mount to finish slewing You can then move the scope manually or with the N S E W buttons to center the star in the eyepiece and press the 9 RECAL button This will recalibrate the mount Additional explanation The GTO drive circuit includes logic for overload protection to prevent burning out the expensive servomotors in case of severe overload on the two axes The primary cause is an unbalanced load in R A If the extra load opposes the motor rotation the motor must work harder to track at the sidereal rate and the current will rise to high levels If the current exceeds the trip point for more than a minute the logic will shut the motor off and tracking stops
30. power cable into the servo box after the keypad controller To turn the unit off simply disconnect the power cable Considerations for observatory installations We suggest that you disconnect your GTO Control Box from 110V when you are not using your mount so that if your observatory experiences a power surge or lightening strike your mount electronics will not be damaged If you operate your mount remotely you will have to leave your power cable connected just as you do for the rest of your electronic equipment You may want to consider surge protectors or other protective measures to protect from voltage spikes POWER Indicator Light This LED will remain illuminated when your power source has sufficient output to drive the motors If the voltage falls below 10 volts the power light will go out and the motors will stop The keypad controller will not function properly For mounts shipped after 02 25 00 If the LED turns yellow this means that your motors are overloaded probably due to an unbalanced load on your mount Refer to the troubleshooting section of the manual for the solution 14 KEYPAD Connector Attach the 5 pin male connector of the keypad controller and lock in place push in the knurled ring then turn RS 232 Connectors These serial port connections are used to connect your mount to your PC computer You must provide your own cables with a 9 pin DB9 male connector to interface with the GTO panel We have provided the lo
31. same location you will need to switch back and forth between them as needed If you use the JMI NGC MAX or Mini MAX Digital Setting Circles you can use the polar align mode in these units instead of a polar alignment scope 1 If the encoders were purchased separately the silver colored R A axis adapter may be inside the R A axis encoder housing If it is remove it now Thread the R A axis adapter into the end of your R A axis if your polar alignment scope is fitted you must remove this first along with the polar alignment scope adapter Use moderate hand pressure to tighten the R A adapter since you may need to remove it to install the polar axis telescope at a later time If you look into the black encoder housing you will see the encoder itself mounted at the rear of the housing When this installation procedure is complete the encoder shaft will insert into the center hole of the R A axis adapter This allows the encoder to read the motion of the R A shaft as the right ascension axis moves Now thread the R A encoder housing onto the R A axis housing You may need to wiggle the encoder housing gently to engage the shaft of the encoder located within the R A axis housing with the hole in the center of the R A axis adapter Again use moderate hand pressure as you may wish to remove this at some time The hardware for your encoders is now installed For actual set up procedures for Micro MAX Mini MAX or NGC MAX digital r
32. sembly so that the threaded holes of the pier top can be seen through each of the four slots Thread the four hand knobs loosely in place you will tighten these later after polar alignment Altitude and Azimuth Adjustments Rough polar alignment For rough polar alignment your goal is to sight the celestial pole when looking through the polar alignment sight hole in the center of the polar axis You will need to make altitude up down and azimuth side to side adjustments to the position of the mount We recommend that you do your rough polar alignment with the R A axis only since you will be making major adjustments to the position of the mount at this time The remainder of the mount telescope and counterweights would add considerable weight and require more hand effort Later you will do your final polar alignment with the telescope and counterweights attached but the adjustments will be small 1 If the R A encoder housing and encoder adapter are installed part ENC1200 Mounted Encoders to use with Digital Setting Circles are available as an optional purchase you may remove them to complete these steps Please refer to the section entitled Installation of Encoders and Encoder Housings 1200 Mount Alternatively you can simply sight up the side of the polar axis to see Polaris If you examine the polar axis assembly you will see that the center of the R A shaft is hollow If you have not done so already loosen
33. st done with the tube in the horizontal position The scope is balanced when it stays put does not move with the clutches loose and movement back and forth about the declination axis has the same feel in both directions Now tighten the declination axis clutch knobs and position the telescope horizontal and the declination axis horizontal The center of the counterweights is now the same height as the middle of the tube Loosen the R A clutch knobs again be careful because if your scope is significantly out of balance it may swing rapidly in the out of balance direction 13 8 Move the counterweight s up or down to achieve the correct balance in R A Again movement back and forth about the R A axis should have the same feel in both directions 9 Try to anticipate any balance problems due to the extra weight of diagonals heavy eyepieces finders solar filters etc If the scope moves by itself when the clutches are loose then the scope is not counterbalanced adequately A small amount of imbalance is permissible and indeed desirable SERVO MOTOR DRIVE GTO Control Box Model GTOCP2 The GTO control box contains all of the circuitry to drive the two servo motors and the logic required to navigate the sky It will be operational and track at the sidereal rate when connected to both motors of the mount and a power source In order to control the movement of the mount you will need to connect at least one of these e Ke
34. the mount with a cord sold for that purpose our part CORDO1 N and S Switch Select northern N or southern S hemisphere as needed When you slide the switch to the opposite position the tracking direction of the drive will reverse The power cord must be removed and re attached to make this work Prevent the Cables from Tangling 15 The movement of the mount across the meridian during slewing functions is calculated so that the cables will not tangle if they are set up properly In addition to the motor and power cables that are provided with the mount you may have additional cables for other accessories These may be powered from the GTO Control Panel or from another power source We suggest that you position your cabling carefully to avoid a tangled mess When your cables are set up move the telescope manually throughout the normal range of movement to be sure that the cables do not catch on anything and that you have enough length Here are a few pointers 1200 Motor Cables Note that the Y cable for the 1200 mount originates at the GTO Control Panel connector then splits into two The short portion connects to the RA motor box and is not likely to be in the way because this axis remains in the same position The longer Dec portion of the cable must be set up properly to ensure that as the Dec axis moves the cable follows smoothly Please insert this cable into the cable mount in the upper left corner of the GTO Servo Contr
35. use a large marine battery that is not a gel cell and hook everything up to it before calibrating the GTO If any problems occur please don t hesitate to contact Astro Physics for assistance ASTRO PHYSICS INC 11250 Forest Hills Road Rockford IL 61115 Telephone 815 282 1513 Fax 815 282 9847 17 Support astro physics com Recommended Reading from our Staff The Backyard Astronomer s Guide Terence Dickinson and Alan Dyer Camden House Publishing 1991 The authors both former editors of Astronomy magazine offer practical insight into astronomical equipment finding your way around the sky polar alignment using setting circles and astrophotography This book provides excellent explanations and is well organized and illustrated All About Telescopes Sam Brown Edmund Scientific Company 1975 Excellent information regarding the principles of mount construction and operation using setting circles eyepiece projection etc Illustrations and formulas galore Many of the instruments pictured are outdated however the underlying principles are timeless Norton s 2000 0 Star Atlas and Reference Handbook edited by lan Ridpath J Wiley Publishers 1989 Star maps information regarding polar alignment of German equatorials and observing techniques 18 INSTALLATION OF ENCODERS AND ENCODER HOUSINGS 1200 MOUNT 1200ENC purchased separately Parts List Right Ascension R A Encoder housing black anodized Declinat
36. with the drives adjusted correctly The purpose of the damper knob is to add a bit of friction to the shaft so that gusty winds do not move the axes in their bearings If there is the slightest amount of backlash between worm and worm wheel a wind load could theoretically move 12 the axis back and forth by that backlash amount Also in the absence of backlash there is always a very tiny clearance 0002 between the shafts and the mating parts The damper knobs force the shaft to make full contact in 3 places to eliminate the associated play R A and Dec Clutch Knobs 1 What do they do The four R A and four Dec clutch knobs depicted in Diagram 2 have the function of connecting the R A and Dec axes to their respective drive worm wheel gears Their function is progressive from no tension axes free to move as required during correct balancing of the telescope to a completely locked up state How can you find out what they really do As shipped all 1200 mounts have all four R A and Dec clutch knobs firmly hand tightened This will give you a good idea of the maximum tightness clutch action that can be achieved by hand effort alone At this point you must bear in mind that for optimum performance all four clutch knobs on each axis R A or Dec should be tightened evenly with the same tension i e all four half tight all four fully tight etc In order to feel the effect of the clutch knobs you may wish to partially
37. ypad controller e Computer with astronomical software such as DigitalSky Voice included or Software Bisque s TheSky purchased separately The GTO Servo Control Box is mounted directly onto the polar axes of the 1200 mount Please remember that this box contains advanced electronics and must be treated with the same care given to other fine equipment You can see that the unit is built to be rugged however it is not indestructible ds SOTO Osean 527 gh m TIEFI R A and Dec Cable Connections A Y cable with 10 pin connectors is included with your mount Attach the connector from which the two cables emerge to the GTO Control Panel Attach the short part of the Y cable to the R A motor housing and the long part of the cable to the Dec motor housing Lock all connectors Refer to the section below for further information about positioning the cables 12V Connector Place the DC power cord included with your mount into the phono plug outlet marked 12V on the GTO Control Panel and lock in place Plug the cigarette lighter plug end of the cord into your power source The acceptable voltage range is 11 5 to 15 Suggested power sources include portable rechargeable battery pack auto or marine battery or power supply filtered and regulated for 110 volts with a minimum output of 5 amps at 12V DC There is no on off switch We recommend that you plug the
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