Celestron AstroMaster LT 60AZ
Contents
1. Dovetail Mounting Bracket Focus Knob CELESTRON ASSEMBLY This section covers the assembly instructions for your AstroMaster LT telescope Your telescope should be set up indoor the first time so that it 1 easy to identify the various parts and familiarize yourself with the correct assembly procedure before attempting it outdoor Each AstroMaster LT comes in one box The pieces in the box are optical tube with attached sky pointer Alt Az mount with attached pan handle 10 mm eyepiece 1 25 20 mm eyepiece 1 25 mirror diagonal 1 25 for 60AZ and 70 AZ The Sky Level 1 CD ROM SETTING UP THE TRIPOD 1 Remove the tripod from the box Figure 2 1 The tripod comes preassembled so that the set up is very easy 2 Stand the tripod upright and pull the tripod legs apart until each leg 1 fully extended and then push down slightly on the tripod leg brace Figure 2 2 The very top of the tripod 1 called the tripod head 3 Next we will install the tripod accessory tray Figure 2 3 onto the tripod leg brace center of Figure 2 2 4 Insert the cut out in the center of the tray flat side of the tray facing down to match the center of the tripod leg brace and push down slightly Figure 2 4 The ears of the tray should appear as in Figure 2 4 5 Rotate the tray until the ears are under the leg brace support of each leg and push slightly and they will lock in place Figure 2 5 The tripod is now completely asse2. QCELESTRON AstroMaster LT Series Telescopes INSTRUCTION MANUAL AstroMaster LT 60AZ 21073 AstroMaster LT 70AZ 21074 AstroMaster LT 76AZ 31036 TABLE OF CONTENTS INTRODUCTION gt 3 si N ENNAN EEEE EEEE EEEE 6 Setting up the Tripod 6 Moving the Telescope Manually 7 Attaching the Telescope Tube to the Mount 7 Installing the Diagonal amp Eyepieces refractor oooococcococcncnccnnncnncnncnnncnncnccnnnccncnncnncnanans 8 Installing the Eyepieces on the Newtonians cmcomsccunconcccunecunccunccnnnconaccnnocrnecrnocinecinos 8 9 5 8 1 2 10 gt gt 10 Aligning the Finderscope 10 Calculating Magnification 11 Determining Field Of VieW 12 General 12 ASTRONOMY BASICS ai ANA A AAA 13 The Celestial Coordinate System ooococconconcnonccncnononccncnanocnconocnccncornccncnrccnccnccrnccncnnccnnon 13 Wiletelamelmigic eitc kee A a eee 14 CELESTIAL OBSERVING csi AAA AAN 15 Observing the 15 15 Observing the Sun ococcccoconoconencononencnnononencononencnnononencononencnncnonencnnonenenncncncncnconenencnnonene 15 Observing Deep Sky Objects oooccococconoconcnnoncnnoncnnoncononconencononconencononccncnccncnccnc
3. northwest the same distance between the two stars to the Andromeda galaxy Star hopping to the Andromeda Galaxy M31 is snap since all the stars needed to do so are visible to the naked eye Star hopping will take some getting used to and objects that don t have stars near them that are visible to the naked eye are challenging One such object is M57 Figure 5 2 the famed Ring Nebula Here s how to find it 1 Find the constellation of Lyra a small parallelogram visible in the summer and fall months Lyra 5 easy to pick out because it contains the bright star Vega 2 Start at the star Vega Alpha a Lyrae and move a few degrees southeast to find the parallelogram The four stars that make up this geometric shape are all similar in brightness making them easy to see 3 Locate the two southernmost stars that make up the parallelogram Beta and Gamma y Lyra 4 Point about halfway between these two stars 5 Move about 72 toward Beta Lyra while remaining on a line connecting the two stars 6 Look through the telescope and the Ring Nebula should be in your field of view The Ring Nebula s angular size is quite small and difficult to see 7 Because the Ring Nebula 1 rather faint you may need to use averted vision to see it Averted vision is a technique of looking slightly away from the object you re observing So if you are observing the Ring Nebula center it in your field of view and
4. of fun and rewarding observations However there are a few things to consider before using your telescope that will ensure your safety and protect your equipment Warning e Never look directly at the sun with the naked eye or with a telescope unless you have the proper solar filter Permanent and irreversible eye damage may result e Never use your telescope to project an image of the sun onto any surface Internal heat build up can damage the telescope and any accessories attached to it e Never use an eyepiece solar filter or a Herschel wedge Internal heat build up inside the telescope can cause these devices to crack or break allowing unfiltered sunlight to pass through to the eye e Do not leave the telescope unsupervised either when children are present or adults who may not be familiar with the correct operating procedures of your telescope 3 OOO JO OFF B WD NO Figure 1 1 AstroMaster LT 70AZ Refractor AstroMaster LT 60AZ refractor similar Objective Lens Telescope Optical Tube Star Pointer Finderscope Eyepiece Diagonal Focus Knob Pan Handle Accessory Tray Tripod Azimuth Lock Alt Az Mount Dovetail Mounting Bracket a O O ON 0 0 Figure 1 2 AstroMaster LT 76 AZ Newtonian Star Pointer Finderscope Eyepiece Telescope Optical Tube Primary Mirror Pan Handle Azimuth Lock Accessory Tray Tripod Alt Az Mount
5. 3625 to attach on one end to the T Ring and the other end to the telescope focus tube Your telescope is now the camera lens SHORT EXPOSURE PRIME FOCUS PHOTOGRAPHY Short exposure prime focus photography is the best way to begin imaging celestial objects It is done by attaching your camera to the telescope as described in the paragraph above A couple of points to keep in mind e Polar align the telescope and start the optional motor drive for tracking e You can image the Moon as well as the brighter planets You will have to experiment with various settings and exposure times Much information can be obtained from your camera instruction manual which can supplement what you can find in detailed books on the subject matter e Do your photography from a dark sky observing site if possible PLANETARY amp LUNAR PHOTOGRAPHY WITH SPECIAL IMAGERS During the last few years a new technology has evolved which makes taking superb images of the planets and moon relatively easy and the results are truly amazing Celestron offers the Nexlmage 93712 which 15 a special camera and included 1 software for image processing You can capture planetary images your first night out which rivals what professionals were doing with large telescopes just a few short years ago IMAGING FOR DEEP SKY OBJECTS Special cameras have been developed for taking images of deep sky images These have evolved over the last several years to become much more economica
6. are toward the three o clock position in the field of view then you must move whichever screw or combination of collimation screws necessary to move the star s image toward the direction of the flaring In this example you would want to move the image of the star in your eyepiece by adjusting the collimation screws toward the three o clock position in the field of view It may only be necessary to adjust a screw enough to move the star s image from the center of the field of view to about halfway or less toward the field s edge when using a high power ocular Collimation adjustments are best made while viewing the star s position in the field of view and turning the adjustment screws simultaneously This way you can see exactly which way the movement occurs It may be helpful to have two people working together one viewing and instructing which screws to turn and by how much and the other performing the adjustments IMPORTANT After making the first or each adjustment it is necessary to re aim the telescope tube to re center the star again in the center of the field of view The star image can then be judged for symmetry by going just inside and outside of exact focus and noting the star s pattern Improvement should be seen if the proper adjustments are made Since three screws are present it may be necessary to move at least two to achieve the necessary mirror movement Figure 7 3 A collimated telescope should appear as a symmetrica
7. at a time and with a collimation tool or eyepiece see how the collimation is affected see the following paragraph below It will take some experimenting but you will eventually get the centering you desire It is best to use the optional collimation tool or collimating eyepiece Look into the focuser and notice if the secondary reflection has moved closer to the center of the primary mirror With Polaris or a bright star centered within the field of view focus with either the standard ocular or your highest power ocular i e the shortest focal length in mm such 85 a 6mm or 4mm Another option is to use a longer focal length ocular with a Barlow lens When star 1 in focus it should look like a sharp pinpoint of light If when focusing on the star it is irregular in shape or appears to have a flare of light at its edge this means your mirrors aren t in alignment If you notice the appearance of a flare of light from the star that remains stable in location just as you go in and out of exact focus then re collimation will help sharpen the image Figure 7 2 Even though the star pattern appears the same on both sides of focus they are asymmetric The dark obstruction is skewed off to the left side of the diffraction pattern indicating poor collimation When satisfied with the collimation tighten the small locking screws Take note of the direction the light appears flare For example it appears to fl
8. ation night time star collimation can be done by closely adjusting the primary mirror while the telescope tube is on its mount and pointing at a bright star The telescope should be set up at night and a star s image should be studied at medium to high power 30 60 power per inch of aperture If a non symmetrical focus pattern is present then may be possible to correct this by re collimating only the primary mirror Procedure Please read this section completely before beginning To star collimate in the Northern Hemisphere point at a stationary Figure 7 1 star like the North Star Polaris It can be found in the north sky at a distance above the horizon equal to your latitude It s also the end star in the handle of the Little Dipper Polaris is not the brightest star in the sky and may even appear dim depending upon your sky conditions Prior to re collimating the primary mirror locate the collimation screws on the rear of the telescope tube The rear cell shown in Figure 7 1 has three large thumbscrews which are used for collimation and three small thumbscrews which are used to lock the mirror in place The collimation screws tilt the primary mir ror You will start by loosening the small locking screws a few turns each Normally motions on the order of an 1 8 turn will make a difference with approximately a 1 2 to 3 4 turn being the maximum required for the large collimation screws Turn one collimation screw
9. ch is most favorable for you To install the diagonal and eyepieces 1 Insert the small barrel of the diagonal into the 1 25 eyepiece adapter of the focus tube on the refractor Figure 2 13 Make sure the two thumbscrews on the eyepiece adapter do not protrude into the focuser tube before installation and the plug up cap is removed from the eyepiece adapter 2 Put the chrome barrel end of one of the eyepieces into the diagonal and tighten the thumb screw Again when doing this make sure the thumb screw 1 not protruding into the diagonal before inserting the eyepiece 3 The eyepieces can be changed to other focal lengths by reversing the procedure step 2 above Figure 2 13 INSTALLING THE EYEPIECES ON THE NEWTONIANS The eyepiece or ocular is an optical element that magnifies the image focused by the telescope Without the eyepiece it would be impossible to use the telescope visually Eyepieces are commonly referred to by focal length and barrel diameter The longer focal length i e the larger the number the lower the eyepiece magnification 1 power Gen erally you will use low to moderate power when viewing For more information on how to determine power see the section on Calculating Magnification The eyepiece fits directly into the focuser of the Newto nians To attach the eyepieces Figure 2 14 1 Make sure the thumbscrews are not protruding into the focuser tube Then
10. constellation of Pisces designated as 0 hours 0 minutes 0 seconds All other points are designated by how far i e how long they lag behind this coordinate after it passes overhead moving toward the west MOTION OF THE STARS The daily motion of the Sun across the sky is familiar to even the most casual observer This daily trek 1 not the Sun moving as early astrono mers thought but the result of the Earth s rota tion The Earth s rotation also causes the stars to do the same scribing out a large circle as the Earth completes one rotation The size of the circular path a star follows depends on where it is in the sky Stars near the celestial equator form the largest circles rising in the east and set ting in the west Moving toward the north ce lestial pole the point around which the stars in the northern hemisphere appear to rotate these circles become smaller Stars in the mid celes tial latitudes rise in the northeast and set in the northwest Stars at high celestial latitudes are always above the horizon and are 5810 to be cir cumpolar because they never rise and never set You will never see the stars complete one circle because the sunlight during the day washes out the starlight However part of this circular mo tion of stars in this region of the sky can be seen by setting up a camera on a tripod and opening the shutter for a couple hours The timed expo sure will reveal semicircles that revolve around the pole Th
11. difficult if not impossible to observe Light Pollution Reduction filters help reduce the background sky brightness thus increasing contrast Star Hopping One convenient way to find deep sky objects is by star hopping Star hopping is done by using bright stars to guide you to an object For successful star hopping it is helpful to know the field of view of you tele scope If you re using the standard 20mm eyepiece with the AstroMaster LT telescope your field of view is approximately 1 If you know an object is 3 away from your present location then you just need to move 3 fields of view If you re using another eyepiece then consult the section on determining field of view Listed below are directions for locating two popular objects The Andromeda Galaxy Figure 5 1 also known as M31 is an easy target To find M31 1 Locate the constellation of i Pegasus a large square visible in the fall in the eastern sky moving toward the point overhead and winter months overhead moving toward the west o Guate 2 Start atthe star in the northeast corner Alpha a Andromedae 3 Move northeast approximately 7 There you will find two stars of equal brightness Delta 6 and Pi w Andromeda about 3 apart o 4 Continue the same direction another 8 There you will find Figures 4 two stars Beta and Mu 1 Andromedae als about 3 apart 5 Move 3
12. e glass window at the alignment star If the Star Pointer is perfectly aligned you will see the red LED dot overlap the alignment star the Star Pointer is not aligned take notice of where the red dot is relative to the bright star Battery 4 Without moving the main telescope turn the Star Compartment Pointer s two adjustment screws until the red dot is directly over the alignment star Experiment as to which way each screw moves the red dot On Off 5 The Star Pointer is now ready for use Always turn Switch the power off after you have found an object This will extend the life of both the battery and the LED Note Your battery be installed already If open the Figure 3 4 battery compartment see Figure 3 4 with a thin coin or screwdriver Put the battery in with the sign facing out Then put the battery compartment back on If you ever need to replace the battery it is a 3 volt lithium type CR 1620 Note The above description applies basically for astronomy If your finderscope is aligned properly you can use it for terrestrial applications also The finderscope acts like a sighting tube The red dot may be difficult to see in the daytime but the dot will let you align objects before looking through the main telescope optics and can be quite helpful CALCULATING MAGNIFICATION You can change the power of your telescope just by changing the eye piece ocular To determine
13. elescope simply means to bring its optical elements into balance Poor collimation will result in optical aberrations and distortions Before collimating your telescope take time to familiarize yourself with all its components The primary mirror is the large mirror at the back end of the telescope tube This mirror is adjusted by loosening and tightening the three screws placed 120 degrees apart at the end of the telescope tube The secondary mir ror the small elliptical mirror under the focuser in the front of the tube also has three adjustment screws you will need optional tools described below to perform collimation To determine if your telescope needs collimation first point your telescope toward a bright wall or blue sky outside 20 CELESTRON Aligning the Secondary Mirror The following describes the procedure for daytime collimation of your telescope using the optional Newto nian Collimation Tool 94183 offered by Celestron To collimate the telescope without the Collimation Tool read the following section on night time star collimation For very precise collimation the optional Collima tion Eyepiece 1 94182 is offered you have an eyepiece in the focuser remove it Rack the focuser tube in completely using the focusing knobs until its silver tube is no longer visible You will be looking through the focuser at a reflection of the secondary mirror projected from the primary mirror During this step ignore
14. eries features a compact and portable design with ample optical performance to excite any newcomer to the world of amateur astronomy In addition your AstroMaster LT telescope is ideal for terrestrial obser vations which will open your eyes with superb high power viewing AstroMaster LT telescopes carry a two year limited warranty For details see our website at www celestron com Some of the many standard features of the AstroMaster LT include e All coated glass optical elements for clear crisp images e Smooth functioning rigid alt azimuth mount with a large pan handle with built in clutch for easy targeting e Preassembled steel leg tripod with 1 legs ensures stable platform e Quick and easy no tool set up e CD ROM The Sky X Level 1 astronomy software which provides education about the sky and print able sky maps e All models can be used terrestrially as well as astronomically with the standard accessories included Take time to read through this manual before embarking on your journey through the Universe It may take a few observing sessions to become familiar with your telescope so you should keep this manual handy until you have fully mastered your telescope s operation The manual gives detailed information re garding each step as well as needed reference material and helpful hints guaranteed to make your observ ing experience as simple and pleasurable as possible Your telescope is designed to give you years
15. ge without notice or obligation Note This equipment has been tested and found to comply with the limits for a Class B digital device pursuant to part 15 of the FCC Rules These limits are designed to provide reasonable protection against harmful interference in a resi dential installation This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions may cause harmful interference to radio communications However there is no guarantee that interference will not occur in a particular installation If this equipment does cause harmful interfer ence to radio or television reception which can be determined by turning the equipment off and on the user is encour aged to try to correct the interference by one or more of the following measures Reorient or relocate the receiving antenna the separation between the equipment and receiver Connect the equipment into an outlet on a circuit different from that to which the receiver is connected Consult the dealer or an experienced radio TV technician for help 24 QCELESTRON 2835 Columbia Street Torrance CA 90503 U S A Tel 310 328 9560 Fax 310 212 5835 Website www celestron com Copyright 2012 Celestron All rights reserved Products or instructions may change without notice or obligation Designed and intended for those 13 years of age and older WARNING This product contains a che
16. iew of the light path of the Newtonian IMAGE ORIENTATION The image orientation changes depending on how the eyepiece 1 inserted into the telescope When using a star diagonal with refractors the image is right side up but reversed from left to right i e mirror im age inserting the eyepiece directly into the focuser of a refractor i e without the diagonal the image is upside down and reversed from left to right i e inverted Newtonian reflectors produce a right side up image but the image will appear rotated based on the loca tion of the eyepiece holder in relation to the ground Figure 3 3 Image orientation as seen with the Reversed from left to right as Inverted image normal with unaided eye amp using erecting de viewed using a Star Diagonal on Newtonians amp as viewed with vices on refractors amp Newtonians a refractor eyepiece directly in a refractor FOCUSING To focus your refractor or Newtonian telescope simply turn the focus knob located directly below the eye piece holder see Figures 1 1 and 1 2 Turning the knob clockwise allows you to focus on an object that is farther than the one you are currently observing Turning the knob counterclockwise from you allows you to focus on an object closer than the one you are currently observing Note If you wear corrective lenses specifically glasses you may want to remove them when observing with an eyepiece attached
17. ing out detail on the planetary surface try using Celestron eyepiece filters OBSERVING THE SUN Although overlooked by many amateur astronomers solar observation is both rewarding and fun How ever because the Sun is so bright special precautions must be taken when observing our star so as not to damage your eyes or your telescope For safe solar viewing use a solar filter that reduces the intensity of the Sun s light making it safe to view With a filter you can see sunspots as they move across the solar disk and faculae which are bright patches seen near the Sun s edge best time to observe the Sun is in the early morning or late afternoon when the air is cooler e center the Sun without looking into the eyepiece watch the shadow of the telescope tube until it forms a circular shadow OBSERVING DEEP SKY OBJECTS Deep sky objects are simply those objects outside the boundaries of our solar system They include star clusters planetary nebulae diffuse nebulae double stars and other galaxies outside our own Milky Way Most deep sky objects have a large angular size Therefore low to moderate power is all you need to see them Visually they are too faint to reveal any of the color seen in long exposure photographs Instead they appear black and white And because of their low surface brightness they should be observed from a dark sky location Light pollution around large urban areas washes out most nebulae making them
18. insert the chrome barrel of the eyepieces into the focus tube remove the plug up cap of the focuser first and tighten the thumbscrews see Figure 2 14 2 The eyepieces can be changed by reversing the procedure as described above CELESTRON TELESCOPE BASICS A telescope 1 an instrument that collects and focuses light The nature of the optical design determines how the light is focused Some telescopes known as refractors use lenses and other telescopes known as reflectors Newtonians use mirrors Developed in the early 16005 the refractor 1 the oldest telescope design lt derives its name from the method it uses to focus incoming light rays The refractor uses a lens to bend or refract incom ing light rays hence the name see Figure 3 1 Early designs used single element lenses How ever the single lens acts like a prism and breaks light down into the colors of the rainbow a phe nomenon known as chromatic aberration To get around this problem a two element lens known as an achromat was introduced Each element has a different index of refraction allowing two differ ent wavelengths of light to be focused at the same rOn ZELER EET ETETETT point Most two element lenses usually made of crown and flint glasses are corrected for red and green light Blue light may still be focused at a slightly different point Figure 3 1 A cuta
19. is description of stellar motions also applies to the southern hemisphere except all stars south of the celestial equator move around the south celestial pole Stars seen near the north celestial pole Stars seen near the celestial equator Stare seen looking in the opposite direction of the north celestial pole Figure 4 2 All stars appear to rotate around the celestial poles How ever the appearance of this motion varies depending on where you are looking in the sky Near the north celestial pole the stars scribe out recognizable circles centered on the pole 1 Stars near the celestial equator also follow circular paths around the pole But the complete path is interrupted by the horizon These appear to rise in the east and set in the west 2 Looking toward the opposite pole stars curve or arc the opposite direction scribing a circle around the opposite pole 3 CELESTRON CELESTIAL OBSERVING With your telescope set up you are ready to use it for observing This section covers visual observing hints for both solar system and deep sky objects as well as general observing conditions which will affect your ability to observe OBSERVING THE MOON Often it is tempting to look at the Moon when it is full At this time the face we see is fully illuminated and its light can be overpowering In ad dition little or no contrast can be seen during this phase One of the best times to observe the Moon
20. is during its partial phases around the time of first or third quarter Long shadows reveal a great amount of detail on the lunar surface At low power you will be able to see most of the lunar disk at one time Change to optional eyepieces for higher power magnification to focus in on a smaller area Lunar Observing Hints To increase contrast and bring out detail on the lunar surface use optional filters A yellow filter works well at improving contrast while a neutral density or polarizing filter will reduce overall surface brightness and glare OBSERVING THE PLANETS Other fascinating targets include the five naked eye planets You can see Venus go through its lunar like phases Mars can reveal a host of surface detail and one if not both of its polar caps You will be able to see the cloud belts of Jupiter and the great Red Spot if it is visible at the time you are observing In addition you will also be able to see the moons of Jupi ter as they orbit the giant planet Saturn with its beautiful rings is easily visible at moderate power Planetary Observing Hints e Remember that atmospheric conditions are usually the limiting factor on how much planetary detail will be visible So avoid observing the planets when they are low on the horizon or when they are directly over a source of radiating heat such as a rooftop or chimney See the Seeing Conditions section later in this section e increase contrast and br
21. isible on the brighter planets like Jupiter and Mars and stars are pinpoint images Under poor seeing conditions images are blurred and stars appear as blobs The conditions described here apply to both visual and photographic observations Figure 5 3 Seeing conditions directly affect image quality These drawings represent point source 1 star under bad seeing conditions left to excellent conditions right Most often seeing conditions produce images that lie somewhere between these two extremes CELESTRON ASTROPHOTOGRAPHY The AstroMaster LT series of telescopes was designed for visual observing After looking at the night sky for a while you may want to try your hand at photography of it There are several forms of photography possible with your telescope for celestial as well as terrestrial pursuits Below is just a very brief discussion of some of the methods of photography available and suggest you search out various books for detailed information on the subject matter As a minimum you will need a digital camera or a 35mm SLR camera Attach your camera to the telescope with e Digital camera you will need the Universal Digital Camera Adapter 93626 The adapter allows the camera to be mounted rigidly for terrestrial as well as prime focus astrophotography e 35mm SLR camera you will need to remove your lens from the camera and attach a T Ring for your specific camera brand Then you will need a T Adapter 9
22. l ring pattern similar to the diffraction disk seen here 23 CELESTRON ASTROMASTER LT SPECIFICATIONS 21073 21074 31036 AM 60 AZ AM 70AZ AM 76 AZ Optical Design Refractor Refractor Newtonian Aperture 60mm 2 4 70mm 2 7 76mm 3 0 Focal Length 700mm 700mm 700mm Focal Ratio 12 0 9 Secondary Mirror Obstruction Dia Area n a n a 31mm 10 Optical Coatings Fully coated Fully coated Fully coated Finderscope Star Pointer Star Pointer Star Pointer Diagonal 1 25 Mirror 1 25 Mirror n a Eyepieces 1 25 Apparent FOV 25 mm 50 20 mm 35x 20 mm 35x 20 mm 35x 10 mm O 40 10 mm 70x 10 mm 70x 10 mm 70x Angular Field of View w standard eyepiece 1 7 1 7 1 7 Linear FOV w standard eyepiece ft 1000yds 89 89 89 Mount Altazimuth Altazimuth Altazimuth Pan Handle Control for Altitude yes yes yes Azimuth Lock yes yes yes Tripod Leg Diameter 1 00 yes yes yes CD ROM The Sky Level 1 yes yes yes Highest Useful Magnification 144x 162x 180x Limiting Stellar Magnitude 11 4 11 7 11 9 Resolution Raleigh arc seconds 2 32 1 99 1 83 Resolution Dawes Limit 1 93 1 66 1 53 Light Gathering Power 73 100 118 Optical Tube Length 28 71cm 28 71cm 26 66cm Telescope Weight 13 5 8kg 16 7 2kg 12 5 4kg Note Specifications are subject to chan
23. l and amateurs can take fantastic images Several books have been written on how to get the best images possible The technology continues to evolve with better and easier to use products on the market TERRESTRIAL PHOTOGRAPHY Your telescope makes an excellent telephoto lens for terrestrial land photography You can take images of various scenic views wildlife nature and just about anything You will have to experiment with focusing speeds etc to get the best image desired You can adapt your camera per the instructions at the top of this page TELESCOPE MAINTENANCE While your telescope requires little maintenance there are a few things to remember that will ensure your telescope performs at its best CARE AND CLEANING OF THE OPTICS Occasionally dust and or moisture may build up on the objective lens or primary mirror depending on which type of telescope you have Special care should be taken when cleaning any instrument so as not to damage the optics If dust has built up on the optics remove it with a brush made of camel s hair or a can of pressurized air Spray at an angle to the glass surface for approximately two to four seconds Then use an optical cleaning solution and white tissue paper to remove any remaining debris Apply the solution to the tissue and then apply the tissue paper to the optics Low pressure strokes should go from the center of the lens or mirror to the outer portion Do NOT rub in circles You ca
24. manufacturer by the magnification equation format the formula looks like this Apparent Field of Eyepiece True Field Magnification As you can see before determining the field of view you must calculate the magnification Using the ex ample in the previous section we can determine the field of view using the same 20mm eyepiece that is supplied standard with the AstroMaster LT 60AZ telescope The 20mm eyepiece has an apparent field of view of 50 Divide the 50 by the magnification which is 30 power This yields an actual field of 1 7 To convert degrees to feet at 1 000 yards which is more useful for terrestrial observing simply multiply by 52 5 Continuing with our example multiply the angular field of 1 7 by 52 5 This produces a linear field width of 89 feet at a distance of one thousand yards GENERAL OBSERVING HINTS When working with any optical instrument there are a few things to remember to ensure you get the best possible image Never look through window glass Glass found in household windows is optically imperfect and as a result may vary in thickness from one part of a window to the next This inconsistency can and will affect the ability to focus your telescope In most cases you will not be able to achieve a truly sharp image while in some cases you may actually see a double image e Never look across or over objects that are producing heat waves This includes asphalt parking lots on hot summer day
25. mbled Figure 2 6 6 You can extend the tripod legs to the height you desire Atthe lowest level the height is 24 61cm and extends to 41 104 You unlock the tripod leg lock knob at the bottom of each leg Figure 2 7 and pull the legs out to the height you want amp then lock the knob securely A fully extended the tripod looks like the image in Figure 2 8 7 The tripod will be the most rigid and stable at the lowest height e Figure 2 1 Figure 2 2 Figure 2 3 Figure 2 4 Figure 2 5 Figure 2 6 Figure 2 7 Figure 2 8 MOVING THE TELESCOPE MANUALLY The AstroMaster LT Alt Az mount is easy to move wherever you want to point it The up and down altitude is controlled by the pan handle Figure 2 10 The side to side azimuth is controlled by the azimuth lock Figure 2 9 The pan handle and the azimuth lock are both loosened by turning the handle and lock coun terclockwise When loose you can find your objects easily and then lock the controls To lock the controls in place turn them clockwise Figure 2 9 Figure 2 10 ATTACHING THE TELESCOPE TUBE TO THE MOUNT The telescope optical tube attaches to the mount via a dovetail slide bar mounting bracket at the top of the mount Figure 2 11 The mounting bar is attached along the bottom of the telescope tube Before you attach the optical tube make sure that the pan ha
26. mical s known to the State of California to cause cancer birth defects or other reproductive harm Item 21061 INST Printed in China 10 00 06 07
27. n use 8 commercially made lens cleaner or mix your own A good cleaning solution is isopropyl al cohol mixed with distilled water The solution should be 60 isopropyl alcohol and 40 distilled water Or liquid dish soap diluted with water a couple of drops per one quart of water can be used Occasionally you may experience dew build up on the optics of your telescope during an observing ses sion If you want to continue observing the dew must be removed either with a hair dryer on low setting or by pointing the telescope at the ground until the dew has evaporated If moisture condenses on the inside of the optics remove the accessories from the telescope Place the tele scope in a dust free environment and point it down This will remove the moisture from the telescope tube To minimize the need to clean your telescope replace all lens covers once you have finished using it Since the cells are NOT sealed the covers should be placed over the openings when not in use This will prevent contaminants from entering the optical tube Internal adjustments and cleaning should be done only by the Celestron repair department If your tele scope is in need of internal cleaning please call the factory for a return authorization number and price quote COLLIMATION OF A NEWTONIAN The optical performance of most Newtonian reflecting telescopes can be optimized by re collimating align ing the telescope s optics as needed To collimate the t
28. nccncnccncnes 16 Seeing 950 18 19 Short Exposure Focus Photography 19 Planetary amp Lunar Photography with Special Imagers 19 CCD Imaging for Deep Sky Objects 19 Terrestrial Photography 19 TELESCOPE MAINTENANCE 20 Care and Cleaning of the Optics s ssseseseeseseseecesereresesesesesesseeceeececeororeseseseseseseeseseseseees 20 Collimation of a 20 AstroMaster LT SpecificationS ssesessssesessesessesesessssesossesessssesessosossssosossososessesoseesososee 24 CELESTRON INTRODUCTION Congratulations on your purchase of an AstroMaster LT Series telescope The AstroMaster LT Series of telescopes come in several different models and this manual covers three models mounted on the Alt AZ Mount an altazimuth is the simplest type of mount with two motions altitude up amp down and azimuth side to side 60mm refractor 70mm refractor and 76mm Newtonian The AstroMaster LT Series is made of the highest quality materials to ensure stability and durability All this adds up to a telescope that gives you a lifetime of pleasure with a minimal amount of maintenance These telescopes were designed for the First Time Buyer offering exceptional value The AstroMaster LT s
29. ndle and azimuth lock are fully locked Then put the dovetail bracket in the horizontal position as shown in Figure 2 10 This will ensure that the mount does not move suddenly while attaching the telescope optical tube Also remove the objective lens cap refractor or the front opening cap Newtonian To mount the telescope tube 1 Remove the protective paper covering the optical tube 2 Loosen the mounting knob and the mounting safety screw on the side of the dovetail mounting platform so they do not protrude into the mounting platform see Figure 2 11 3 Slide the dovetail mounting bar into the recess on the top of the mounting platform figure 2 12 4 Tighten the mounting knob on the dovetail mounting platform to hold the telescope in place 5 Hand tighten the mounting platform safety screw until the tip touches the side of the mounting bracket NOTE Never loosen any of the knobs on the telescope tube or mount other than the pan handle and azimuth locks Mounting Knob amp Safety Screw in the dovetail bracket Shown is the 90AZ telescope tube 0 Figure 2 11 Figure 2 19 INSTALLING THE DIAGONAL amp EYEPIECES REFRACTOR The diagonal is a mirror assembly that diverts the light at a right angle to the light path of the refractor This allows you to observe in a position that is more comfortable than if you looked straight through Also the diagonal can be rotated to any position whi
30. phere from volcanic eruptions also affect transparency Ideal conditions are when the night sky is inky black Sky Illumination General sky brightening caused by the Moon aurorae natural airglow and light pollution greatly affect transparency While not a problem for the brighter stars and planets bright skies reduce the contrast of extended nebulae making them difficult if not impossible to see To maximize your observing limit deep sky viewing to moonless nights far from the light polluted skies found around major urban areas LPR filters enhance deep sky viewing from light polluted areas by blocking unwanted light while transmitting light from cer tain deep sky objects You can on the other hand observe planets and stars from light polluted areas or when the Moon 1 out Seeing Seeing conditions refers to the stability of the atmosphere and directly affects the amount of fine detail seen in extended objects The air in our atmosphere acts as a lens which bends and distorts incoming light rays The amount of bending depends on air density Varying temperature layers have different den sities and therefore bend light differently Light rays from the same object arrive slightly displaced creat ing an imperfect or smeared image These atmospheric disturbances vary from time to time and place to place The size of the air parcels compared to your aperture determines the seeing quality Under good seeing conditions fine detail is v
31. s or building rooftops e Hazy skies fog and mist can also make it difficult to focus when viewing terrestrially The amount of detail seen under these conditions is greatly reduced e If you wear corrective lenses specifically glasses you may want to remove them when observing with an eyepiece attached to the telescope When using a camera however you should always wear corrective lenses to ensure the sharpest possible focus If you have astigmatism corrective lenses must be worn at all times CELESTRON ASTRONOMY BASICS Up to this point this manual covered the assembly and basic operation of your telescope However to un derstand your telescope more thoroughly you need to know a little about the night sky This section deals with observational astronomy in general and includes information on the night sky and polar alignment For telescopes with equatorial mounts the users have setting circles and polar alignment methods to help them find objects in the sky With your altazimuth mount you can use a method called star hopping which 1 described in the Celestial Observing Section later this manual Good star maps are essential in helping you locate deep sky objects and current monthly astronomy magazines will help you locate where the planets are THE CELESTIAL COORDINATE SYSTEM To help find objects in the sky astronomers use a celestial coordinate system that 1 similar to our geographical co ordinate sy
32. stem here on Earth The celestial coordinate system has poles lines of longitude and latitude and an equator For the most part these remain fixed against the back ground stars The celestial equator runs 360 degrees around the Earth and separates the northern celestial hemisphere from the southern Like the Earth s equator it bears a reading of zero degrees On Earth this would be latitude However inthe sky this is referred to as declination or DEC for short Lines of declination are named for their angular distance above and below the celestial equator The lines are broken down into degrees minutes of arc and seconds of arc Declination readings south of the equator carry a minus sign in front of the coordinate and those north of the celestial equator are either blank 1 no designation preceded by a plus sign Figure 4 1 The celestial sohere seen from the outside showing R A and DEC The celestial equivalent of longitude is called Right Ascension or R A for short Like the Earth s lines of lon gitude they run from pole to pole and are evenly spaced 15 degrees apart Although the longitude lines are separated by an angular distance they are also a measure of time Each line of longitude is one hour apart from the next Since the Earth rotates once every 24 hours there are 24 lines total As a result the R A coordinates are marked off in units of time It begins with an arbitrary point in the
33. the magnification of your telescope simply 1 divide the focal length of the telescope by the focal length of the eyepiece Figure 3 5 used In equation format the formula looks like this Focal Length of Telescope mm Magnification Focal Length of Eyepiece mm Let s say for example you are using the 20mm eyepiece that came with your telescope To determine the magnification you simply divide the focal length of your telescope the AstroMaster LT 60AZ for this example has a focal length of 700mm by the focal length of the eyepiece 20mm Dividing 700 by 20 yields a magnifi cation of 35 power Although the power 1 variable each instrument under average skies has a limit to the highest useful mag nification The general rule is that 60 power can be used for every inch of aperture For example the Astro Master LT 60AZ is 2 4 inches in diameter Multiplying 2 4 by 60 gives a maximum useful magnification of 144 power Although this is the maximum useful magnification most observing 1 done in the range of 20 to 35 power for every inch of aperture which is 48 to 84 times for the AstroMaster LT 60AZ telescope You can determine the magnification for your telescope the same way DETERMINING FIELD OF VIEW Determining the field of view is important if you want to get an idea of the angular size of the object you are observing To calculate the actual field of view divide the apparent field of the eyepiece supplied by the eyepiece
34. the silhouetted reflection from the primary mirror Insert the collimating cap into the focuser and look through it With the focus pulled in all the way you should be able to see the entire primary mirror reflected in the secondary mirror If the pri mary mirror is not centered in the secondary mirror adjust the secondary mirror screws by alternately tight ening and loosening them until the periphery of the primary mirror is centered in your view DO NOT loosen or tighten the center screw in the secondary mirror support because it maintains proper mirror position Aligning the Primary Mirror Now adjust the primary mirror screws to re center the reflection of the small secondary mirror so It s silhouetted against the view of the primary As you look into the focuser silhouettes of the mirrors should look concentric Re Newtonian collimation views as seen through the focuser using the collimation cap Secondary mirror needs adjustment Primary mirror needs adjustment peat steps one and two until you have achieved this Remove the collimating cap and look into the focuser where you should see the reflection of your eye in the second ary mirror Secondary Mirror Primary Mir a firror Mirror Clip Both mirrors aligned with the collimating cap in the focuser Both mirrors aligned with your eye looking into the focuser 5 1 Night Time Star Collimating After successfully completing daytime collim
35. then look off toward L the side This causes light from the object O O VEG viewed to fall on the black and white sensitive rods of your eyes rather than your eyes color sensitive cones Remember that when observing faint objects it s important to try to observe from a dark location away from street and city lights The average eye takes about 20 minutes to fully adapt to the darkness So always use a red filtered flashlight to preserve The Ring Nebula your dark adapted night vision These two examples should give you an idea of how to star hop to deep sky objects To use this method on other objects consult a star atlas then star hop to the object of your choice using naked eye stars Figure 5 2 SEEING CONDITIONS Viewing conditions affect what you can see through your telescope during an observing session Condi tions include transparency sky illumination and seeing Understanding viewing conditions and the effect they have on observing will help you get the most out of your telescope Transparency Transparency 1 the clarity of the atmosphere which is affected by clouds moisture and other airborne particles Thick cumulus clouds are completely opaque while cirrus can be thin allowing the light from the brightest stars through Hazy skies absorb more light than clear skies making fainter objects harder to see and reducing contrast on brighter objects Aerosols ejected into the upper atmos
36. to the telescope However when using a camera you should always wear correc tive lenses to ensure the sharpest possible focus If you have astigmatism corrective lenses must be worn at all times ALIGNING THE FINDERSCOPE The Star Pointer is the quickest and easiest way to point your telescope exactly at a desired object in the sky It s like having a laser pointer that you can shine directly onto the night sky The Star Pointer is a zero magnification pointing tool that uses a coated glass window to superimpose the image of a small red dot onto the night sky While keeping both eyes open when looking through the Star Pointer simply move your telescope until the red dot seen through the Star Pointer merges with the object as seen with your unaided eye The red dot is produced by a light emitting diode LED it is not a laser beam and will not damage the glass window or your eye The star pointer is powered by a long life 3 volt lithium battery CR1620 see Figure 3 4 Like all finderscopes the Star Pointer must be properly aligned with the main telescope before it can be used The alignment procedure is best done at night since the LED dot will be difficult to see during the day 10 To align the Star Pointer finderscope 1 Toturn on the Star Pointer turn the switch to the on position see Figure 3 4 Locate a bright star or planet and center it in a low power eyepiece in the main telescope 3 With both eyes open look through th
37. way view of the light path of the Refractor optical design A Newtonian reflector uses a single concave mir ror as its primary Light enters the tube traveling to the mirror at the back end There light is bent forward in the tube to a single point its focal point Since putting your head in front of the telescope to look at the image with an eyepiece would keep the reflector from working a flat mirror called a diago nal intercepts the light and points it out the side of the tube at right angles to the tube The eyepiece is placed there for easy viewing 13 7 lt 77 Po nnn ne nnn nn Newtonian Reflector telescopes replace heavy lenses with mirrors to collect and focus the light 7 providing much more light gathering power for the money spent Because the light path 1 inter Figure 3 1 cepted and reflected out to the side you can have focal lengths up to 1000mm and still enjoy a telescope that 1 relatively compact and portable A Newtonian Reflector telescope offers such impressive light gathering characteristics you can take a serious interest in deep space astronomy even on a modest budget Newtonian Reflector telescopes do require more care and maintenance because the primary mirror is exposed to air and dust However this small drawback does not hamper this type of telescope s popularity with those who want an economical telescope that can still resolve faint distant objects Cutaway v
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