The CR-150 HD 6" Refractor Model #21017 INSTRUCTION MANUAL
T A B L E ▲ ▲ O F C O N T E N T S INTRODUCTION ............................................................................................................................. 4 How to Use this Manual .................................................................................................................. 5 A Word of Caution .......................................................................................................................... 5 TheRefractor OpticalSystem........................
▲ CELESTIAL OBSERVING ........................................................................................................... 3 6 Observing the Moon ....................................................................................................................... 36 Observing the Planets .....................................................................................................................37 Using the Lens Cap Aperture Stop.............................................................
I N T R O D U C T I O N Welcome to the Celestron world of amateur astronomy! For more than a quarter of a century, Celestron has provided amateur astronomers with the tools to explore the universe. The line of Celestron refractors continues in this proud tradition. Each telescope is made of the highest quality materials to ensure durability and stability. And, your Celestron refractor is versatile — it will grow as your interest grows.
How to Use This Manual This manual is designed to instruct you in the proper use of your Celestron refracting telescope. This includes assembly, initial use, and long term operation and maintenance. There are four major sections to the manual. The first section covers the proper procedure for setting up your Celestron refracting telescope. The second section covers basic operations that are common to all telescopes.
The Refractor Optical System Developed in the early 1600s, the refractor is the oldest telescope design. It derives its name from the method it uses to focus incoming light rays. The refractor uses a lens to bend or refract incoming light rays, hence the name (see Figure 1-1). Early designs used single element lenses. However, the single lens acts like a prism and breaks light down into the colors of the rainbow, a phenomenon known as chromatic aberration.
ASSEMBLING YOUR C R - 1 5 0 H D AT POLARIS C The CR-150 HD (#21017) refracting telescope is offered on a German equatorial mount. The CR-150 HD is shipped in two boxes.
The CR-150 HD 1 16 15 14 2 13 12 11 3 4 5 10 6 7 8 9 Figure 2-1 1. Lens Cap (not shown) 2. Dovetail Slidebar 3. Declination Lock 4. Declination Setting Circle 5. Counterweight Shaft 6. Counterweights 7. Tripod Leg 8. Accessory Tray 8 • The CR-150 HD 9. Leg Extension Clamp 10. Latitude Adjustment Screw 11. Focus Knobs 12. Eyepiece 13. Finderscope Bracket 14. Finderscope 15. Tube Mounting Rings 16.
Assembling the CG-5 Equatorial Mount Setting Up the Tripod The tripod comes fully assembled with the metal plate, called the tripod head, that holds the legs together at the top. In addition, the brackets that support the accessory tray are also attached to the tripod. Stand the tripod upright and pull the tripod legs apart until the leg brace assembly for the accessory tray is fully extended (see figure 2-2). The tripod will now stand by itself.
Attaching the Accessory With the tripod set up, you are ready to attach the accessory tray to the tripod. Tray There are three wing bolts that hold the accessory tray to the bracket. 1. Locate the three wing bolts. 2. Place the accessory tray over the bracket and position it so the thread holes in the accessory tray are above the slotted holes in the bracket. 3. Insert the wing bolts up through the slotted holes in the bracket (see figure 2-3). 4.
Attaching the Equatorial The equatorial mount allows you to tilt the telescope’s axis of rotation so that you Mount can track the stars as they move across the sky. The CG-5 mount is a German equatorial mount that attaches to the tripod head (i.e., metal plate on the tripod). On one side of the plate there is an “N” which signifies north. This side of the tripod will face north when setting up for an astronomical observing session. Above the “N” is a peg about 3/4" high that points straight up.
Attaching the R.A. Slow Motion Knob With the mount securely in place, you are ready to attach some of the accessories (the telescope tube will be added last). Start with the Right Ascension (R.A.) slow motion knob. The R.A. slow motion knob allows you to make fine pointing adjustments in the direction the telescope is aiming (once it is attached to the mount). To install the knob: 1. Locate the hard plastic shell under the R.A. shafts. 2. Remove either of the two oval tabs by pulling tightly. 3.
Attaching the Declination Slow Motion Knob Like the R.A. slow motion knob, the DEC slow motion knob allows you to make fine pointing adjustments in the direction the telescope is pointed. The DEC slow motion knob attaches in the same manner as the R.A. knob. The shaft that the DEC slow motion knob fits over is toward the top of the mount, just below the telescope mounting platform. Once again, you have two shafts to choose from. Use the shaft that is pointing toward the ground.
Attaching the Counterweight Bar and Counterweights The last item to be mounted before the telescope tube is the counterweight bar and counterweights. Used to balanced the telescope, the counterweight bar attaches to the opposite side of the mount as the telescope. To install the counterweight bar: 1. Retract the counterweight bar lock nut by turning it counterclockwise. This will expose the threads on the end of the counterweight bar. 2. Thread the counterweight bar into the mount completely.
Attaching the Telescope With the mount fully assembled, you are ready to attach the telescope to the to the Mount mount. The optical tube attaches to the mount using a dovetail slidebar that is fastened to two tube rings that clamp around the tube. • Before you attach the optical tube, fully tighten the right ascension and declination clamps. This will prevent the telescope from moving suddenly once attached to the mount. 1. Loosen the hand knob on the side of the CG-5 mount. 2.
Balancing the Telescope To eliminate undue stress on the mount, the telescope should be properly balanced around the polar axis. In addition, proper balancing is crucial for accurate tracking if in R.A. using an optional motor drive. To balance the mount: 1. Release the R.A. Clamp and position the telescope off to one side of the mount (make sure that the balance bracket thumbscrew is tight). The counterweight bar will extend horizontally on the opposite side of the mount (see figure 2-9). 2.
Balancing the Telescope The telescope should also be balanced on the declination axis to prevent any in DEC sudden motions when the DEC clamp is released. To balance the telescope in DEC: 1. Release the R.A. clamp and rotate the telescope so that it is on one side of the mount (i.e., as described in the previous section on balancing the telescope in R.A.). 2. Lock the R.A. clamp to hold the telescope in place. 3.
Adjusting the Mount in Altitude For the purpose of polar alignment, there are two directions in which the mount can be adjusted; vertically, which is called altitude and horizontally, which is called azimuth. There are several ways to align on the celestial pole, some of which are discussed later in this manual. This section simply covers the correct movement of the mount during the polar alignment process. To adjust the mount in altitude (i.e.
Disassembling and Transporting Your CR- The entire telescope and mount is light enough to pick up and carry outside for a casual observing session. If, however, you want to transport your CR-150 HD to a 150 HD remote observing location, you must partially disassemble it. Here’s how: 1. Remove the telescope from the equatorial mount. Return it to the shipping carton to ensure safe transportation. 2. Remove the three wing bolts that hold the accessory tray to the tripod. 3.
T E L E S C O P E B A S I C S Once your telescope has been fully assembled, you are ready to attach the accessories and have a look. This section deals with basic telescope operations that are common to all Celestron refractor telescopes. Attaching the Accessories There are several accessories that come standard with all the Celestron refractor telescopes. The installation and use of each of these is described in this section.
Eyepieces are commonly referred to by focal length and barrel diameter. The focal length of each eyepiece is printed on the eyepiece barrel. The longer the focal length (i.e., the larger the number) the lower the eyepiece magnification (i.e., power) and the shorter the focal length (i.e., the smaller the number) the higher the magnification. Generally, you will use low-to-moderate power when viewing. For more information on how to determine power, see the section on “Calculating Magnification.
Focusing To focus your telescope, simply turn either of the focus knobs located under the focus tube (see figure 4-1). Turn the focus knobs until the image is sharp. Once sharp, turn the knobs toward you to focus on an object that is closer than the one you are currently observing. Turn the knobs away from you to focus on a more distant object than the one you are currently observing. When working with any optical instrument, there are a few things to remember to ensure you get the best possible image.
Figure 4-2 The finder comes mounted in the finder bracket. To mount the finder to the telescope, the finder bracket attaches to the mounting bracket on the telescope. Aligning the Finder The CR-150 HD comes with a 9x50mm finder. The finder is designed to help you find objects that are easily overlooked in the main optics of the telescope. The first number used to describe the finder is the power. The second number is the diameter of the objective lens in millimeters.
Image Orientation It should be noted that the image orientation will change depending on the viewing configuration. When using the star diagonal, the image is right-side-up, but reversed from left-to-right. If inserting the eyepiece into the accessory adapter (i.e., without the star diagonal), the image is inverted (upside down and reversed from left-to-right). This holds true for the 9x50 finder as well as the telescope.
Nighttime Observing Looking at objects in the sky is quite different than looking at objects on Earth. For one, many objects seen in the daytime are easy to see with the naked eye and can be located by using landmarks. In addition, objects on the ground are stationary, at least for the most part. In the night sky you will see a tremendous amount of stars through the telescope that are not visible to the naked eye. One way to find objects (at least initially) is by using other stars to guide you there.
Calculating Magnification You can change the power of your Celestron CR-150 HD telescope just by changing the eyepiece (ocular). To determine the magnification for your telescope, you would simply divide the focal length of the telescope (1200mm) by the focal length of the eyepiece that you are using. In equation format, the formula looks like this: Focal Length of Telescope (mm) Magnification = ———————————————— Focal Length of Eyepiece (mm) Let’s say, for example, that you are using a 20mm eyepiece.
General Photography Hints Your Celestron telescope can be used for both terrestrial and astronomical photography. Your telescope has a fixed aperture and, as a result, a fixed f/ratio. To properly expose your subjects photographically, you need to set your shutter speed accordingly. Most 35mm single lens reflex (SLR) cameras offer through-thelens metering that lets you know if your picture is under or overexposed.
A S T R O N O M Y B A S I C S This section deals with observational astronomy in general. It includes information on the night sky, polar alignment, and using your telescope for astronomical observations. The Celestial Coordinate System In order to help find objects in the sky, astronomers use a celestial coordinate system which is similar to our geographical coordinate system here on Earth. The celestial coordinate system has poles, lines of longitude and latitude, and an equator.
Motion of the Stars Like the Sun, the stars also appear to move across the sky. This motion is caused by the Earth’s rotation. For observers in the northern hemisphere, all stars appear to move around the north celestial pole. For observers in the southern hemisphere, all stars appear to move around the south celestial pole. This means that over a 24hour period, any given star will scribe out a complete circle around its respective celestial pole.
Polar Alignment In order for the telescope to track the stars it must meet two criteria. First, you need a drive motor that will move at the same rate as the stars. For the CR-150 HD there are two optional motor drives (#93518 and #93523) that can be fitted to it. The second thing you need is to set the telescope’s axis of rotation so that it tracks in the right direction.
Finding the Pole Figure 5-4 The position of the Big Dipper changes throughout the year and throughout the night. For each hemisphere, there is a point in the sky around which all the other stars appear to rotate. These points are called the celestial poles and are named for the hemisphere in which they reside. For example, in the northern hemisphere all stars move around the north celestial pole.
Latitude Scales The easiest way to polar align a telescope is with a latitude scale. Unlike other methods that require you to find the celestial pole by identifying certain stars near it, this method works off of a known constant (your latitude) to determine how high the polar axis should be pointed. The latitude range varies depending upon the telescope you own. The range for the CG-5 is 40°.
Pointing at Polaris This method utilizes Polaris as a guidepost to the celestial pole. Since Polaris is less than a degree from the celestial pole, many amateurs simply point the polar axis of their telescope at Polaris. Although this is by no means a perfect alignment, it is close. To align using this method: Align the finderscope with the main optical tube as described in the "Aligning the Finder" section earlier in the manual.
Declination Drift This method of polar alignment allows you to get the most accurate alignment on the celestial pole and is required if you want to do long exposure deep-sky astrophotography through the telescope. The declination drift method requires that you monitor the drift of selected guide stars. The drift of each guide star tells you how far away the polar axis is pointing from the true celestial pole and in what direction.
Polar Alignment Finders There are two finders specifically designed for polar alignment that can be used with the CR-150 HD telescopes. These finders can be purchased as optional accessories for the CR-150 HD. The first finder, known as the 7x50 Polaris finder (#937858P), is used as a regular finder. The second finder is the polar axis finderscope (#94221). Its sole purpose is polar alignment and can NOT be used to find objects in the telescope.
C E L E S T I A L O B S E R V I N G With your telescope set up, you are ready to use it for celestial observing. This section covers visual observing of both solar system and deep-sky objects. Observing the Moon In the night sky, the Moon is a prime target for your first look because it is extremely bright and easy to find. Often, it is a temptation 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.
Using the Lens Cap Aperture Stop As mentioned in the introduction, all refractive optics will exhibit some amount of chromatic aberration due to the prism effect of lenses. Chromatic aberration will become more pronounced the farther the incoming light rays are off-axis (i.e. passing through the edge of the objective lens) and virtually unnoticeable on-axis (passing through the center of the objective lens).
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. The Celestron Sky Maps (#93722) can help you locate the brightest deep-sky objects. Most deep-sky objects have a large angular size. Therefore, low-to-moderate power is all you need to see them.
Star Hopping You can use your setting circles to find these objects (as described earlier in this manual) or try star hopping. Star hopping is done by using bright stars to guide you to an object. Here are directions for two popular objects. The Andromeda Galaxy, M31, is an easy first target. To find M31: 1. Locate the constellation of Pegasus, a large square visible in the fall and winter months. 2. Start at the star in the northeast corner. The star is Alpha (α) Andromeda. 3.
Star hopping may take some getting used to since you can see more stars through the finder than you can see with the naked eye. And, some objects are not visible in the finder. One such object is M57, 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 is easy to pick out because it contains the bright star Vega. 2.
Viewing Conditions Viewing conditions affect what you can see through your CR-150 HD telescope during an observing session. Conditions include transparency, sky illumination, and seeing. Understanding viewing conditions and the affect they have on observing will help you get the most out of your telescope. Transparency Transparency is the clarity of the atmosphere and is affected by clouds, moisture, and other airborne particles.
Once adjusted to the outdoor temperature, don’t touch the telescope tube with your hands. When pointing the telescope, hold the telescope by the star diagonal. If observing with others, make sure no one stands in front of or directly below the telescope tube. The images produced by Type 2 seeing conditions don’t move as quickly as those produced by Type 1 conditions, but the images are quite blurry. Fine detail is lost and the contrast is low for extended objects. Stars are spread out and not sharp.
C E L E S T I A L P H O T O G R A P H Y After looking at the night sky for awhile you may want to try photographing it. Several forms of celestial photography are possible with your Celestron CR-150 HD telescope. The most common forms of celestial photography, in order of difficulty are: short exposure prime focus, piggyback, and projection photography. Each of these is discussed in moderate detail with enough information to get you started.
Short Exposure Prime Focus Short exposure prime focus photography is the best way to begin recording celestial objects. It is done with the camera attached to the telescope without an eyepiece or camera lens in place. To attach your camera, you need the T-adapter and a T-Ring for your specific camera (i.e., Minolta, Nikon, Pentax, etc.). The CR-150 HD focuser has a built-in T-adapter and is ready to accept a 35mm camera body. The T-Ring replaces the 35mm SLR camera’s normal lens.
The exposure times listed here should be used as a starting point. Always make exposures that are longer and shorter than the recommended time. Also, try bracketing your exposures, taking a few photos at each shutter speed. This will ensure that you will get a good photo. If using black and white film, try a yellow filter to reduce the light intensity and to increase contrast. Keep accurate records of your exposures.
Piggyback The easiest way to enter the realm of deep-sky, long exposure astrophotography is via the piggyback method. Piggyback photography is done with a camera and its normal lens riding on top of the telescope. Through piggyback photography you can capture entire constellations and record large scale nebulae that are too big for prime focus photography. Because you are photographing with a low power lens and guiding with a high power telescope, the margin for error is very large.
The exposure time depends on the film being used. However, five minutes is usually a good starting point. With slower films, like 100 ISO, you can expose as long as 45 minutes. With faster films, like 1600 ISO, you really shouldn’t expose more than 5 to 10 minutes. When getting started, use fast films to record as much detail in the shortest possible time.
Projection Photography This form of celestial photography is designed for objects with small angular sizes, primarily the planets and individual lunar features. Planets, although physically quite large, appear small in angular size because of their great distances. Moderate to high magnification is, therefore, required to make the image large enough to see any detail. Unfortunately, the camera/telescope combination alone does not provide enough magnification to produce a usable image size on film.
T E L E S C O P E M A I N T E N A N C E Refractors are generally very low maintenance telescopes. Cleaning is really all that is needed, and even that is minimal if the telescope is stored properly. Care and Cleaning of the Optics Occasionally, dust and/or moisture may build up on the objective lens of your telescope. Special care should be taken when cleaning any instrument so as not to damage the optics.
O P T I O N A L A C C E S S O R I E S The following is a partial list of optional accessories available for your Celestron CR-150 HD. CD-ROM (93700) - Celestron and Software Bisque have joined together to present this comprehensive CD-ROM called The Sky™ Level 1 - for Celestron. It features a 10,000 object database, 75 color images, horizontal projection, custom sky chart printing, zoom capability and more! A fun, useful and educational product. PC format.
• Lanthanum Eyepieces (LV Series) - Lanthanum is a unique rare earth glass used in one of the field lenses of this new eyepiece. The Lanthanum glass reduces aberrations to a minimum. All are fully multicoated and have an astounding 20mm of eye relief — perfect for eyeglass wearers! They are available in the following focal lengths: 2.5mm, 4mm, 5mm, 6mm, 9mm, 10mm, 12mm and 15mm. Celestron also offers the LV Zoom eyepiece (#3777) with a focal length of 8mm to 24mm.
Motor Drive System - #93518 By adding the MDCG-5 Drive System to your mount, you add the capacity to automatically track objects in the sky, a convenience you’ll be sure to enjoy during long viewing or astrophotography sessions, when manual tracking can become tiring. Furthermore, the Drive System will enhance high-power visual observing. It attaches to the R.A.
THE MESSIER CATALOG The Messier Catalog, compiled by Charles Messier, was the first extensive listing of star clusters and nebulae. Messier’s primary observational purpose was to discover comets. He compiled this list so that others searching for comets would not be confused by these objects. His list still remains popular today because all of these objects are easily visible in amateur telescopes. M# NGC# Const. R.A.
M# NGC# Const. Mag Type M36 M37 M38 M39 M40 NGC 1960 NGC 2099 NGC 1912 NGC 7092 Aur Aur Aur Cyg UMa 5 5 5 21 12 36.3 52.0 28.7 32.3 22.2 34 32 35 48 58 08 33 50 26 05 6.0 5.6 6.4 4.6 8.0 Op. Cl. Op. Cl. Op. Cl. Op. Cl. dbl M41 M42 M43 M44 M45 NGC 2287 NGC 1976 NGC 1982 NGC 2632 CMa Ori Ori Cnc Tau 6 5 5 8 3 47.0 35.3 35.5 40.0 47.5 -20 -5 -5 19 24 44 27 16 59 07 4.5 4.0 9.0 3.1 1.2 Op. Cl. D. Neb. D. Neb. Op. Cl. Op. Cl.
M# NGC# Const. R.A. HMS DEC °‘ Mag Type Proper Name M81 M82 M83 M84 M85 NGC 3031 NGC 3034 NGC 5236 NGC 4374 NGC 4382 UMa UMa Hya Vir Com 9 9 13 12 12 55.8 56.2 37.7 25.1 25.4 69 69 -29 12 18 04 41 52 53 11 6.8 8.4 7.6 9.3 9.2 Sp. Gx. Ir. Gx. Sp. Gx. El. Gx. El. Gx. Bodes Nebula M86 M87 M88 M89 M90 NGC 4406 NGC 4486 NGC 4501 NGC 4552 NGC 4569 Vir Vir Com Vir Vir 12 12 12 12 12 26.2 30.8 32.0 35.7 36.8 12 12 14 12 13 57 24 25 33 10 9.2 8.6 9.5 9.8 9.5 El. Gx. El. Gx. Sp. Gx. El. Gx.
LIST OF BRIGHT STARS The following is a list of bright stars that can be used to align the R.A. setting circle. All coordinates are in epoch 2000.0. Star Name 56 • Constellation Epoch 2000.0 R.A. DEC HMS °‘“ Magnitude Sirius Canopus Arcturus Rigel Kent. Vega CMa Car Boo Cen Lyr 06 06 14 14 18 45 23 15 39 36 09 57 40 37 56 -16 -52 +19 -60 +38 42 41 10 50 47 58 44 57 02 01 -1.47 -0.72 -0.72 +0.01 +0.
FOR FURTHER READING The following is a list of astronomy books that will further enhance your understanding of the night sky. The books are broken down by classification for easy reference. Astronomy Texts Astronomy Now .................................................................................................... Pasachoff & Kutner Cambridge Atlas Of Astronomy .......................................................................... Audouze & Israel McGraw-Hill Encyclopedia Of Astronomy ............
CELESTRON ONE YEAR WARRANTY A. Celestron International (CI) warrants this telescope to be free from defects in materials and workmanship for one year. CI will repair or replace such product or part thereof which, upon inspection by CI, is found to be defective in materials or workmanship. As a condition to the obligation of CI to repair or replace such product, the product must be returned to CI together with proof-of-purchase satisfactory to CI. B.
Celestron International 2835 Columbia Street Torrance, CA 90503 Tel: 310-328-9560 Fax: 310-212-5835 Web site: www.celestron.com Copyright 1999 Celestron International All right reserved (Products or instructions may change without notice or obligation). Item #21017-INST 10-99 Price $10.
