ENGLISH AstroMaster Series Telescopes INSTRUCTION MANUAL ● AstroMaster 90 EQ # 21064 ● AstroMaster 90 EQ-MD # 21069 ● AstroMaster 130 EQ # 31045 ● AstroMaster 130 EQ-MD # 31051
Table of Contents INTRODUCTION ........................................................................................................................................3 ASSEMBLY .................................................................................................................................................6 Setting up the Tripod ................................................................................................................................6 Attaching the Equatorial Mount ....
Congratulations on your purchase of an AstroMaster Series telescope. The AstroMaster Series of telescopes come in several different models and this manual covers four models mounted on the CG-3 German Equatorial Mount --90mm refractor and 130mm Newtonian and then both of these sizes with a motor drive. The AstroMaster 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.
1 2 16 3 4 15 5 14 13 8 9 12 7 6 10 11 Figure 1-1 AstroMaster 90 EQ Refractor 1. 2. 3. 4. 5. 6. 7. 8. Telescope Optical Tube Dovetail Mounting Bracket RA. Setting Circle Star Pointer Finderscope Eyepiece Diagonal Focus Knob R.A. Slow Motion Cable 9. 10. 11. 12. 13. 14. 15. 16. 4 Latitude Adjustment Screw Accessory Tray Tripod Counterweight Bar Counterweights Equatorial Mount Dec.
12 1 2 14 3 11 10 4 13 5 6 7 9 8 Figure 1-2 AstroMaster 130 EQ Newtonian 1. 2. 3. 4. 5. 6. 7. Eyepiece Tube Ring Telescope Optical Tube Primary Mirror Dec. Slow Motion Cable R.A. Slow Motion Cable Latitude Adjustment Screw 8. 9. 10. 11. 12. 13. 14. 5 Accessory Tray Tripod Counterweights Dec. Setting Circle Star Pointer Finderscope R.A.
This section covers the assembly instructions for your AstroMaster telescope. Your telescope should be set up indoor the first time so that it is easy to identify the various parts and familiarize yourself with the correct assembly procedure before attempting it outdoor. Each AstroMaster comes in one box. The pieces in the box are – optical tube with attached sky pointer and tube rings (130 EQ only), CG-3 equatorial mount, counterweight bar, two 4.8 lbs. (2.2kg) counterweights, R.A. & Dec.
Attaching the Equatorial Mount The equatorial mount allows you to tilt the telescopes axis of rotation so that you can track the stars as they move across the sky. The AstroMaster mount is a German equatorial mount (CG-3) that attaches to the tripod head. To attach the mount: 1. 2. Remove the equatorial mount from the box (Figure 2-10). The mount has the small latitude adjustment screw (locking bolt) attached. The large latitude adjustment screw (Figure 2-10) will be threaded into the hole.
Attaching the Slow Motion Cables The AstroMaster mount comes with two slow motion control cables that allow you to make fine pointing adjustments to the telescope in both R.A. and Declination. To install the cables: 1. 2. 3. 4. Locate the two cables with knobs on them (both are identical is size and length) and make sure the screw on each cable end does not protrude through the opening. Slide the cable onto the R.A. shaft as far as it will go. There are two R.A. shafts, one on either side of the mount.
Figure 2-17 Dec. Lock Knob on top of Dec. circle & R.A. Lock Knob on top of R.A. circle Figure 2-18 Mounting Knob & Safety Screw in the dovetail bracket Shown is the 114 EQ telescope tube Installing the Diagonal & Eyepieces (refractor) The diagonal is a prism 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.
Moving the Telescope Manually In order to properly balance your telescope, you will need to move your telescope manually at various portions of the sky to observe different objects. To make rough adjustments, loosen the R.A. and Dec. locking knobs slightly and move the telescope in the desired direction. To make fine adjustments, when the knobs are locked you turn the slow motion cables. Both the R.A. and Dec. axis have locking knobs to clutch down each axis of the telescope.
Figure 2-22 Figure 2-23 Adjusting the Equatorial Mount In order for a motor drive to track accurately, the telescope’s axis of rotation must be parallel to the Earth’s axis of rotation, a process known as polar alignment. Polar alignment is achieved NOT by moving the telescope in R.A. or Dec., but by adjusting the mount vertically, which is called altitude. This section simply covers the correct movement of the telescope during the polar alignment process.
A telescope is 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 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 3-1).
Image Orientation The image orientation changes depending on how the eyepiece is 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 image). If 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).
On/Off Switch Battery Compartment Figure 3-4 Figure 3-5 To align the Star Pointer finderscope: 1. 2. 3. 4. 5. To turn 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. With both eyes open, look through the glass window at the alignment star. If the Star Pointer is perfectly aligned, you will see the red LED dot overlap the alignment star.
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 manufacturer) by the magnification. In equation format, the formula looks like this: True Field = Apparent Field of Eyepiece ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ Magnification As you can see, before determining the field of view, you must calculate the magnification.
Up to this point, this manual covered the assembly and basic operation of your telescope. However, to understand 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. The Celestial Coordinate System To help find objects in the sky, astronomers use a celestial coordinate system that is similar to our geographical coordinate system here on Earth.
Figure 4-2 All stars appear to rotate around the celestial poles. However, 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).
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, you can simply point the polar axis of your telescope at Polaris. Although this is by no means perfect alignment, it does get you within one degree. Unlike the previous method, this must be done in the dark when Polaris is visible. 1. 2. 3. Set the telescope up so that the polar axis is pointing north – see Figure 4-6. Loosen the Dec.
Figure 4-6 Aligning the equatorial mount to the polar axis of the Earth Polar Alignment in the Southern Hemisphere Polar alignment to the South Celestial Pole (SCP) is a little more challenging due to the fact that there is no very bright star close to it like Polaris is in the NCP. There are various ways to polar align your telescope and for casual observing the methods below are adequate and will get you reasonably close to the SCP.
Pointing at Sigma Octantis This method utilizes Sigma Octantis as a guidepost to the celestial pole. Since Sigma Octantis is about 1° degree from the south celestial pole, you can simply point the polar axis of your telescope at Sigma Octantis. Although this is by no means perfect alignment, it does get you within one degree. Unlike the previous method, this must be done in the dark when Sigma Octantis is visible. Sigma Octantis has a magnitude of 5.
Declination Drift Method of Polar Alignment 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. To be able to do this type of astrophotography you will also need to have an optional motor drive and other astrophotography accessories. The declination drift method requires that you monitor the drift of selected stars.
Aligning the Setting Circles Before you can use the setting circles to find objects in the sky you need to align the R.A. setting circle which is incremented in minutes. The declination setting circle is scaled in degrees and it is factory set and should not need any adjustments. On the R.A. setting circle there are two sets of numbers on the dial – one for the northern hemisphere (top) and one for the southern hemisphere (bottom). In order to align the R.A.
Motor Drive To allow tracking of celestial objects, Celestron offers a single axis DC motor drive for the AstroMaster equatorial mount. Once polar aligned, the motor drive will accurately track objects in Right Ascension as they move across the sky. Only minor adjustments in Declination will be necessary to keep celestial objects centered in the eyepiece for long periods of time.
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 addition, little or no contrast can be seen during this phase.
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.
The AstroMaster 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.
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.
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. Repeat 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 secondary mirror.
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 as a 6mm or 4mm. Another option is to use a longer focal length ocular with a Barlow lens.
You will find that additional accessories for your AstroMaster telescope will enhance your viewing pleasure and expand the usefulness of your telescope. This is just a short listing of various accessories with a brief description. Visit the Celestron website or the Celestron Accessory Catalog for complete descriptions and all accessories available. Sky Maps (# 93722) – Celestron Sky Maps are the ideal teaching guide for learning the night sky.
AstroMaster Specifications Optical Design Aperture Focal Length Focal Ratio Secondary Mirror Obstruction -- Dia. - Area Optical Coatings Finderscope Diagonal 1.25" Eyepieces 1.25" Apparent FOV -- 20mm at 50° -- 10mm at 40° Angular Field of View w/20mm eyepiece Linear FOV w/20mm eyepiece -ft/1000yds Mount RA & DEC Setting Circles RA & DEC Slow-Motion Cables Tripod Leg diameter 1.
Celestron 2835 Columbia Street Torrance, CA 90503 U.S.A. Tel. (310) 328-9560 Fax. (310) 212-5835 Website www.celestron.com Copyright 2008 Celestron All rights reserved. (Products or instructions may change without notice or obligation.) Item # 21064-INST Printed in China $10.
