Orion 9541 Getting Started, Attaching the Diagonal GoScope, StarMax, SkyScanner, 18X = 350mm20mm

Thumbscrews

Focus knobs

Figure 8: Detail of the TableTop 100 focuser

on the retaining clip and remove the old battery. Do not over bend the retaining clip. Then slide the new battery under the battery lead with the positive (+) side facing down and replace the battery cover.

Attaching the Diagonal

GoScope 80

Attach the 90˚ star diagonal to the optical tube. First remove the caps from the diagonal and unthread the cover on the rear of the GoScope. The knurled ring on the diagonal connects to the threads on the rear of the GoScope. Tighten this ring firmly. If you wish to change the orientation of the diagonal for a more comfortable viewing angle, you must first loosen the knurled ring on the diagonal. Rotate the diagonal to the desired viewing angle, and retighten the knurled ring to lock the diagonal into place. (See Figure 6.)

StarMax 90

Remove the cap from the eyepiece adapter on the rear of the optical tube and insert the chrome barrel of the mirror star diagonal. Secure the diagonal with the thumbscrews on the eyepiece adapter. Now, insert the chrome barrel of the 25mm eyepiece into the star diagonal. Secure the eyepiece with the thumbscrews on the star diagonal. (See Figure 7.)

SkyScanner 100

This section is not applicable if you own the SkyScanner 100. This is because this telescope is a Newtonian reflector and this telescope type does not have the focus travel to support this accessory. Please skip to the next section.

Inserting the Eyepiece

Loosen the eyepiece securing thumbscrews. Insert the chrome barrel of the low-power eyepiece into the focuser and secure it with the thumbscrews. Set aside the high-power eye- piece for use later. (See Figure 8.)

Your telescope is now fully assembled and should resemble the appropriate image on the cover of this manual. Remove

the dust cap from the front of the telescope when it is in use. Replace it when you are finished observing.

Eyepiece Selection

By using eyepieces of different focal lengths, it is possible to attain many magnifications or powers with the TableTop. Your telescope comes with two eyepieces: one for low power, wide field viewing, another for detailed high power observation. Other eyepieces can be used to achieve higher or lower pow- ers. It is quite common for an observer to own five or more eyepieces to access a wide range of magnifications.

To calculate the magnification of a telescope-eyepiece com- bination, simply divide the focal length of the telescope by the focal length of the eyepiece. The example below uses the GoScope 80mm TableTop with a focal length of 350mm as an example. See the Specifications table at the end of this manu- al to determine the focal length of your particular model.

Magnification = Focal Length of Telescope (mm) Focal Length of Eyepiece (mm)

For example, the TableTop 80, which has a focal length of 350mm, used in combination with the 20mm eyepiece, yields a magnification of 18x:

18X = 350mm20mm

Whatever you choose to view, always start by inserting your lowest-power (longest focal length) eyepiece to locate and center the object. Low magnification yields a wide field of view, which shows a larger area of sky in the eyepiece. This makes finding and centering an object much easier. Trying to find and center objects with a high power (narrow field of view) eyepiece is like trying to find a needle in a haystack!

Once you’ve centered the object in the eyepiece, you can switch to a higher magnification (shorter focal length) eye- piece, if you wish. This is recommended for small and bright objects, like planets and double stars. The Moon takes higher magnifications well.

The best rule of thumb with eyepiece selection is to start with a low power, wide-field eyepiece, and then work your way up in magnification. If the object looks better, try an even higher magnification eyepiece. If the object looks worse, then back off the magnification a little by using a lower-power eyepiece.

Getting Started

It’s best to get a feel for the basic functions of the TableTop during the day, before observing astronomical objects at night. This way you won’t have to orient yourself in the dark! Find a spot outdoors where you’ll have plenty of room to move the telescope, and where you’ll have a clear view of some object or vista that is at least 1/4 mile away. It is not critical that the telescope be exactly level, but it should be placed on flat ground or pavement to ensure smooth movement.

The TableTop was designed specifically for visual observation of astronomical objects in the night sky. Like all Newtonian reflector telescopes, it is not suited for daytime terrestrial

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