Orion 9800 Terrestrial Viewing, Astronomical Viewing, A. The Moon, 900mm25mm =, What to Expect

Your Aristocrat 60mm comes with a 25mm focal length Plössl eyepiece that provides 36x magnification. The Aristocrat can accept any 1.25" eyepiece (the most common eyepiece bar- rell diameter). Orion also makes several brass eyepieces that will provide different magnifications for your Aristocrat 60mm.

To calculate magnification, or power, of a telescope-eyepiece combination, simply divide the focal length of the telescope by the focal length of the eyepiece:

Telescope Focal Length (mm) = Magnification

Eyepiece Focal Length (mm)

For example, the Aristocrat 60mm, which has a focal length of 900mm, used in combination with the 25mm eyepiece, yields a magnification of

900mm25mm = 36x

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 much larger area in the eyepiece. This makes finding and centering an object much easier. Trying to find and center objects with higher power (narrow field of view) is like trying to find a needle in a haystack!

5. Terrestrial Viewing

Your Aristocrat 60mm excels in terrestrial daytime viewing. It employs a correct-image finder scope and a correct-image diagonal to provide views that are right-side up. This will allow you to comfortably view nature, vistas, boats, etc. Do not view through a closed window or bug screen as they will cause distortions to your images. Stick with magnifications below 100x, since at higher powers images rapidly lose sharpness and quality due to “heat waves” caused by sun-heated air.

Remember to aim well clear of the Sun, as the unfiltered rays of the sun through the telescope can cause permanent eye damage.

6. Astronomical Viewing

The Aristocrat 60mm was designed primarily for terrestrial daytime viewing, but it can be used for astronomy. We recom- mend using an optional 90° star diagonal when viewing the night sky.

What to Expect

So what will you see with your telescope? You should be able to see bands on Jupiter, the rings of Saturn, craters on the Moon, the waxing and waning of Venus, and several bright deep-sky objects. Do not expect to see color as you do in NASA photos, since those are taken with long-exposure cam- eras and have “false color” added. Our eyes are not sensitive

enough to see color in deep-sky objects except in a few of the brightest ones.

What about tracking?

As you view objects in the night sky, you will notice that they slowly move out of the telescope’s field of view. This is due to the rotation of the earth. To keep an object in the telescope’s field of view (to “track” it), you will need to make small adjust- ments to the altitude and azimuth position of the telescope. To move the telescope in azimuth (left/right), unlock the azimuth lock knob and turn the telescope a very slight amount. To move the telescope in altitude (up/down) loosen the altitude lock lever and make the needed adjustment.

Remember that you are seeing these objects using your own telescope with your own eyes! The object you see in your eye- piece is in real-time, and not some conveniently provided image from an expensive space probe. Each session with your telescope will be a learning experience. Each time you work with your telescope it will get easier to use, and stellar objects will become easier to find. Take it from us, there is big difference between looking at a well-made full-color NASA image of a deep-sky object in a lit room during the daytime, and seeing that same object in your telescope at night. One can merely be a pretty image someone gave to you. The other is an experience you will never forget!

Objects to Observe

Now that you are all set up and ready to go, one critical deci- sion must be made: what to look at?

A. The Moon

With its rocky surface, the Moon is one of the easiest and most interesting targets to view with your telescope. Lunar craters, marias, and even mountain ranges can all be clearly seen from a distance of 238,000 miles away! With its ever- changing phases, you’ll get a new view of the Moon every night. The best time to observe our one and only natural satel- lite is during a partial phase, that is, when the Moon is NOT full. During partial phases, shadows are cast on the surface, which reveal more detail, especially right along the border between the dark and light portions of the disk (called the “terminator”). A full Moon is too bright and devoid of surface shadows to yield a pleasing view. Make sure to observe the Moon when it is well above the horizon to get the sharpest images.

Use an optional Moon filter to dim the Moon when it is very bright. It simply threads onto the bottom of the eyepieces (you must first remove the eyepiece from the focuser to attach a filter).You’ll find that the Moon filter improves viewing comfort, and also helps to bring out subtle features on the lunar sur- face.

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