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  • Setting up Your Telescope

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  • telescopes

Setting up Your Telescope


Screws on the Bottom of a Reflector Telescope

DO NOT TIGHTEN! These screws are used to align the primary mirror. If you tighten these, your reflector telescope will no longer be in alignment and images will suffer. Worse yet, the mirror may come loose in the cell and you will need to reassemble the telescope!

Adjusting Your Telescope

After your telescope is assembled, you will need to adjust the finder scope. The finder scope is the small telescope on top of the main telescope. When your finder scope is properly adjusted, any object you have centered in it will also be visible in the eyepiece of the main telescope. A little effort here will make the telescope much easier to use at night.

Adjusting the Finder Scope

It is easier to make the initial adjustment to your finder scope by day than to fumble around with the adjustments in the dark. Insert the eyepiece marked with the biggest number in the telescope. Focus on a distant object (far out on the horizon, if possible) and center it in the eyepiece field of view. Securely lock the telescope into position on the tripod. Adjust the finder scope (in its mount or with adjustment knobs if provided) until the object centered in the eyepiece of the telescope is also centered in the finder scope. When you begin your observing session under the stars, you will need to make more precise adjustments to your finder scope , but this will get you started.

Adjusting Mounts for Manual Telescopes

This will depend on the type of mount you are using. For a manual (non-computerized) alt-az mount or a Dobsonian telescope mount no adjustment is needed. Just point your telescope at your first object and begin to observe. For a non-computerized equatorial telescope mount , you will need to polar align (align the mount with the North Star) as per instructions in your manual.

For GOTO telescopes (computerized telescopes), follow the instructions in the manual - most will require you to polar align (point north) to begin and then input additional information such as date, time, latitude and longitude, or nearest large city.

Best Telescope Observing Locations

The best locations for astronomy will be rural areas far from large cities that pollute the night sky with outdoor lighting. This "light pollution" washes out many of the faint objects of interest to an astronomer, as does the light from the moon. A small telescope when used under a dark, moonless sky can match the performance of a larger telescope used under a light polluted sky or a moonlit sky. (Most astronomers do not hold the moon in high regard for this reason.)

Telescope Observing at Home

Do not set up your telescope in your living room. Observing through the window of a house will drastically reduce the performance of your telescope. Go outside. If possible, set your telescope up away from buildings, parking lots, patios or other objects (wooden or cement) that absorb heat by day. These objects radiate heat back into the sky at night and will create air currents that degrade the images in your telescope . A backyard lawn, shielded from streetlights is a good place for suburban dwellers to begin.

Telescope Observing Right After Setting Up

Yes you can observe right after you set up, but your telescope won't be operating at peak efficiency and neither will you.

For you, it will take at least a half-hour of uninterrupted darkness for the pupils of your eyes to open to their fullest and be at their most sensitive to faint objects in the night sky. Furthermore, sudden exposure to bright light will quickly cause you to loose your dark adaptation. To read a star map or see the controls on your telescope , cover your flashlight lens with several layers of red plastic or paint it with several layers of red nail polish. Red light has the least effect on dark-adapted eyes.

For your telescope, it will require time for the optical system to "cool" to the temperature of the night air. While it is cooling, the lens or mirror will be changing shape and images produced will be distorted. Cool-down time is short with a small telescope, but it may take thirty minutes or more for a larger telescope to be at its best.

Other Things to Consider Before Observing

Dress warmly! The winter sky offers some of the best objects for a telescope and it is a shame to cut an observing session short because you didn't bundle up. Even if you live in a warm area, or view during other seasons of the year, you will be surprised how quickly the air cools at night.

What to Observe First

Try to observe with a plan. Choose a few easy objects (large and bright) that can be seen from your location and time of year. Check one of the popular astronomy websites such as Sky&Telescope and Astronomy Magazine, for a list of objects currently visible in the night sky.

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