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Stargazing June 15th ✦ 6pm-10pm
Stargazing June 15th ✦ 6pm-10pm

Assembling the Telescope

Since there are different requirements for imaging than for visual observation, the setup of your telescope will likely be slightly different for CCD imaging than you may be used to for visual observing. Everything must be more precise when it comes to imaging: alignment, balance, tracking and focus all must be more accurate than is necessary for viewing.

Location, Location, Location

Where you set up for CCD imaging is critical. Unstable platforms, limited views, and light breezes that might otherwise go unnoticed during visual observing become sources or frustration when imaging.

Decks and flat roofs often provide a means of escaping neighbors' lights or getting above the trees and other obstructions. However, no matter how well built, decks and roofs are notoriously bad imaging locations. Vibrations are easily induced by the slightest movement of the observer. These vibrations quickly ruin pictures, manifesting themselves as trailed or blurry images.

Consider where you will be aiming your telescope. Light sources which are easily blocked by a hand while viewing can cause trouble for imaging. A small tree branch which may not be noticeable through the eyepiece can blur a picture. Also, keep in mind local sources of bad seeing, or atmospheric turbulence. Roofs, chimneys, and roads all give off heat during the night which can lead to mushy images if the telescope is pointed in their direction. And remember that you will sometimes be imaging objects fainter than you would normally view, so you may aim toward a section of the sky you would avoid when visually observing.

Wind causes plenty of headaches for imagers. On a real windy night it is probably best to stay indoors, or at least stick to visual observing. However, you would hate to have an otherwise perfect night ruined by a little breeze. If you can set up in a location which is protected somewhat from the wind, it will make imaging much easier.

Obviously, finding the perfect location satisfying all of the above requirements will be difficult, if not impossible, but getting the best spot you can will be rewarded with better images. Some careful planning before dark always pays off!

Computerized Telescopes

When using a computerized goto telescope, it is best to do the initial star alignment with the camera in place. If you do the alignment using an eyepiece, you will then have to rebalance the telescope when you put the camera equipment on, and this will lose your alignment. To do the alignment with the camera in place, simply follow the standard procedure you use for visual alignment with the finderscope, then instead of looking through the eyepiece to center the star, simply view the star in a continuous 1-second exposure mode in the camera software. Most programs allow you to overlay crosshairs on the image to precisely center an object. See the section on Finding objects for more details on this procedure.

Setup Tips

Every telescope will be different in its setup for CCD imaging. Many of the specifics for each type of scope are covered in the sections on Balancing and Polar Aligning. Below are some helpful tips which apply to most every telescope used for imaging.

  • Lower the Tripod. Most telescopes have adjustable tripod legs for leveling and height adjustment. When you observe visually you might set the legs higher to accommodate a comfortable viewing position. However, since for CCD imaging you will not be looking through an eyepiece, you can lower the tripod to provide additional stability and wind protection. Just remember if you are in your backyard to leave it high enough that you can see your targets over any obstructions like fences or houses, and to be able to see Polaris for polar aligning.

  • Know Where All Your Equipment Is. It may seem obvious now, but you might be surprised what you can forget in the dark! Once the sun is gone and the stars are out you will want to easily locate your equipment and avoid tripping over any wires or the telescope tripod. Keeping everything close at hand will help a lot once you start imaging. You won't want to be hunting for a part and potentially bump your scope during an image! A handy item is a large table (preferably one that folds for easy storage and transportation) to set your laptop computer on, along with accessories, charts, etc. It is a good idea to always lay everything out in the same manner each time you setup. For example, I always place my table in exactly the same location relative to my tripod (on the west side), I put the battery in exactly the same spot next to the tripod (on the northwest side), I lay out my computer and camera in the same way on the observing table (laptop on the left or west side, power supply for the camera on the very right edge, closest to the telescope), and so on. Power cords always run in the same locations to help avoid tripping and tangling, etc.

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