From the December 2005 issue

I’m having trouble centering the objects I want to observe in my telescope. Can you help me?

By | Published: December 1, 2005 | Last updated on May 18, 2023
Just about all observers align their finder scopes every time they go out to observe. It makes observing easier, more efficient, and more enjoyable.
Here’s how to do it: In daylight, set up your telescope. You’ll want to use the eyepiece that gives you the lowest magnification, so it will be the one with the largest number on it. For example, if you have two eyepieces labeled 10mm and 25mm, choose the 25mm eyepiece.

Point your scope toward a distant, not-too-large terrestrial object — like the top of a telephone pole or the edge of a building. Center it in your eyepiece and focus.

Without moving your telescope, look through the finder. Most finders have crosshairs that meet in the field of view’s center. If you’re having trouble locating objects when moving from the finder to the telescope, the object you just targeted with the finder won’t appear in the scope’s field of view either. You’ll need to reposition the finder so its crosshairs appear
centered on the spot where the scope is now pointing.

Either three or six adjusting screws hold a finder in place. Look through the finder and slowly turn one of the screws. Move the finder onto the target as best you can, then repeat the process for the other screws until the finder’s crosshairs are pointing where you want them. Now your finder is aligned.

When you go out at night, use the finder to locate the object you want to view. The finder’s low magnification and wide field of view make it easy to find what you’re looking for. And now, when the object appears centered in your finder scope, it should also be centered in your telescope.

If your scope gets bumped or frequently moved, you might have to align your finder scope again. But each time you do, it will take you less time. — MICHAEL E. BAKICH, ASSOCIATE EDITOR