How do I align a telescope finder scope?
Daytime alignment method
Do this in daylight to avoid frustration. Pick a distant object like a telephone pole or chimney at least a quarter mile away. Insert your lowest-power eyepiece and center the object in the telescope's view.
Now look through the finder scope. It will likely be pointing somewhere else. Use the finder's adjustment screws (usually three) to move the crosshairs until they are centered on the same object. Tighten the screws gently—over-tightening can strip threads or break the finder.
- Choose a distant, stationary object
- Center it in the main eyepiece
- Adjust finder screws until crosshairs match
- Tighten screws gently
Nighttime check and tips
After dark, point at a bright star or the Moon and verify the finder is still aligned. If not, fine-tune using the same screws. Some finders use a small setscrew to lock the alignment; if yours has one, snug it after adjusting.
If your finder has a focus adjustment, focus it so the crosshairs are sharp. A blurry finder makes alignment harder. Also, make sure the finder's bracket is securely attached to the telescope tube—any wobble will throw off alignment.
- Recheck alignment at night
- Focus the finder if possible
- Ensure bracket is tight
- Avoid bumping the finder after alignment
Common mistakes
- Trying to align the finder at night without a bright object; it's much harder than doing it in daylight.
- Over-tightening the adjustment screws, which can damage the finder or strip the threads.
- Assuming the finder stays aligned forever; it can shift during transport, so check it each session.
