A misaligned finder scope is the single most common reason beginners can't locate anything in their first week of ownership — the main telescope and the finder are simply pointing at slightly different patches of sky. The fix takes about five minutes and is far easier to do in daylight than after dark.
Why daylight alignment works better
Aligning at night means hunting for a star with your main telescope in the first place — the exact problem you're trying to solve. Using a stationary daytime target removes that chicken-and-egg problem entirely.
Step-by-step alignment
- Choose a distant target. Pick something at least a few hundred metres away — a chimney, an antenna, a distant treetop. Anything closer will cause a parallax mismatch between the finder and the main scope.
- Centre it in the main telescope first. Using your lowest-power eyepiece, point the main tube at the target and centre it precisely in the field of view. Lock the mount once it's centred so it can't drift.
- Check the finder scope. Look through the finder without moving the main telescope. The target will likely be off-centre, or outside the field entirely.
- Adjust the finder's alignment screws. Most finders have two or three small thumbscrews around their mounting ring. Adjust them alternately, a small amount at a time, until the same target sits centred in the finder's crosshair or red dot.
- Recheck the main scope. Look back through the main eyepiece to confirm the target hasn't drifted, then re-check the finder once more.
Keeping it aligned
Finder alignment can shift slightly during transport, so it's worth a thirty-second check on a bright star or the Moon at the start of any session where the telescope has travelled since last use — far quicker than repeating the full daylight process every time.
If your finder is a red-dot rather than magnified
The process is identical, except you're centring a projected red dot on the target instead of crosshairs — the same alternating-screw adjustment applies, and daylight still works fine as long as the dot is visible against the target's background.