How to Align a Telescope Finderscope: Complete Step-by-Step Guide
AllenDing
How to Align a Telescope Finderscope: Complete Step-by-Step Guide
Nothing is more frustrating than finally getting your telescope set up, pointing the finderscope at a bright star, looking through the main eyepiece — and seeing nothing. The problem? Your finderscope isn't aligned. Here's exactly how to fix it, step by step, so your finderscope and main telescope always point to the same place.
Why Finderscope Alignment Matters
A telescope's main eyepiece has a very narrow field of view — often just 1° or less. Finding anything in the night sky by looking through the main eyepiece alone is like trying to find a house by looking through a drinking straw. The finderscope solves this problem: it has a much wider field of view (5°–10°), letting you roughly aim the telescope before fine-tuning with the main eyepiece.
But only if it's aligned. If your finderscope is off by even a few degrees, the object you center in the finderscope won't be anywhere near the main eyepiece's field of view. Alignment ensures that when you center a target in the finderscope, it's also centered in the main eyepiece.
Types of Finderscopes
| Type | Magnification | Field of View | Pros | Cons |
|---|---|---|---|---|
| Red Dot Finder | 1x (no magnification) | Very wide (~20°) | Simple, cheap, easy to use | No magnification; less precise |
| Optical Finder (6x30, 8x50) | 6x–8x | Moderate (~5°–7°) | Precise, shows faint stars | Needs alignment; adds weight |
| Telrad / Rigel QuikFinder | 1x | Very wide | Projects concentric circles | Needs batteries; less precise for faint objects |
Step 1: Initial Alignment (Daytime Method — Recommended)
Aligning during the day is far easier than at night. Here's the best method:
1.1 Set Up in Daylight
- Set up your telescope during the day, preferably pointing at a distant landmark (a telephone pole, chimney, or tree branch at least 500 meters away).
- Insert your lowest-power eyepiece (longest focal length, e.g., 25mm) into the main telescope.
- Focus the main telescope on the distant landmark so it appears sharp in the eyepiece.
1.2 Center the Landmark in the Main Eyepiece
With the landmark centered in the main eyepiece's field of view, do not move the telescope. Now look through the finderscope.
1.3 Adjust the Finderscope Screws
The landmark probably won't be centered in the finderscope. Use the alignment screws on the finderscope mount (usually three small Phillips-head screws) to adjust the finderscope's aim until the landmark is centered in the finderscope's crosshairs (or red dot).
Key tip: Adjust screws gradually. Turn one screw at a time and watch how the reticle moves. The screws work in pairs — loosening one and tightening its opposite adjusts the aim in that axis.
Step 2: Fine-Tune at Night
Daytime alignment gets you 90% of the way there, but a final nighttime check is essential for precision.
2.1 Pick a Bright Star
Wait for dusk/night, then point your telescope at a bright star (Sirius, Vega, or Capella are excellent choices). Center the star precisely in the main eyepiece using your highest magnification (shortest focal length eyepiece).
2.2 Check the Finderscope
Look through the finderscope. Is the star centered in the crosshairs (or is the red dot on the star)?
- Yes: Your alignment is good. Move to Step 3.
- No: Make small adjustments to the finderscope screws until the star is centered.
2.3 Verify with a Second Star
Move the telescope to a different bright star in a different part of the sky. Center it in the finderscope, then check the main eyepiece. If it's also centered, alignment is complete. If not, repeat the adjustment process.
How Often Should You Check Alignment?
| Situation | Check Alignment? | Reason |
|---|---|---|
| Before every observing session | ✅ Yes | Transportation/vibration can shift alignment |
| After transporting telescope in a car | ✅ Yes | Bumps and vibrations almost always shift it |
| After a long observing session (>3 hours) | ✅ Recommended | Thermal expansion of the tube can shift aim |
| Between targets on the same night | ❌ No | Alignment holds once set |
| After collapsing/extending tripod | ✅ Yes | Mount flexure can introduce error |
Common Alignment Mistakes
- Aligning on a close object (<50m) — parallax error throws off alignment at infinity
- Only doing a daytime alignment without nighttime verification
- Overtightening finderscope screws (can strip threads)
- Forgetting to lock the finderscope bracket after adjustment
- Use a distant object (500m+) for daytime alignment
- Check alignment on at least 2 stars at night
- Tighten all 3 screws evenly (finger-tight, not wrench-tight)
- Re-check alignment if the telescope was transported
Red Dot Finder: Special Considerations
Red dot finders are the most popular choice for beginner telescopes (including all Koolpte models) because they're intuitive — you simply look through the window and see a red dot projected onto the sky. But they have one quirk:
Battery life. Red dot finders consume battery even when "off" if the switch is left in the ON position. Always turn the finder fully OFF after each session, and carry a spare CR2032 battery in your accessory case.
Also note: red dot finders can be hard to see under very dark skies (the dot appears dimmer against a truly black background). If this happens, cup your hand around the finder to block stray light, or use a piece of cardboard to make a shadow over the window.
Conclusion
A properly aligned finderscope is the difference between frustration and joy in amateur astronomy. The daytime method gets you 90% of the way there in 5 minutes; a quick nighttime verification completes the process. Make alignment part of your standard setup routine, and you'll spend more time observing and less time hunting for targets.
New to your telescope? Read our first-time setup guide, which includes finderscope alignment as part of the initial assembly process.
For more on getting the most out of your equipment, check our telescope accessories guide to see which add-ons are worth buying.