Many astro photographers know the problem: one focuses as precisely as possible but in one or two corners, the stars are not pinpoints. Often, the result is a compromise by "tricking" the focus to a point where most of the image field has the best focus possible or cropping the image.
Some possible causes of this problem:
- a tilted camera sensor (fragments of a millimetre are enough)
- a tilted focuser
- a tilted focal plane of the telescope (common at Newtonian telescopes)
- tilted optical accessories by unprecise clamping
The solution: With the tilting mechanism, the camera's sensor is aligned with the focal plane no matter what causes the tilt. You just have to keep the orientation of the complete accessory train.
And that's how it works: The best way is a calibration by test images. Identify the "bad corner" in your photo and begin adjusting the tilting mechanism.
- Loosen the counter screws (the small setting screws)
- Slightly turn the adjustment screws close to the "bad corner"
- Take a second image. If the situation has become worse, turn the adjustment screw in the other direction until the image is satisfying.
- Finally, tighten the counter screws again.
You can use the T2-Tilter to adjust the Camera imaging plane, reduce newton ring problem when imaging ha-solar.
