ASTAP warning inexact scale message

Stacking program, astrometric (plate) solver, fits file viewer

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ASTAP warning inexact scale message

Forum: General discussions ASTAP

Creator: Manoocher Haghighat

Created: 2022-09-21

Updated: 2022-09-21

Manoocher Haghighat - 2022-09-21

I have taken many images using reducer (Pls see the attachment). The issue is the warning message I get from ASTAP plate solving (see bottom right side of the image). ASTAP is confused and can’t center and sync the image taken by the camera. As the result, all images are not centered correctly. That is why NINA support team expressed the incompatibility of the telescope and reducer combination.

**Is anything you could advice to fix this problem? **

Equipment settings:
Vixen without reducer: FL=540mm, F-ratio=5, Aperture=108mm
Vixen with reducer: FL=362mm, F-ratio = 3.35mm, Reducer=0.67
Altair 294c camera: Resolution = 4128X2808, Pixel size = 16.05x12.61

Helix-Reducer.png

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han.k - 2022-09-21

? Just enter the value ASTAP is suggesting, 470 mm. The value is absolute correct! That will improve solving reliability

The FL/focla length is adjustable by the distance between reducer and telescope and distance between camera and reducer or telescope.

You can check the values in the FOV calculator of ASTAP. Opne ASTAP, load an image, solve it and go to tab pixel math 2 (ctrl+A) . The FOV calculatoris far right.

Cheers, Han

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han.k - 2022-09-21

I uploaded a crop of your screenshot to nova.astrometry.net. It reports an image height of 1.76 degrees. Compare that with the reported 1.77 degrees by ASTAP.

https://nova.astrometry.net/user_images/6492446#annotated

Han

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