# 天体と道具を分離する方法はありますか？

これは、APOから取得したhcg79の画像です。この写真に天文学的な特徴と楽器的な特徴を分離する方法があるかどうか、私は興味がありますか？ありがとうございました。

A priori it is very difficult to distinguish the origin of any particular feature from just one image.

For that reason it is established workflow, especially in astronomical context, to create 4 kind of images:

• the light frame R. That's the actual image of what you are interested in
• the dark frame D. That's an exposure of identical length and at identical conditions, but with closed apperture. That takes care to assess the sensor reading in the absense of anything visible
• the bias frame B. That's a short-duration image which allows to assess the read-out noise
• the flat field F. That's an image of a perfectly white / grey area which allows to assess the different sensitivity of the individual pixels.

Then you can obtain the corrected image C via $$C = (R-D-B) \cdot \frac{}{F - D - B}$$

https://en.wikipedia.org/wiki/Flat-field_correction