Flats in a pure RGB image....

[Emanuele]

This is not about PI so I am posting here....

I had a very interesting read - Vincent Peris replies here in the forums - about shooting pure RGB and how it is much better than LRGB.

So I am wondering: how do you take flats in a pure RGB image? Usually Luminance is the only one affected and thus flats are taken with the Lum filter only.
But in a pure RGB image...... ?

Thank you,
E.

[Carlos Milovic]

No... flats should be taken on every filter you have. The filter position may affect the intensity distribution. I have seen that.

[Jack Harvey]

Agree.  We take 5 flats for each wide band (L,R,G,B) and any narrowband filters (Ha, OIII, SII) we use for an image

[vicent_peris]

Yes, flats must be taken for every filter you use. Even more, if you take the camera away from the telescope, flats will change when you put it again in the focal plane. OTOH, light distribution can be affected also if we change focus position.


Vicent.

[dhalliday]

But in a pinch I find (for mono RGB work) that I can often use ONE of the flats for all 3 filter sets...
Just saying...

 
Dave

[Niall Saunders]

Flats are not difficult to acquire, and so are well worth the effort.

I take flats for ANY change in the optical path - and I take fresh flats every time there is a change. It takes me about 10 minutes to grab 30 new flats.

Cheers,