Rate my flats..

[paul mc c]

Hello all, never really knew if my flats are good or bad, any ideas please.

Tia Paul.

[ollypenrice]

If they work, they're good. If they don't, they're bad. When you take an astrophoto and apply them, do you see the defects seen in the first two flats. (ie slight vignetting, severe dark dust bunnies on the left, smaller ones near the centre and dark spots most notably near the centre?)  The small dark spots may not disappear because the source must be close to the sensor and little signal may be getting past them.

What are we looking at in the third image? I don't know this software.

Olly

[paul mc c]

For some reason I never had a problem but I have just installed a reducer and I am now getting some of the dark darker streaks as seen in the left bottom corner, the third one is just the non stretch image.

Images are just raw shots in Asiair.

[Adam J]

I think there would be benefit in blowing the dust off your camera / filters. But that is not because the flats are not working looks like they are, Its more because you dont want the situation when dust moves during a project and then your flats will not work. 

 

Adam 

[ollypenrice]

Just now, paul mc c said:

For some reason I never had a problem but I have just installed a reducer and I am now getting some of the dark darker streaks as seen in the left bottom corner, the third one is just the non stretch image.

Images are just raw shots in Asiair.

As long as the same defects appear in the lights, these flats will fix them. There is really no way of knowing till you try them.

If your flats were perfect, ie totally flat, you wouldn't need them.

However, Adam's point is correct.

Olly

[paul mc c]

Maybe a clean is in order🥴🥴, will do that tomorrow.

[Elp]

When you take flats with the air you can simply use autorun mode, set a set of flats and leave the exposure to auto. When you start the autorun sequence it.automatically exposes multiple times when your cameras looking at a flat panel (or whatever method you use) then it'll settle on one exposure and run off the set. It's a pretty foolproof method of taking flats and I assume that's how you've done it. What you do have to watch out for is a too bright light panel (if you use one), one that's not sitting square or off centre to your front objective leaving vignette which is not in your lights, or making sure for certain your image train has not altered including focus. My last session trialling my Starfield I think when I pointed the scope up so I could rest the flat panel on top of the dew shield the imaging cameras usb cable touched the tripod leg and hence rotated the flattener (so whole imaging train), when I tried calibration the dust motes were rotationally offset so it didn't calibrate the lights properly.

You live and you learn to do better.

[h107]

On 02/03/2024 at 18:26, ollypenrice said:

If they work, they're good. If they don't, they're bad. When you take an astrophoto and apply them, do you see the defects seen in the first two flats. (ie slight vignetting, severe dark dust bunnies on the left, smaller ones near the centre and dark spots most notably near the centre?)  The small dark spots may not disappear because the source must be close to the sensor and little signal may be getting past them.

What are we looking at in the third image? I don't know this software.

Olly

I very much used to do this in thinking if the flats were "right or not" but definitely went on the thing if they work then they must be doing alright.