Flats and Dark Flats in IP

[Quark (Trevor)]

High all,

I have been following the various thread on Darks, Flats and Dark flats with great interest.

I am resolved to take darks for my flats and this may seem a silly question, but how do I treat them using IP.

How do I apply my Dark Flats to my Flats in IP?

Do I load, just my flats and dark flats into IP to create a Master Flat, not sure if IP will do that and then load my Lights, Darks and Master Flat to calibrate my Lights.

Any help with this matter would be greatly appreciated.

Regards
Trevor

[Geoff45 (Geoff)]

Treat the flat as the light and process by dark frame subtraction to create a master flat. Then use that in processing your real lights.

[RB (Andrew)]

Originally Posted by ghsmith45

Treat the flat as the light and process by dark frame subtraction to create a master flat. Then use that in processing your real lights.

??

[Hagar (Doug)]

If you must use darks for your flats (Not required) treat them as bias files. Really at the calibration step in IP the requirement is for Bias files to remove the read noise from the CCD snd it's electronics. The read noise will be captured on these darks but be aware that any imperfections or hot pixels etc captured during this process will be largely very random and may well impart some iof these imperfections into your lights during the process.
Probably a more important part of the process is the stacking method used for your lights in the final part of the process. This can remove or reduce a lot of minor abnormalities depending on the quality of your lights.

[Terry B]

Originally Posted by Quark

High all,

I have been following the various thread on Darks, Flats and Dark flats with great interest.

I am resolved to take darks for my flats and this may seem a silly question, but how do I treat them using IP.

How do I apply my Dark Flats to my Flats in IP?

Do I load, just my flats and dark flats into IP to create a Master Flat, not sure if IP will do that and then load my Lights, Darks and Master Flat to calibrate my Lights.

Any help with this matter would be greatly appreciated.

Regards
Trevor

Median stack the dark flats and save it as masterflatdark.
Subtract the masterflatdark from each flat then median stack these frames.
To be more accurate each flat should be normalised (to an arbitary value that is near the average level of your flats) before the median stacking.

[Quark (Trevor)]

Thanks for the replys,

I really do appreciate the advice.

Sure seems to be a contraversial subject.

Regards
Trevor

[Geoff45 (Geoff)]

Originally Posted by RB

??

What I meant was that he could do two processing runs in IP. First, click on the tab "select light frames" and select the flats, then click on the tab "select darks" and select the flat darks. This will create a dark subtracted master flat. Open up the automatic image processing again and select image lights, image darks and the master flat under the appropriate tabs.

This rigmarole seems to be necessary because IP does not have a "flat darks" tab.

[Quark (Trevor)]

Originally Posted by ghsmith45

What I meant was that he could do two processing runs in IP. First, click on the tab "select light frames" and select the flats, then click on the tab "select darks" and select the flat darks. This will create a dark subtracted master flat. Open up the automatic image processing again and select image lights, image darks and the master flat under the appropriate tabs.

This rigmarole seems to be necessary because IP does not have a "flat darks" tab.

Thanks for the clarification there Geoff,

You have it in a nutshell, the reason I asked the question is because, as you say, IP has no tab for flat darks.

Thanks for this explanation.
Regards
Trevor