How do I create a false flat in PixInsightLE

[blinky]

I see a few folks manage to create a false flat in PixInsight, how do I do this? I have found how to subtract the skyglow to make the background black, is this the same and I am getting confused

[Roy Batty]

Craig,

If you are using the dynamic background extraction DBE tool then you are on the right track. If I remember rightly there is quite a good tutorial as part of the PixInsight online help. Once the false flat is rendered you then use the "Math" function to subtract it from the original image. It sounds as though your there already.

cheers

RB

[Beyond_Vision]

The function is called Dynamic Background Extraction this is a link to the tutorial

http://pixinsight.com/tutorials/LE/DBE-example/en.html

Regards

Kevin

[blinky]

Yep thats what I am doing, I thought that may be the same thing under a diffrent name :oops:

So how good do you guys think it is? Does it replace the need for a lightbox to take 'real' flats?

[SteveL]

So how good do you guys think it is? Does it replace the need for a lightbox to take 'real' flats?

Close, but not a "replacement"....

[Roy Batty]

Well ....having never done "real" flats I can't personally make a comparison, but it has certainly allowed my processing to come on. I've found you end up with a good even field that allows most importantly from my perspective the background to remain in concert with the subject.

Does that make any sense ?

RB

[blinky]

Sounds good to me Roy.

Steve if you wanna make me one of your lightboxes I will do a comparison

[SteveL]

nice try

[Psychobilly]

Just a quicky on DBE and the Pixelmath op that follows?

Subtract or Divide the false flat?

The tutorial say Divide for CCD and Subtract for Scanned Film images?

Thanks,

Billy....

[trevboyd]

I've tried with all options, Billy. I think divide seems to work the best.

As an aside, I always seem to end up with a purple/blue cast to images afterwards - does anyone else have this problem? I wondered if its due to orange light pollution (the inverse of orange being purple/blue) - example attached below.

Trev

[Psychobilly]

Thanks Trev,

I have been usign Divide so far and it seems ok.

Anyone using the latest full version rather than LE.

I am thinking of purchasing it as some of the example processed images look pretty amazing...

I will get the 30 day trial first once I have some more data to try with it.

Billy...

[Beyond_Vision]

A false flat will not remove any imperfections in the image due to dust or dirt in the optical path or on the CCD camera sensor. The imperfections are often called 'dust bunnies' for what ever reason. They are usually circular slightly darker patches in the image.

Regards

Kevin