Quote:
Originally Posted by Shiraz
yes, no and no  you need only one 33,000ADU flat for each 3,300ADU light to get 10x . The only question is if you are including the bias in your 3300 for the lights - it will reduce the numbers a bit if you have not subtracted the bias. Regardless, a good rule of thumb for your system would be to take one 30,000 flat for every light - it is not critical that you get it exact but err on the "longer" side.
30,000ADU flats are good to get above read noise and below saturation - but you could use other flats if you compensate. For example if you wanted to use flats of 15,000 ADU, you would need twice as many of them as you would need of 30,000 ADU flats. the total ADU in all of your flats just has to add up to 10x the total sky ADU in your lights.
making a few guesses on your imaging system characteristics, you would need maybe 30 flats of 30,000 ADU for each 10 hours of imaging. |
I will give it a go and get back to you with the results. It is easy to get all the flats I need for each project. Its worth a try to get a defined result.