What is the "definative" method of making flats in Maxim DL???

[SlimPaling]

I am getting a bit confused about the best way to make flat frames in Maxim DL .... there seems to be more than one way of doing it from what I have found on the 'net.

Can somebody please sort me out at all?

OK .... I have a f6 Refractor , Moravian G2 Mono camera and a flat field foil. I am using Maxim DL to make (hopefully) accurate flats.

What is the best way to make a set of flats of the correct exposure in Maxim DL???

Mike

[Xilman]

What I do in MaximDL is 90% of what I would do with any software package, such as EKOS. I take lots and lots and lots of images, storing them in a single directory on disk.

Zeroth: clean the optical surfaces, including the camera window. No point in making life harder for yourself and the image calibration process when you are taking science images.

First configure Maxim DL's camera control to auto-save each image taken into a newly created directory and set the camera's cooling to the temperature typically used when observing.

Second take a series of bias and darks, the latter at (usually) 60 seconds each, at each of the binning levels typically used when observing. Somewhere between 20 and 30 of each is generally enough to smooth out most of the Poisson noise. These darks and flats will typically last for months before needing to be retaken.

Third I put a fluorescent panel directly in front of the telescope aperture and try hard not to let any extraneous light leak through.

Then, or each filter likely to be used (including no filter) and at each binning level, take a guessed exposure length and find out roughly how bright is a typical pixel, using the standard MaximDL tool. Then calculate how long, roughly, each would have to be to give 40-60% maximum values. For a 16-bit camera like mine, this would be 25,000 to 40,000 say. Take between 9 and 25 images at each setting (thereby reducing Poisson noise by a factor of 3 to 5).

Finally, after all this you have a directory full of calibration subs. I then convert them to master bias, dark and flat images. The Set Calibration tool has a nice wizard to make the process relatively straightforward. Once the master files are built, I delete the individual subs which form them, purely to save disk space.

All this is well documented on pages 137-144 of the Maxim DL 6 manual.

Of course, once the calibration files are in place the camera control is configured always to use them automatically.

HTH,

Paul

[SlimPaling]

26 minutes ago, Xilman said:

Then, or each filter likely to be used (including no filter) and at each binning level, take a guessed exposure length and find out roughly how bright is a typical pixel, using the standard MaximDL tool. Then calculate how long, roughly, each would have to be to give 40-60% maximum values. For a 16-bit camera like mine, this would be 25,000 to 40,000 say

Hi Paul ... thanks for your reply ...

As usual I am stumped by certain things that you mention in the above quote 😞

Q1: what "standard tool in Maxim" do you mean????

Q2: when you sat "25,000 to 40,000" .... which window in Maxim are you looking at?

Mike

(PS: there might be more questions to come !)

[SlimPaling]

35 minutes ago, Xilman said:

Then, or each filter likely to be used (including no filter) and at each binning level, take a guessed exposure length and find out roughly how bright is a typical pixel, using the standard MaximDL tool. Then calculate how long, roughly, each would have to be to give 40-60% maximum values. For a 16-bit camera like mine, this would be 25,000 to 40,000 say. Take between 9 and 25 images at each setting (thereby reducing Poisson noise by a factor of 3 to 5).

Hi again ... 3 minutes later!     Sorry!

I am attaching a screen shot of what I got last night when inspecting one of my Lum flats showing two graphs in Maxim.

What should I be looking for in these graphs? Are there other graphs in Maxim that would be helpful?

Mike