Atik 314L+ Flat and Bias - Are These Normal?

[JacobvonChorus]

Hello,

Attached are some flats and biases from my Atik 314L+. The bias is a stack of 60. I have a linear one and stretched one. I also included a stack of 60 flats. The exposure was 1 second binned 1x1. I calibrated the frames with the master bias. I have a linear one and a stretched one. Is this normal?

Jacob von Chorus

MasterBias.tif

MasterBiasStretched.tif

MasterFlat.tif

MasterFlatStretched.tif

[johnrt]

They don't look far off to me. The flat maybe over exposed. Have you tried to calibrate a set of images with them?

[JacobvonChorus]

The flat was not overexposed, the highest pixel value wasn't saturated, the mean was around 35000ADU. I did try to calibrate a set of images but they still looked kind of weird.

Jacob

[swag72]

The flat was not overexposed, the highest pixel value wasn't saturated, the mean was around 35000ADU. I did try to calibrate a set of images but they still looked kind of weird.

With flats I aim for an ADU of about 23k - I'd certainly not have them as high as 35k

[johnrt]

Here's one of my Lum flats with my ED80 for you to compare - I would expose something around 0.05 seconds to get this result.

edit; for some reason I'm not allowed to upload .fits files????

[RobH]

I would agree with Sara that the flat looks a bit bright. I too would go for an ADU of around 20k, although your flat may well work at the current value.

Flats are different depending on the camera. With my H18, I found that a flat with an ADU of about 8k would work best, but the real key is where the peak is in the histogram. It works best if it's one third to half the way along the scale from the black point I've found.

The lines on the bias are quite normal. I just checked a master bias from a while back from my 16HR (same chip) and it has the same.

The test is, do they work ok?

If they calibrate the image correctly, then they're fine.

Cheers

Rob

[Gina]

I use an ADU of around 25,000. That stretched flat appears to show dust on a filter as it is out of focus. Or I suppose it could be on the camera window. I'll post a flat or two of mine tomorrow. 314L+ mono plus EFW2 and Astrodon Ha 5nm & OIII 3nm and Baader LRGB.

[JacobvonChorus]

It would be dust on the sensor window. The only other optic would be the main objective lens of my ED80.

Jacob