533MC Pro Flats

mattrsmith

Please can someone help me, I'm starting to think my 533 is faulty somehow.

My flats have recently developed this really horrible red pattern - Image attached - Please note this is the low res jpg that the ASIAIR produces, not the FITS file. I think I have tried pretty much everything. This is subsequently being added to my final stacked image. If I stack without flats the pattern isn't there. (but dust bunnies are)
Things I've tried -
Using and iPad, natural light and LED panel as my light source with white t-shirt or paper to diffuse light.
DSS and Pixinsight to process
darks, flat darks, bias calibration frames
I use the ASIAIR pro to get my flats, I've used auto exposure and manually adjusted to get the correct histogram.

my set up:
Williams Optics GT71 with Flat6A III 0.8 reducer
ZWO EFW
ZWO ASI533MC PRO
ASI AIR PRO
Please help me!

Tech@ZWO

mattrsmith My flats have recently developed this really horrible red pattern

If it is not like this in the past, you can submit a ticket in https://support.astronomy-imaging-camera.com/#Product and add some Fits(via Google Drive if file is too big).

Coriorda

Did you ever get a resolution to this ? My flats look very similar to yours ! Thanks

charles18

Mine looks like that too in particular when doing narrowband, and I get some mottling as well with my 294mm. Though this is very low level has I can't see it without the auto-stretch. I think this is 'mostly normal' (in quote because it's still non-ideal) for these camera and is typically due to some protective layer on top of the sensor.

If your flats overcompensating, it could be either that your flats are not applied properly (check the bias) or that the t-shirt is not doing a good job at diffusing the field. I use a thin piece of white acrylic with a 20$ LED tracing tabling which works ok.