I think something isn't right about this flat but I don't know what
Most likely condensation on the sensor.
I can immediately confirm that your suspicion is correct. If that’s a flat, it is not right.
You haven’t provided enough information for anyone to help you. Here’s what you should provide:
1) Information about the data being shown: Is it being displayed as stretched or linear data?
2) Information about your equipment: scope, camera, filter, focus, light source?
3) Detailed information about how you are taking the flat data. Spacings, exposures, bias/darks, etc.
4) Show a calibrated image so that we can see what the flat calibration is doing.
With that information, a lot of folks here can provide advice and assistance.
John
You haven’t provided enough information for anyone to help you. Here’s what you should provide:
1) Information about the data being shown: Is it being displayed as stretched or linear data?
2) Information about your equipment: scope, camera, filter, focus, light source?
3) Detailed information about how you are taking the flat data. Spacings, exposures, bias/darks, etc.
4) Show a calibrated image so that we can see what the flat calibration is doing.
With that information, a lot of folks here can provide advice and assistance.
John
Thanks John and Andrea!
I think it's condensation on the camera sensor and/or the filter. I left the scope out all night, covered under a 365 Telegizmos cover. There was some dew in the morning when I shot the flats. I will reshoot the flats this afternoon and see if that resolves it.
1. It's linear data
2. Scope: Skywatcher Esprit 100ED, Camera: ZWO ASI2600MC, Filter: Optolong 2" L-Enhance.
3. 30 flats, same gain and temperature as lights. Same image train and focus. No calibration yet, the flat I posted is right out of the camera.
4. I will re-shoot and calibrate.
I think it's condensation on the camera sensor and/or the filter. I left the scope out all night, covered under a 365 Telegizmos cover. There was some dew in the morning when I shot the flats. I will reshoot the flats this afternoon and see if that resolves it.
1. It's linear data
2. Scope: Skywatcher Esprit 100ED, Camera: ZWO ASI2600MC, Filter: Optolong 2" L-Enhance.
3. 30 flats, same gain and temperature as lights. Same image train and focus. No calibration yet, the flat I posted is right out of the camera.
4. I will re-shoot and calibrate.
It was condensation on either the sensor or the filter. I re-shot the flats and they seem OK now:
