Dear all
I purchased a 3 nm Antlia filter but suspect I have a bad copy; would appreciate any advice
I also purchased a 3 nm Optolong filter - and it works perfectly with the same telescope and camera ( Sharpstar Z4 and the ZWO ASI 533MM)
I have attached both flats- same telescope same camera ASIAIR auto flats - should be obvious I hope which is the one I am whingeing about- the first one is the Antlia Ha filter
Auto flats using ASIAIR but I had similar results when targeting 32000 ADU using NINA
Also have no problem using the same telescope and the Antlia triband filter- flat looks normal and the result after stacking is just fine ( obviously not the same camera but a 183 MM)
I wouldn’t worry about how the flat looks if it all calibrates out- but the stacked stretched image shows haze all around the centre of the image which cannot get rid of with background calibration or gradient exterminator or anything I try
I obviously reached out to Antlia and they responded saying this ( the Ha flat) is normal
Seems to me that’s not right but would appreciate if one of you knowledgeable people can please comment
Thanks in advance
PS Hate to say this but the OIII Optolong filter delivers tighter stars - don’t know if this pure selection effect - ie I had better seeing on the nights when I used the Optolong
All of which makes me wish I had bought the Optolong 3nm instead
