Can Newton rings on a '224 with Ha imaging be solved?

sanderp

Hi,

tried my ASI224 with my PST for the first time yesterday. First note is that a UV block filter is absolutely required even though the PST is an Ha scope. I guess it gets warm enough that the IR is completely flooding the sensor. No Ha detail is left. I thought the Ha filter in my PST was broken and had a huge bandpass all of a sudden.

Anyway, the IR block filter solved that and solar detail returned. So then I found out that the ASI224 has terrible Newton rings. My QHY5L-IIc gives much nicer images, no Newton rings visible.

Is there any hope of resolving this with some slight tilting? I've seen suggestions of using flats but I haven't had a chance yet to try that. I have to admit I'm skeptical that the interference pattern stays in the same place enough to allow flats to remove them but I may well be wrong about that. Certainly worth a try.

I've seen posts of someone who bought a T2 tilt adapter but ended up adding his own bolt to increase the tilt. Not really fond of buying a $90 accessory only to drill new holes in it righ away.

The ASI174 doesn't have these Newton rings? Why is the 224 so susceptible?

Thanks,

Sander

riklaunim

You can check what happens when you manually tilt/rotate the camera a bit. IMX224 isn't Micron so Newton rings should be removable. Maybe the filter interferes too.

Sam@ZWO

224 should be better than 120 sensors

you can open the camera cover to check if the sensor board installed flat or not

I think maybe a assembly problem

sanderp

Hi Sam,

a casual inspection of the camera shows the assembly is fine. Each of the 4 corners of the sensor are equally close to the black gasket. I will gladly open the camera further if you think I should and take a closer look.

That said, if the sensor was tilted we'd actually expect less Newton ringing effect, right? The typical fix for this artifact is to tilt the entire camera so a tilted sensor should not be a problem.

As I reported in the yahoo group I was not able to test for newton rings without the powermate because I could not reach focus. I did not see Newton rings in the out of focus image. I did see them in the 2.5 powermate out of focus flats I took. This suggests that native PST F/ratio is not a problem.

Sander

Sam@ZWO

thanks for the report

you can wait for our low profile adapter to test it again with direct focus