M42 and M43 - with some weird stars...

[lazjen]

...besides the usual tilt affected ones.

On the right of the image, you'll see some super bright stars that have a weird effect around them. I suspect it's due to some internal reflections as I did a setup change on Xmas eve removing the 0.6 FR to examine the tilt issue further. The combination/placement of the extra spacers/extensions I required to get to focus I think has given this effect.

I'm not going to chase it down though as I'm going to go back to the 0.6 FR (which did not show this problem) and either fix the tilt issues or just crop as required.

As it's only a short integration time, it's a bit grainy and would obviously need a lot more data to improve.

221895

Larger version: https://flic.kr/p/22Ny9RY

Details:

Sharpstar 107PH on G11

ZWO ASI 1600MM-C @ -15C, 75 Gain, 13 Offset.

I processed in PixInsight using HDR, each RGB channel was a mix of 180 and 10 sec. R had 12 exposures for each duration, while B and G had 11 each.

[Atmos]

Chris, what you’re seeing there is a diffraction pattern caused by the micro lens’ on the ASI1600 and it’s lack of an anti-reflective coating.

https://www.astrobin.com/full/321338/0/

Mine shows the same artefact. Yours looks like it has some other issues as well (tilt) but it is quintessentially the same thing.

The only fix for this issue is to get a new camera that has AR coatings. We can blame Panasonic for making it this way, not something QHY or ZWO can fix.

[lazjen]

Interesting. Is it the same reason for the other stars that have the larger circular halos as well? And you just get different shapes because of how it reflects?

I guess the reducer changed things enough to not make the same shape. Weird. It's a lot different for my Ha image which had the reducer: https://flic.kr/p/22JRfZE

[strongmanmike]

Really like the clours in this Chris and the core processing is pretty ok too :thumbsup:

Mike

[lazjen]

Thanks Mike. I did my best to resist pushing things too far. :)

[Ross G]

A very nice photo Chris.

I like the detail and colour.

The weird reflections are a worry.....I have a similar camera yet to be fully tested!

Ross.

[lazjen]

It's being discussed over at Cloudy Nights as well: https://www.cloudynights.com/topic/565014-new-to-narrowband-imaging-question-about-strange-pattern-in-bright-star-halo/

And as I mentioned above, a change in my setup gave less of the problem appearing. I think if you get it, consider experimenting with your setup - maybe a different combination will help. Also, you may have to vary your exposure times, etc.