Iris Nebula with ASI533

[PeterCPC]

Lovely and clear last night. Got 25 300s subs on the Iris using my Esprit 100 and ASI533 Pro.

Processed in APP and a couple of small tweeks in Affinity Photo. First real target using this combination of equipment and quite pleased with the result.

Thanks for looking.

Peter

[MarkAR]

Nice result though I do see some hot pixels. Did you use calibration frames?

[PeterCPC]

Yes, calibrations frames were applied.

Peter

[Adreneline]

Very nice result Peter.

I agree with @MarkAR about the hot pixels but what is odd is that the stars are nicely round but the hp's are elongated all in the same direction.

What might be causing that to happen?

Still a really nice image though.

Adrian

[MarkAR]

2 minutes ago, Adreneline said:

hp's are elongated all in the same direction.

Probably dither.

[Adam J]

7 minutes ago, Adreneline said:

Very nice result Peter.

I agree with @MarkAR about the hot pixels but what is odd is that the stars are nicely round but the hp's are elongated all in the same direction.

What might be causing that to happen?

Still a really nice image though.

Adrian

I do see some trailing on the smaller stars if I am honest.

[Adam J]

5 minutes ago, MarkAR said:

Probably dither.

no dither would be random. Unless its set to dither RA only....but that would be an odd choice.

[PeterCPC]

I am scratching my head over this. I need to look into it a bit more I think. I did not dither this time. There must be an issue with the calibration subs I think. My guiding was extremely good on this.

Peter

Edited September 21, 2020 by PeterCPC

[PeterCPC]

Weirder and weirder - I have just looked at the darks and BPM and the hot pixels are all round (square) so why do they look elongated on the stacked image? Any ideas?

Peter

[PeterCPC]

Just did an integration using DSS and these hot pixels are not showing. So this is definitely an issue with APP. I have asked on the APP forum but does anyone else have any ideas? APP users.

Peter

[Adreneline]

15 minutes ago, PeterCPC said:

any ideas? APP users.

Hi Peter.

All very strange. I always use APP to calibrate, register and integrate and I've not noticed any issues at all.

I've just been scouring my latest image of the Heart & Soul in SHO for hot pixels and can't find any - my master dark seems to have worked very well.

I've also just had a detailed look at the master dark in PixInsight and can see no evidence of anything elongated.

Not very helpful I know but I will certainly be interested to know if APP is the culprit; I'm using version 1.082.

Adrian

[PeterCPC]

Well I seem to have made progress together with another APP user (thanks xs4allan). For those who may find this useful:

For more than 20 lights  set the integration to average, then adaptive rejection with a Kappa low of 6.0 and high of 2.2, then enable a new BPM to be created.

Here is the new image. No hot pixels.

Peter