M45 The Seven Sisters

[The Thing]

Is it a cluster or is it a nebula? My previous version of this ever popular target is in the Diffuse Nebula section on my website, thought I'd give the target the benefit of the doubt.

20x250s Subs, Gain 120 (Unity), Offset 8, Temp -15C.

Image date, time and location:  2019-08-31 02:00 Manche, France
Telescope aperture and focal ratio: TS1506UNC f4, TS Komakorr
Camera and filters used: ZWO ASI294MC Pro, Baader Neodymnium 1.25" filter
Processing applied: Pixinsight (ABE,PCC,SCNR,HDRMT,HT,CSat,DT for PI users), Darktable

[Carole]

Looking good Duncan

[MarkH]

My opinion would be a star nursery in a nebula with new stars being born out of an expended supanova.

[MarkH]

Sorry great image Duncan.

[The Thing]

Thanks both. It's a bit blingy but everything I tried to reduce the main stars produced rings and/or blobs in the cores. I am surprised they go so big as my ASI294 has an enormous well depth which usually contains the photons very well. They are not saturated on the subs. Any ideas of a process to use? Or maybe I need to tweak the sigma settings in PI when stacking.

[Carole]

I think you are stuck with big spikes on these stars.

Carole

[Hugh]

I think it is a very atmospheric picture! Even better when you click into it and get is as a separate picture.

M45 is recognised as an open star cluster.

Thanks

Hugh

[NoelC]

Its spectacular Duncan
I think the spikes make it.
As you say - everyone has done it, but this takes it to another level.

Noel

[The Thing]

Thanks everybody.

[ApophisAstros]

Such a lot going on ,good one,
Roger

[RobertM]

Nice capture Duncan.  As you say there are artefacts around a lot of the stars and my impression is of too much noise reduction on the dark dusty bits.  I can get similar 'dark lanes' appearing when I've pushed processing a bit too far.  That said, it is one of the most difficult targets so I'm not surprised it's caused you some grief.

I would be extremely surprised if those stars didn't have saturated cores with 250s subs - I would even be surprised if you said they were 30s.  It might be worth double checking your subs and stacking to see what's going on.

Current thinking is that it's a cluster of hot blue stars passing through and illuminating a molecular cloud.  In a few millennia the cluster would have passed by and the illumination faded.

Robert

[The Thing]

Thanks Robert, the lack of subs was down to me learning Voyager between clouds. I can't get it to do a meridian flip. This was my second target of the night as it was on the 'right' side of the meridian. I fell the solution to the big stars and spikes is lots of shorter exposures. I did 120 x 120s subs of IC59 (next to Gamma Cassiopeia) last night so I'll see today if there is an improvement.

[MarkS]

That's looking good Duncan but I think you've introduced some artifacts during processing: rings around stars and a weird overall background effect I can best describe as "blobbiness".

Mark