Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: JonH on Sep 17, 2012, 21:59:16

Title: M45 taken at Rother Valley DSC
Post by: JonH on Sep 17, 2012, 21:59:16
This is the first image I have had a proper go at processing taken at Rather Valley last weekend.
My processing skills still need a LOT of work!
15 x 5min subs and 8 darks stacked and a little fiddling in DSS then finished off on PS.
Equinox 80ED
NEQ6
Modded Canon 450D
CLS Filter
QHY5 on ST80


(http://farm9.staticflickr.com/8461/7997369041_59fedb8a11_c.jpg)
Title: Re: M45 taken at Rother Valley DSC
Post by: MarkS on Sep 17, 2012, 22:34:02
Hi JonH,

It's great to see an image from someone new!

You've certainly begun to pull some nebulosity from around the main stars and it's quite possible there is still more that can be done with your data.  I love the star colours - you've preserved them well.  It also looks like your guiding was pretty good.

You won't like me for saying this, but in a dark location like Rother Valley you really didn't need to use the CLS filter for a broadband target like the Pleiades.  There's little light pollution and the the effect of the filter it is to cut the incident light by approximately half - which is bad news.

Anyway, well done - you've made a great start!

Mark



Title: Re: M45 taken at Rother Valley DSC
Post by: JonH on Sep 17, 2012, 22:48:41
To be honest I still have a LOT to learn, all the gear and no idea springs to mind!
Mostly I'm just fiddling, change that, try this and seeing what happens.
I would have liked to get more time on this as it was still quite low on the horizon when I started but then the clouds rolled in.
Next clear night though and I will defiantly be adding to it (if I can figure out star masks)
Title: Re: M45 taken at Rother Valley DSC
Post by: Carole on Sep 17, 2012, 22:57:55
Well done Jon, you are coming on in leaps and bounds.  You certainly have the energy, potential skills and enthusiasm to make great headway in imaging.

Carole
Title: Re: M45 taken at Rother Valley DSC
Post by: Mac on Sep 18, 2012, 00:17:46
nice image.

Mac
Title: Re: M45 taken at Rother Valley DSC
Post by: MarkS on Sep 18, 2012, 07:51:22

A suggestion that might improve the image is to make the background less black.  It is always tempting to make the background jet black because we wrongly think that's what the night sky ought to be like.  But some faint nebulosity will also be lost.

Mark
Title: Re: M45 taken at Rother Valley DSC
Post by: The Thing on Sep 18, 2012, 08:13:51
Excellent result Jon.

More subs and a gentler hand on the processing would improve matters. The APT help explains framing masks quite well.
Title: Re: M45 taken at Rother Valley DSC
Post by: JonH on Sep 18, 2012, 08:25:02
I will bear that in mind when I come to re-process it Mark, I also noticed the darker you make it the more noise becomes apparent. But that might just be my eyes....
I was hoping it would be clear this weekend so can get a good idea what the skies are like where I'm moving too and add to it before the moon gets really bright, but so far the forecast says NO!
Will have to have a read up on that Duncan.

Jon
Title: Re: M45 taken at Rother Valley DSC
Post by: mickw on Sep 18, 2012, 08:28:23
Nice one Jon, I agree with the other comments - be gentle with it
Title: Re: M45 taken at Rother Valley DSC
Post by: Carole on Sep 18, 2012, 11:46:47
QuoteThe APT help explains framing masks quite
Has any-one found this of much use?
I find that stars are so faint with the DSLR that I can't see the stars in the framing mask. So for me it only works where there are really bright stars in the FOV.  Shame as it would have been a good tool and one of the reasons I wanted to use APT.

Maybe post processing could be something to consider for a future imaging session.

Carole
Title: Re: M45 taken at Rother Valley DSC
Post by: JonH on Sep 18, 2012, 11:49:25
Quote
Maybe post processing could be something to consider for a future imaging session.

YES! I like this idea!
Title: Re: M45 taken at Rother Valley DSC
Post by: Mike on Sep 18, 2012, 13:09:40
Yeah I find stars very faint in APT with LiveView. Even with increasing the brightness and gamma it will only show the brightest of stars. Unless you are using a big light bucket scope I doubt there is anything that can be done about that.

Title: Re: M45 taken at Rother Valley DSC
Post by: The Thing on Sep 18, 2012, 17:28:14
Quote from: Carole on Sep 18, 2012, 11:46:47
QuoteThe APT help explains framing masks quite
Has any-one found this of much use?
I find that stars are so faint with the DSLR that I can't see the stars in the framing mask. So for me it only works where there are really bright stars in the FOV.  Shame as it would have been a good tool and one of the reasons I wanted to use APT.

Maybe post processing could be something to consider for a future imaging session.

Carole

I use framing masks all the time. Forget live view. Set up a plan taking 1sec exposures at ISO 1600, M size. Use shift click to run it continuously while framing. Easy.
Title: Re: M45 taken at Rother Valley DSC
Post by: Mike on Sep 18, 2012, 17:30:08
I'll give that a go some time.
Title: Re: M45 taken at Rother Valley DSC
Post by: Carole on Sep 18, 2012, 17:56:40
Thanks Duncan, info copied and pasted to my useful info folder.

Carole
Title: Re: M45 taken at Rother Valley DSC
Post by: Jim on Sep 18, 2012, 19:28:54
Well done Jon.
Title: Re: M45 taken at Rother Valley DSC
Post by: JonH on Oct 10, 2012, 23:15:38
As my processing has move on a bit I decided to have another go at this, all the same as before except stacked in Iris this time.
I'm not entirely sure if I have done something wrong or not, I have managed to pull out more detail and star colour but also found a great big halo around one of the central stars. Quite what the deal is with that I don't know, but it wouldn't go away!

Anyway, here it is.....

(http://farm9.staticflickr.com/8195/8075219866_5e22e8d036_c.jpg)

Larger version:
http://farm9.staticflickr.com/8195/8075219866_b4b0ab97c5_k.jpg (http://farm9.staticflickr.com/8195/8075219866_b4b0ab97c5_k.jpg)
Title: Re: M45 taken at Rother Valley DSC
Post by: The Thing on Oct 11, 2012, 08:35:28
Looks good. The large version has a lot more nebulosity. Don't know what the coloured haloes are but they are on the brightest stars and off centre so probably internal reflections of some sort. Also the magenta colour isn't Italy usually a feature M45...
Title: Re: M45 taken at Rother Valley DSC
Post by: MarkS on Oct 11, 2012, 08:50:07

The haloes are around all the brighter stars.

Is your CLS filter new (in which case it shouldn't produce haloes) or is it secondhand (in which case it could be an older type)?

Astronomik had a policy of replacing the older halo producing filters - it was necessary to send them a sample image plus a complete description of the imaging chain - in particular where exactly the filter sits in that chain.  Dunno if that replacement policy had an end date.

Mark
Title: Re: M45 taken at Rother Valley DSC
Post by: JonH on Oct 11, 2012, 10:08:18
I'm still having trouble getting the colours right, the difference between my tv and laptop seems to be one extreme to the other, the reds really couldn't be much further apart!

My CLS filter was indeed second hand so have no idea at all about how old it is so will have to look into that for sure!
Trying my best not to sound too dumb here, but image chain???
Title: Re: M45 taken at Rother Valley DSC
Post by: MarkS on Oct 11, 2012, 10:56:28
Quote from: JonH
Trying my best not to sound too dumb here, but image chain???
I meant optical train (all the optical components) not imaging chain.
Title: Re: M45 taken at Rother Valley DSC
Post by: JonH on Oct 11, 2012, 12:09:58
That makes sence. I had no idea the older CLS filters could cause that problem, google didn't give me anything much about it so will be dropping them an email soon as i get a chance.