M27 HaRGB WIP 6-7-13

[Carole]

This is the first time I have imaged in 2 months.  Have been beset with problems both on the domestic front and with trying to get flats to work on the Newtonian with the Atik Mono camera.  I was getting some awful artifacts with the Atik flats and after much frustration and head scratching I finally realised that my manual filterwheel leaks light and therefore flats have to be done at night.  But having bought myself an EL panel, it was still not removing dust bunnies.  Have now discovered that I dare not move the filter wheel until after I have done flats as with a manual filterwheel the dust can move.  

I wanted to see if I could get the skirt around M27 and happily I can see it on this Ha image.  I am planning to try to add colour to this tonight to complete the RGB bit of the title, with the QHY8L, so this is a work in process:

OK, waffle over:

11 x 1200 secs 7nm Baader Ha filter with Atik383L @ -15 degrees
Skywatcher Newtonian 200 PDS with coma corrector I think this is f4.6 (ish)
Captured in artemis and processed in DSS and PS CS3
NEQ6

As this is a Crop a full frame is not that brilliant, but it's on the gallery if you want to look

[JohnP]

Well that's showing up very nicely Carole - a great start - the 7nm Baader is great at blocking out all the crud...

I tried this myself almost a year ago from bromley with 7nm + Atik 314 - through ED80 with similar exposure 10 x 10mins  - Interesting to compare the two - you captured a ton more stars - I am guessing due to faster focal ratio of scope..
http://jpastronomy.co.uk/graphics/2012%20Atik314L/m27-10x10mins.jpg

Nice one - John

[Fay]

You did well, Carole, stars and detail very good

[Carole]

Thanks Fay.  Yes John, it was your image that inspired me to give this a "go".

Carole

[Mike]

Nice image Carole with lots of detail. Looks on the soft side to me though, unless it is how it was processed.

[Carole]

Thanks Mike, I never really know what people mean by soft:

Slightly out of focus, or not sharp edges?

It could be the way I processed it as I don't like stars to be white blobs, I like a slightly "rounded" edge to them.  Also this being a CROP might show up any imperfections.

I got some OSC data on this last night, just going to do my flats and process it (hopefully these can be done during the daytime as no filterwheel to leak light!!!

Carole

[Mike]

Yeah, as in 'soft focus'.

[Carole]

Thanks Mike, yes I think you are right. 

Carole

[Mike]

If the raw frames are sharper then perhaps its the processing. Or try some unsharp mask on it after stacking.

[Carole]

I'll take a look at the Raw frames.

Carole

[Carole]

I've checked the subs and the unstretched stack and I think it's the processing.  I think it's my efforts to pull out the faint skirt that did it.

Will try a re-post-process when I add the colour.

Carole

[MarkS]

Nice image Carole - especially to get that shirt appearing.  Unfortunately it is true that if you stetch an image enough to make very faint detail (such as the skirt) appear then it will also make the stars appear big and blobby.  I can't see any way around that without somehow processing the stars differently to the nebulosity.

[Carole]

Thanks Mark, 
Hopefully some colour on the way.
Will have a think about the processing when I re-do it.

Carole

[RobertM]

That should end up being a really good image Carole but you need to get to grips with stretching the faint nebulosity without the star bloat.  You're fairly determined so it shouldn't take you too long to get there

[MarkS]

... you need to get to grips with stretching the faint nebulosity without the star bloat. 

I'd like to know how to do that as well!

[julian]

Nice start Carole

[Carole]

Thanks Robert and Julian.

Not having much success yet in getting any colour to show up in the Skirt with OSC or DSLR, probably a futile exercise from Bromley, so am now trying with RGB filters, if that fails I'll have a go with Oiii and Sii.

Carole

[MarkS]

Carole,

You won't see the skirt in RGB from Bromley (at least not unless London suffers a complete power blackout) because of light pollution.

You were able to see it in Ha because it is narrowband.  So you'll need to use the Ha as your red channel in any colour image you produce.

Mark

P.S. There's a 10% chance of an X-class flare today from that giant sunspot according to Spaceweather.  Pete Lawrence and Damian Peach have images of the sunspot.

[JohnP]

Mark - this was from Bromley in 2008 - HA + RGB - you can almost see skirt in colour... John

http://jpastronomy.co.uk/graphics/2008/m27-jul08.html

[Carole]

I had a feeling that would be the case.  I have tried adding the Ha into the red channel but it doesn't do much.

Well since I am halfway through doing filters, I might as well finish the job as I've only done one previous LRGB image, so need the practice, though I do find filters a real chore with separate flats etc.

This is a combi I have done with RGB data from the DSLR 900sec subs @ 400iso and I didn't take any darks as they never seem to make any difference, and considering this was the hottest day of the year, lowering the ISO seems to make a lot of difference.

Ha added as luminosity layer and also into Red channel.
The skirt is a bit more noisy than the mono version.


Carole

[Fay]

Tell me about it!

[Carole]

Glad you agree Fay. 
I am seriously considering doing colour with the DSLR and using a lower ISO (as above) and ditching the RGB filters and just having a set of L,Ha,Oiii,Sii.

Carole