Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: Whitters on Apr 09, 2011, 07:18:57

Title: Back to M51 after too many years...
Post by: Whitters on Apr 09, 2011, 07:18:57
Realised I had not images M51 for years. Spent most of the evening farting about getting the scope polar aligned, after an abortive go with pempro.
Had an hour spare so thought I would have a go at M51, an old favourite I know, but it has been quite a time since my last image.
(http://www.astrocats.co.uk/astronomy/images/MX916/2011_04_08/M51_IRB_7x600_DDP.jpg)
Usual set up WO110 f6.5 MX916 IRBlock Astronomiks filter, seven 600second exposures. DDP in Maxim then curves and levels.

For comparison this was my last M51 image taken on 14th April 2001
(http://www.astrocats.co.uk/astronomy/images/MX916/April14_2001/M51.jpg)
Ten 20 second exposures C8 MX916
Title: Re: Back to M51 after too many years...
Post by: Carole on Apr 09, 2011, 08:32:57
Very nice Paul.  Big step up from your one in 2001

Carole
Title: Re: Back to M51 after too many years...
Post by: MarkS on Apr 09, 2011, 08:34:31
Paul - what an unbelievable difference between those images!  You must be really pleased.

You're going to have to re-visit all those old friends doing a proper job of acquiring multiple subs and then processing.

Mark
Title: Re: Back to M51 after too many years...
Post by: Rocket Pooch on Apr 09, 2011, 08:39:54
Hi Paul,

Fantastic to see the difference between the two images.

Chris
Title: Re: Back to M51 after too many years...
Post by: Fay on Apr 09, 2011, 08:53:57
Well done Paul, I think we always revisit what we have done before
Title: Re: Back to M51 after too many years...
Post by: Mike on Apr 09, 2011, 10:30:43
Really nice Paul. Massive improvement.
Title: Re: Back to M51 after too many years...
Post by: The Thing on Apr 09, 2011, 10:47:10
That's lovely.

I've just realised what your observatory reminds me of. One of those sewing boxes that opens up sideways in tiers!

(http://www.comparestoreprices.co.uk/images/unbranded/w/unbranded-wooden-sewing-box.jpg)
Title: Re: Back to M51 after too many years...
Post by: Mac on Apr 09, 2011, 11:34:32
Nice capture.
Mac
Title: Re: Back to M51 after too many years...
Post by: RobertM on Apr 09, 2011, 11:46:44
Just goes to show how things move on doesn't it.

Great image Paul, the only slight thing I would mention is that there are some sharpening artifacts around the foreground stars on M51.  Other than that it's really excellent.

Robert
Title: Re: Back to M51 after too many years...
Post by: Whitters on Apr 09, 2011, 18:45:51
Thanks folks.
Duncan it was that which gave my brother in law the idea.
Title: Re: Back to M51 after too many years...
Post by: JohnP on Apr 09, 2011, 19:37:13
Hi Paul, Looks very good & glad to see you making use of your dark skies & new obsy. My only comment would be that you have clipped blacks. The background is way too black.

Very nice though - John
Title: Re: Back to M51 after too many years...
Post by: PhilB on Apr 10, 2011, 07:17:29
Interesting comparison. Very nice image
Title: Re: Back to M51 after too many years...
Post by: Whitters on Apr 11, 2011, 23:32:36
Another 50 minutes exposure, and another rough process, not as harsh, I'll take a look at the background, but i need more integratioins to be able to have a smooth background. and will need to be cropped.
thanks for your comments and suggestions.

(http://www.astrocats.co.uk/astronomy/images/MX916/2011_04_10/M51_April10a.jpg)
Title: Re: Back to M51 after too many years...
Post by: Whitters on Apr 12, 2011, 05:37:55
John one other problem I have is that I process my images on a laptop, and if I don't get the viewing angle of the screen right then the resulting image comes out much darker on other screens. I have just looked at the latest version on the iPad and again the background has fewer details and is much darker than what it looked like on the screen when I was processing it. I run my laptop with a calibrated screen but as I say depending on what angle I have the screen at or the angle I view the screen I get different final results on say the iPad or a CRT. Any advice?
Title: Re: Back to M51 after too many years...
Post by: MarkS on Apr 12, 2011, 08:05:51
Looking very good now Paul.  The new image is noticeably smoother and the fainter stuff is beginning to emerge now.  The processing is also better - it has no obvious sharpening artifacts.

To make any further obvious improvement you'll need to double the total exposure time once more (or get yourself faster optics!)

There is a stunning difference between this and your first M51 in 2001.

Mark
Title: Re: Back to M51 after too many years...
Post by: mickw on Apr 12, 2011, 08:55:28
Nice work Paul, its like a different subject compared with 2001
Title: Re: Back to M51 after too many years...
Post by: Whitters on Apr 23, 2011, 08:43:47
Now with 4 hours and 50 minutes , the last 10 min sub was unusable :-(
(http://www.astrocats.co.uk/astronomy/images/MX916/2011_04_21/M51_Sigma3_DPP_LowProcessed.jpg)
Title: Re: Back to M51 after too many years...
Post by: Whitters on Jun 27, 2011, 23:15:39
And now at last following several weeks of poor weather M51 with it's guest star

(http://www.astrocats.co.uk/Astronomy/Images/MX916/2011_06_26/M51_IRB_Sum_Curves_Levels.jpg)

WO110 f6.5
MX916 Astronomik IRBlock
26th June 2011 - 3x 600 seconds, sum with levels and curves applied
Title: Re: Back to M51 after too many years...
Post by: MarkS on Jun 28, 2011, 07:06:30

Nice one Paul!

Mark
Title: Re: Back to M51 after too many years...
Post by: Fay on Jun 28, 2011, 07:53:41
well done Paul, that is very nice. I must try & get it with it's "guest"

Fay
Title: Re: Back to M51 after too many years...
Post by: JohnP on Jun 28, 2011, 09:14:01
Paul - However, you processed the last image (with the guest star) do this to the other 4hrs of data. You have processed it a lot better without being too harsh on the blacks & whites - it looks altogether a lot more natural to me. The stretch you have applied is a lot more gentle.

Great capture & nicely processed - John
Title: Re: Back to M51 after too many years...
Post by: RobertM on Jun 28, 2011, 10:54:59
Great capture Paul, there's lots of detail showing with the 5 hour exposure.  Any thoughts on adding colour ?  I agree with John about the contrast stretch, it seems to have affected the stars a little too much - it's a subtle thing though.

Robert
Title: Re: Back to M51 after too many years...
Post by: Carole on Jun 28, 2011, 10:59:34
Well done Paul, it looks like the SN is expanding.
I agree about the stars in the first image, but prefer the galaxy in the first one.
A combination of the galaxy in the first and stars in the 2nd would be my preference.

carole
Title: Re: Back to M51 after too many years...
Post by: Whitters on Jun 28, 2011, 23:48:45
Thanks folks, John Yes I can see the difference, I'll have another go at the five hour one. The problem I have is I process on a laptop so the screen angle is different each time so what looks ok comes out clipped. Has anyoone got any advice on how to get round this?

The image above had levels and curves applied, tyhis destroys the photomtric accuracy. So does not applying flats, I hope to get the flats at the weekend. This image has only had levels applied.
(http://www.astrocats.co.uk/Astronomy/Images/MX916/2011_06_26/M51_IRB_Sum_LevelsOnly.jpg)
Title: Re: Back to M51 after too many years...
Post by: MarkS on Jun 29, 2011, 00:03:35

BTW, this supernova is easily visible through a scope, well I certainly saw it through the C11.  A good target for a a 20" Chris! 

Mark