Back into imaging at last - M16 in Ha

[multiweb]

Hi Guys, just finished processing that one. 10x600s in Ha, dark/flat calibrated on my newly flocked 5” newtonian last night. Probably need more data but I’ve put nearly 5h on M8 so something had to give - Still processing M8 - will post later. Trying to do a HaL RGB :whistle:.

Full frame is at: http://www.multiweb.com.au/astro/M16_Ha_20090703_f.jpg (http://www.multiweb.com.au/astro/M16_Ha_20090703_f.jpg) [2.44MB]

Enjoy - Comments/tips most welcome :)

[TrevorW]

Really nice image Mark tracking etc looks spot on. I like the errie look of HA images something surreal about them is this possible with a DSLR

Cheers

[Hagar]

Very nice Marc. The detail all beit small is really good. I think I am starting to enjoy Ha as a mono image. Still not taken by false colour NB offerings.

[bokglob]

nice work there marc:thumbsup: really good depth and detail,very impressed! looking forward to your m8.

[jase]

Good to see you back imaging again Marc. The presented FOV really suits the target well. I can't help but imagine if there's more that could be extracted from the data?? - specifically in the shadows. Perhaps a two point curve would push it further while controlling the highlights relative to the mid-tones. Overall, there is good details on display. Looking forward to seeing how you'll handle the HaRGB blends either with this image or your planned M8. A great result - well done.

[peter_4059]

Looks good Marc. The Ha really brings out that loop. Might have to get one ;)



Peter

[multiweb]

Thank you all for the positive feedback guys :thumbsup:



Yes Jase, I've always noticed I get this problem when saving greycale pics to JPEG. The TIFF 16 bits version does show a lot more nebulosity in the dark areas and better contrast in the light areas but the picture always darkens a bit when I save to JPEG for the web. Maybe the optimisation from TIFF 16 bits to JPEG 8 bits is not handled very well in PS or am I doing something wrong? The orginal is a TIFF 16bits. :shrug:

[TheDecepticon]

Good shot! Ha is awesome, always great depth and detail!:thumbsup:

[dpastern]

That's a new re-introduction back into imaging Marc - I'd be happy with that. Sure, more data is always nice, but it's a never ending task then ;-)

Dave

[marc4darkskies]

Nice job Marc - some good detail there! :thumbsup: A bit more data would consolidate it though and give you more processing latitude. Bring on the colour! :)

Cheers, Marcus

[Prickly]

Hi Marc,

Excellent image and a nice scale for the chip with the new 5 inch. Your hard work has surely paid off. Were you using a Meade DSI?

You might want to experiment a little with exposure times. I'm aiming at around 40 images per session to decrease the noise and working out from my imaging time how long to make the exposure. Works ok on bright objects. Dimmer ones will no doubt need longer. These chips are so sensitive its amazing how much detail comes out even at short exposures. Have seen galaxy shots posted on this website through a GSO 12 f5 with only 5sec shots - but lots of them made me think this may be a good way to go. If you are using a DSI with envisage the shorter subs will give you lots of images for drizzle to. Also less critical if some cloud drifts across etc.

Others (more knowledgable) may no doubt argue for sure stay at 10mins but I like experimenting around with things. My impressions are it does seem to work pretty well.

Cheers
David

[jase]

Marc,
What is your working colour space?
-Its fine to process an image in aRGB, but you'll want to convert to sRGB at some point if the goal is web reproduction. As the gamut range is different between the two, there are some tasks best done in the desired final colour space.
Did you convert the image from greyscale to RGB?
- To be in compliance with colour space it should be converted to RGB and not left in greyscale.
Are you soft proofing the image against your calibrated monitor profile?
- Soft proofing can make it easier to visualise the effect of output based on device or colour space profiles. The concept and set up of soft proofing is too much to cover conclusively here, but in short it can assist you in the validation of your work. Maybe worth investigating.

Keep at it!

[Alchemy]

very good resolutin with a 5 inch newt, well done


clive

[lesbehrens]

nice

[Tamtarn]

Very nice Marc we look forward to seeing your M8. Has the flocking helped by the way?

[multiweb]

Thank you all for the good feedback . Much appreciated. :)


Thanks Marcus . I'll stick more data in Ha to start with. I don't know how to blend in Ha yet. Fred's doing a talk next week at the club astro-meeting so I'll wait till then to hear it from the horse's mouth. :)


Thanks David. Nope. I use a QHY8 on a newt (Celestron Nexstar 130SLT). My image scale at prime focus is approx 2.5 arc sec/pixel. Nice "widish" field but at the limit of undersampling.


Wow! Couple of things I seriously need to check ... Thanks for the offer Jase. I definitely have got more reading to do and will get back to you as not to waste your time with trivial questions. Good point. I never took notice that I'm in 16bits greyscale space. :whistle:


Thanks Clive - I bought an artifical star from astrozap - best thing I've ever done. I have setup my scope in the garage looking at the AS 60m away or so in a black bucket over a grassy field. It's great because you can do that anytime even during the day. I also bought Suiter's book. Still not understanding everything but I'm getting there slowly. Anyway the proof is in the pudding. Glad you've noticed. :thumbsup: That's a $400.00 scope off the shelf . ;)


Thanks guys - glad you like it. Has the flocking helped? HUGE difference. The improvement in contrast is massive. To give you an idea: shooting flats with my EL-sheet in the past, with a Ha filter I would need a minimum of 4s exposure to reach the desired level of 9000ADU. Now to reach the same level I have to do 11s exposures. Just shows how much stray light use to contribute to the final illumination pre-flocking.

[Omaroo]

Excellent Marc - a very pleasing image to me. I'm falling for Ha, and I really have to get a filter soon otherwise I'll go bonkers seeing takes like yours and not being able to sample some too.

It's nice to what you're getting out of the 5" newtonian. I'm keen to my new 6" to work, and on the basis of what you're achieving I can't wait.

Thanks Jase too, in reference to presenting mono web images in RGB colourspace. Good tip. :thumbsup:

[multiweb]

Thanks Chris. Yeah I can't wait to see what your new Tak's like on DSOs. Should be pretty cool. :)

[Craig_L]

Nice detail Marc. Look forward to the finished image with RGB. You've encouraged me to try my Baader Ha filter on this target with the DSLR.

Craig

[multiweb]

Sounds good. I wasn't aware they had Ha filters for DSLR. Looking forward to your shots too. :thumbsup:

[Craig_L]

No they don't, it's just a 2 inch filter that screws into the front of the Canon adaptor. Craig

[richardo]

Hi Mark,
looks like things are coming together with the newt! (go the newts!)
What flocking material did you use?
Good to see you up and running again.
Can be hard this time of the year with the weather.

This is not the easiest object to pull out the data on. Generally I've had to really concentrate on what areas I'm happy with after the first initial stretch, then find myself selectively masking these areas off in PS and concentrating on the out laying areas as there's quite a bit of nice subtle nebulosity to be found.

I brought your image into PS cs3 and did a quick shadow/highlight as a quick check, and while it did bring out a lot more to the surrounding areas, the lack of total exposure time is the main setback to this approach.

I think you could possible bring a bit more out, ( as Jase mentioned) by selectively masking certain areas and applying perhaps curves to other areas but the noise will be the limiting factor with this image, unless you get some more data. I know hard when you have your sights on something else.:D

All in all, you've picked up some nice details to the main object.
I do see some coma radiating out to the corners.... what corrector are you using and have you checked the spacing from it to the CCD/ window?

Any ways, good you're back in the saddle and look forward to your M8 image.

All the best for now
Rich

[multiweb]

Thanks Rich. Yeah I need definitely more data on this one. Coma's a bugger. I have a MPCC but no real way to modify the spacing. I've always had this problem and I'm not sure how to resolve it. The spacer doesn't allow to shift back and forth even a couple of mills. It's one solid piece of aluminum :shrug: I was thinking at one stage to make a spacer that I could shorten like a helicoidal focuser but I haven't found anything anywhere ressembling it.

[Bassnut]

Excellent work Marc, even zoomed in at 400%, detail in the core is very good. Ive seen some strange star distortions in some of your other images that maybe guiding related, but not with this one (apart from possible coma or whatever Rich points out, not that bad really)

[multiweb]

Thanks Fred. Previously on axis I had some nasty astigmatism. Crossed stars. My diagonal plane was tilted and my primary also rotated on its axis. I've fixed those two things since then so on axis is as good as the scope resolution will be. The outside of the field... well, it's a different story. I need to find a way to accurately space my coma corrector. At the moment it's really bugging me coz I have to play with star masks and deconvolution and it's a lot of stuffing around to "hide" things. :whistle: