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multiweb
30-07-2011, 07:16 PM
I did these two shots Thursday night and Friday night, Friday being the night with the best seeing we had in a long while in Sydney. Both nights were relatively dewy but transparency was good enough.

These two shots were meant to test two new lenses I got recently. A 35mm and a 28mm. This time I resisted the urge to do a mosaic and instead stayed on one field and went deep. :P

The first shot is centered on IC4628 and consists of 35x600s so close to 6h. With a SMC Pentax -M 35mm 1 f-stop, QHY8 + 2" Baader Ha 7nm.
Bigger field here (http://www.astropic.net/astro/prawn_35mm_ha_f.jpg)[952KB] and 1:1 here (http://www.astropic.net/astro/prawn_35mm_ha_ff.jpg). [2.1MB]

The second shot is centered on M8 and consists of 25x600s so a bit over 4h. With a SMC Pentax -M 28mm 4 f-stop, QHY8 + 2" Baader Ha 7nm.
Bigger field here (http://www.astropic.net/astro/M8_28mm_ha_f.jpg)[952KB] and 1:1 here (http://www.astropic.net/astro/M8_28mm_ha_ff.jpg). [2.3MB]

Both fields are uncropped. Image scale and field sizes are respectively 33asp and 48x32 degrees for the 28mm lens and
46asp and 39x26 degrees for the 35mm lens.

Very minimal processing was done as I found there is really no point boosting contrast or deconvoluting those widefield shots. Stars are so tiny you lose them straigh away with any sharpening. No noise reduction either. Just DDP in CCD Stack and saved as scaled TIFF.

Overall pretty happy with the two new lenses. They weren't much to look at externaly as they are very old. Late 70s I suspect but the 35mm was surprisingly good even fully opened.

I should get some cool color with these two next time I manage to get out to a dark site. Thanks for looking :)

PS: I anybody manages to platesolve those in unimap let me know. I haven't had much luck so far and I'd really like to see the constellation outlines, etc...

Added montage of 2 panels here (http://www.astropic.net/astro/milkyway_ha_aratoscorpius_f.jpg)[1.35MB]

Mighty_oz
30-07-2011, 08:21 PM
Nice, i like the 35mm one out of those 2 as u can see more details :)
Wish Perth skies would clear so i could do what u are doing, taking pics ! :(
But at least we can still view the skies through endevours such as your and the others.

multiweb
30-07-2011, 09:03 PM
Thanks mate - yeah the 35mm is a better lens too. About time you guys get some rain in WA. I hear it's been very hot and dry last summer.

gregbradley
30-07-2011, 10:42 PM
Gee Marc they are both very good. It seems you have struck a winner here - no star aberrations or at least in that file size, and a great field of view.

I have a few old Pentax lenses. What are the specs of the 35mm?

I like these better than the other lens shots you had as these seem more perfect.

Greg.

multiweb
31-07-2011, 03:49 PM
Thanks Greg. :thumbsup: I'm getting better at focusing and starting to understand how far to stop so practice makes perfect. The 35mm is F2:8. Specs are here (http://www.pentaxforums.com/lensreviews/SMC-Pentax-M-35mm-F2.8-Lens.html) and the 28mm here (http://www.pentaxforums.com/lensreviews/SMC-Pentax-M-28mm-F2.8-Lens.html).

Ross G
03-08-2011, 10:27 PM
Hi Marc,

Great photos. Those wide angle lenses are a treat.

There is so much sharp detail (...and thanks to your previous wide angle shots I now know the names of all the objects in your photo!..).


Thanks.


Ross.

Paul Haese
04-08-2011, 10:52 AM
I like the mosaic image. Good detail and plenty to see. The big glossy's just stand out so well. Contrast looks good too.

multiweb
04-08-2011, 01:26 PM
Thanks for the feedback guys. I'm looking forward to add some color maybe tonight. :thumbsup:

SkyViking
04-08-2011, 01:51 PM
Those look very good :) I like how you've got the relative brightness between the various nebulae spot on, it looks very natural.

jase
04-08-2011, 03:12 PM
Very nicely done Marc. Quite a few familiar, yet extremely faint emission nebulae that you've picked up. Of course the usual suspects are there too. Agree, no point going hard with deconv etc, at least not when you're heavily undersampled. I like the image centered on the prawn having recently shot this myself. I can see a few other interesting projects in these images. Thanks for sharing. Looking forward to more of your super wide field imaging adventures...colour?

multiweb
04-08-2011, 04:51 PM
Thanks Rolf. :thumbsup: There's a lot of data in there so I didn't have to push anything and the relative brightness were easy to keep.


Thanks Jase. Not wrong - undersampled alright. I have a mono now with a smaller pixel size even. I calculated I'll more than double my image scale so I should be able to get a lot more details for the same FL. Every time I debayer to red and I see those 3 pixels going to the trash I cringe. You do loose a lot data especially in widefields. I can see some nice interesting structures in the bayer matrix that just don't make it to the final.

atalas
04-08-2011, 05:14 PM
Great work Marc...I like the mosaic the best.

multiweb
04-08-2011, 07:19 PM
Thanks Louie. :thumbsup: Me too. I'm trying to do some colour tonight see what comes up. :question:

bokglob
04-08-2011, 08:19 PM
Genuinly impressive Marc, incredible detail. No.2 is a ripper! Some colour will be gravy,but as they are, still mesmerizing. Looking forward to more:thumbsup:

LucasB
05-08-2011, 06:56 AM
That is a beautiful mosaic! I love the detail in these Ha images you taken. Very enjoyable to look at. Nice work :thumbsup:
Lucas

multiweb
05-08-2011, 07:49 AM
Thanks a lot guys. :thumbsup: I tried some color last night which turned out pretty s||thouse. Giving it another go again tonight then back to NB methinks. :shrug:

sally1jack
05-08-2011, 01:54 PM
very nice:thumbsup:

multiweb
07-08-2011, 11:55 AM
Thanks Phil. :thumbsup: