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View Full Version : Indulgence for another cosmic landscape...



Diane Miller
04-26-2015, 01:45 PM
The Rosette Nebula. Large (twice the diameter of the moon) but too dim to see.

Canon 7D Mk II, Canon 300mm f/2.8, ISO 1600, 60 sec exposures at f/5.6. (I was trying for starbursts on the larger stars but they weren't that big. Normally I'd be wide open and a somewhat shorter exposure time.) Stack of 54 exposures (tracked with an Astrotrac) for noise reduction, to allow the very weak signal to be brought up. (In each raw file you can barely see a faint smudge of the nebula.)

There is no way to know where to stop when "stretching" tonal detail this much -- it's just a judgement call when it starts to look overcooked. The red is authentic and could be brought out more with a modification to the camera that allows more transmission of the hydrogen alpha spectral line which most nebula emit.

There is a lot of dim nebulosity in this region, giving a look of red contamination in the darker areas.

Don Railton
04-30-2015, 08:02 AM
Hi Diane.

Sorry I have taken sooo long to comment but been off work for a week preparing for and celebrating my daughters wedding. Very little time for photography. I think this is probably your best yet astro photo yet. It is quite beautiful and well detailed, and it could easily be sitting on my "Mr Lincoln" bush outside. Not sure how you find things like this to photograph when they are so difficult to see... but you have done a good job I think anyway.

DON

Gabriela Plesea
04-30-2015, 02:57 PM
Congratulations Diane, I think this is one awesome capture, surreal and beautiful and great PP work by the way:cheers:

Kind regards,

Diane Miller
04-30-2015, 08:32 PM
Good enough excuse, Don! Many Happy Return to the newlyweds, and hope you had time for some pictures! And thanks, Gabriella!

Here's the "before" version after stacking to reduce noise so tonalities can be stretched enough to bring out the dim areas. Don't think I said but it's 34% of the original full frame, which makes it easier not to have to be so precise centering the object.

Terry Johnson
04-30-2015, 10:14 PM
Diane, a wonderful image. Nikon now has a D810A, the 'A' standing for astrophotography, which has been modified to allow 'H-Alpha' waves through to the sensor. Just a comment...Terry Johnson

Diane Miller
04-30-2015, 10:22 PM
Canon has a similar version for one of their cameras -- not sure which one, but maybe the 6D. You can also have mods done by the folks at LifePixel (who do wonderful IR conversions) and probably other places. That would add to an image like this!

Don Railton
04-30-2015, 11:25 PM
Good enough excuse, Don! Many Happy Return to the newlyweds, and hope you had time for some pictures! And thanks, Gabriella!

Here's the "before" version after stacking to reduce noise so tonalities can be stretched enough to bring out the dim areas. Don't think I said but it's 34% of the original full frame, which makes it easier not to have to be so precise centering the object.

Hi Diane,

This image impresses me even more, given the obvious difficulty in finding a subject like this. Thanks for the congratulations, I will pass them on..

Don Lacy
05-01-2015, 07:14 PM
Wonderful image Diane , I am in awe of the amount of technical skill and knowledge it takes to make these images.

Morkel Erasmus
05-02-2015, 04:09 PM
This rocks Diane. Love seeing these and please keep posting them.

Dvir Barkay
05-03-2015, 08:30 PM
Yes, like people have said before me, this is lovely. I. before I got into photography as an absolute space nut and always tried to capture stuff with my old gear and never got anything even half way decent. The best way to do this is to get a telescope and a tracking mount, but a good version of each can run you at least 3 grand. So I think that these are extremely impressive considering you didn't use a dedicated tracking astro mount and a telescope.

Diane Miller
05-03-2015, 09:28 PM
Thanks, everyone!

The Astrotrac is a tracking mount, but not a Go-To, which lets you dial in an object and it slew to it. (I wish…) The AT is "relatively" inexpensive and portable to remote locations. Finding an object is more of a challenge. But it does let me use the telephoto lenses I already have, rather than investing in a telescope, which can be on par expense-wise with a long prime telephoto. Processing is easier now, with the 7D2, thanks to information from Roger Clark. It still takes a stack of shots over an hour or more for the low-hanging fruit, and a bottomless pit after that.

Andrew McLachlan
05-05-2015, 07:15 PM
Love it Diane...fabulous work!!!

BenBotha
05-15-2015, 04:47 AM
12 out of 10-enough said.
Ben

Diane Miller
05-15-2015, 09:35 AM
Thanks guys! :S3:

I still want to do some work on it, to quench some of the small nebulous detail in the BG. It's real, but looks too much like noise or artifacts.