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View Full Version here: : M20 Trifid Nebula - low-cost gear, pretty decent result


Amaranthus
05-11-2014, 02:03 PM
I started in serious astrophotography about 6 months ago with a 'learning kit' that was fairly low cost. It consisted of a wide-field apo (Orion ED80T CF), a solid mid-range mount (AZ-EQ6) and a low-cost mono CCD (the Orion StarShoot G3). Overall, the whole package, with filters etc. weighed in at a <$4.5K budget, which seemed decent to me for a first kit. I'm pretty happy with the result. My plan is to soon upgrade the CCD, get a longer FL apo to compliment and wide field (I also have a long FL 8" SCT that I've not used much for AP so far), and keep using the mount for now.

People have complained about the low resolution (752 x 582 pixels, 8.3 microns) and meager cooling (-10C below ambient, at best) of the StarShoot G3 CCD (http://www.telescope.com/Orion-StarShoot-G3-Deep-Space-Monochrome-Imaging-Camera/p/101473.uts) but it has a deep well capacity (50,000e-) and is actually pretty sensitive and low noise (a Sony ICX419ALL chip). The key is to know your camera - in particular, this baby MUST be drizzled (with many subs) to get effective resolution. Overall, I'd definitely recommend it for CCD novitiates, as it teaches you most of what you need to know for LRGB and NB work, without a heavy financial risk.

Anyway, see attached image of M20 taken with this setup...

Full capture details and a high resolution version can be viewed here:
http://www.astrobin.com/134243/

A fairly long integration of the reflection (blue) and emission (red) nebula of M20, the fabulous 'Trifid Nebula'. This is a large HII region in Sagittarius, located about 5,200 light years away.

The image was captured a few months ago from my Adelaide surburban backyard, using an Orion ED80T CT apo astrograph (at f/4.8), mounted on an AZ-EQ6. The CCD camera was an Orion StarShoot G3 mono, guided with PHD2 using a think OAG and an ASI120MM-S guide camera. It's taken me a while to dedicate the time required to do the processing!

The image is composed of the following:
Lum = 56 x 5 min
Ha = 18 x 10 min
R, G & B = 56 x 5 min for each channel
Total integration time of 21.7 hours.

I used the Ha data to really make the central emission region stand out above the background. I developed a synthetic luminance channel by blending an exposure-based weighting of the L, Ha, R, G and B luminances. All subs were unbinned.

Captured from late Aug to early Sept 2014, as weather permitted. Pre-processed with flats (light box), bad pixel map (based on 70 darks) and bias in Nebulosity. Aligned and Drizzled in DSS. Post-processed in StarTools.

Shiraz
05-11-2014, 02:42 PM
very impressive result Barry - you certainly are breaking new ground for that level of equipment and the image stands up well in comparison with ones from much more expensive setups.

cometcatcher
05-11-2014, 04:21 PM
That's awesome Barry!

How do you think that camera would perform on my slower ED100 at F7.2? (that's with focal reducer)

Amaranthus
05-11-2014, 04:30 PM
Thanks a lot Ray -- I like breaking ground :)

Kevin, thanks. I think the G3 would work really well with an ED100, although the FOV would be a little narrow at 31 arcminutes (it's a 1/2" chip). Still, that would squeeze in the full-moon equivalent, and would be great for galaxies etc. You'd have an undrizzled resolution of 2.5 arcsec/pixel, but with 3x drizzle that would go down to <1 arcsec/px equivalent.

cometcatcher
05-11-2014, 05:29 PM
That's what I had in mind. ;) There's lots of itty bitty galaxies I want to image. It's either that or I get an RC8 for them with my DSLR.

Amaranthus
05-11-2014, 05:43 PM
Well Kevin, if you get that mono CCD, you can also start using your fast 120mm achro at f/4 as a narrowband imager. It works great with that setup! I've done a Helix with this arrangement, and it looks amazing (still in post processing...)

Camelopardalis
05-11-2014, 06:49 PM
Pretty decent must be understatement of the year, it's beautiful Barry :thumbsup:

RickS
05-11-2014, 10:18 PM
You've shown the reflection neb very well, Barry.

Rex
05-11-2014, 10:58 PM
Top Shot Barry!

Ross G
05-11-2014, 11:03 PM
A great looking photo Barry.

I love the colours and detail.

Excellent work!

Ross.

SimmoW
06-11-2014, 05:30 AM
Yes, a large effort and great payoff, well done!

Spookyer
06-11-2014, 07:37 AM
Very nice work.

sjastro
06-11-2014, 10:12 AM
Nice image Barry.

You should rotate the image so the reflection nebula is at the top.

I think it would add impact to the image as most viewers are familiar with this orientation.

Clear skies

Steven

Amaranthus
06-11-2014, 10:57 AM
Thanks Dunk, Rick, Rex Ross, Simon, Brett & Steven for the positive feedback!

Ross -- I checked out your work - superb stuff, so that's high praise!

Steven - I wanted to try a non-traditional orientation, to make it look more rose like ;)

atalas
06-11-2014, 03:51 PM
Nice work Barry.

SpaceNoob
10-11-2014, 02:13 PM
Thats a keeper! Awesome image Barry :eyepop:

Amaranthus
10-11-2014, 03:00 PM
Cheers Chris & Louie! I was pretty happy with it, especially given the constraints I was working under :)

Geoff45
10-11-2014, 04:22 PM
Nice work Barry, especially after only six months. Getting the bright double star in the Trifid is good. Lots of beginners blow it out so that it looks like a bloated oval star. Don't worry about the low cost of your gear. A few minutes ago I happened to be looking through Astrobin images taken with high end gear--16803 chips, scopes of 17" and up, good mounts. Some of the results were pretty shoddy. Expensive gear is no guarantee of a decent image. Care with technique and getting the best out of the gear you have is the way to go.
Geoff