Horsehead Nebula - UPDATED with new synthetic luminance approach

[swannies1983]

I collected about another 2.5hrs of data and did a reprocess, which included trying to reduce some reflections (these may or may not be due to a recently identified flaw with the GSO RC8). They are still there but not as prominent as they were before.

Details
Scope: GSO RC8
Mount: EQ6
Imaging camera: Modded Canon 30D, ~10hrs of data (5min exposures) @ ISO1600
Location: Backyard (~35km south of Adelaide). Shot over about 8 nights with temperature ranging from 15-25 degrees.

Lights, darks and flats calibrated in DSS and processing done in CS3.

Feedback more than welcome :)

Picture located here (1.5MB) (http://www.flickr.com/photos/47268787@N05/8383721676/sizes/l/in/photostream/)

Edit: updated picture post #14

[WingnutR32]

I like it, Dan. Very well done for a modded dslr.

Cheers for sharing

[Larryp]

Nice image, Dan:thumbsup:

[jjjnettie]

Awesome work Dan.
It goes to show these older camera's can still compete with the newer models. :)

[swannies1983]

Thanks for the comments :). Yeah, I am pretty impressed with what the 30D can do under light polluted skies. Mind you, all these fantastic images on this site are really making me want a CCD lol

[DJT]

Beautifully processed Dan but We say paah to cooled ccd's ;)

There's an art in itself to matching darks to lights with that temperature range. Nicely done.

[midnight]

Fantastic Dan.

Great work and good to see the 30D in action.

Darrin...

[Ross G]

A great looking photo Dan.


Ross.

[swannies1983]

I only tend to take 5 darks for each imaging session. Seems to control the hot pixels pretty well.



Thanks. Yeah, the 30D is performing pretty well. I was a bit reluctant to get one but I'm happy I did now.



Cheers Ross.

I actually am working on a different technique to generate a synthetic luminance layer. It looks much better than what I was able to produce with the current version.

[David Fitz-Henr]

That's a great image Dan; nice colour processing as well!

[stevous67]

Nice HDR work Dan - good work, looks great.

Steve

[cybereye]

Nice to see a great looking Horsehead with the RC8 - well done!! :thumbsup:

Cheers,
Mario

[strongmanmike]

A solid horse that and I like to framing, worth the effort for sure Dan.

How dark are your skies 35km south of Adelaide?

Mike

[swannies1983]

Thanks Mike. My skies are generally dark towards the west (out to sea), south (further away from the CBD), and east (towards hills). North is my worst sky as it's looking towards Adelaide. I can see the Milky Way and both the LMC and SMC on moonless nights.

I have done another reprocess. I generally follow Scott Rosen's workflow which involves using a synthetic luminance image made from the grayscale version of the RGB image. However, I read up that one can identify the best colour channel and use this as a synthetic luminance image. Given this region in mainly Ha, the red channel produced the best SNR. I did however layer mask in the Flame region from the grayscale RGB as it looked better than the one in the red channel.

I had issues with star halos when blending the synthetic luminance and RGB because of differences in star sizes (smaller in luminance compared to RGB). This is a common issue when blending Ha data with RGB data. However, I followed this (http://users.westconnect.com.au/~sjastro/Tutorial/star_halos.html) which simply involved using a Minimum Filter on the stars in the RGB image before combining the synthetic luminance data.

I'm really pleased with the results and think it's an improvement from my previous attempt. Always learning new tricks!

Any feedback is more than welcome :)

Link to image (3MB) (http://www.flickr.com/photos/47268787@N05/8401833164/sizes/l/in/photostream/)

[strongmanmike]

Yep, tricks are continually learned even after years of imaging and processing :thumbsup:

Sounds like you have a reasonable sky overhead, it helps.

Mike

[swannies1983]

Thanks David and Steve. Much appreciated.




Yep Mario. I am really enjoying the scope at the present time. Reflections aside, it's capable of producing some great images, even with an oldish dslr.