The Dark Tower: A Cometary Globule in Scorpion

[nandopg]

Hello,
This is my attemp on The Black Tower. Image in full resolution HERE (http://www.astrobin.com/full/111170/B/)

This image was stacked as follows:
Ha: 15x 20' bin 1x1
RGB: 12x 15' bin 1x1 per channel
Bias, Darks and Flats applied
CAPTURE:
Scope: Skywatcher Esprit 120mm f/7
Mount: Skywatcher EQ-6 Pro
CCD: ST-8300M
CCD Guia: Lodestar
Processing: Pixinsight

Note about Processing: In this image I have not added Ha data to the Blue's and Green's channels, as most of the processing of the images in the web. I added only to the red channel. Before blending the Ha with the true red channel, I subtracted the Ha average luminance from the red channel average luminance, creating and index. The final Ha-red blend was a percentage of this index determined empirically.

[topheart]

Hi,

Nice image! Very timely. :thanx:

I will repro my image to the colour balance you have!!

Cheers,
Tim

[gregbradley]

Very nice image. There seems a bit of patchiness in the middle sections of the image. Did you use any minimum filter on the image?

Interesting Ha blend. I'll have to try out the Ha into the red technique. Can't say I've ever heard of adding Ha to the green channel of an LRGB, narrowband yes but not LRGB.
Greg.

[Shiraz]

interesting technique and the result is attractive - nice work

[nandopg]

Thank you Tim, I appreciated your comments. I hope you can manage to get your image balanced wonderfully.
Regards,
Fernando


Hi Greg,
Thank you for your time to comment this image. I appreciated your kind comments.
As for the usage of minimum filter, in PI the things are a bit different than in PS, as you have much more control when you erode a structure. In the case of star reduction, you should use a star mask that can be prepared in several different ways. The way I prefer, the mask is generated in the early stage of the permanent stretch, where the fatter stars start to appear. With this mask the reduction will be applied only on the fatter stars, being all the rest of the image, including the small stars, protected.
I tried to see the patches you mentioned, but all I found were some speckles and artifacts due to the conversion of a 64 bit floating point image to the highly compressed jpg file format.
This method of blending Ha to red channel actually avoid the overload of red onto the image.

Best Regards,
Fernando


Thanks for the kind comment Ray, appreciated.
Fernando

[strongmanmike]

Yes I agree, an interesting technique, a slight variation on the traditional way of blending Ha, the result is pretty good too :thumbsup:

Mike

[nandopg]

Thank you Mike, very generous your remarks.

Best Regards,
Fernando

[Tony_]

Great image Fernando!

I was going to try this one at some stage - but looking at your exposure times I doubt whether anything less than a few hours will capture enough and my imaging time is limited.

[nandopg]

Hi Tony,
Don't let exposure time be a barrier. Capture the subs slowly at the possible pace, it is worth the labor because is so nice to see the photons hitting the sensor of your camera forming this image !!
My best advice is for you go ahead and do it.

Regards,
Fernando

[Paul Haese]

Nice image Fernando. I like the colour and the back ground is very smooth.

[nandopg]

Hi Paul,
Thanks Paul, I really appreciate your kind comment.
Best Regards,
Fernando

[Regulus]

It's a nice result, and I particularly like the composition of it.
Well done.
That scope/camera setup gives nice colour and shape to stars too.

Trev

[nandopg]

Thank you Trevor, appreciated your kind comment.

Yes, I think this scope is very nice and the ST-8300 fits like a glove. I am very happy with this set-up that complete with a Moonlite precision focuser. I enjoy very much to image with this setup.