Image of the day

Captured by
Douglas Rollain

Lion Nebula SH2-132 - RC71

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Posts Made By: Jim Thommes

February 17, 2008 12:16 AM Forum: CCD Imaging and Processing/Deep Sky

RGB combine question

Posted By Jim Thommes
Luca,
I would go with average over sum. If you toss a subexposure for tracking errors or jet/satellite, with average, you don't have to worry about radjusting scale on the other channels.

But I agree with Ditmar - I love a sigma clip average. It really eliminates the effects of single frame artifacts. But actually I use a "sigma Combine" average in Astroart (plugin). Is that the same as a Sigma Clip?


February 17, 2008 12:24 AM Forum: CCD Imaging and Processing/Deep Sky

Horse's other neighbors

Posted By Jim Thommes
Henry,
Very nice widefield image with great detail.

The dark nebula is LDN 1622 - sometimes known as the Dancing Dolphins (might be Eric's -Enrico name for the object).


February 18, 2008 04:37 AM Forum: CCD Imaging and Processing/Deep Sky

Yet another M108/M97

Posted By Jim Thommes
Mike,
Nice image! looks great to me with framing that gets both objects.

Nice to see you posting - hope there is more to come.

February 18, 2008 04:45 AM Forum: CCD Imaging and Processing/Deep Sky

Sharpless 280

Posted By Jim Thommes
Thanbks for the comments guys!

Henry,
You got quite a bit of stuff in that widefield image. Yes, you have Sharp[less 280 there as well.

Dan,
Yup, I'm taking this C8 about as far as it will go. The image suffers a bit at this f/ratio. but it is selected mainly for the FOV. This can work for me because of the small CCD I use.

February 21, 2008 04:48 AM Forum: CCD Imaging and Processing/Deep Sky

Back to greyscale practice :-((

Posted By Jim Thommes
Luca,
Very nice M42 and great detail. I'm not sure you really need any more practice at monochrome images. I think you should give color a try again. Remember in color its all about balance between the channels.

Typically I take great care to preserve the correct intensity scale between the RGB channels. Whatever I do to one channel, I do to all equally. When I saw yor last color attempt - it seemed you were individually scaling or stretching the RGB exposures.


February 22, 2008 04:34 AM Forum: CCD Imaging and Processing/Deep Sky

M67

Posted By Jim Thommes
Thanks folks for the comments.

Jim, I really appreciate your comment on my website. Its good and encouraging feedback. I guess I'll pay the hosting fee another year.

Luca, It isa interesting to hear your comment on the common name - King Cobra Cluster. I have always called it that but I see there is only very spotty reference to this common name on the internet.


February 24, 2008 11:07 PM Forum: CCD Imaging and Processing/Deep Sky

Tarantula Nebula

Posted By Jim Thommes
Nice image Greg. Thanks for posting the Narrow band images. My interest is really picking up, I'll have to get some filters.


February 24, 2008 11:13 PM Forum: CCD Imaging and Processing/Deep Sky

M41

Posted By Jim Thommes
Looks pretty Good Jason! As Richard says not a lot of time is neede for an objetc like this. Color looks great. I think that is what could be impacted the most by dicey conditions.

I hear ya about the weather.


February 24, 2008 11:14 PM Forum: CCD Imaging and Processing/Deep Sky

Eta Carina

Posted By Jim Thommes
Very lovely image Greg.

February 26, 2008 04:45 AM Forum: CCD Imaging and Processing/Deep Sky

M 67 - 5" tmb and one shot color

Posted By Jim Thommes
Nice Dietmar. I really like how that glass of yours manages the star sizes so well.

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