M83

[Terry B]

Dear All
I had a go at imaging M83 last night and played with the image tonight. I still think that this image processing mullarchy is witchcraft and need lots of practice. I don't own photoshop and all the tutorials seem to use it. I can't justify the cost at present.
I decided to swap the camera and guider on my expensive VC200L scope and the cheap skyview 120mm "guider". The result is very well guided images and a wider field in the 120mm scope. It seems a bit silly to image through the cheap refractor but the result wasn't too bad. There is quite a bit of blue fringing so I had to sharpen the blue channel significantly to get rid of the blue ghosting.
The exposures are lum 3mins x 10, and 15 min total on each colour.
I still haven't work out the best way to add the subframes. Is a simple sum or a median stack better? The sum always results in saturated stars but seems to give more detail in the extended areas.

[Prickly]

Wow - thats one of the best achromat photos Ive seen. By the way that Eq6 of yours really does track well doesnt it!

People are happy to shoot through achromatic camera lenses but rarely seem to bother too much with achromatic refractors which seems a little ironic.

You could try a baader uhcs filter. It knocks out some light pollution, reduces blue fringing and seems to accentuate the Ha. I have tried this on my vixen neoachromat with good effect (posted an image some time back of eta carina).
Suspect a baader contrast booster would also reduce the fringing - or just keep doing what your doing with the processing.

Looks fantastic!

David

[iceman]

Lovely image Terry, I wish I could get photos like that. Beautiful work.

[duncan]

Hi All,
Terry what is the black patch to the right of the galaxy? Is it a dark neb or an artifact from processing? Curious.
Cheers,
Duncan
Lovely shot and is my favourite galaxy.:thumbsup:

[Dr Nick]

Wonderful image! ;)

[Terry B]

If you mean the area around the bright star on the right of the image, it is artifact. There was lots of blooming around that star and I removed it (but not very well).
In the galaxy itself there is still a dark pixel on the right of the galaxy that I missed removing.
Cheers

[little col]

nice image :thumbsup:

[Ric]

A very nice image of M83 Terry, the arms are showing a lot of nice detail.

Cheers

[Garyh]

Nice m83 Terry exp with just a 120mm achro!!!
you will have to get a minus violet filter now!!
but well done!!

[spearo]

Well Done Terry,
I'm not sure if it's worth trying but some people talk of using the Gimp software as a free alternative to Photoshop. Might be worth a look.
well done
cheers
frank

[Terry B]

I actually have gimp but it is in linux and I have to dual boot to access it. I have had a little play with it and will have to some more. I have paint shop pro in windows but it doesn't seem to have the "curves" function that makes custom stretching of images easier to do. Gimp does have but I am yet to work out how to use it. :shrug:

[spearo]

Best of luck with this dual boot! Its Wayyyyy past my level of technical know-how!
cheers
f

[ispom]

Terry, your shoot is in competition with yesterdays APOD !

http://antwrp.gsfc.nasa.gov/apod/ap070724.html

[Terry B]

Well, something to aim at I suppose. Maybe with a few more hundreds of hours practice.:D