Deep space dobography part 2

[rustigsmed]

Hi all,

Clear skies on Saturday night in Melbourne, so I managed to get some imaging in before moonrise.

Eta Carina 55x 20sec @ iso 3200
Horsehead 80x 20sec @ iso 3200
NGC 1300 95 x 20 sec @ iso 3200
Eta Carina 55x 20sec @iso 3200

All images taken with a SW12" dob and a canon 600d (modified).

I would like to know which processing of Carina people prefer, i think i might need to redo somewhere in between.

NGC 1300 didnt turn out as bright as i would've liked, i lost quite a lot of detail in bringing the background glow darker (and on my work monitor definitely looks over saturated) - i'll need to learn how to seperate the background from the galaxy and reprocess.

The horsehead took a lot of time on photoshop, but got a result in the end - it didn't look like the dob tracking was going to be able to accomplish capturing its faintness for a while there (esp with the neighbours lights on!! grrr).

i've waited almost a year to image Eta Carina, definitely larger than I expected (a lot bigger than when i last viewed in my old 6" newt) - a coma corrector and perhaps a mosaic mission are on the cards.

It was also the first time i've used flats. slowly getting there...

Clear skies

Rusty :thumbsup:

[orestis]

:eyepop:WOW, Simply stunning photos and all with a dob, respect :thumbsup:.

Does the Dob actually track them so the objects are still images like a Schmidt cassegrain would?

I prefer the first eta carina shot.

Despite the neighbours lights :mad2: you still managed an amazing shot of the horsehead and although the ngc 1300 shot is dim at least its there with spiral arms and everything.

Thanks for posting
Awesome work keep posting
Orestis:thumbsup:

[jjjnettie]

Excellent work Russell.
What program do you use to process your images?
I ask because the back grounds of your Eta Carinas are very green, and there is a plug in for Photoshop that you can use that will fix that. It's called "HLVG" http://blog.deepskycolors.com/archivo/2010/04/26/hasta-La-Vista-green.html

[rustigsmed]

ThanksOrestis, :thumbsup: yes i have the skywatcher goto synscan system, which is on an alt-azimuth mount. when on this type of mount, the object stays in the field of view but it starts rotating as the sky moves. An equatorial mount counteracts ('offsets' might be a better word) the rotation of the image whilst keeping the object in view. That's why only short exposure times are possible ~20seconds as the image noticeably starts rotating.




Hi jjjnettie! thanks!

i use DSS and Photoshop 6. Hmmm, now that you mention it they do look green :sadeyes: Unfortunately i do my processing on a cheapo small laptop which doesn't have a fantastic screen.

Thanks for that link though - I will definitely download and have a crack at un-greening the Carina!

[madbadgalaxyman]

Hi Russell,

I am very happy with your image of NGC 1300.....short exposures are great!!

Often, the most interesting parts of galaxies are their centralmost parts, and these parts can be well and truly burnt out on long exposures.

Your image clearly shows a feature of NGC 1300 which is not so easily seen on the typical long exposure of this galaxy with a CCD camera.....the central ring of supergiant star forming regions.

Here is the tight innermost ring in NGC 1300, in an exposure with the VLT (used with the EFOSC2 instrument):

129855

Here is a low resolution version of a Hubble Space Telescope image (taken with the F435W filter)(similar to a blue-sensitive Johnson "B" photometric filter) showing this innermost ring of young bright stars and clusters:

129856
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In fact, it is the shortness of your exposures that makes this central feature stand out so very much!

I forget how large, in angular terms, this small central ring is, but it seems to me it might be observable visually.

cheers
bad galaxy man

The tight rings immediately surrounding the central starlike nuclei of galaxies are sometimes known, "in the trade", as "circumnuclear starbursts or "circumnuclear starburst rings. ("nuclear rings" is another way they are known.)

Ring structures often occur at various spatial scales, and a single galaxy can have several different rings within it;
for instance, the two main spiral arms of NGC 1300, when traced out a long way (to very faint levels), curve around to form a ring structure (a nearly complete ring).

Ring structures in galaxies were described by Buta and Combes, in Fund. Cosmic Physics, 1996, vol. 17, p.95;

http://ned.ipac.caltech.edu/level5/Rings/paper.pdf

Another useful guide to the variety of ring phenomena is the "De Vaucouleurs Atlas of Galaxies"

[Stu Ward]

Nice Dob Imagery my friend

I have done a few myself, amazing what you can get out of a non astrophotography scope

[rustigsmed]

wow, thanks mad bad galaxy man! thats a fantastic amount of information! thanks for taking the time out to fill us in! I did recall reading the nucleus was a 'grand-design spiral nucleus' didn't get much further. I will probably be able to bring some more detail out with some processing ... now that i know what i'm looking for :thumbsup:



Thanks Stu, yep the tracking on these goto dobs are pretty impressive for what they are, and modern dslr's have come a long way.


I tried updating my CS6 with the HLVG plugin but it hasn't worked... hmmm will try again tonight.

[Ross G]

Great captures Russell.

Ross.

[rustigsmed]

Cheers Ross,

Clear skies