NGC300 redo with extra hours

gregbradley · #1 18-10-2010, 08:27 PM

I added more time to my earlier image of NGC300.

I am quite happy with this one and I am getting a handle on how I process my images from the Planewave CDK17 and my area.

LRGB 280 70 60 60. All 10 minute subs.

FLI Proline 16803 at -35C (standard temp), Paramount ME, MMOAG, Lodestar, Astrodon Gen 11 filters,
Planewave CDK 17.

From my backyard observatory:

http://www.pbase.com/gregbradley/image/129528894

Greg.

Hagar (Doug) · #2 18-10-2010, 09:39 PM

Very nice Greg, some great detail and colour. Your setup seems to be working very nicely. Your stars are great for this huge focal length.

gregbradley · #3 18-10-2010, 11:40 PM

Quote:

Originally Posted by Hagar

Very nice Greg, some great detail and colour. Your setup seems to be working very nicely. Your stars are great for this huge focal length.

Thanks Doug.

The Paramount is an amazing mount. I drift aligned it over several nights and then used T-Point (which you can use on any mount) to further refine the polar alignment. I refine it a tad every now and then a bit more.

It is about 90 arc seconds off possibly closer now after an adjustment last night. I saw the autoguider errors fall more so that means I am closer. Probably under an arc minute now.

Also the MMOAG and Lodestar work very well once I was able to work out how to focus it!

Greg.

TheDecepticon · #4 19-10-2010, 12:02 AM

Another fine shot, Greg!

strongmanmike (Michael) · #5 19-10-2010, 12:34 AM

Looking good Greg, the extra exposure has lifted the image nicely.

Mike

Shano592 (Shane) · #6 19-10-2010, 03:53 AM

Beautiful work! Really crisp.

I love finding the galaxies hiding the backgrounds of these types of images.

gregbradley · #7 19-10-2010, 07:12 PM

Quote:

Originally Posted by TheDecepticon

Another fine shot, Greg!

Thanks for that. I am getting the hang of this new rig and how to process its images better.

Quote:

Originally Posted by Shano592

Beautiful work! Really crisp.

I love finding the galaxies hiding the backgrounds of these types of images.

I know what you mean. I have a few galaxy images on the run at the moment and one of them I counted up about 30 background galaxies and I was only looking at less than half the image. Amazing what aperture can pick up.

gregbradley · #8 19-10-2010, 07:13 PM

Quote:

Originally Posted by strongmanmike

Looking good Greg, the extra exposure has lifted the image nicely.

Mike

Thanks Mike.

Also the weather was very clear and I think there was some high cloud in some of the original exposures. But yeah there is no substitute for decent exposure time.

Greg.

Ken · #9 19-10-2010, 09:21 PM

Great image Greg the pink Ha regions really add to the detail, glad your gear is performing well. Must add this one to my to do list, actually I took a quick 60 second exposure of it on the weekend while mucking about and it looked good even with lots of Moonlight.
Clear skies KEN.

Octane (Humayun) · #10 19-10-2010, 09:26 PM

Oh, Greg. That's sensational! The pink is to die for.

Minor criticism, has this been flat-fielded correctly? The image is noticably darker in the bottom quarter. And, there's a dodgy pixel towards the centre of the galaxy.

Other than that, wow, what a system.

H

gregbradley · #11 20-10-2010, 08:04 AM

Quote:

Originally Posted by Ken

Great image Greg the pink Ha regions really add to the detail, glad your gear is performing well. Must add this one to my to do list, actually I took a quick 60 second exposure of it on the weekend while mucking about and it looked good even with lots of Moonlight.
Clear skies KEN.

Its a beautiful galaxy and quite large. It is very similar to the northern hemisphere M33 but perhaps prettier. It has a lot of Ha areas.
Have fun imaging it.

Greg.

Quote:

Originally Posted by Octane

Oh, Greg. That's sensational! The pink is to die for.

Minor criticism, has this been flat-fielded correctly? The image is noticably darker in the bottom quarter. And, there's a dodgy pixel towards the centre of the galaxy.

Other than that, wow, what a system.

H

Hi Humi,

Yeah I noticed that bright blue colour noise pixel yesterday and deleted it and reposted it. A bit like a zit eh? You must have looked at it just before I did that.

I did flat field these and I have done a correction and it is even now. It was done over several nights even though the total exposure is not high - a lot were thrown out due to cloud. I did some fresh flats halfway through so the first half may have not flatted as well as the 2nd lot. Flat fielding is more critical with this scope. I think its the corrected Dall Kirkham design where you have a corrector in the baffle tube, much like the Tak BRC250 (its corrector is just before the focuser and its an RC mirror). The BRC250 flats show quite a bright central area and so does the CDK. No problem if flats are well done and fresh but there is little tolerance unlike my refractors where occassionally I'll use an old flat and it does not matter much.

So I think I will be cleaning my camera more often and also taking great care with flats. For example they need to be about 3-4 seconds exposure which means right at the best time at dusk to achieve this. I did some at about 30 seconds and they did not work well at all.

I have also noticed the scope brings out the Ha areas really well. I noticed that on the Sculptor image that Ha areas came out really well even though no Ha was taken.

Greg.