NGC 3511 + NGC 3513 - Pushing the boundaries

[codemonkey]

This pair don't seem to be imaged very often, can only find a couple of images around.

Didn't really intend to get this much data (just over 10hrs), it just kinda happened. Not a huge amount of data for many of you, but one of my longer integrations.

These guys are reasonably bright, but the extra time did bring out some fainter details. Took longer than expected for noise levels to clear up to a reasonable level, but could probably do with another 10hrs to be honest.

NGC 3513 is only 2.9' x 2.4' so I'm probably pushing the boundaries of what you can reasonably image with a 120mm 'frac.

Attached is the +10hr integration, and a single 5min lum sub for reference. I'd recommend viewing the higher res / full res on Astrobin (http://www.astrobin.com/full/293975/C/) though.

[cometcatcher]

Nice pair of galaxies Lee. I want em now. :P

[clive milne]

That is very, very good Lee!

[billdan]

Looks very pretty Lee, nice colour and detail in the galaxies.

I'm not trying to be picky but the stars near the bottom of the frame have diffraction spikes, any idea why?

Cheers
Bill

[Camelopardalis]

That's a beauty Lee, well done :thumbsup:

[codemonkey]

Thanks Kevin; go for it mate, keen to see what you can get out of 'em :-)



Thanks very much Clive :-)



Thanks Bill! Good question. As you note, it's only on the stars towards one side of the frame, even though there's equally large stars on the other without the effect. I'm not sure what it is yet. The ASI 1600 does have some weird diffraction patterns on bright stars, but they look different to this and would (you would expect) appear across the entire frame.

I recently cleaned the Esprit's objective, and I'm wondering whether some residue has been left behind that might have caused it? Then again, I went and looked back and found the same thing on my earlier image of NGC 1808 and friends, and I'm pretty sure I cleaned it after taking that...

So no, to answer your question, I'm not sure what it is but I'm speculating that it's something on my objective or something on my filters.



Thanks very much Dunk! :-)

[Slawomir]

A beautiful image Lee. Colours are well balanced and the entire image is very pleasing to the eye :thumbsup:

As for the spikes, I think these can be also introduced by a correcting lens or maybe something not perfectly smooth in the focuser's drawtube? I used to have tiny tiny spikes with my previous telescope and suspected the camera (microlenses on the CCD), but these are gone with my latest telescope.

[RickS]

Nice catch, Lee.

[Placidus]

Bravo! A lovely pair of interesting galaxies, very well photographed and with lots of detail. Excellent colour in both the galaxies and the stars. A hunt around reveals many tiny background galaxies too. Inspiring.

[codemonkey]

Thanks Suavi :-)

Hmm. Interesting point. I did recently introduce some flocking into the optical train to get rid of some nasty reflections. I think that might have been right around when I photographed NGC 1808. Could be that's the cause.



Cheers Rick :-)



Thanks very much :-) Attached are my favourite tiny background galaxies in this FOV.

[strongmanmike]

Excellent work on this pair Lee, interesting visually and lovely colour, enjoyed the view thanks. Love the little background fuzzies and I agree, the one in the crop is indeed very cool :thumbsup:

Mike

[marc4darkskies]

Sorry I missed this earlier Lee - I was preoccupied. Nicely done :thumbsup: Great colours with some good detail.

[markas]

Great detail and colour on these little objects! Very nice image.

Mark

[codemonkey]

Thanks Mike :-)



Thanks Marcus :-) Probably could have done a touch better with the detail if I'd continued on with high gain short exposures, but going back to 300s subs reduces overhead significantly so ultimately it becomes another toss-up between SNR (by getting more effective imaging time) vs resolution.



Thanks Mark :-) I did quite a bit of RGB on this which probably helped colour up the fainter things.

[topheart]

Very nice pair!
Well done Lee!
Cheers,
Tim

[imhimmelkommter]

I think so too! Well done!

[codemonkey]

Thanks very much, Tim and Michael! :-)