NGC1365 Fornax Barred Spiral

[andyc]

Hi all, I finally managed a fairly unbroken imaging session, and collected over an hour on one object the other night - NGC1365 in Fornax, taken from my backyard in southern Sydney. Framing was terrible - I just plonked it on the galaxy and started imaging, missing some good neighbouring objects :P. But the result for NGC1365 and the area around it is my best galaxy image yet. I also have to thank IISer Erik, who sold me an MPCC and now I have pretty good star images right across the field of the DSLR :thumbsup:.

I'm not quite getting the background completely flat just yet, maybe pushing the data further than I should? Might need to try a more sensitive setting of DBE in PixInsight? I also think the registration didn't work 100% - the dust lane in the core of the galaxy appeared doubled, which it certainly isn't in Martin Pugh's signature images. Always more to work on!

100 minutes of 5-minute subs, EOS 60D at ISO640. Skywatcher 150mm Newtonian on HEQ5pro, Orion mini autoguider. Darks, flats and bias frames subtracted. Processed in PixInsight and Photoshop.

Larger version of the wide field here (http://www.pbase.com/andycasely/image/158275499/original).

Larger version of the galaxy crop here (http://www.pbase.com/andycasely/image/158275500/original).

[doppler]

Nice pic Andy, maybe a bit over cooked, but I am no expert in processing. You must have a lot of patience though, I would use a lot higher iso and cut my exposure time, but I am a lazy astrophotographer.
Good work.
Rick

[RickS]

Looks good, but still very noisy (not surprising for 100 mins at that image scale with a DSLR and less than dark skies.) If your registration was off it would be most visible in the stars.

Cheers,
Rick.

[rustigsmed]

nice work andy.

rusty

[andyc]

Thanks everyone!



Hi Rick, I've read a bit about ISOs, and I'm yet to be convinced there's anything to gain from going over about ISO400-800, except for noise and lost dynamic range. Though I could do with testing this more fully, there's logic that suggests you don't register any more photons to different intensity levels above this point. So hopefully I'm not wasting time! And I'm pretty happy to reach a limiting mag of 19.9 from the suburbs! I want to try stacks of the same exposure and ISO400/800/1600/3200 to be sure, in case one study in particular on a slightly older (40D) camera is not relevant to the 60D.



Hi different Rick! Yes, not quite as smooth as I'd like, and a bit brown in the colour, can't wait to try dark skies. And you're right about the registration, which appears otherwise excellent, so I can't quite explain why the dust lane is not quite so good. Might look into it some more if I continue to get very cloudy skies :sadeyes:

[jsmoraes]

I see that with ISO 400 and 800 we have better noise rate, but the main issue for me is that Canon has the trend to saturate the RGB pixels easily, making all stars white color.
My experience says that I got better stars and clouds color with ISO 400. I use ISO 800 only if the target if very faint. ISO 1600... unusual !