NGC 300 in colour

[Placidus]

We've added 12 hours total of 2x2 binned RGB to our previous 10 hrs unbinned monochrome shot. Pleasingly similar to Shiraz's recent LRGB photo.

Full size image here. (www.mikeberthonjones.smugmug.com/Category/Astrophotography-at-Placidus/i-5B86DkF/0/O/NGC%20300%20L%2010hrs%20RGB%204hrs% 20each.jpg)

Things to see:

- A near face-on barred spiral. The centre is neither very bright nor very orange. Indeed, a very blue galaxy given it doesn't seem to be tidally disrupted. Wikipedia reports ESO studies showing it is probably gravitationally bound to NGC 55, which is fiercely distorted and even more blue.

- Lots of tiny pinprick blue dots marking out the otherwise faint spiral arms.
The larger blue dots are presumably OB associations of hot young stars. Some of the tiny ones may conceivably be individual stars.

- Half a dozen or so conspicuous red rings [HII regions] similar to those seen in Barnard's Galaxy. Can't wait to try photographing these in H-alpha.

- A seahorse-shaped tidally disrupted galaxy with a vertical tidal tail at about ten o'clock and 2/3 of the way out from the centre.

- Squillions of background galaxies, many edge-on spirals, many red ellipticals, some in distinct clusters.

Aspen CG16M on 20" PlaneWave CDK on MI-750 fork.

Very best,
Mike n Trish

[codemonkey]

Awesome work guys. Nice tight stars, great FOV with lots of little interesting fuzzies in the background.

Colour looks a touch greenish to me? Clearly I'm not one to be talking about colour on NGC 300 though lol.

[Placidus]

Thanks, Lee.

In a panic, I checked the underlying data:

Just the main galaxy:
R 11595
G 11689
B 11727

So within 1% of colour neutral, but very slightly blue, as makes sense for this galaxy.

Whole image:
R 3828
G 3607
B 3330

So very slightly red of neutral.

If the galaxy's looking green, it might be an optical illusion produced by comparison with the very slightly red background, or it might be that your monitor is a touch out of calibration.

If lots of people think it looks too aqua or turquoise, I'd be happy to tweak it a touch.

Very best,
Mike

[RickS]

A very classy image, M&T! Heaps of detail and nice colour in NGC 300 with the added bonus of an interesting background. The seahorse is very cool.

It doesn't look green to me at all but I'm on my laptop, not the calibrated screen at home. The blue bits and Ha regions really do look a lot like M 33!

Cheers,
Rick.

[rustigsmed]

fantastic work as usual M&T. loving the background galaxies and detail in the galaxy ... maybe if I was to observe one thing it would be (from a personal view) i'd like the galactic bulge to be a smidge brighter? but perhaps just personal taste, colours look great, everything looks great! :)

Russ

[Shiraz]

straight to the top of the class M&T. that is an amazing detailed and colourful image with a fascinating background to the main galaxy. technically excellent as well.

[Placidus]

Thanks for the encouragement, Rick. Glad you spotted the seahorse!



Thanks Russ. The centre of this fellow is a puzzle. I agree with you that it would look better if it were a touch brighter. And a touch more orange, too! But it fought back. I suspect it is a bit odd as galactic centres go.



Cheers, Ray. You set the bar very high, and with a 12" too.

One systematic trouble that we're having (not wanting to attract too much attention to it) is flats. We've just ordered a 24 inch precision wide spectrum electroluminescent panel from Optec. What with the low dollar, dinner will be spaghetti on toast for a few weeks. But it might mean that we can do flats for each filter, and do them more regularly, before the dust bunnies hop to the next carrot patch.

[Shiraz]

thanks very much, but it's a 10".

in theory, flats for each colour should help with SNR - have you any experience with doing it this way?

[gregbradley]

A sensational image.
Greg

[topheart]

Hey MnT,

Very very well done!!

I like it just the way you have presented it.

I can't see any trouble with optical gradients or dust do-nutting.....have you been using sky flats??

Thanks for sharing this beauty.

Cheers,
Tim

[Placidus]

All the more kudos to you!



Used to do flats for each filter separately. Helped with dust donuts. Also helped with my half-baked observation that vignetting seems slightly different for each colour. Don't know if that's really true. Only stopped because it's such a pain. Hope to get back to doing separate per-filter flats.



Thanks, Greg! We think it's our best galaxy so far.



Thanks muchly Tim. Yes, sky flats through the observatory dome slot. We suspect that's the problem: scope not centred in slot, slot not pointing at evenly lit part of sky, uneven light, light bouncing off the side of the slot or rattling around inside the dome, diffuser not good enough, who knows. We really hope that the new giant flat screen will help. If not, it will make a great talking piece, and a reasonable interior worklamp!

[topheart]

I am finding the same issues with my 20 inch in the 3.5M Sirius dome.....please let us know how you go with the ultra-expensive interior worklamp!!
:):)

Cheers, Tim

[strongmanmike]

Colour looks good to me guys :thumbsup:

Mike

[Atmos]

That is looking pretty darn good! Well done on the capture :)

[RobF]

Mmmmm. Galaxy.
Love it :)

[Regulus]

Really lovely image. The Hi-Res is a delight to look at.
Well done.

Trev

[Placidus]

Thanks guys. Glad you like it. Tonight, after some heated debate with my co-pilot as to whether we should do another night of Luminance on NGC 300 (Trish's vote) as the seeing is extremely good, or whether to do some H-alpha to try to really nail those red rings, we did a 20 minute test shot in H-alpha and it is looking plausible. An added reason to do H-alpha: Our neighbour is out ploughing the midnight field with about 3 gigawatts of headlamps. Straight out of that episode of Midsomer Murders, with the aliens in the crop circle.

[codemonkey]

Sorry if I caused a panic, I didn't mean to! It's a brilliant image, and you're right, it could well be an optical illusion or my monitor calibration. Once again, great works guys :-)