M83 over ARO domes

[ericwbenson]

Hi,
Not sure if I should post this here or in the nightscape section, since this one is a composite image of a simple 350D snapshot at dusk of our remote observatory site near Arkaroola, and a very deep space look at M83 with the CDK20. I put this together on a whim so I just used the mosaic tool in MaxIm for simplicity. The M83 data is the same as I posted here a couple of years ago, but 'colour enhanced' compared to before (I pushed the saturation lots + some unsharp masks etc).

I made a larger size version of this image the background on my website homepage here:
http://www.faintgalaxy.com

Cheers,
EB

[gregbradley]

Very arty Eric and that is a lovely M83.

Greg.

[clive milne]

Nice one Erik.
I like the subtle visual cues; the brightening of the horizon and the star field reflected on the dome skins. Having such a good M83 doesn't hurt either.

I'm almost reluctant to add the following suggestions for fear that they might imply a deficiency in the shot, but the realism could be enhanced with a couple more tricks.
* Perhaps add a gradient that approximates atmospheric extinction... easier said than done. You couldn't just reduce the intensity of the stars, it would also require reducing their apparent size to remain consistent with the rest of the shot. The simple way to do it would be to progressively reduce their number as you approach the horizon. (delete the brighter ones whilst reducing the overall number and consider whether the background galaxy on the far left would actually be visible)
* Maybe consider adding distortion (spherical surface rendering) to the star field reflected in the surface of the domes.

Incidentally, I am curious to know if you (or Mark) have kept a record of the astronomical seeing conditions at Arkaroola and whether your experience is consistent with the figures measured during the site evaluation of Mt Searle by the ANU? It seem like a phenomenal site.

best,
c

[ericwbenson]

hmmm, good suggestions, but I'm not sure I really would know how to do either! I am not a user of photoshop unfortunately (or fortunately?!) Maybe some rainy day I might learn.



Well, Mark uses a TAK106 with STL11K, his sampling is 3.5"/pix, he has great seeing pretty much all the time. With my setup at 0.53"/pix I can still get mushy data. However due to my interminable equipment bad luck (well it seems that way to me at least), I have not had enough telescope time to make a long term judgement about the validity of the published data. Let me say that I can make deep images with 1.8" overall FWHM fairly easily, 1.5" has been possible (the Antennae for example), on good nights I will observe 1.3" for multiple long exposures. All of these numbers are obviously not at zenith, but generally > 60 deg altitude. I have, while doing testing/collimation on the scope, been there to witness ~0.9" on some shorter exposures. Our site is not the highest peak in the area (we picked one that had a road to the top) so I would think we get worse low level seeing than Freeling Heights due to turbulence coming off the other peaks, however the mid level and high level jet stream stuff would be consistent for both sites.

I have the paper by Wood (1995) but not the paper by Hogg (1965). Do you have the later? I have also found a paper by a masters student, Hotan (2012), but I can find serious deficiencies in the results.

Cheers,
EB

[Ross G]

A bit of fantasy!

Something different Eric....I love it!

More please.

Ross.

[Q.]

Original ! I love it too !
Cheers
Q

[PeterM]

So good and well put together. It's real astro-art. Love this stuff when done so well. Just perfect for a 27 inch screensaver.

[clive milne]

Well, there is the extraordinary claim of 0.35" seeing on the Arkaroola resort web page. However, I have not found much to lend substance to it.

In the 1965 Proceedings (Mt Stromlo, ANU, Bok) on page 72, there is a reference to:
Hogg, A.R., 1965. A telescope in the desert. Australian Physicist 2, 29.
But that draws a blank searching via google.

best

c