Abell 2744 is one of the Hubble Frontier Fields - regions selected for very deep study using gravitational lensing. The linked image shows the region surrounding the Hubble region, as well as the cluster core - most of the tiny spots of light are far off galaxies - there are only a few stars in this part of the sky.
The redshift of the galaxies in the main core is z=0.308, which means that this light has been travelling about 3.25 billion years - so it started out when simple life was just getting going here on earth. The redshift moves some near-UV absorption bands into the blue in the current universe, which is why many of the galaxies have a yellow/orange cast. I cannot get my head around the distances involved (photons can go a long way in 3 billion years, travelling at 300,000 km every second) - and it is mind boggling that every small galactic spot represents the light from about 100,000,000,000 stars.
The cluster is probably the result of the collision of 4-5 smaller clusters and the visible stuff accounts for only about 5% of the mass (ultra-hot gas and dark matter the rest). This much mass forms a strong gravitational lens, but local seeing does not permit enough resolution to see any of the many small arcs. I am pretty well at the stray/sky light limit for my system - galaxies are readily detectable down to a little deeper than Vmag 23, but there is probably not much more available.
The image has a fair bit of noise (ie is pretty ugly) in order to maximise the bottom end dynamic range and the scale has been increased to 120% to improve the visibility of smaller objects.
I had great fun imaging this region - hope you find it interesting. Thanks for looking. Regards Ray
Awesome! The cluster of red galaxies in the centre stands out beautifully. And such distance! The rest of the frame has some interesting creatures in it too.
(Possible typo: The post says 2744 but the links say 2667.)
wow, that's amazing Ray. Love it.
noise, what noise? just beautiful.
Cheers
Alistair
ah...well, there is a bit, but thanks very much anyway
Quote:
Originally Posted by Placidus
Awesome! The cluster of red galaxies in the centre stands out beautifully. And such distance! The rest of the frame has some interesting creatures in it too.
(Possible typo: The post says 2744 but the links say 2667.)
Splendid work.
Thanks very much M&T. hopefully the typo has been fixed - thanks for pointing it out. am currently working on 2667 as well.
What was the length of the subs Ray and how many?
was this from a dark site?
what's the faintest magnitude galaxy/object in this image?
Cheers
Alistair
Hi Alistair. taken from a rural township - sky about a mag brighter than dark (guess) along with with a neighbour's always-on outside light and a pesky streetlight that almost gets the solar panels working.
190xL 44xB 36xG 44xR all 5 minutes.
According to SIMBAD (if I read it right), the limit is around mag23 (V) - see attachment. Not real deep, but enough to show some detail.
Quote:
Originally Posted by Paul Haese
Faint suckers. Reminds me of the words. In a galaxy a long time ago. I wonder if there are beings looking back this way wondering the same thing.
yes I agree, some of the stuff out there can only bring a sense of wonder - what other hobby even comes close.
Quote:
Originally Posted by RickS
Great stuff, Ray! It's good to bump against the limits
Thanks Rick - Hubble images quickly show just how limited our ground-based systems are - but it sure is fun to push things a bit.
Very cool image Ray, few outside the astro community would really understand the sheer enormity of such an image, congratulations and thanks for having a shot at it Your work is such an inspiration, you plug away like the rest of us with rather modest equipment in a modest setting but manage to produce some of the best work coming out of OZ and without spending lifetimes on data collection, well done
A fabulous image Ray. Its hard to imagine all those dots are galaxies.
Greg.
thanks Greg. it sure is breathtaking to realise what this sort of image shows - I find it very difficult to comprehend.
Quote:
Originally Posted by strongmanmike
Very cool image Ray, few outside the astro community would really understand the sheer enormity of such an image, congratulations and thanks for having a shot at it Your work is such an inspiration, you plug away like the rest of us with rather modest equipment in a modest setting but manage to produce some of the best work coming out of OZ and without spending lifetimes on data collection, well done
Mike
Very generous Mike - it is a very productive community to be part of. This image won't win any prizes and no-one will go OOH when they look at it. But I feel very lucky to be alive when we can afford equipment that will allow us to peer at and vaguely understand some of the bare bones of the universe - even if imperfectly. how much fun is that .
Back on earth though, it would be nice to find somewhere with reliably good seeing. I have 5 hours of data from last night with 5-6 arcsec blobs in it .
Back on earth though, it would be nice to find somewhere with reliably good seeing. I have 5 hours of data from last night with 5-6 arcsec blobs in it .
regards Ray
Tell me about it ...ah sigh, the dreaded pom pom stars...
Back on earth though, it would be nice to find somewhere with reliably good seeing. I have 5 hours of data from last night with 5-6 arcsec blobs in it .
regards Ray
Yep those northerlies last night produced lovely sized stars even in NB for me. FWHM readings were in the 4-5's for the RC. Urgh! Even the AOX cannot produce miracles in poor seeing. A rarity from my location but it does happen from time to time.
Yep those northerlies last night produced lovely sized stars even in NB for me. FWHM readings were in the 4-5's for the RC. Urgh! Even the AOX cannot produce miracles in poor seeing. A rarity from my location but it does happen from time to time.
Err, umm - how can an AOX produce miracles in poor seeing?
Not much to say other besides what's been said already; great work Ray!
thanks very much Lee.
Quote:
Originally Posted by strongmanmike
I did
Tell me about it ...ah sigh, the dreaded pom pom stars...
yep, they leave a lot to be desired
Quote:
Originally Posted by Paul Haese
Yep those northerlies last night produced lovely sized stars even in NB for me. FWHM readings were in the 4-5's for the RC. Urgh! Even the AOX cannot produce miracles in poor seeing. A rarity from my location but it does happen from time to time.
It was pretty ropey seeing up this way - looked like turbulence from the Snowtown windfarm.
Quote:
Originally Posted by CosmicEcho
Err, umm - how can an AOX produce miracles in poor seeing?
I think that Paul was making the point that AOX cannot help when seeing is poor - current AO works best in good seeing.
It was pretty ropey seeing up this way - looked like turbulence from the Snowtown windfarm.
I think that Paul was making the point that AOX cannot help when seeing is poor - current AO works best in good seeing.
regards Ray
Someone I know has a 30" at Black Springs and he reckons the wind farm nearby has resulted in very poor seeing there some nights.
I don't have any such excuse other than the hills zone is 40km from me and a northerly will create eddies but I did not think it would travel that far.
And; yes I was being facetious about the AOX not being able to help in crap seeing. Rounds stars but not tight. Detail not tight either.
.
...ah sigh, the dreaded pom pom stars...
