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First light from High Halden

Started by MarkS, Apr 11, 2011, 23:15:46

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MarkS

M81, M82, NGC3077, NGC2961 on Wed 6 April 2011.

Modified Canon 350D on Bananascope (Tak Epsilon 180ED F2.8 ) with IR/UV filter only.

18 x 5min ISO 800
6 x 5min ISO 100



Larger version here:  http://www.markshelley.co.uk/Astronomy/2011/m81_06042011.jpg

There are a few dust bunnies and gradients I still need to sort out.
I took another 24 subs at ISO 800 two days later - I'll add them in at some later date.

Mark

Mike

Absolutely stunning Mark.   :o
We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology. Carl Sagan

Whitters

WOW! jaw dropping already, the colours in M82 are so dlicate. Stunning

julian


Carole


Mac

Stunning.
That actually looks 3D,
It seems if the larger galaxy is standing proud.

No stopping you now.

Mac.

MarkS


I took a measurement of sky brightness (light pollution) at zentih the same night and found it to be 30% brighter than the darkest I've ever recorded in that general area (i.e. Tuesnoad, Lydd, Norwood Farm, Appledore, Rother Valley).

I don't know if that was a good night, a bad night or an average night - I need a few more measurements under varying sky conditions to be sure.  However, the neighbours tell me the Milky Way looks good - one of them told me he got the whole family out of bed to go and watch a particularly good meteor shower!

Mark

RobertM

Great image Mark, very well processed as usual.  Those extra subs should help bring out a bit more detail, especially in M82.

Just goes to show what dark skies and an ultra fast astrograph can do in the right hands.

Robert

Rocket Pooch

Hi Mark,

Good image very nice, why do you still have noise in the image?  Also can we see a full size one?

Chris

P.S. Hee hee easy without London in the way ain't it.


Jim

Georgous image Mark. Out of interest why do you image using two different ISO's?

mickw

Very nice Mark, great colours and detail
Growing Old is mandatory - Growing Up is optional

Fay

Fantastic as ever, Mark. & you did not even have to drive to Dungeness car park to get it!!!!!!!!!



Fay
It is healthier to be mutton dressed as lamb, than mutton dressed as mutton!

JohnP

Good to see first light Mark - Congratulations - It must be nice being able to walk out into your back garden & have dark skies instead of having to 'pack up home' & drive for an hour or two.

Image looks very promising - Like you say still needs some work - Their are some strange looking gradients & noise to be dealt with but nothing I am sure your expert processing skills cannot handle.

I am thinking there is lots of Inter Flux Nebula (IFN) (think thats what you call it) floating around between these two just wondering if with your skies & scope you have any chance of capturing it - maybe you already have & that is what is causing the gradients?

Great first light anyway... :-)

John

MarkS

Quote from: Jim
Georgous image Mark. Out of interest why do you image using two different ISO's?

Jim,

The Canon 350D camera is only 12 bit i.e. it has a limited dynamic range.  So I need to take different length exposures to cover the whole dynamic range and prevent the brighter parts burning out.

In this particular case I was experimenting with changing the ISO (instead of the exposure length) to achieve the same effect.

For processing, I take each group of subs and stack them into separate images which I then combine into a single HDR (high dynamic range image) before appling my usual arcsinh range scaling.

Mark

Rocket Pooch

Jim & Fay,

It's similar to the QSI, if you saturate your stars, normally over 50k ADU you cannot create a good colour image because saturated RGB = White.

However, I think the QSI and Atik 314L are less prone not just because they are 16bit cameras and can therefore give a better scale of the readout, but because the chips saturate slower than the DSLR's. 


Something like this


well depth by chrissuddell

There are instances when you take multiple exposure lengths with astro ccd's like M42, I'll dig out some subs and show the exposure and scaling you can do with the QSI.

Chris