First light from High Halden

[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.   

[Whitters]

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

[julian]

WOW                

[Carole]

Fantastic Mark.

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

[Fay]

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



Fay

[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]

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