Eagle LRGB Leg Granges

[Rocket Pooch]

Hi,

Ok this took a little while to process, but here it is, M16 (Eagle nebula) LRGB

L=9x5 minutes HX916 binned 1x1
RGB 6x2 minutes HX916 binned 2x2

Aligned and stacked AIP4WIN LRGB completed in photoshop.

[Rick]

Great photo. Seeing the big picture, it's now much clearer to me why it's called "The Eagle".

[Mike]

Another great image from the Suddell Image Factory.

[Fay]

Chris,

that looks absolutely fantastic! Such short exposures as well.
On a very good night, do you think as good an image could be got here with the same exposure length?

Fay

[Rocket Pooch]

Hi Fay,

From my back garden no is the answer because its too low and there's too much light pollution, if it we're higher I would be able to do an Ha S2 and OIII image but definitely not a LRGB.

At Leg Granges the sky reading from my camera was 3398 adu's is I subtract darks this comes down to 422 adu's
At Tuesnode facing away from Ashford its 4110 with darks removed it comes down to 1,000 adu's
In my back garden facing anywhere its approx 12000 with darks removed this comes down to approx 9,000 adu's[/li][/list]


This means that the background noise is approx 20 times less at les grages than my house Tuesnode is approx 9 times less, the Eagle nebula cloud has a ADU reading of 1380 - 4990 ADU's, with my skys at home I have a background reading of 9,000 ADU's, so the eagle cloud would get lost in the background noise.

So the only way to reduce the background noise would be with the use of Narrow band filters, they reduce the background noise a lot, but the also need 10x the exposure so I would be taking 20-30 minute subs to get the same detail.

Chris




P.S. The lowest sky background reading I have measured so far was at woodlands park, it was 245.  But the reading at Les Granges are probably a little high because it was warmer than the -5 to 5c we image in here in winter and autumn.

[Fay]

Good grief, Chris, the answer seems to be no, then? Although we have to do what we can with the skies we have most of the year.
It will make us a bit fed up after seeing your images from France, knowing we cannot attain that quality,
Although there are a lot of very nice images that have been taken by the club, from local climes.



Fay

[Rocket Pooch]

I think it could be taken from Kent no problem, but not from Orange Mottingham, not in RGB anyway.

[Mike]

I think even from my garden, which isn't too bad on the light pollution front, it would be hard. As Chris says, in Narrow Band it would be reasonably easy. I have this in Ha somewhere that I did about 2 years ago, though nowhere near as good a STN ratio that Chris has.

[Whitters]

Stunning image Chris

[Rocket Pooch]

Thanks Paul, when you get a chance have a look at my album http://www.deep-sky-photography.com/album/index.html can you let me know if the bubble and ngc6888 are really grainy, I think the s/w is compressing them a bit.

And I've updated the format a bit.

[Fay]

Chris, I notice that when I put an image on the forum they look grainy, not as good as when on the laptop, which is a bind.


Fay

[Rick]

Specialist image manipulation programs like Photoshop will probably do a better job of displaying an image file than web browsers. Also, if they're viewing the original tiff (or whatever) rather than the jpeg they may fool you into thinking the jpeg looks better than it does, so always check the jpeg to see whether it's mangled during compression.

Check whether they're being re-sized or compressed along the way when you upload them. Many upload sites will re-size large images, and some upload programs (and emailing programs) will re-compress images on the fly.

The new OAS gallery is set to accept images up to 8MB without re-sizing them, but it will produce a scaled-down version for quick display if the image is over 800 pixels wide. You can view the full-sized version by clicking on the quick display version. However, if you make use of the image cropping and scaling functions in the gallery then the imaage will be re-compressed when you save the changes, and this could affect its quality.

[Fay]

Thanks for that, Rick.

Fay

[JohnP]

Chris - great image & expertly processed - Well worth the wait.

Fay - The Eagle is definitely doable from Bromley/ Orpington - although like Chris & Mike say don't expect the quality & smoothness of Chris's. Check my webpage I imaged it using only 10secs exposures & a cheapo skyglow filter (L only though no RGB)... You'll need to plan & setup in advance though the window of opportunity to capture it is small....

Cheers,  John