M7

[rogerg]

G'day all,

For some reason I love this shot of M7. I have a feeling I might end up picking holes in it and tiring of it, but for now I really like it :)

http://www.rogergroom.com/items/M7_June2010

As I comment on the page, there isn't much variation in star colour captured whic is perhaps a negative, and there's the wonderful distortins I'm battling with the WO FFv3, but the overall golden dusty, sparkling look of the stars/image I really like for some reason :)

I'm not sure ... maybe it's poorly processed and if processed properly it would have more colour? more variation? MabyeI haven't got the white balance right and it's too yellow, I don't know for sure but I'm reasonably confident I've got the coour true to what I captured on the night :shrug:

Roger.

[Octane]

Similar to my field from a few weeks ago, through the ED127.

I think you have a bit too much red there, Roger. Try easing back on the red and perhaps introduce a bit of green.

H

[TrevorW]

Go for gold Roger

[mental4astro]

Stunning amount of detail. Cripes, one of the dust features immediately to the right of the centre of M7 looks like a winged man!

M7 too is one of my favourite clusters. As a youngester, I only could see, and knew of, only the main stars forming this naked eye cluster. Didn't give it too much telescopic attention since until a chart available through IIS showed that M7 is a 4 for the price of one special, with another open cluster (seen here to the bottom right of M7- 'smaller' stars, more densly compacted cluster), a planetary nebula (too small to be seen at this scale), and a faint, small globular cluster (washed out, and probably to small also to make out clearly).

I'm still to find the planetary, but the globular is a little challenging to make out through the glare and confusion of all the bright main cluster stars.

Not doing imaging, I do have a question about the iso speed selected. Of cause this ain't film, but how would a slower speed setting affect the picture, other than making for a slower exposure. I wonder if the speed settings would not affect the colour rendition of the camera somehow. Might there be a colour imbalance occuring at this iso setting somewhere in the hardware?

Alex.

[rogerg]

Thanks H .. seems obvious now. I've updated the image to a new less red one, tweaked the green too. I think it's better without a doubt. Thanks!



:)



Interesting to hear about the Planetary ... I'll have to look at my 100% size image just in case :)

Good question about the ISO. I chose 1600 because it was a cold night so wasn't too worried about noise (noise being the biggest problem of higher ISO) and in the end I'm glad I chose the higher ISO because noise really wasn't a problem in this particular night.

As for colour I think there is a variation between ISO's on colour balance. I think there have been other people in IIS which have done some ISO tests in recent times and shown a difference in colour, I think that was tested ISO 400 vs 800 but sure 1600 would show a variance too. Interestingly you don't notice it in short "terrestrial"/"normal" photographs (or I haven't at least) but in the long exposure the ISO does seem to have an impact on the colour balance. Perhaps it's that which made my original image redder :)

[Octane]

Roger,

Gettin' there. I reckon you can push it a bit further, too.

I found two green blobs with a red middle in my version and I thought it was random noise so cloned them both out. I found out later on that they were planetary nebulas, haha!

H

[Hagar]

Very nice image Roger.

[rogerg]

Well, believe it or not I just found a planetary neb in the image! Thanks for making me take a second look!

Here's a crop with the planetary near the top-centre. Very blue/green.

:)

PS. JPG compression ratio is quite high but I wanted a large enough image to include some of M7 to give perspective.

[mental4astro]

Nice one Roger! I'll use this image of M7 as reference to visually track down the planetary too.