How to lift the Veil?

[Camelopardalis (Dunk)]

Folks, so I gathered some data on the Veil at Astro Fest, 90 minutes worth, and it's really really faint some nice colours and detail coming through (in the bigger versions!), but the central portions especially are really faint. One interesting thing is the red hue across the whole mid-section of the image, while the left and right edges are much more black, so I'm guessing this is the much much fainter overall nebulous bubble.

I've been trying to be careful with the curves tool to try to lift the nebulosity over the "noise" of the starfield but it also comes at the expense of highlighting some of the similarly coloured stars.

Any ideas as to how I can enhance it further? Is it just a case of more extended subs or more subs, or do I need gather some OIII data and throw that into the mix?

Oh, and as with my other images making the onslaught, this is the ZS71+EQ6+1100D, 23x 4 minute subs (+darks+bias).

As always, any suggestions and experiments welcomed

[cometcatcher (Kevin)]

Nice shot Dunk!

Probably does need more data but I think more could be squeezed out of what you already have as well.

Another on my "to do list" now that I have cleared some northern sky.

[Camelopardalis (Dunk)]

Thanks Kevin! It's really a lovely object, although easier to see visually to some extent, just not as much detail

[cometcatcher (Kevin)]

Would you have a RAW unmodified TIFF straight out of DSS I could have a play with Dunk? I'm seeing a lot of potential in the data.

[RickS (Rick)]

Originally Posted by Camelopardalis

One interesting thing is the red hue across the whole mid-section of the image, while the left and right edges are much more black, so I'm guessing this is the much much fainter overall nebulous bubble.

Dunk,

I'm afraid that reddish area looks more like a gradient or uncorrected vignetting in the red channel. It doesn't correspond well to what I've seen in deep images of the Veil.

Good luck pulling some more detail out of the data. I'm sure there's more there if you go digging for it.

Cheers,
Rick.

[Camelopardalis (Dunk)]

Originally Posted by RickS

I'm afraid that reddish area looks more like a gradient or uncorrected vignetting in the red channel. It doesn't correspond well to what I've seen in deep images of the Veil.

Thanks Rick, so now must be a good time to learn about flats

[RickS (Rick)]

Originally Posted by Camelopardalis

Thanks Rick, so now must be a good time to learn about flats

It's always a good time to learn about flats, Dunk You need everything working as well as possible for a difficult northern target like that.

[Camelopardalis (Dunk)]

so I'm guessing flats from a brisk Sydney winter afternoon aren't ideal?

[RickS (Rick)]

Originally Posted by Camelopardalis

so I'm guessing flats from a brisk Sydney winter afternoon aren't ideal?

Taking flats some time after the lights is never ideal but they may still be helpful. In a perfect world you'd take the flats before making any changes to the optical train.

[Mosc_007 (Charles)]

One thing you didn't mention is weather your 1100D is modified or not. If this Nebula is mostly Ha then a stock camera wont pick it up much at all. The Ha is filtered out of the stock camera.


Charles

[Camelopardalis (Dunk)]

Originally Posted by RickS

Taking flats some time after the lights is never ideal but they may still be helpful. In a perfect world you'd take the flats before making any changes to the optical train.

Noted... and now I understand why I just took some flats with a double thickness t-shirt and I must have had the dew shield on wonky Is there anything to be gained by taking the flats without the (flimsy) dew shield on? Or does that change the light rays too much?

Anyhow, here's another go...it's better...I think...took less curve stretching to bring out the nebulosity.

[Camelopardalis (Dunk)]

Originally Posted by Mosc_007

One thing you didn't mention is weather your 1100D is modified or not. If this Nebula is mostly Ha then a stock camera wont pick it up much at all. The Ha is filtered out of the stock camera.

The 1100D is stock, unmoved. According to Wikipedia (FWIW), it's a OIII emitter, so I'm thinking next time around I'll stick the filter on and see what happens.

[RickS (Rick)]

Originally Posted by Camelopardalis

Noted... and now I understand why I just took some flats with a double thickness t-shirt and I must have had the dew shield on wonky Is there anything to be gained by taking the flats without the (flimsy) dew shield on? Or does that change the light rays too much?

Anyhow, here's another go...it's better...I think...took less curve stretching to bring out the nebulosity.

Generally it's safest to leave everything the same as it was when you did the lights although taking the dew shield off should be OK unless it was causing vignetting (it would be a very poor design if it was...) Making good flats can be a bit of a challenge.

[Camelopardalis (Dunk)]

Thanks Rick - the evil dew shield is just a small foam mat I rolled up and gaffer taped together at astrofest, after discovering dew on the objective on the first night just using the WO shield. I stuck it on this afternoon to replicate, as closely as possible in daylight, the original conditions.

I might give it another go without foam mat tomorrow then, although I'd prefer to focus on something astro proper at night instead of a distant cloud

Btw, in the above image I noticed fuzzy rings appearing around the bright stars too. I don't see the effect in the first try, despite all the extra curve stretching involved

[cometcatcher (Kevin)]

The repo looks much better Dunk.

[LewisM]

Best I can do with the supplied JPEG

[Camelopardalis (Dunk)]

Thanks Kevin!

But WOW! LewisM...amazing...that came out of my ropey JPEG?!

[LewisM]

It's all there - just stretch each channel rather than the entire image

[Camelopardalis (Dunk)]

Thanks LewisM - will give it a try!

[LewisM]

Go here: http://www.atalas.net/

And click on LEARN. Watch Louie's tutorials. Helped me enormously. Plus he's a forum member here too