a couple of fails...

[glowingturnip]

In the interests of full disclosure, I thought I'd share a couple of my attempts that have *not* gone quite as I'd wish...

Firstly, can you guess what this is ?

Yep, that's right, it's the Helix Nebula !  23x 300s ISO400, flats darks and bias, equipment as per sig, unmodded DSLR at prime focus.

I'm really not sure what's happened with this one.  It's listed as having an apparent magnitude of +7.6, but it was completely invisible in the eyepiece and virtually invisible in the individual subs.  It was only because I was able to get my Synscan centering spot-on to the 3 surrounding named stars that made me carry on at all.  I've managed to capture the central star, and that's mag +13 so how come the nebula itself is so faint in this pic ?   However much I stretch it I can't get anything more than this green smear.

My DSLR is unmodded so will have missed a lot of Ha, but there should be plenty of visible light spectrum stuff in this nebula too.  I was using an LP filter (can't remember the make and don't have it here) which I think has harmed my red channel a little, though I used the exact same set-up for my Lagoon Nebula pic (http://stargazerslounge.com/topic/225492-lagoon-nebula-m8/) which I'm quite pleased with.  I don't think I needed the LP filter really, I could see the LP dome above the nearest town (Malaga) and was shooting through the top of it, but could have done without the filter really, its effects on my Eagle neb pic were fairly obviously detrimental.  Lastly the ISO400 was a bit of an experiment and I think not entirely successful, will go back to ISO800.

And then there's this fairly pretty open cluster, that you might not recognise, because it's usually surrounded by gorgeous clouds of swirling nebulosity:

Yep, it's the core of the Heart Nebula, NGC896 !  15x 300s at ISO400, same set-up as above but without the LP filter this time, and the result of several hours battling with nightmare backlash tracking.

Fairly obvious what's gone wrong with this one - no Ha, and I think a modded DSLR is in my near future, if Santa is kind...

Fairly pleasant as it stands and I could press on and process it properly as an open cluster, but I don't really want to have the only pic of the Heart Nebula on the internet without any nebulosity showing !  That faint smudge right in the middle is about the only nebulosity I can get (the lightness in the top corners is amp-glow from my rubbish DSLR (hint hint Santa) that I haven't bothered processing out).

ho hum !

[Tinker1947]

I think you require a Filter to show Nebula at the best.....this is a visual filter so not to sure if it works  with a DSLR....

http://www.firstlightoptics.com/uhc-oiii-visual-filters/baader-uhc-s-filter.html

[D4N]

Yeh photographing emission nebula with an unmodded DSLR requires a lot of patience

I was a bit miffed at the dust bunnies I got from stripping the filter out of my camera but glad I did it as even a single 5min sub shows up these nebula.

Remember that the magnitude is the objects total brightness, this is being spread over a large area so it looks faint.

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[glowingturnip]

I think you require a Filter to show Nebula at the best.....this is a visual filter so not to sure if it works  with a DSLR....

http://www.firstlightoptics.com/uhc-oiii-visual-filters/baader-uhc-s-filter.html

it's a UHC/LP filter I was using, but I'm not happy with it.  Actually I did notice that when taking my flats with the filter in place using a laptop whitescreen, that the flat's red channel was almost entirely removed (it's there without the filter).  Laptop screen isn't going to be a whole-spectrum light-source, but I was surprised the whole channel was gone.  Maybe I need to look at a better UHC filter.

Remember that the magnitude is the objects total brightness, this is being spread over a large area so it looks faint.

aha - just googled 'surface brightness' - yep, makes a lot of sense !

Anyway, a couple of do-over's to save for better equipment I think.

[D4N]

I use my iPad for flats and a Baader UHC-S filter and don't have a problem with the colours, the blue gets slightly more exposure but I suspect that this is due to the output of the iPad rather than restrictions from the filter.

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