Horsehead & Flame processing issues / queries...

[AndyUK]

Hi all - After nearly 7 weeks of waiting, everything finally conjoined and I was finally able to get my first ever "synguided" image using my new MN190 with my newly modded 40D... (LOTS of 1st lights last night...!)

Having always set my heart on the Horsehead and Flame nebulae (and it now having risen above the house at a reasonable hour), I eventually got everything set up. I was expecting to have to use at least 600s subs, but quickly found with the full moon that the most I could get without blowing the histogram was 180s. Still I got 27 subs and 20 darks (no flats. flat darks or bias) and stacked them in DSS. I then applied curves / levels and tried some other "tweaking" in CS5 to try and get more colour / colour contrast (and in the absence of flats, I've used gradient xterminator...)

The result is less than I was hoping for, but I'd really welcome some comments on what's going on. I have some dust in the path somewhere (which I know flats will get rid of), but I can't seem to get anything else out of this. Also, as this is only a 180s exposure, I imagine that with longer exposures, Alnitak is REALLY going to dominate - Is there anyway to somehow reduce it...?

Is there anything more I can do with / get out of this, or should I simply accept that on bright moon nights, it's pointless trying to image anything other than Luna herself? I've seen other images of this taken with an MN190 but at the moment I seem a bit lost...

[carastro]

I've managed to get a bit more out of it but the histogram looks a bit awful, but might help if you just want a picture to show. But as you are aware it is greatly suffering from lack of flats.

Carole

[johnh]

Looks washed out with Moonlight, unfortunately there is no filter to reduce effects of the moon unless using an Ha filter which DSLR's can use but exposures will be a lot longer. You will need curves to darken the backgd and raise the faint signal. Only night clear there is a big Moon - welcome to imaging!

John.

[steppenwolf]

Hi Andy, the Moon certainly was in the wrong place for you. I too have had a look at the data and reduced the size of Alnitak:-

This is what I did if it is of any interest -

1. Adjust levels to even out the histogram and clean gamma

2. Convert to LAB Mode and increase contrast of ‘a’ channel to boost red

3. Clone out part of the filter fare around Alnitak

4. Select Alnitak and reduce size using filter – distort – pinch

5. Duplicate layer and smooth copy. Blend with original until noise just appears

6. Duplicate background layer and move to top of stack

7. Sharpen this duplicate layer

8. Convert sharpened layer to Layer Mask:- Layer – Layer Mask – Hide All

9. Use brush to ‘paint in’ some sharp features like the filaments of the Flame, Horses ‘mane’ and the centre of Alnitak

10. Flatten layers and gently tweak Curves to brighten a little (I probably overdid this as it has revealed the vignetting!)

[AndyUK]

Cheers all - You've all managed to get much more out of this than I did, but I think I'll leave DSO's alone from now on when the moon's up - I'd really hope with longer and more subs (and no moon!) I'd get a better image than this(?)

I'll admit I've been avoiding flats to date, and been relying on Gradient Xterminator to do its stuff - Until I sent the camera away to be modded, none of those blotches were visible so I was actually quite surprised to see them (and how bad they were), so I guess my days of avoiding flats are now well and truly over!

And when the moon's full (and the sky's clear), I guess I'll just have to concentrate on webcam work but could certainly do with lots more practise on setting up and taking mosaics anyway...

Steve - Is there a well-known technique for reducing stars...? I do have Noel Carboni's tools and just realised that there's a function in there I could have tried, but, where possible I prefer to try and do it myself as I have more control!

[steppenwolf]

I'd really hope with longer and more subs (and no moon!) I'd get a better image than this(?)

Oh yes, don't worry, you will - don't underestimate just how bright the Moon is!

Is there a well-known technique for reducing stars...? I do have Noel Carboni's tools and just realised that there's a function in there I could have tried, but, where possible I prefer to try and do it myself as I have more control!

Noel's actions are very good but are not intended to work on such a significant object as Alnitak - it is designed to work on the 'background' stars on which is does a good job. There are various techniques for reducing the size of an individual star but the one that works best for me is the method detailed above but you will need to use it carefully as it drags inwards everything within the selection. For example, I haven't corrected it because it was just a down and dirty adjustment to your image but Alnitak has a close companion and this technique will drag that star inwards as well thus upsetting the correct separation between the two. The solution is to select this star first and copy it, carry out the 'pinch', clone out the companion and then paste it back again from the clipboard.

[ollypenrice]

The beginning and of end of this is the moon. I would never go anywhere near RGB imaging with the moon up. I would see it as a total non starter, which is a pig because we have had ten of the most perfect nights in history right through full moon. But right now I could go outside and read by the darned thing. Grrr....

Olly

[AndyUK]

Cheers again Steve - My apologies for apparently asking a redundant question. For some reason I didn't see the process first time around. I'll store this for future reference (thanks!).

It's so frustrating after all the nights (days) of cloud, rain, fog etc we've had over the last 7 weeks - I was really hoping that my first light out with the whole setup would result in a really impressive image... that I could show to my wife and justify all the recent expense (and maybe get clearance for more funds!).

Having said that, she was pretty impressed with the results here... although of course I can't claim them as mine as I didn't process them!

Olly - If nothing else I think I've now learnt that lesson myself - I shan't try it again. We've had another beautiful clear evening tonight (okay, the clouds are now moving in), but after last nights efforts (and the not so successful result), I've satisfied myself with lunar viewing instead - It's incredibly bright again tonight... but I'm just SO desperate to see what this MN190 can do!

[ollypenrice]

I know how you feel but fear not, the 190 will do wonders...

Olly

[AndyUK]

Thanks for that Olly... I guess It'll just be my technique and post-processing that will let me down then...!

[steppenwolf]

Andy, you are well on the way and your image was taken against a backdrop that was never going to work out yet you still captured one of the most challenging objects - remember, you can't realistically even see this object through an eyepiece (yeah I know, people have but ...!). I think you are going to be really impressed when you repeat this in the right conditions.

[AndyUK]

Thanks Steve - I was feeling quite depressed about it yesterday...

I had (have) such high expectations and I was comparing this with other 190 shots on the internet - I know that my processing skills are severely lacking, but I was hoping that, relatively speaking, the capture of the subs would be comparatively easy (given dark skies and some good flats!) and the processing is something I can "play with" on those all too regular cloudy nights...

I needed this encouragement though - Thanks again (also to Olly). I'll keep my fingers crossed that we get some clear skies in a week or so's time...!