M42 - first attempt

[dawson]

My first attempt at a DSO.

 

I hadn't planned to do it, I was just playing with my scope and checking it's Goto accuracy and stumbled on M42 and thought I'd have a go at imaging it. The first 5 second image was so convincingly M42 I thought I'd get a few frames and stack them for a laugh and see what happened! this is 20 x 5 second frames, 10 x 10 second frames and 5 x 20 second frames, no dark frames. I had stacked the data the other night but it was very B&W and Pat commented if I'd purposefully taken B&W. So I've watched a few online DSS tutorials and re-stacked the data and played with the RGB/K levels and luminance and saturation and come up with a lovely colourful image.

 

Why is the image so grainy?  Lack of data? Lack of darks? Lack of operator skills

 

Thanks for any comments

 

James

 

[dawson]

Here is a screen shot of the settings I'd got. I tried to mimic what one guy on a tutorial was doing, but there was no sound so I wasn't exactly sure what I was meant to be doing. I shifted all the colours to the left on a flat part of the line. Then tried to get the line to go up through the grey peak and make the overall curve exponential, but I don't understand what it all means. I set saturation to 18% as he did.

 

James

[catman161]

I think that looks awesome James. I'd be proud of that as a first DSO. Great colour and definition-good stuff. Onwards and upwards

[Brantuk]

Congrats James - great first dso - I'll bet you're excited now - but beware it's like a drug and imagers do get addicted lol.

Well done!

[dawson]

I forgot to add the screen shot:

 

 

[dawson]

Thanks Pat. There were some 20 second exposures but I felt the stars weren't looking as sharp as the shorter exposures and I think my mount was struggling. But I will try a load of 20 second exposures next time. M42 was being very kind to me and being in an area of the sky not moving very fast

 

I didn't do any processing outside of DSS. I will wait until I've got more data and then have a better go next time (if the cloud ever breaks).

 

Thanks again for the help.

 

Once I've got more data I could really do with sitting down with someone who knows how to use these software packages as I'm really just playing with things I don't understand. How many darks should I take? Is there an easy way to take darks once the dew filter is on without upsetting the alignment and tracking?

 

James

[dawson]

OK. So how many light frames do you think I should aim to get, if my maximum exposure is 20 seconds per frame, and probably 15 seconds to be safe.

 

James

[+Graham]

James

I can only tell you what I do.

 

The simple answer to your question is as many as you can get.

The more lights the more data the better the image.

On M42 I use 30 second subs and anywhere between 200 - 300.

This gives you the chance to weed out the crap subs and still have a huge amout left.

 

Darks you need a ratio of 3 to 1 up to a max of 21 Darks.

Any more than 21 has no effect and can make things worse due to signal to noise ratio.

Always use an odd number, for some reason DSS likes odd numbers. (must be a maths thing)

 

More important is the flats.

Again max of 21. These will get rid of the imperfections in the light train - dust bunnies, dirt marks ect.

 

Looking at your screen grab.

The second slider down move to the right. This will move the Black point on the curve down.

You want this to be as low as you can on the front of your RGB spikes.

I find it is best not to move sliders 3 and 4 too much as these are the ones that will create the 'grainey' effect.

 

The best piece of advice I got about using DSS was from Stephen.

Always move the RGB spikes to the curve.

Make an adjustment to the curve using a slider then with the RGB locked together move the spikes back into position on the curve.

 

Set the Saturation level to 18.

 

That is a great first attempt and like the rest of us will get better as you do more.

The best learning aid is experience.

Keep playing with the sliders and note what each one does and how it effects the final outcome of the picture.

[BAZ]

That's impressive for a first image, OK it's a bit noisy, but you have good "fish mouth" detail, and the trapezium.

 

You do realise you are past the point of no return now! You are an imager.

[dawson]

Once I've stacked the frames get this screen. How far to the left should I slide the coloured peaks? The resultant TIFF file is 26MB; would anyone be up for playing with it for a few minutes to see how far off I am with the settings given my data?

 

James

 

[catman161]

Hey James,

Have a watch of this-25mins long but may help you.

http://www.youtube.com/watch?v=UWWaKkCUm6c&sns=em

[dawson]

Off to make a coffee then going to watch that Felix, and download a new version of GIMP.

 

James

[dawson]

Well, that was lengthy. two hours of online tutorials on processing DSS images in photoshop. Now at least I've got an idea what 'layers' means, as it was double dutch to start with. I know Pat told me not to waste any time on the existing data I've got, but it was useful to just use it to go through the motions of playing with layers and levels and curves [check me out with the lingo]   

 

Anyway, as Pat suggested, the resultant image on this occasion is no better but now at least I've got a rudimentary idea of what I'm meant to do. Image below.

 

I now want to grab some better data and get this hands on tutorial by Pat and see what results I can get.

 

Thanks again all.

 

James

 

[catman161]

Glad it helped. Onwards and upwards with the experience and downwards goes the bank balance

[dawson]

Yes, I'm still coming Pat. I'm grateful for the offer.

 

James

[Guest Wayne]

I know nothing about imaging. But that looks great. I'll get there one day.

[Guest spacedex]

Great start my first one is worse than this mine was over exposed

John

[dawson]

I din't think there is any chance i'll ever get an over exposed DSO image with my current set up, my maximum exposure time is about 20 seconds!

James