Double Cluster Unguided - My first "Proper" DSO Picture:

[Bizibilder]

I took this on the 10th October but have only just gotten around to processing it! 11 subs of 2mins each plus 7 darks. (I took 24 subs but rejected the others for various faults like trailing and one with a double image!

Processed in DSS (using a couple of tutorials -thanks to those that write these!) and Photoshop ( Thanks Steve Richards for "Every Photon Counts"). I have cropped about 5% from the extreme edges.

As you can see I need to learn a lot but I'm happy with this as my first image with "proper" (ie 16bit) software. I know that it is far from perfect so comments and suggestions greatfully received!!

[Beyond_Vision]

Thats a pretty good first 'proper' attempt at DSO you have some reasonable colour to the stars and the tracking looks good. The focus is slightly soft and there is some coma to the edges. Adding a coma corrector and using some flats would give it a real lift

Much better than my first attemts

Regards

Kevin

[Bizibilder]

The coma corrector is on my shopping list (among one or two other bits!). At the moment I have no easy way of taking "flats" - or is there a way that I don't know about - it seems some sort of evenly illuminated light box is called for - quite a job with 8" aparture! I believe that I must take them at the same time as the lights? What do es everyone else do?

[Beyond_Vision]

You can put a white T-shirt over the scope and take a series of images at dusk or dawn when there are no stars visible in the framewith. Use an exposure which gives a peak in the histogram of around halfway. If you fancy making a light panel yourself look up Earlsmann Lighting on the net and go for the A3 size electroluminescent panel. It comes with a PSU that runs off of 12V. A mains PSU can be bought as an optional extra. To protect the delicate panel you cn sandwich it between Perpex.

Regards

Kevin

[Deneb]

I think you've accomplished that quite well as unguided. If you can't afford a light panel for your flats, you can build a lightbox out of foam board & quality tracing paper for your diffusers. What ISO was this taken with ?

Nadeem.

[ollypenrice]

The key thing is flats. Absolutely essential. You can indeed do them at dawn-dusk though I never had much luck with this. A light box is easy enough to make and cheaper than a panel. You can use expanded polystyrene sheet for the structure. The inside should be white and the bulbs should have a full-ish spectrum. I had some that gave insufficient blue.

A thought on coma correctors. Some are rather long and push the camera a long way out from the scope, raising the difficulty of keeping everything orthogonal.

How did you focus? I use FWHM in my Artemis Capture software or a Bahtinov mask now that I have them.

Olly

[Bizibilder]

Thanks for the help, all of you:

Kevin: Thanks for the info about light panels - I think they may cost a few bob so may have to go on the shopping list! This may sound daft but which histogram do I look at to see if I have the right exposure of the flats? - Do I take a pic and use the histogram that the camera shows or do I download and use software? Once I have "calibrated" my flat this way can i simply use the same settings for all flats (at the same ISO)? Also how many flats do I need to take?

Olly and Nadeem: What type of bulb(s) should I consider for a light box? Is there a favoured "brand"? I should have mentioned ISO, sorry, it was ISO800. Focussing - I do have a Bahtinov print out for the 200P - I just have not had time make the mask! (On list of things to do!!) So I just aim the scope at a bright star (usually Deneb at the moment) and use "live view" to get it as sharp as possible, then a couple of 5sec exposures to check. My version of a coma corrector will have to be the crop tool for a while! - the trouble with the double cluster is that it is pretty much full-frame.

I don't have a lappy yet so computer conrol of the scope or camera is a no-no.

At the moment I just want to concentrate on trying to get some half decent images with the kit that I have. I am a complete beginner with digital photo processing so DSS, PS etc are each a real "mystery bag" of tricks. I am quickly beginning to learn that there is far more to astro photo's than just "click and print". So one step at a time is the way to go - a bit like a good science experiment - only change one parameter at a time or you will get confused

As an aside I have downloaded IRIS software as it apparently has a "gradient removal tool" however I have absolutely no idea how IRIS works I will look around the forum or start a thread to ask if there are any tutorials on it. I did open a picture in IRIS but all i got was an almost total "white out" over the whole screen so I need to get past that stage first .

Sorry about all the questions I assure you there will be more!!

[Deneb]

For my lightsource for the lightbox I have used a bright LED wall light,which consists of around 20 leds. You can buy them from Tesco, Asda, Morrisons or any other DIY shop.

Nadeem.

[Bizibilder]

Thanks Nadeem - I just downloaded your double cluster pics as a bit of inspiration!!

[ollypenrice]

I'm in France so bulb makes won't mean much. Nadeem seems to have it taped. I'll try his LEDs.

Olly

[Bizibilder]

Thanks Olly - will do.

[Deneb]

Hi

I think your data is holding some more detail, this is what I have prized out of it... hope you don't mind...

Nadeem.

[Bizibilder]

No problem! What did you do to get the extra details?

[Deneb]

Help to get rid of the vignetting with Gxterminator, used colour balance, slightly altered the blue channel in the histrogram, used curves, lowered the saturation & adjusted the RGB channels in the levels. Then used some noise reduction.

Nadeem.

[Bizibilder]

I don't have a gradient exterminator and I can't fathom the one in CS5 (I think thats what it is!) but I have had a play and I reckon I'm close to your result Nadeem? - (apart from the slight vignetting - which looks far worse on here than on my screen at home!!)

[Deneb]

Go easy on the Blue Channel... & don't clip the Black point too much..

Nadeem.

[planetdnb]

not bad!

[dlp]

Bizibilder - For flats I think it's safe to use your PC (lcd) screen, 'whited out'. There's a tool calledAl's Virtual Lightbox (Al's Virtual Light Box - IceInSpace)

which simplifies things.

David

[Bizibilder]

Thanks but I don't have a lappy!!

[dlp]

Thanks but I don't have a lappy!!

Guess you have a desktop with a screen?

[Bizibilder]

Yes but I'm not lugging that ouit to the obsy!

[dlp]

OOps!

[Bizibilder]

Yes but the flats have to be taken at the telescope with the optical train intact and still pointing at the object that was being imaged. If anything moves the flat will not match the light frames and won't be of any use. If you move (or bump!) the scope/camera you may move any dust etc on the sensor etc.

[Bizibilder]

I've just spent a couple of hours reprocessing this image!! Mainly to try and get rid of the "red glow" in the centre. I found a tutorial that went through gradient removal by creating a new layer, blurring one using gaussian blur, inverting that image and combining the two layers so produced. It seems to have achieved what I was aiming for! I have included the "new" image here.

The downside is I have lost a bit of star colour! (but I'll work on that tomorrow!!)

As you may have gathered I won't let go on this one!!

[Cloudwatcher]

"As you may have gathered I won't let go on this one!"

That's the ticket.......... you've got at least another three weeks work left in that one.

You might like to try a quick fix that goes like this.......... use the magic wand to isolate the background, desaturate, add a deep blue filter then select inverse which isolates the stars and saturate to suite.

Here is half of one I did earlier.