My first DSO image.

[Dbswales]

Hi everyone, just thought I'd post my first ever attempt at trying to image. I'm so chuffed with the fact that I actually managed to get something resembling a result! 

I struggled getting many subs due to the time constraint I had with my target disappearing behind next doors trees but it's definitely given me the bug which has been mentioned so often when it comes to imaging.

Any criticism is welcome as I know I have miles and miles to go. 

Oh, and if anyone has any recommendations for another brightish target with an idea of what sort of subs I need to take I'd be really appreciative.

im using a 600d canon, heq5 with a 130pds.

thanks.

Dan

[alacant]

I think it's excellent, far better than my first go. You could try lowering the contrast. That way I think you'd get more extended whispy bits. From where I am, Orion is getting low when the seeing is good later on in the night so you could have a go at a galaxy. You should be able to fit m81 and m82 in the same field and they are high up all night at the moment. Or if you like globulars there is m3 which is also well placed. A few suggestions anyway. Good luck and HTH.

 

[Knighty2112]

Very nice for a first stab at a DSO. Looks pretty natural to me too. Well done!  

[Dave In Vermont]

My word! Your first image?? VERY well done!

You've go 'the touch' for A-P. Please do continue.

Great!

Dave

[brantuk]

Great shot - very nice start. You've got the top half of M42 and the faintest hint of the Running Man, so I'd guess a few longer subs would bring out more of the bottom half and RM. Then some shorter subs to capture the trapezium - but how to combine them all I'll leave to someone more adept at processing than I. You're a natural though that's for sure.

[DougM43]

You'll get no criticism from me, that's a great image.

[iwols]

thats excellent is it cropped much

[ollypenrice]

Well done. You have, inadvertently, thrown a good bit of your own image away! The black point is clipped. Here's a demo I use in tutorials.

This is how the image should look. Note the histogram in the Photoshop window.

The background sky is quite light and the faint nebulosity shows around the galaxy. If we bring the black point slider (the left hand arrow in the histo window) too far to the right we crop out all that signal and 'black clip' the image. Like this...

The histo should always have a flat line in place to the left of the main peak. Don't use black clipping to get rid of noise or gradients in the faint parts of a picture. There are better ways to do that.

Worth another look at your data in my view.

Olly

 

 

[carastro]

Excellent first image, but I agree with Olly.

Get your original unprocessed stack and re-process it again without clipping the data.  See Olly's example.  Beginners always try to get the sky too dark (often to cover noise) and then lose data while they are at it.

I think you'll find you have an even better image once you have done that.

Carole 

[Dbswales]

Thank you all so much for your words of encouragement and fantastic advice. Yes, you're totally right, I really did try and get the 'dark a bit darker'. I'll definitely try and process the image again using the histogram tip above. That is a great tip which I didn't know about so thanks again for that. I'll have a go again tomorrow and see how it shapes up.

Thanks again everyone for your kind words, it's really helpful and encouraging to a complete novice like myself who really doesn't know his flats from his darks. I have noticed that even though I can trawl through 'the bible', it's not until you set up and make gargantuan mistakes that little things lodge in your brain. 

[wxsatuser]

Mistakes help us learn, the learning curve.

Your doing ok for a first go, mine were a lot worse than that and I did'nt have SGL to put me right.

Sometimes it's hard to see that small line of signal to the left so always give it a bit of leeway, as Olly points out.

Re your original post about subs.
The general rule with a dslr is to expose so the peak of the in camera histogram reachs at least 20%, the first line for Canons.
Won't go into all the technical jargon but this basically sets the exposure for your sky brightness.
You can push this a bit, may be upto 40% and you can be under most likely no lower than 15%.

Don't worry if this does'nt give you the long exposures you expected, just take more of them, it's total exposure that counts.

[Astrosurf]

Excellent first image! You're good. And great advice on here.

Alexxx

[2STAR]

On ‎23‎/‎03‎/‎2016 at 22:31, Dbswales said:

Hi everyone, just thought I'd post my first ever attempt at trying to image. I'm so chuffed with the fact that I actually managed to get something resembling a result! 

I struggled getting many subs due to the time constraint I had with my target disappearing behind next doors trees but it's definitely given me the bug which has been mentioned so often when it comes to imaging.

Any criticism is welcome as I know I have miles and miles to go. 

Oh, and if anyone has any recommendations for another brightish target with an idea of what sort of subs I need to take I'd be really appreciative.

im using a 600d canon, heq5 with a 130pds.

thanks.

Dan

If I get anything resembling that for my first go I will be more than Happy lol, very nice image

[Dbswales]

Thanks again for all your encouragement and advice.

I took some more subs last night of M42 with nearly double the original amount for the original image with a view of maybe getting a bit more information into the final image. As you can tell, not such a massive improvement which was disappointing but hey ho, onwards and upwards!

I'm stacking through DSS and processing in Pixinsight with the aid of Harry's videos which are really invaluable but something's obviously going astray when it comes to trying to follow his lead as I can't seem to get the background as I'd like it. Maybe its the light pollution due to the fact that M42 is quite low when I can get to it. Maybe it's just because I'm missing the point that Harrys making during the videos or maybe it's just because I'm trying to get too much out of my DSLR and suffering from too many hot pixels. Maybe going back to a 30 second sub would be better. The new pic below was 45 seconds. Maybe someone can advise me where to look at.

Thanks again everyone, I know there's obviously loads of room for improvement but I'm having a blast trying to get something decent out.

Dan

 

 

 

[spaceman_spiff]

That's a great image Dan,

I can see much more faint detail (the nebula really does look like it stretches into space). The running man is now visible and the colours are not too saturated. Good job! 

The jpg compression is a bit nasty though!

Dan.

[wxsatuser]

45sec subs are quite short, your doing quite well with them but you really want to get into the minutes,
unless you want to take hundreds of frames.

If you have LP? an LP filter will definately improve your sub times.
I know it's more money but an Astronomik CLS clip filter or an IDAS P2 will pay big dividends.

[Owmuchonomy]

This target can benefit from short and long subs. Within M42 there is a wide dynamic range. You have the fainter outer wispy nebulosity and in the core you have the bright hot blue/white stars. It is possible to blend your short and long exposures to bring out the best of both. So the shorter exposures for the bright core and the longer for the faint stuff. You could challenge yourself with this to build on your excellent first effort. Great stuff. You could also post your image in the "Imaging with the 130 PDS" epic thread.

[ollypenrice]

You now have much more of the faint signal but the background has been overstretched so we see a lot of colour noise in it and some large scale vertical banding.

To fight the colour noise the best technique is to dither guide. That is, to move the mount slightly between subs. It can be done automatically by several capture packages or you can just do it yourself. Even if it isn't moved between every sub it will help.

In Photoshop there is a commercial set of Actions from Noel Carboni which have a banding removal routine. It is supernaturally effective in my experience.

Once you have done a stretch which has lifted your background to about 23 per channel (again I'm talking about Photoshop) you can 'pin' the curve at that level, put a second fixing point below that and then left the curve carefully above the background level. This will pull out more data without stretchng the background up into the noise.

Olly

[Dbswales]

That's great advice again and so many things that I can maybe try, not only this particular set of subs but in the future. Fantastic information which I'm so grateful for. 

Yes Dan, the jpg compression was a nightmare. I just couldn't get it below the 1024kb that were permitted. I must have tried half a dozen times to reduce it so in the end, the attachment was really pants. 

Olly, I think I am dithering through APT but will check it out the next time I can manage to get out in the clear skies. Pouring down here at the moment so I might have another go with the processing. 

Ill go for the LP filter in the next week or so and will see how I get on. I guess I should be concentrating on another image further skywards but until that tree in my neighbours garden, falls down this week with the help of my chainsaw, I'm struggling to get PA and will probably be off when I slew to another target that isn't so visible through the scope. 

Thanks again for all your great comments and superb advice.

Dan