How did he manage this?

[Beulah]

I am sorry to say that I am venturing slightly into the Dark Side albeit through widefield astrophotography as I was fortunate enough to be able to buy an EQ1 mount a good drive and have access to a DSLR.

There is no intention of modding the DSLR as it is on a kind of 'permanent loan' and I want to use it for normal photography as well.

So, I hunt around, learning that a modded DSLR enables increased sensitivity to H-alpha and then discover this webpage from a widefield astrophotographer who creates this image WITHOUT the modification...

http://www.nightskyi..._1_250212_l.jpg

from

http://www.nightskyi.../wide_field.htm

So how did he manage to capture the 'reds' in the first image?

I know I'm jumping the gun a bit, but it's been cloudy here for ages and I would have been out there yesterday trying my hand at this relatively new branch of amatuer astronomy... Theory takes leaps and bounds and actual practice lags way behind..

[nmoushon]

Just because you dont have a modded DSLR doesnt mean you wont pick up the 'reds'. You wont get them as bright or pick up the faintest parts but you will easily pick up the brighter 'reds'. No special trick.

[laser_jock99]

Just because you dont have a modded DSLR doesnt mean you wont pick up the 'reds'. You wont get them as bright or pick up the faintest parts but you will easily pick up the brighter 'reds'. No special trick.

An un-modded cam will pick up the reds okay if the nebula is bright enough. You should have no probs on the common targets. This photo of the Lagoon & Triffid was with a bog standard DSLR

[steppenwolf]

I am that widefield imager I'm afraid! The key to this image was in the post processing. Gently stretching the data iteratively and adjusting the contrast using 'levels' and 'curves' to accentuate the various areas of colour was how I got the general objects to show through. I then worked on the red content - it was there, albeit in an attenuated form because of the Canon's IR filter but enough red component is present to work on and tease out. A typical way of doing this is to copy your stretched data to a new file, convert that new file to 'Lab Colour' using the 'Mode' option under 'Image' in PhotoShop, select the 'a' channel and boost its contrast. This dramatically increases the red component of your image. I then copy and paste this new image on top of the original as a new layer and then adjust the opacity to get the level of red that suits my taste.

A Canon IR filter typically attenuates the Ha and SII portions of the light from emission nebulae by about 78% but that still leaves 22% to work on!

The following images show a single 30 second sub-frame (captured as a JPEG to my shame!), an image showing the effect of stacking 20 such frames (slightly cropped) and then the finished image after working hard on it in PhotoShop:-

[jgs001]

And, if you struggle pulling the red out with a few subs... chuck a load more at it . As long as there's some information in each sub (albeit a tiny amount), the more you add, the more chance you have of pulling the red out. Like you, I never expected to capture the Bubble nebula with an unmodded dSLR, but I did (with something in the order of 150 x 30 second exposures at f/5).

[Beulah]

Sorry about the delay in replying as I have been rushed off my feet today!

Thank you all so much for your replies.

nmoushon, thanks for that. I really didn't know as some 'modding' service websites advertise drastic before and after pics and claim capturing H-alpha is 'very, very difficult'...

Laserjock, great image. The quality of your skies is spine-tingling stuff. Can't wait for those targets to come round again...

Steve, I didn't realise it was you - I saw 'Southern Sky' and I thought it was some lucky Aussie imager... You are a lucky bloke for being able to stand under all that beauty. You've got some fabulous results there - Got to buy your book when I get paid soon!

John - thanks. Taking notes right now!

[Psychobilly]

I think you will be pleasantly suprised how much of the red stuff the 500D will pick up...

Peter...

[Beulah]

That's very reassuring Peter.

Had a gander outside & cloud is still lingering...

[nmoushon]

Sorry about the delay in replying as I have been rushed off my feet today!

nmoushon, thanks for that. I really didn't know as some 'modding' service websites advertise drastic before and after pics and claim capturing H-alpha is 'very, very difficult'...

Ya they do that for sales purposes. Try to get people to think it's a MUST HAVE! I think I still have my M20 shots...not sure if computer crash deleted it or not...if I do I post and show what I got with my unmodded 450D.

[steppenwolf]

You are a lucky bloke for being able to stand under all that beauty.

Holiday of a lifetime that was. Newer DSLRs like the 450D that I used for that image and the 500D that you have apparently go do seem to fare better than earlier ones like my original 300d so as Peter has said, you could be pleasantly surprised. I too use a motorised EQ1 for the image. I hope you get some great results!

No chance of any imaging tonight though as we are in the middle of a little bit of a storm with worse threatened.