HA Image of M20 with M21 Open cluster

[Striker]

HI Guys,

Another HA image with Baader H-Alpha 45nm filter.

Image taken between 8:00-9:30 pm tonight

8 x 10 minutes ISO 800 guided images.

Autoguiding using a cheap $100 acho held on by rubber washers because it too small to fit my 125 mm guide rings....lol

Normal imaging train of moded 350D on ED80.

I'm happy with the autoguiding...considering

I hate compressing widefield shots into a small 150KB file because you loose so much data when doing so here is a less compressed image.

Warning 600KB
http://www.users.on.net/~striker/M20HA.jpg

[h0ughy]

very nice , should combine that wit ha colour shot! Long time, to get what you did, awesome, up there with Scott Alder Tony!

[EzyStyles]

very nice tony. thats a huge image :)

[Dennis]

Hi Tony

Wow - that is a spectacular image, I really enjoy these wide fields.

Cheers

Dennis

[strongmanmike]

Tony

That could be a really good image if you reprocess it without what ever filter you used in the processing that has given it, what to me looks like a filamentous spider web kinda fake look, remininecnt of the minimum filter in PS. This spider web effect is usually from using the star shrinking filter, offset filter, minimum filter or improper use of deconvolution or some other similar sharpening tool.

If you try reprocessing it, please post the result as I know there is a better image in that data, I can feel it :thumbsup:

Mike

[Striker]

Thanks for your comment Mike.

I used a star reduction in ImagesPlus......I have redone this image without the process you mentioned...all I have done is split the channel and ticked the luminance box in IP which gives me a grey scale image.....then used digital development keeping an eye on the histogram so I dont clip it too much...then sent to PS for slight level and curve changes...I also ran this through some very minor noiseware....but no star reduction used.

You can clearly see the stars are larger then my original...is this any better Mike...I really dont know any techniques enhancing grey scale images then what I normaly do with color images.

http://www.users.on.net/~striker/M20test.jpg

[Dennis]

Hi Tony

I just viewed both images side by side, and the second image has a more natural look to it. When you posted the original, it looked a cracker and the “difference” didn’t become apparent until I viewed 1 & 2 side by side, so Mike must have a pretty good eye!

Cheers

Dennis

[Phil]

Great shot keep up the good work
Phil

[Striker]

Your not wrong Dennis.....he has a better eye then me...I know what Mike is saying but previous images I have done showed up more of this spider web affect as Mike stated then this one.

I'm glad I have learnt something from this image..thanks Mike...I was just really experimenting with star reduction as some of the nebs I have imaged looked better without the full size stars taking away from the Neb...just experimenting....because I honestly dont know what I am doing anyway....lol
Thanks

[strongmanmike]

Hi Tony

I think the second version is more natural looking, sure it isn't as tight but I guess you have to decide what you want more, tight stars but a fakish look or less tightness but a more natural appearence...?

Tough decision at times:confuse3:

The best thing is to get precise focus and maintain it throughout the exposures as the temp chnages. Get as much exposure as possible to increase signal to noise and then you can sharpen harder with reduced artifacts.

Good work in trying the reprocess though :thumbsup:

Mike

[tornado33]

Nice shot there, one can see how the Ha filter supresses the blue but enhances the red of the Triffid.
I take it you focus by taking short test images then checking focus, or using software like DSLR focus?. I found visual focussing is impossible with the Ha filter. Through the 10 inch Sirius is just bright enough to see lol. I take short 10 second shots, and zoom in and check star images on camera display.
Scott

[Striker]

Yes Scott...I use DSLR Focus taking 2 second exposures to adjust focus...I couldn't belive it when I first looked through the view finder on the camera...couldn't see a dam thing...I though I left the ED80 Scope cap on...lol...but no it was just the filter.