Keyhole: high res H-alpha

[strongmanmike (Michael)]

Well I have to say even at that mizerly sized image and image res you insist on displaying it does look very nice Peter Lots of magical subtle detail as you say

Just as a comparison, I have cropped the same piece of field from my Ha image from last year to see what the difference is (taken at low altitude unfortunately so not perfect).

You have used a 14.5" RC at what?..5000mm FL? and a 7nm Ha while I used a 6" APO at 1140mm FL and a broader 13nm Ha filter. My image is only 3X10min exposure so could have used a lot more, you used 10min subs too but how many I'm not sure..?

I didn't use an AO device, I assume you did?

I have reduced my image resolution to match your small 1400 X 900 size at just 400k too for a fairer comparison

Overall the res is deffinitely better in yours but strangely in some areas it appears slightly better in mine..?

As usual I would love to see a higher res version of your image as I am sure in fuller res the difference would be more marked..?

Here's my image:

http://www.pbase.com/strongmanmike20...81932/original

You have handled Eta itself better than I, looks great

The lack of halos around the brighter stars in your version is good too, I hope my new low reflection Astronomik filters that I have just installed will eliminate this?

Again excellent work (even displayed at low res)

Mike

[Peter Ward]

Originally Posted by strongmanmike

Here's my image:

http://www.pbase.com/strongmanmike20...81932/original

You have handled Eta itself better than I, looks great

Thanks Mike. Yes, I have seen your excellent H-alpha Eta image before.

Agreed, downsizing (even Hubble) images can make them look like they are just average res, but I figure 1400 by a 1000 odd is big enough for public forums.....and is larger than many of the posts here on ISS.

My estimate is: the RC was delivering about 4x (in area) smaller stars than you've linked to.

Sure, the focal length and AO helped quite a bit IMHO, but the seeing on the night was pivotal.

[strongmanmike (Michael)]

Originally Posted by Peter Ward

Thanks Mike. Yes, I have seen your excellent H-alpha Eta image before.

Agreed, downsizing (even Hubble) images can make them look like they are just average res, but I figure 1400 by a 1000 odd is big enough for public forums.....and is larger than many of the posts here on ISS.

My estimate is: the RC was delivering about 4x (in area) smaller stars than you've linked to.

Sure, the focal length and AO helped quite a bit IMHO, but the seeing on the night was pivotal.

I guess the 7nm Ha helped shrink the stars a bit too..? If I had a PME and larger objective plus a permanent obs I'd have gone for the Astronomik 6nm set rather than the 13nm that I did but I had to weigh it all up I guess.

Your final image is sure to be excellent and it would be great to see it in fuller res....before the David Malin awards

Mike

[AlexN]

Lovely start to what will be a ripper no doubt... I too would love to see a full res shot I like to swim in pretty pictures!

[gregbradley]

Originally Posted by Peter Ward

Yes, the FFC was installed, but the slightly eggy edge stars are an unfortunate side effect of using AP's Barcon.

That said, I consider the stellar FWHM's to be extremely tight as the effective focal length was 5,400 mm.

Oh, so you 2X or so your focal length? Quite a challenge.

Greg.