Keyhole: high res H-alpha

Peter Ward · #1 19-03-2009, 12:23 PM

I made the comment earlier that seeing is *really* important when it comes to high-res deep sky imaging.

I've pulled the colour version posted earlier at the URL below and replaced it with the new B&W version (for now

)

http://www.atscope.com.au/BRO/gallery37.html

The res is not too shabby and shows features I've never really noticed before: shock waves coming off Eta itself.

Cheers

multiweb (Marc) · #2 19-03-2009, 12:43 PM

Beautiful shot - extremely sharp.

Garyh · #3 19-03-2009, 12:52 PM

Now that is a awesome shot Peter!
Great resolution for sure

I`ve noticed the last few nights the seeing has been pretty good up this way as well.
cheers

Tom Davis (Tom) · #4 19-03-2009, 01:04 PM

Excellent detail!

Tom

bloodhound31 · #5 19-03-2009, 01:28 PM

Peter, I'm not normally a fan of B&W, but shots like that could easily change my mind.

Good job mate.

Baz.

bluescope · #6 19-03-2009, 01:52 PM

Very nice image Peter ... what bandwidth Ha filter did you use on this ?

Peter Ward · #7 19-03-2009, 02:01 PM

Quote:

Originally Posted by bloodhound31

Peter, I'm not normally a fan of B&W, but shots like that could easily change my mind.

Many thanks Baz, Tom, Gary, Marc.

Many moons ago I spent a good deal of time developing and printing B&W and later Cibachrome prints.. B&W gives you a great appreciation of the light and shade in a scene.

Imaging in H-Alpha was virtually an impossibility for amateurs then, but with CCD's the process is quite straightforward.

I for one, hope it enjoys a renaissance.

Peter Ward · #8 19-03-2009, 02:05 PM

Quote:

Originally Posted by bluescope

Very nice image Peter ... what bandwidth Ha filter did you use on this ?

Baaders are 7nm.

bluescope · #9 19-03-2009, 02:24 PM

Thanks Peter ... I'm tossing up whether to get an Ha filter and have a thread going in equipment discussions forum which has pro and cons of different filters from different people ... gets a bit confusing.

Where do you buy the Baader 7nm from and how much ?
Having said that I imagine you get it yourself

Peter Ward · #10 19-03-2009, 03:00 PM

Quote:

Originally Posted by bluescope

.........pro and cons of different filters from different people ...

Where do you buy the Baader 7nm from and how much ?

I'm pretty happy with the contrast and lack of ghost reflections from the Baaders.

They are available from various vendors here and in the USA... priced between $375 (2" cell) to about $500 (50.8mm STL version).

You might save $50 in GST by going USA direct, but then again you might loose that in postage...

jase (Jason) · #11 19-03-2009, 03:49 PM

Excellent resolution Peter. Very fine details on display of this show-piece target. What was the duration of the subs? Given this is a bright object, I'd imagine relatively short even though its through a Ha filter. The mid tones really dominate this image which I feel has suppressed the highlights too much. Personal taste, but I'd like to see a little more contrast to emphasise the exotic details. You still using log stretching? Perhaps that's the cause for the dynamic range woes? Still a real nice scene. Well done.

Peter Ward · #12 19-03-2009, 04:39 PM

Quote:

Originally Posted by jase

Excellent resolution Peter. Very fine details on display of this show-piece target. What was the duration of the subs?.....

I use my usual 10 minute urban subs. Processing as you say is often a matter of taste. I prefer subtle to overcooked but appreciate your candid feedback. A "snappier" version is now in place.

My usual drill is to: reduce, errant pixel clean up, then stack. I then use a two pass gamma scale in MaxIm. Final tweaking in PS. Nothing fancy but works for me.

bluescope · #13 19-03-2009, 05:11 PM

Quote:

Originally Posted by Peter Ward

I'm pretty happy with the contrast and lack of ghost reflections from the Baaders.

They are available from various vendors here and in the USA... priced between $375 (2" cell) to about $500 (50.8mm STL version).

You might save $50 in GST by going USA direct, but then again you might loose that in postage...

Yes the postage to Oz from most of the US dealers that I know of is ridiculous even on small items such as filters ... I mean ... come on what do they weigh guys.
Which Oz dealer would you recommend Peter ?

p.s. I think the new version does has more depth and the humunculus stands out better IMO.

Peter Ward · #14 19-03-2009, 05:16 PM

Quote:

Originally Posted by bluescope

Which Oz dealer would you recommend Peter ?

You're kidding... right?

I only have STL versions in stock.

My Astro Shop has some keen pricing.

bluescope · #15 19-03-2009, 05:22 PM

Quote:

Originally Posted by Peter Ward

You're kidding... right?

I only have STL versions in stock.

My Astro Shop has some keen pricing.

Thanks Peter

jase (Jason) · #16 19-03-2009, 05:41 PM

The snappier version is on the money. The subtle contrast tweaks have made a notable difference. Well done.

Octane (Humayun) · #17 19-03-2009, 06:40 PM

Peter,

That's very, very beautiful.

Are you going to add RGB or SHO to this?

Regards,
Humayun

gregbradley · #18 19-03-2009, 06:52 PM

Nice shot. But that is coma I see at the corners? Elongated stars in the corners yet round in the centre of the image.

Are you using a flattener?

Greg.

pgc hunter · #19 19-03-2009, 07:01 PM

that's a beautiful pic. Look at how well the Rude finger is defined. Interesting to note that both the homunculus and the middle finger salute appear to be a similar size, perhaps making the latter a viable target visually in larger scopes.

Peter Ward · #20 19-03-2009, 07:10 PM

Quote:

Originally Posted by gregbradley

Nice shot. But that is coma I see at the corners? Elongated stars in the corners yet round in the centre of the image.

Are you using a flattener?

Greg.

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.