The Lagoon Nebula in Halpha F4.5

gregbradley · #1 14-07-2011, 05:42 PM

I took this the other night I took the Helix Halpha.

Again the beginnings of a narrowband image.

Planewave CDK17 with reducer giving F4.51.

15 minute subexposures and Vixen 95VMC guide scope with SBIG ST402 camera.

2 hours and 30 minutes.

http://www.pbase.com/image/136407602

I am really starting to like my CDK now.

Greg.

multiweb (Marc) · #2 14-07-2011, 05:54 PM

oooh yeah! Sweet shot.

alan meehan (Alan) · #3 14-07-2011, 05:55 PM

Nice image Greg shows some lovely detail to the outer edges ,almost 3d
AL

John Hothersall · #4 14-07-2011, 06:28 PM

My goodness that is a stunner, lovely round stars and detail just shines, superfast especially for S2 will work so well.

John.

Paul Haese · #5 14-07-2011, 07:10 PM

Nice stars, great data, lovely field (which is what I get with the TSA). Only thing I would do is to use curves to make the image a bit darker. I had a little play and I think the contrast and detail looks a lot better when the image, particularly the nebula, is slightly darker. Great to see such an image so close up and I would imagine at hi res as being pretty interesting looking.

DavidTrap (David) · #6 14-07-2011, 07:20 PM

I agree with Paul - I was going to say something smart like "you need to stop it down". Out of curiosity, what was the "well count" (not sure of the correct term) for the brighter areas of the nebulosity after 15min subs?

I've still working out how to adjust levels & curves for Ha images - I have struggled to find a balance where they look to have depth.

DT

peter_4059 (Peter) · #7 14-07-2011, 07:20 PM

Nice start Greg. It was great to meet you at AAIC.

Peter

RBA (Rogelio) · #8 14-07-2011, 07:50 PM

Quote:

Originally Posted by Paul Haese

Nice stars, great data, lovely field (which is what I get with the TSA). Only thing I would do is to use curves to make the image a bit darker. I had a little play and I think the contrast and detail looks a lot better when the image, particularly the nebula, is slightly darker.

Well, it depends what Greg wants to present in the image. I'm definitely a "let me see the details" type of guy, and there's lots of details in there that could be brought out without sacrificing the fact this is a brutally bright object.

Ross G · #9 14-07-2011, 08:08 PM

Great photo Greg.

It has amazing detail and I love the contrasts.

Thanks.

Ross.

RobF (Rob) · #10 14-07-2011, 08:29 PM

The thing that really catches my eye is the extent of the neb. You don't normally take in those extremities. Will be keen to see where you head with this one Greg.

TheDecepticon · #11 14-07-2011, 08:31 PM

That is awesome Greg, it will be nice in full colour.

CoolhandJo (Paul) · #12 14-07-2011, 10:08 PM

It's shots like this that give you the reason why it's called the lagoon. The outer rim detail is awesome.

Paul Haese · #13 14-07-2011, 10:10 PM

Quote:

Originally Posted by RBA

Well, it depends what Greg wants to present in the image. I'm definitely a "let me see the details" type of guy, and there's lots of details in there that could be brought out without sacrificing the fact this is a brutally bright object.

I agree, there is always more than one way to skin a cat too.

gregbradley · #14 14-07-2011, 10:39 PM

Quote:

Originally Posted by alan meehan

Nice image Greg shows some lovely detail to the outer edges ,almost 3d
AL

Thanks Al.

Quote:

Originally Posted by John Hothersall

My goodness that is a stunner, lovely round stars and detail just shines, superfast especially for S2 will work so well.

John.

This rig is now pretty awesome. I just recollimated it and it is running a bit better now as well.

Quote:

Originally Posted by Paul Haese

Nice stars, great data, lovely field (which is what I get with the TSA). Only thing I would do is to use curves to make the image a bit darker. I had a little play and I think the contrast and detail looks a lot better when the image, particularly the nebula, is slightly darker. Great to see such an image so close up and I would imagine at hi res as being pretty interesting looking.

Thanks Paul. I had a look and yes I agree. I did another version yesterday that is darker and very contrasty. I looked at it again tonight and I thought naw - it doesn't show enough of the extended nebula. But a bit darker does bring out more detail and folds in the nebula etc. I have posted the new darker version and I think its a bit better.

Quote:

Originally Posted by DavidTrap

I agree with Paul - I was going to say something smart like "you need to stop it down". Out of curiosity, what was the "well count" (not sure of the correct term) for the brighter areas of the nebulosity after 15min subs?

I've still working out how to adjust levels & curves for Ha images - I have struggled to find a balance where they look to have depth.

DT

The 16803 has 100,000 well depth and I'd have to check but I don't think it got oversaturated. Perhaps the very central bright stars in the hourglass nebula only.

Quote:

Originally Posted by peter_4059

Nice start Greg. It was great to meet you at AAIC.

Peter

Great to meet you too.

Quote:

Originally Posted by RBA

Well, it depends what Greg wants to present in the image. I'm definitely a "let me see the details" type of guy, and there's lots of details in there that could be brought out without sacrificing the fact this is a brutally bright object.

Welcome to this forum Rogelio and it was great to meet you and your lovely family at AAIC.

Quote:

Originally Posted by Ross G

Great photo Greg.

It has amazing detail and I love the contrasts.

Thanks.

Ross.

Thanks Ross.

Quote:

Originally Posted by RobF

The thing that really catches my eye is the extent of the neb. You don't normally take in those extremities. Will be keen to see where you head with this one Greg.

The fast f ratio and large aperture make this a good rig to explore these sorts of things. I hope it will show up detail I haven't seen before.
Being at my home observatory if we get regular clear weather which is starting to happen lately then I can get really long exposure images.

Quote:

Originally Posted by TheDecepticon

That is awesome Greg, it will be nice in full colour.

Hopefully in a few days.

Quote:

Originally Posted by CoolhandJo

It's shots like this that give you the reason why it's called the lagoon. The outer rim detail is awesome.

That detail came up very well.

Quote:

Originally Posted by Paul Haese

I agree, there is always more than one way to skin a cat too.

Cheers for your input Paul.

Greg.

RBA (Rogelio) · #15 15-07-2011, 07:18 AM

Quote:

Originally Posted by gregbradley

Thanks Paul. I had a look and yes I agree. I did another version yesterday that is darker and very contrasty. I looked at it again tonight and I thought naw - it doesn't show enough of the extended nebula. But a bit darker does bring out more detail and folds in the nebula etc. I have posted the new darker version and I think its a bit better.

Your last version definitely shows a lot more detail in the lagoon area, but as you said, the fainter stuff around it is a bit harder to see.

Adding contrast to bright areas without sacrificing the hard earned fainter signal is not hard. I'm not a big fan of curves - most people can achieve good results with them, but I just can't

For this, I think in Photoshop the Shadows and highlights tool might be your friend, I don't know if that's what you used. In PixInsight the HDRWT tool will do wonders, especially if used with a luminance-based mask that protects everything but the brighter areas.

But in the end it comes down to what your goals are, of course!

gregbradley · #16 15-07-2011, 08:28 AM

Thanks for the tips Rogelio. I did that and I agree its an improvement.

Cheers mate.

Greg.

atalas · #17 15-07-2011, 12:42 PM

Nice work Greg.

marco (Marco Lorenzi) · #18 15-07-2011, 02:03 PM

Impressive result Greg, perhaps a bit too "flat" IMHO. Furthermore, I would love to own a piece of equipment as yours

Reading the former comments, I find always amazing how we all look at the same image with different eyes, some preferring it lighter, some darker, not to mention the big debates that color images always rise..

Clear skies
Marco

gregbradley · #19 15-07-2011, 02:04 PM

Thanks Louie.

I spent about 3 hours collimating the scope last night and it seemed to be sharper afterwards and round stars to the corners with the reducer which is quite an optical feat. Its not that hard to collimate however not quite as easy as the manual implies either!

Greg.

jase (Jason) · #20 15-07-2011, 05:36 PM

Dramatic image Greg, remarkable in fact! Pleased to see you ironing out the folds in your set up. Looking forward to seeing more from this 17" F/4.5 configuration.