LHaRGB of Tarantula

[telecasterguru (Frank)]

Paul,

I think you have done a very good job of pulling it all together.

Frank

[Paul Haese]

Thanks all for the comments and suggestions.

Originally Posted by gbeal

Aye, T'is a lovely shot Paul, as we have come to expect from you. The corners suffering slightly? Being picky I know.
What is the dew issue? Is it the secondary? If so, perhaps look at a specific dew heater, like I got from the SDM man, it goes inside the secondary holder and just has a wire protruding.
Gary

Gary, the corners have problems due to it not being flat fielded and collimation needs more attention. A perfectly valid observation for sure.
Dew is not only the secondary but also the primary. I will take a look at the SDM option, it might work quite well and remove this particular problem. Thanks.

Originally Posted by gregbradley

You're on a roll Paul.

Very nice.

Now for some serious exposure time.

Greg.

Yeah my thoughts too. Any suggestions? I was thinking 10 hours. 4.4 is not quite enough.

Originally Posted by Bassnut

A good effort Paul, but. This is a difficult one to not look messy, more to do with processing than capture. Just IMO, uniqely, Trant sometimes presents better with less overwhelming star action, and less neb extention to preserve the 3d effect the narly bits can provide. Its an artistc interpretation of course, your rendition is natural, but to stand out, sometimes extra thought on processing is handy.

A Sid in this regard, as a second choice might be interesting?

Fred, totally agree about this area, even guiding just slight off like this effort can make it look wrong. I would welcome any suggestions you have about lessening the stars and increasing the 3D effect.

Pardon my ignorance but what is Sid? Can you explain how to do this?

Originally Posted by AlexN

Agreed... If you upped the strength of the Ha in the data it should dull out the stars a bit and you could numb down the stars and bring in more of the sharp detail that Ha provides... You could be ultra daring, and remove the stars all together Dare to be different!

Alex how do I up the Ha strength? How do I numb down the stars? I have not explored this yet.

Originally Posted by strongmanmike

Excellent Paul

You are improving at a rate of knotts with that new setup

If you are after contructive critique the only thing I would say is it does look a bit monochromatic...?..not sure why but could be due to the ha blending . The sharpening looks to get noticably stronger towards the centre and imparts a flattened look to the image but this is perhaps just the undercorrected optics..?

Only minor feedback above though, this is great work.

Mike

Mike, with the blend I just stacked one lot and then the red and then summed them together. Do you have a suggestion for how I should blend it? Did I do the wrong thing?

I did a mask and sharpened the image that way using the one I learnt on Ken Crawford's site. Did you have a suggestion for making it look better?

Thanks once again for everyones comments.

[AlexN]

How did you go about doing the LHaRGB layering Paul?

I generally use clip masks to combine RGB channels from the 3 registered images, then take the red channel into a separate window in PS, layer in the Ha registered frame, set it to screen blending mode, and set the opacity to anywhere between 45~75%, higher sometimes for predominantly red targets.. Blending the Ha with the red will ensure better saturation of reds in the final image... The stronger you make the Ha (higher % opacity) the less stars will show through in that channel. If you were to blend the Ha into your L channel the same way as mentioned before, but say, 30~40% opacity, that would numb out the stars a fair bit..

You could remove them all together by iterative use of the dust and scratches tool in photoshop... Set radius to 12 and set Threshold to 50-120, by looking at the enlarged image, set the threshold so that the center of the brighter stars disappears but image stays sharp.
Next, lower radius two points to 10 and set threshold to 30-80. Follow the image quality and details when setting your threshold, too high, you won't properly remove the star, too low and you'll remove detail from the image highlights. Repeat several iterations with incrementally lower values, the more iterations the better. In the last iteration, radius should be 1 and the Threshold between 3-10. If there are leftovers from brighter stars, use the clone tool or spot healing brush to clean them up.

Sometimes this can leave a funny looking affect in the darker zones of the image, by creating a duplicate layer of the starless image, and applying a 4px gaussin blur, or a slight median filter to the duplicate, use a hide all mask to only blend in the smoothed background, but not the blurred details in the nebula, you can end up with a very smooth, inky black background with no stars and retain a very sharp, star free image of the nebula...

[Octane (Humayun)]

Paul,

That's quite a beauty. Well done.

P.S. A "Sid" is a Sidonio. That is, a reprocess.

Regards,
Humayun

[Phil Hart]

that's impressive depth and detail for tarantula. i'm a long way short of that with my focal lengths.

i'd be interested to see the result if you blended some Ha into the Luminance and whether you can maintain the nice rich colour balance. i find it so attractive to use the contrast of the Ha in the luminance (and reducing star sizes) but so hard to maintain a natural colour balance?

[Paul Haese]

Thanks Alex for the blending technique. The image link below is a Ha Luminance blend at 65%. I really like the way it looks but it clearly needs more data.

Thanks Humayun for clearing that up.

Phil what do you think? I like this myself.

Click Here

[bloodhound31]

Not keen on the color, but the detail is astounding Paul. Awesome work. I always enjoy looking at your posts.

Baz.

[strongmanmike (Michael)]

Here ya go Paul, I just added a few hours of data for you

http://www.pbase.com/strongmanmike20...92913/original

It's a 50/50 blend of our data sets

Wadda ya recon?

Your latest version is a marked improvement on the first rendition by the way

Mike

[Paul Haese]

Hey thanks Mike, that is super. 50% more data looks the go. Will have to do a narrow band mix with it though.

Yes I like it too, amazing what a little change in blend can produce.

[strongmanmike (Michael)]

Cool huh?

Just Sidonio'd it again though so have another look - blink it with your original it's even sharper now

The first round was a straight 50/50 mix nothing else, now I have reduced the star ray bottom left, increased contrast and saturation a tad and due to all the extra data managed to sharpen it up further, I recon it looks great.

Mike

[Phil Hart]

Originally Posted by Paul Haese

Thanks Alex for the blending technique. The image link below is a Ha Luminance blend at 65%. I really like the way it looks but it clearly needs more data.

Thanks Humayun for clearing that up.

Phil what do you think? I like this myself.

Click Here

I think that's a good result.. very subjective but I would choose your 'natural' colour balance over Mike's, although obviously the extra data is good. just blending in HA is hard enough, mixing in tricolour narrowband HA-OIII-SII is certainly getting adventurous!