C/2008 A1 McNaught -26 Sept

peeb61 (Paul) · #1 27-09-2008, 09:12 AM

Folks,
A good mate, Joe P and myself ventured out last night to have another look at this comet. To me it certainly does look brighter.

Here is a single shot of 4 minutes at 800ISO.
Copped and adjusted in CS3. I used Noiseware for noise reduction.

Paul

RB (Andrew) · #2 27-09-2008, 09:41 AM

Very nice Paul, my only advice is to maybe adjust your colour balance a little.
There's a cyan colour cast which shows up in the sky background.

If you have a look at the histogram you'll notice the green and blue channel misalignment giving you two peaks.

Certainly looking like a nice comet though.
Thanks for sharing.

peeb61 (Paul) · #3 27-09-2008, 10:06 AM

Thanks Andrew,
So in the histogram are we aiming for just the one peak? (Three combined?)
Just curious. This processing is still really new to me.

Paul

RB (Andrew) · #4 27-09-2008, 10:10 AM

Quote:

Originally Posted by peeb61

Thanks Andrew,
So in the histogram are we aiming for just the one peak? (Three combined?)
Just curious. This processing is still really new to me.

Paul

Yes that's right one single peak, three channels combined.
I'll do a quick reprocess and screenshots of what I mean and post back here in a little while to show you.

peeb61 (Paul) · #5 27-09-2008, 10:18 AM

Thanks Andrew,
Your a gentleman!
Paul

RB (Andrew) · #6 27-09-2008, 10:34 AM

Quote:

Originally Posted by peeb61

Thanks Andrew,
Your a gentleman!
Paul

Oh shucks now you made me blush.

OK first I opened the image and made the first adjustment:
Image | Adjustments | Colour Balance

Shadows radio button, Red = +12, Green = +1, Blue = -6
Mid radio button, Red = +2, Green = 0, Blue = +4
Highlight radio button, Red = +26, Green = -25, Blue = -30

Then goto Image | Adjustments | Levels

Here we shift the histogram back down a little to balance the sky b/g.

Levels: Black Point slider move up to 13 and Mid point slider move to 1.09, leave the Highlights slider on 255.

You can experiment to suit your taste and obviously what looks better on your screen and go from there but this gives you a quick idea.

Here's the before and after screenshots.

PS I enjoyed reading your escapades with Joe P, yourself and others in your group chasing McNaught back in 2007 in the magazine article.

peeb61 (Paul) · #7 27-09-2008, 11:25 AM

Thanks Andrew,
I will follow these instructions and have a go myself, you make it look so easy! the difference in the two images is amazing.

McNaught.....Mate that was THE comet and its surprising how many people missed it on that Saturday night because they inside watching The Bill! I couldn't phone enough people to go outside and have a look.

We made a couple of trips to Berrima in the week leading up to it for higher ground to take stacks of images, they were nights to remember I can tell you.

Glad you enjoyed the article, it was surprising it got published! I wonder how Lyle Rumble's going? This is one magazine we need back.

Paul

RB (Andrew) · #8 27-09-2008, 11:41 AM

Quote:

Originally Posted by peeb61

Thanks Andrew,
I will follow these instructions and have a go myself, you make it look so easy! the difference in the two images is amazing.
Paul

Cheers Paul, yep have a go, it's always fun to share info and learn from each other.

I certainly have fond memories of The Comet Of the Century too.
We didn't expect it but what we saw at Lostock at IISAC 07 just blew our minds.

Looking forward to more from you buddy.