From: "Eric" <eddot1103a@mindspring.com>

Date: July 27, 2006 2:30:30 PM MDT

To: <Astro_IIDC@yahoogroups.com>

Subject: Re: [Astro_IIDC] Archimedes final and comparison

Hi Alan,

Thanks for that little tip!  I applied the technique and, sure enough, when carefully applied, additional details are revealed on the crater floor!  I could see this method perhaps being applied to another lunar image I've been scratching my head with, Aristillus.  The light level per frame is quite weak with that one and I figure I must have captured it too close to the terminator.  Seeing, I think, was better than for Archimedes, but any contrast/ sharpening boosts to the stack gives it an unnatural appearance in a very short time.  

Like I think you mentioned one time and I am finding as well and that is to keep the unsharp masking radius fairly low to bring out the best lunar detail.    

Thanks again-

Eric

----- Original Message -----

From: Alan Friedman

To: Astro_IIDC@yahoogroups.com

Sent: Thursday, July 27, 2006 1:08 PM

Subject: Re: [Astro_IIDC] Archimedes final and comparison

Hi Eric -

Nice work. The extra alignment points helps resolve quite a bit of additional detail on the floor of Archimedes. Something you might try (if you haven't already) is to apply some additional iterations in Photoshop CS2 of despeckle followed by unsharp mask using a tight pixel radius (.5 - .8). If you do this globally on the image you will begin to create artifact in the high contrast areas and larger craterlets. But if you use Photoshop to select just the smooth areas of the crater floor (feathering the selection by 5 or 10 pixels or so) you will draw out many other small details. The tight pixel radius for unsharp mask is helpful for creating a natural result and keeping the craterlet size in accurate proportion. 

best -

Alan

On Jul 26, 2006, at 7:34 PM, Eric wrote:

Hi guys,

Well, I've extracted about as much detail as I'm going to for this composite.  I have posted comparison images.  On the left, is the original 415 stacked images composite using 5 alignment points.  The right image is the same number of stacked images (415), but alignment points were increased to 17.  If you look carefully, there is definite improvement, although mostly subtle:

  http://www.mindspring.com/%7Eastro4565/Archimedescomparison.jpg

I was never able to improve the interior craters because the contrast wasn't enough to cause the software to align on for a stack.  I also ended up using a Win program called Iris to do the 17 points, although the initial image on the left was aligned in IIDC.  I think the lack of contrast and noise levels caused IIDC to eliminate about half of the stacked frames.  

Eric