From: "Tim" <tjp314@pacbell.net>

Date: November 27, 2007 5:47:17 PM MST

To: Astro_IIDC@yahoogroups.com

Subject: Re: Schiller

Hi Duane:

The problem with the suggestion that it's two craters that overlap is

that there should be a rim between the two, where their ejecta sheets

interacted.  Likewise, if they formed at different times, the younger

crater's rim should extend across the line between them.  With an

oblique impact (and they really have to be very low angles - like less

than 5 degrees - in order to not form a circular crater), you really

can form an elliptical crater.  I think that those folks I know who

work on the physics of these things will say that the appearance of

two (or more) overlapping craters is due to the impactor breaking into

multiple pieces before impact, but not separating by enough distance

to form two separate craters.

-Tim.

--- In Astro_IIDC@yahoogroups.com, "Duane" <macastronomer@...> wrote:

I can see how it's debatable, but with a nice shot like this, it

sure looks like two craters to 

me. I popped that out there with a couple circles showing what I

think clearly looks like 

two nice ovals:

http://homepage.mac.com/deal/schiller20060410_1628.jpg

--- In Astro_IIDC@yahoogroups.com, Alan Friedman <alan@> wrote:

Hi Duane -

I think the jury is still out on the formation of Schiller (but  

leaning towards an oblique impact):

http://www.lpod.org/index.php?s=schiller&paged=3

Looking straight down via Lunar Orbiter images (or in earth based  

images taken at a low sun angle) that bizarre caldera topped

mountain  

is clearly seen as two separate features - a long hill with a crater  

on the floor of Schiller just behind.

Thanks,

Alan

On Nov 27, 2007, at 2:32 AM, Duane wrote:

Hi Alan,

Nice shot. It makes me eager for ver. 4 but then again I know this  

image is from you and

part of me knows you're taking it beyond my capability :)

I never looked at Schiller closely before, but it appears to be

two  

craters joined (and

flooded) together creating the potato shape, doesn't it? Maybe  

that's already known, but

then again self discovery is good too.

Thanks for sharing and keep'em coming.

Duane

.