From: "Raoul Schlesser" <gr842@yahoo.com>

Date: October 26, 2005 11:33:23 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: Mars moons - Phobos & Deimos

Hi Alan,

thanks for the comment.

the main problem I found is excessive light scattering near the much brighter planet disc, 

so there really is only a relatively narrow exposure window that works... too long and you 

overexpose everything due to scattering, and too short exposures simply don't have the 

required S/N to see the moons. 

Yesterday night we had horrible seeing, so I will try again under better conditions. Getting 

tighter focus should make it even easier to detect the moons, even at shorter exposures. 

Also, timing is everything, it's really helpful to image when the 2 moons are at their 

greatest elongation away from Mars, like yesterday night.

When I first tested the DMK camera I managed to identify stars down to 18th magnitude 

using a 3" APO on a stack of 20x30sec exposures. This really surprised me very positively 

- I had bought the camera with planetary work in mind only.

FWIW, in 2003 I made a short animation of the 2 moons using a Canon 10D DSLR:

http://home.nc.rr.com/rschlesser/MarsMoons_anim.gif

Time an weather permitting, I'd like to try something similar again this year... we'll see.

All the best,

raoul

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

Great capture!

I experimented with this one night but didn't expose long enough.

30 second exposures with the DMK and my 10" record stars down to about 

19th magnitude.

best,

Alan

http://home.nc.rr.com/rschlesser/MarsMoons20051026.jpg