Finally, some decent seeing 15-Aug-2003!

I finally got a night of decent seeing Friday morning. I was out Thursday morning, and the seeing was the usual 6, maybe 7. Couldn't sketch because it was so damp and dewy, when I tried using the eraser it was tearing up the paper! Had to give up. Anyway, set the alarm for Friday 2:00 a.m. (had to use the travel alarm, because we got caught in the blackout, but Mars observing must go on!), and boy I'm glad I did. Seeing was probably 8, maybe better, plus no dew! Here's the sketch. I got the SPC a little fat N-S, otherwise I'm happy with the sketch. I noticed that Mare Sirenum (to E) and Mare Cimmerium (to W) appeared to be connected, although they are not in any of the maps I've seen. Has anyone else noticed this?

Regards,
Doug

Attached Image:

Hi Doug,

Great sketch. I find that the ability to split or break up albedo features is more or less tied to magnification/image scale.

For example, in my 6" refractor, I get the most detail and contrast at about 375x. At 400x I believe I get a better handle on separating details. At least I think so.

400x doesn't show me more detail in the 6" than at 375x or maybe even 350x, but it gives me a large enough image scale that makes the break up of albedo features seem easier to sort out.

Sol Robbins

I wouldn't go so far as to say they're connected, but in my 10" f/8 the separation at the southern edge of the becomes very indistinct, like there's 'almost' a bridge there -- but at certain moments they appear separate through and through. I think the contrast of the albedo features becomes much less at that extremity. The 'gap' overall has a very mottled and 'inconsistent' appearance to me.

Thanks for the input, Sol & Paul. Right now, 340x is as high as I can go, with the 4.8 Nagler being my shortest FL. I'm thinking of getting a 4mm Radian, which would give me just over 400x which would be perfect for that scope, but wow, that's a lot of $$$!

Doug