Re: OR, Moon: 5/11/2008

Now, if THAT isn't enough to get me out looking at the moon, I don't know
what is. Thanks for the great report! All of that mind candy right there
for the taking...

Heather

On Sun, May 11, 2008 at 10:32 PM, Marek Cichanski <marek.cichanski@No-Spam>
wrote:

> I just got in from a very pleasant little Moon session, and I thought I'd
> write up a quick OR. I didn't take any written notes, this is just a quick
> and dirty OR from memory, looking at Rukl as I write...
>
> This was my first real Moon session with the "Montebello Special", the 10"
> f/5 dob built around the old primary mirror from my 2002-era XT10. It has
> a
> 2.14" secondary, a bit smaller that the original one IIRC, and uses
> exclusively 1.25" eyepieces. For tonight's session I mostly used the 13mm
> type 6 Nagler, for a magnification of 96x. Towards the end of the session
> I
> popped in the 7mm type 6 Nagler, for a magnification of 179x.
>
> Seeing wasn't anything to write home about, commonly only 2 out of 5 by my
> judgement, with reasonably frequent intervals of 3, and very rare moments
> of
> 3.5 or 4. Still, it was useable, with a little patience.
>
> The near-perfect first quarter phase made the maria Serenitatis and
> Nectaris
> the stars of the show tonight. The color contrasts between the lavas in
> Serenitatis were very prominent. Perhaps I should say 'albedo contrasts',
> since both of the lava types look grey, but I can't help thinking of the
> recent spate of 'saturation-enhanced' images taken by amateurs. A nice
> example can be seen on Russ Croman's site, for example:
>
> http://www.rc-astro.com/photo/id1018.html
>
> There's another nice example on Chuck Wood's LPOD site:
>
> http://www.lpod.org/?p=529
>
> According to Wood's "The Modern Moon" (your one-stop shopping place for
> actual lunar geology, as opposed to quasi-scientific 'selenology'), the
> color contrast in Serenitatis is due to differences in composition between
> lavas of various ages. Most of the darker material forming the
> southeastern
> 'rim' of the mare is a bluish, high-titanium basalt sampled by Apollo 17
> and
> dated at around 3.8 to 3.7 Ga. The youngest basalt in the central basin is
> thought, from crater counts, to be around 3.4 to 3.0 Ga. As Chuck Wood
> puts
> it, "Thus, the lava-filling history of this lunar basin lasted 700 to 800
> million years, a span of time that is immense by the standards of
> terrestrial geology."
>
> Immense it is... this 700+ million year history is considerably longer
> than
> the entire Phanerozoic Eon, for example. In other words, it's a span of
> time
> that is pretty well equal in duration to the entire history of
> multicellular
> life on Earth, and predates that history by billions of years. As Arthur
> C.
> Clarke put it in "2001": "Here was age inconceivable, but not death, for
> the
> Moon had never lived... until now".
>
> I really get a kick out of how much great mind candy there is on the Moon,
> and how it can be inspired by something as simple as the color contrast in
> Serenitatis.
>
> A funny thing just occurred to me - I've enjoyed looking at 'presolar'
> quasars, whose light predates the origin of the solar system, and is thus
> older than any rock I'll ever see. Some quasars, however, are definitely
> not
> 'presolar', such as the famous 3C273 in Virgo. The discovery of the
> redshift
> in the spectral lines of 3C273 opened the door onto a whole new world of
> cosmology, once it was realized that this object is ca. 2 billion
> light-years distant. But here in Mare Serenitatis, we can look at a story
> written in rock, and it's older than the much-vaunted light from 3C273. I
> get a kick out of that, too.
>
> An interesting part of the terminator tonight was the region shown in Rukl
> map 34. I saw what looked like a steep-sided plateau between Godin B and
> the
> crater Lade (shown on Rukl 45). It seemed quite distinct and real, but
> Rukl
> shows no plateau there. It was a powerful illusion of an elevated plateau,
> even though it was just a low-lying area bordered by some funny shadow
> effects. Curiously enough, there really IS an "interesting plateau"
> (Rukl's
> words) to the west of Godin. That area was still largely in shadow,
> though,
> and I didn't see the plateau.
>
> The Rima Ariadeus showed up reasonably well, as did the eastern end of the
> Hyginus rille.
>
> The real star of tonight's show, though, was the libration zone along the
> eastern limb of the Moon. I don't have the exact information on tonight's
> libration, but I'd just about be willing to bet that the eastern limb was
> rather heavily librated towards us. I could see the terra material on the
> far side of Mare Smythii quite distinctly, for example. Ditto for Mare
> Humboltianum. The crater Neper showed up very nicely as a prominent albedo
> feature between Marginis and Smythii, with its central-peak complex
> standing
> out nicely against the lava-flooded floor. I could also see the crater
> Goddard on the northeastern edge of Marginis, and I'm reasonably confident
> that I could also pick out Hubble. Some cliffy topography that was
> silhouetted against the black sky beyond the limb might have been part of
> the large crater Joliot. All in all, it was a really neat view of the
> eastern libration zone. It's always a thrill to 'see the far side of the
> Moon'.
>
> The seeing wasn't generally good enough to justify going beyond the 13mm
> Nagler, but I eventually tried the 7mm Nagler, just for grins. and even
> though the seeing was mostly funky, it certainly produced some grins!
> Until
> I built this scope, I had mostly used my 6" f/10 Mak-Cass, which has
> roughly
> the same focal length as the Newtonian that I was using tonight. With
> eyepieces like the 7mm Nagler, the view through the Mak-Cass was often
> quite
> nice, but it was a bit dim, and was near the scope's diffraction limits.
> But
> with 10" of aperture, the Moon looked considerably brighter and sharper. I
> can't wait to get my equatorial platform up and running again, and to have
> a
> night of good seeing. I have a feeling that the 10" will provide some more
> memorable Moon sessions.
>
> All in all, a pleasant little spring evening with the Moon.
>
> Oh, and if you haven't seen the high-def video from Kaguya yet:
>
> http://www.planetary.org/blog/article/00001421/
>
> Marek
> --
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