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We may not know

Dave North


Came down near the wire, but I finally got a couple of interesting questions for this month. Both share a characteristic in that they really ask, why not? And both share the same answer:

I don't know.

Which doesn't make them any less interesting.

The first comes from Bill Arnett, who wondered why there isn't anyone running a periodic survey of the Moon to see what new craters have appeared.

This is a darn good question.

Of course, even with adaptive optics, we wouldn't be able to see all the microcraters that appear, but we should be able to see some fairly small ones.

Bill speculated "There must be lots of them every year a few 10s of meters in diameter." May be right, maybe not, but in any event we just don't know!

It would be great to be able to cover the prime zones of the visible side, but even if just some smaller sample areas were covered, we could get a count of some sort.

One thing I don't know is whether it makes any significant difference if one is counting on the "leading" edge or the "trailing" edge. Since the Moon is tidally locked, it has a leading edge in its orbit around us ... but of course it follows our orbit too, which means some fraction of the month it has a net velocity along its trailing edge with respect to the sun.

But it does net out to a leading edge, and whether that has any effect on larger cratering numbers is a mystery to me.

We don't have such an "edge" of course because of spinning on our axis. But we sure do know the leading edge counts with meteor showers!

"Why not?" is practically an impossible question to answer with any meaning, of course. It's rhetorical, but if somebody higher up the research food chain decides this is a good idea, remember where you heard it first (and that it wasn't my idea).

If they're already doing it and we don't know about it, you can remember who doesn't know jack...

The other "why not" question is, why isn't Rukl's Atlas Of The Moon back in print yet?

Now there's a question I really don't know the answer to. It certainly has been popular, and there's definitely demand.

But it's missing in action.

Various rumors abound, and surface from time to time. The best I know is Kalmbach sold the rights to Sky Publications, who planned to issue a new edition (which I'm told Antonin Rukl was working on).

This seemed to be taking way too long years ago when I first started getting bugged by the missing book. I do recall being chastised by some SkyPub apologists who said matters were well in hand and a magnificent new atlas would soon be issued.

That was at least a year ago, probably more like two.

SkyPub has since published several inferior atlases, and when I say inferior I mean way inferior. It would seem simply reprinting the existing edition might have been a worthwhile effort, considering how long the market has been dead dry.

But no.

Then again, maybe they don't watch eBay or amazon where they are in hot demand, and often sell for somewhat more than the old list price.

Maybe they don't know it used to be the amateur Moon Bible.

But of course the various Big Decision Makers at SkyPub all read this column every month, and when you see Rukl's great book back in print, you'll know which agitator finally got them to wake up.


I guess this is just kind of an "I don't know" month.

Oh, by the way: there will be a "moonrise" lunar eclipse May 15; be set up around 8:30 and you'll be able to watch an eclipsed Moon rise somewhere above the east hills (depends on where you are, of course).

Best to make sure you have a clear horizon. Should be fun to watch, since it will remain eclipsed as twilight sets in, plus there will be the unnatural coloration of both the eclipse and the horizon.

There's also an annular solar eclipse on May 31, but as best I can bone out from the numbers, we won't see it at all.

Oh well!


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