[time-nuts] telling time without a clock

Jim Lux jimlux at earthlink.net
Thu Jan 26 19:35:52 EST 2012


On 1/26/12 2:55 PM, Jim Palfreyman wrote:
> As a reasonably experienced occultation observer (and the very reason I got
> into being a time-nut - so I could time these observations), the main
> problem is that the number of binocular-observable occultations is actually
> quite rare. When the star appears or disappears behind the bright limb it
> is actually hard to see - even if the star is very bright. When the moon is
> nearly full, even disappearances behind the dark limb are hard.

Yes, that's what I observed when I was trying it a while ago..

>
> So ideally you want bright star disappearences on a dark limb with a moon
> before first quarter. (Last quarter as well - but then it's a reappearance
> and you don't quite know where to look).

that would sort of limit you to 1 week out of 4. But better than 
nothing, for a technique that requires no outside assistance.

>
> This limits the number of bright stars quite drastically. And then you have
> clouds...
>

Yeah, that is something I don't have a feel for.. How many stars are 
candidates? I assume you could get a moon RA/declination list, and then 
run that against the star list.

  This is one of those things that  I was hoping there's probably 
someone who has a program that can do the search trivially.

I have a moon ephemeris, but I haven't found a convenient star catalog 
(something in ASCII that has ID, RA, Dec, Mag would be nice)






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