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Dear Kermit,
Here is more Lunars from Indiana.

March 30. SNO-T, IC-=0'3, Kepler scope,
wristwatch 2 sec fast, termometer 61F,
barometer 29.13, height 10 m over the sea level
(from the local airport web site. I think that in general temperature,
pressure and height do not affect the results, unless one of these
quantities is extremal).
Sun-Moon: GMT, Sextant readng:
23:30:25 91d19'8
23:33:07 91d20'6
23:34:10 91d20'8
23:35:35 91d20'8
23:37:03 91d20'9
23:40:40 91d21'8
Greenwich date March 31, Venus-Moon, near limb:
00:11:45 46d28'
00:13:53 46d29'2
00:18:28 46d30'2
00:20:30 46d30'9
00:21:40 46d31'6
Now I want to try Jupiter, though it is still daylight, Sun just set.
Cannot find it in day light. Apply the usual
method: preset Frank's "Predicted Lunar" (as in old almanacs) on the
sextant, and
point the horizon glass at the Moon, then rotate the sextant
trying to find Jupiter.
Unfortunately the Moon is too high, so I must look almost vertically.

So I lay on my back on the balcony, catch the Moon and
rotate the sextant slowly. I find it. From this laying position I obtain:
00:23:50 59d33'7
00:25:50 59d34'8
Now I know well where Jupiter is, and can find it with my naked eye,
so I stand up and point the horizon glass at the Jupiter:
00:28:30 59d34'8
00:30:05 59d35'2
00:32:00 59d35'7
Now Mars is visible: Moon (far limb)-Mars:
00:35:20 52d37'
00:37:45 52d36'4
00:39:20 52d35'8
OK. Now it is time to reduce.
Reduction with Frank's calculator shows that the results for
Sun and Venus are excellent.
Jupiter is excellent when I stand upright. But when laying on the floor,
the result is disappointing...Could it be that SNO-T is not rigid enough?
So that when I point it vertically, the reading changes?
Not likely. Perhaps it is my eye that works differently when I lay on
my back:-)
Mars is also disappointing this time... Errors I obtained are 0'4 and 0'6.
Well, the reseults are not always good.
I always argued with Frank that the best one guarantee with the Lunars
is 1/4 degree of longitude, even in excellent conditions.
It is true, frequently I can do much better than that,
but I think one cannot
GUARANTEE better than 1/4 degree in longitude.
The brightest things (Sun and Venus) give the best results.
Perhaps my eyes are ageing...

Alex.

   

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