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Re: Lunars with SNO-T
From: Frank Reed CT
Date: 2004 Oct 24, 03:24 EDT
From: Frank Reed CT
Date: 2004 Oct 24, 03:24 EDT
Alex E wrote:
"Moon-Altair:
GMT 4:06:49 4:09:58 4:13:10 4:17:12 4:18:57
DIST 51d22.2' 51d23.3' 51d23.8' 51d24.1' 51d34.3'
ERD 0.0' +0.5' +0.3' -0.2' -0.4'
ERL +0.3' +13.5' +8.7' -7.3' -12.2'
AVERAGE GMT: 4:13:13 AVERAGE DIST: 23.54'
ERROR IN DISTANCE: 0.0' ERROR IN LONG: 0.4' "
First, a note: the error in lon is just 30x the error in distance in the calculator on my web site as it stands. This is about right (+/-10%) in the majority of cases. I might make it more meaningful at some later time...
Second, nice job! I maintain that lunars are NOT difficult if you have a reasonably good sextant with a very good telescope AND if you get some practice with sight accuracy (such as the ones you've been posting on). In my experience, you can expect a couple of tenths of a minute of arc as a reasonable error in the measured distance.
And wrote:
"Moral: DO average:-)"
Yes. It was always recommended for lunars. It's not tough to do four or five in a row over the course of ten minutes.
And:
"Comments: 1. NOW I finally understand what the cross-wires in the scope are for."
I think their importance is exaggerated. Can you tell me how you find them useful? My scope has no cross-wires, and I get excellent results.
And:
"2. It is SO hard to hold the sextant "handle up" with
your right hand. Some French "reflecting circles" had
two handles, one on each side."
Once you have things lined up, you can often find a more comfortable pose by flipping the sextant over.
And wrote:
"Thanks to Frank for his wonderful site."
You're very welcome.
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois
"Moon-Altair:
GMT 4:06:49 4:09:58 4:13:10 4:17:12 4:18:57
DIST 51d22.2' 51d23.3' 51d23.8' 51d24.1' 51d34.3'
ERD 0.0' +0.5' +0.3' -0.2' -0.4'
ERL +0.3' +13.5' +8.7' -7.3' -12.2'
AVERAGE GMT: 4:13:13 AVERAGE DIST: 23.54'
ERROR IN DISTANCE: 0.0' ERROR IN LONG: 0.4' "
First, a note: the error in lon is just 30x the error in distance in the calculator on my web site as it stands. This is about right (+/-10%) in the majority of cases. I might make it more meaningful at some later time...
Second, nice job! I maintain that lunars are NOT difficult if you have a reasonably good sextant with a very good telescope AND if you get some practice with sight accuracy (such as the ones you've been posting on). In my experience, you can expect a couple of tenths of a minute of arc as a reasonable error in the measured distance.
And wrote:
"Moral: DO average:-)"
Yes. It was always recommended for lunars. It's not tough to do four or five in a row over the course of ten minutes.
And:
"Comments: 1. NOW I finally understand what the cross-wires in the scope are for."
I think their importance is exaggerated. Can you tell me how you find them useful? My scope has no cross-wires, and I get excellent results.
And:
"2. It is SO hard to hold the sextant "handle up" with
your right hand. Some French "reflecting circles" had
two handles, one on each side."
Once you have things lined up, you can often find a more comfortable pose by flipping the sextant over.
And wrote:
"Thanks to Frank for his wonderful site."
You're very welcome.
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois
