NavList:

   

Reply

On 10 Dec 2004 at 8:48, Fred Hebard wrote:

> Regarding those inaccuracies, it would be helpful to see the entire
> series of observations for each of the lunars.

I only have a couple of these already transcribed (I'm working from
digital photographs of microfilm--it can be very difficult to make out
some of Thompson's writing). I'll include a couple of other runs that were
near Rocky Mountain House (but since he was on the trail I don't have a
true position for the resulting longitude--I include them only as typical
examples of his observation).

Feb. 24 1801 Regulus
9:48:38  30?36'30"
9:49:32  30?36'00"
9:50:23  30?35'50"
9:51:13  30?35'15"
9:52:07  30?34'45"
9:52:55  30?34'30"

Feb. 24 1801  Aldebaran
9:55:31  57?19'45"
9:56:38  57?20'00"
9:57:36  57?20'30"
9:58:28  57?21'00"
9:59:16  57?21'15"
10:00:07  57?21'45"
10:00:56  57?22'00"
10:01:48  57?22'15"

Nov. 26, 1800 - Aquilae (Altair)
8:53:05  81?17'45"
8:53:55  81?17'45"
8:54:38  81?18'00"
8:55:20  81?18'30"
8:56:00  81?18'45"
8:56:52  81?19'30"
8:57:38  81?19'15"
8:58:29  81?19'30"

Nov. 26, 1800 - Aldebaran
9:01:43  49?5'45"
9:02:52  49?5'15"
9:03:20  49?5'00"
9:04:15  49?4'45"
9:05:12  49?4'15"
9:06:10  49?4'00"
9:07:08  49?3'45"
9:07:58  49?3'15"

I don't know if you can conclude much about Thompson's skill from these
runs. They look pretty smooth to me when I plot them.

Nowhere in Thompson's notebooks do we ever find any of his calculations,
so we can't say whether errors crept in during the reduction phase (in my
own limited experience, I often get the last couple of decimal places of
tabled log values wrong by adding the corrections in my head and losing a
place between the table and when I write the value down). Although of the
sights that I have checked, the corrections he writes down are exactly the
same as I get using Witchell's method so I think his calculations were
probably OK.

Ken Muldrew.

   

Reply