The earth magnets that are in hard drives are
plated with a shiny silver substance, and are extremely hard to pull off of a
refridgerator!! :-}
Peter
- Original Message -
From:
John
Carmichael
To: JOHN DAVIS ; [EMAIL PROTECTED]
Cc: Sundial List
Sent: Tuesday,
Hi John,
For holding strength through a thick piece of glass you would need a
magnet that had such a strong field over that gap. The Rare Earth
magnets, although extremely strong at short distances have a field
that falls off quickly with distance. Two long flat bar Alnico magnets,
on
Some months ago I started marking the ceiling to show when I get satellite
outage. I have since been making dots on the ceiling and noting the time and
date. Today, 3 Feb. 2005 the Sun at 12:00:00 noon was at the same place it was
on 6 Nov. 2004 and if I read my writing correctly at
I have started this project. I found that a simple lipstick mirror secured
to a decorative molding piece anchored mid-way within the window frame works
best.
If you are not doing the mathematical calculations (and simply marking the
ceiling over a year's time), then keep in mind that there
Theissue one must be careful of when using such a magnetic gnomon,especially with SGS is causing cracking, breaking, or no less than unsightly marringwhenapplying/ removing such a gnomon.
On another previous issue - slippage. It seems like a good idea for if one intends to use a magnetic
Greetings fellow dialists,
The other day I bought a copy of Weir's Azimuth Diagram. This was the first
time I had seen it although I had read about it in earlier days. It is a
remarkable document, devised by Captain Weir in 1890. Its purpose is to
enable a navigator to find the azimuth of a
Hi Judith and all,
I don't know your elevation but I put you at 600ft.
Well here it is, they are both within 3 1/2 arc min of each other and would
only appear to be about .1 inch off from each other at 8' from mirror!!:
2/6/05 Azm = 172deg 18' 07 Alt = 34deg 09' 11 Alt w/ref. = 34deg 10'
For calculations like this I would recommend the Dialists Companion. It
can be downloaded from the NASS site, specifically
http://www.sundials.org/publications/dcomp/ . The program was originally
released as part of the North American Sundial Society's Digital Compendium
as one of the many
