Hi Jim,
I cannot really help you other than to say that the following are the
coefficients for a 9th order polynomial which calculates in decimals of a
minute the Equation of Time at Noon for each day in 2010 (not a leap year)
where x is the serial number of the day ie Jan1 is 1 and Dec
All programs that calculate the sunrise/sunset times use an eye
height of 0m. Many take the refraction in their calculations.
But what is the effect of a normal eye height of 1.5 m when the
observer is standing at sealevel like the beach. And when the eye
height is even considerabel higher
Dear friends,
days are getting shorter.
May I recommend you the ?Lichtuhr?, vulgo ?light-watch? or an unusal
indoor-sundial?
www.lichtuhr,de
Point to english version and the second screen ?design? and
?3D-animation?.
I own a CD with further details and I try to get the permission of the
The Explanatory Supplement to the Astronomical Almanac has several separate
and extensive discussions on this topic, in particular section 9.33 in the
1992 edition, page 487. A small portion of the section is:
At sunrise and sunset the apparent altitude of the upper limb on the
horizon is zero
An indoor-sundial???
Good Lord!
There is only a Black Forest cuckoo missing or a Big Ben striking
mechanism
Just in case you want to try a real indoor- reflex-sundial, try the
little YouTube film below!
* ** *** * ** ***
Reinhold R. Kriegler
Lat. 53° 6' 52,6 Nord; Long.
Hello Roger Bailey,
According to the United States Naval Observatory (
http://aa.usno.navy.mil/data/docs/EarthSeasons.php) the 2009 equinox falls on
sept 22 at 21:18:00 UT. This is 61 minutes different from your value. Who is
right?
Jos Kint
Eeuwfeestlaan 38
9840 De Pinte
Tel: 09.282.57.61
Hi James, Dialists,
Not exactly the polynomials, but ICE (Interactive Computer Ephemeris) from the
Naval
Observatory originally, is still available and covers up to 2047. It is
freeware and now public
domain. It is available from a number of places. It is a DOS program and the
latest
Dear Jos,
You raise an interesting point...
According to the United States Naval Observatory
... the 2009 equinox falls on sept 22 at 21:18:00 UT.
This is 61 minutes different from your value.
Who is right?
I would use the USNO time myself but your question
isn't as easy as it seems...
I am wrong. I quoted the time listed in the RASC Observers Guide wrong. They
list 21:19 UT. Close enough for sundials.
Regards, Roger
From: Jos Kint
Sent: Wednesday, September 23, 2009 11:29 AM
To: sundial@uni-koeln.de
Subject: exact time of 2009 Autumn equinox
Hello Roger Bailey,
I agree. I have a polar dial with an equinox line and I see this every
equinox. It's not that subtle. You can see it easily over just a few hours.
-Original Message-
From: sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni-koeln.de] On
Behalf Of Frank King
Sent: Wednesday,
10 matches
Mail list logo