Re: [guide-user] Ephemerides in Guide - new formulae for visual brightness of Mercury and Venus

Wolfgang Renz Jan 20, 2012


André Franke wrote:
> some time ago I discovered that the "Himmelsjahr" in Germany has
> implemented new formulae for the calculation of the brightness of
> Venus and Mercury.
> ...
> The according formulae can be found in
> "The Astronomical Journal, 129:2902-2906, 2005 June# 2005.

Not just the german Himmelsjahr uses the new formulae but also the us/brit
"The Astronomical Almanac" since 2007 !
See the USNO page:
Topocentric Configuration of Major Solar System Bodies: U.S. Cities and Towns
"Expressions for the apparent visual magnitudes of the major planets (ex-
cept Mercury and Venus) are from Harris (1961) [1]. The expressions for
the magnitudes of Mercury and Venus are based on the parameters given
in Hilton (2003) [2] and are the same as used in the 2005 and 2006 editions
of The Astronomical Almanac. The Mercury and Venus magnitudes differ
slightly from the 2004 edition (and earlier editions) of The Astronomical
Almanac, which used the earlier Harris (1961) expressions. Later editions
(2007 onward) of the The Astronomical Almanac use the magnitude ex-
pressions for Mercury and Venus as given in Hilton (2005) [3]."
[1] Harris, D. L., 1961, in Planets and Satellites edited by G. P. Kuiper and
B.A. Middlehurst, (Chicago), pp. 272-342.
[2] Hilton (2003), Private communication.
[3] Hilton (2005) The Astronomical Journal, 129, 2902-2906.
= (its erratum)

> It would be great if even apparent diameters in " (arcseconds) could be shown
> when calculating ephemerides.

I second this request.

Clear skies

Wolfgang Renz, Karlsruhe, Germany