[LEAPSECS] New Explanatory Supplement & Almanac

Barberi scbarberi at verizon.net
Fri Feb 15 11:22:17 EST 2008

"David Malone" wrote:

> The Astronomical Almanac 2006 contains these definition and

> equations. However, I would suggest you wait until the

> 2007 edition is available (any day now). You should also

> note that at the IAU in the summer, there will be proposals

> to adopt a better precession model, ie one that is dynamically

> consistent and not just an update to Lieskie. This will

> probably make some end figure changes in the equations!


> I thought that they were suggesting that there was to be an update

> to the explainatory suplement in 2006 to explain the ERA stuff, but

> now I reread it, it seems likely the information is probably in the

> Almanac, not the suplement. I haven't had a chance to look at the

> 2006 almanac or suplement to confirm this yet.

Jim Williams at the USNO has indicated to me that the next edition of the
Explanatory Supplement is
"moving forward slowly if at all." (He is not the editor, but he and Myles
Standish did write one of the chapters.)

The 2006 Astro.Almanac has implemented the IAU resolutions up to and
including 2003. It indicates that the 2009 edition will implement the P03
precession / ecliptic, and the re-definition of TDB.
I don't have a copy of the 2009 edition yet, but it is available now:
See also U.S. Naval Observatory Circular No. 179:

Stephen Barberi

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