Re: Meeus Calculator

On Mar 28, 10:17 pm, danger.dan...@xxxxxxxxx wrote:
I certainly will get a copy of the book and play with some of the
algorithms in Excel. In the meantime, does anyone who has already
worked on setting this sort of thing up know when the next date is
that the scenario I mentioned will occur? (ie: the sunset time and
the moonrise time coincide)

A short answer is that the times when sunset and moon rise nearly
coincide are around the dates of the full Moon, since by definition
the full Moon occurs when the Moon's apparent position is 180 degrees
from the Sun. The date and time of the full can be found in most
planetarium programs, including Virtual Moon Atlas. A table of full
Moon dates and teims can be found at the USNO at:

http://aa.usno.navy.mil/data/docs/MoonPhase.html

I don't recommend going down the self-coding route unless there is no
other alternative. Typically, amateurs use Cartes du Ciel or
Astroplanner to answer sunrise and sunset questions graphically.

I have a few personal Excel spread*** projects that incorporate VBA
code that I wrote after Meeus and Duffet-Smith algorithms. I have not
done the eclipse prediction algorithms. I am assuming that is what
you are after with simultanous sunset/moonrise.

The VBA modules are heavily commented and back reference to Meeus and
Duffet-Smith. Please feel free to use them as you see fit.

The spreadsheets include cells for the current lunar and solar
altitude and azimuth in the local horizon system that link back to the
VBA code.

Current solar position RA-Dec is function: PositionSolarCoords
Current lunar position RA-Dec is function: PositionMoonCoords
Function to convert RA-DEC to alt and az is: Equ2Horizon_coord_convert

Project/Spread*** pages are at:

Spread*** to Make Annual Dark Sky and Lunar Observing Calendar (Dec.
2006)
http://members.csolutions.net/fisherka/astronote/plan/anndarksky/AnnualDarkSkyTable.html

Lunar Observing Planning Spread*** (April 2006)
http://members.csolutions.net/fisherka/astronote/plan/MoonPlan/MoonSpdtProject.html

Deep Sky Observing Planning Spread*** (July 2006)
http://members.csolutions.net/fisherka/astronote/plan/ObSpdht/ObSpdhtProject.html

The first two spreadshees can be modifed to answer the question
generally over the next 10 months, when will the Moon rise within 1
hour of sunset. Usually, this will narrow the target dates enough to
that simple checking in a planetarium program will get you targeted on
specific opportunities.

For eclipse predication, try the USNO Multi-Year Interactive Computer
Alamanc (MICA), available through www.willbell.com.

Java is more portable and TDriver's Java apps look good.

Geisen also has some good astronomy java applets.
http://www.jgiesen.de/astro/english.htm

Enjoy - Canopus56


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