QT Luong

A new utility by Jeff Conrad has been posted:
Sun/Moon Calculator.
Here the description by Jeff:

I have updated the Sun calculator so that it now gives rise and set
times and positions for the Moon as well as the Sun.

With the default settings, the calculator
will provide the basic information that photographers usually need:
<ol>
<li> A table of Sun and Moon rise and set times and azimuths
<li> A table of Sun and Moon positions throughout the day
</ol>

I've also added a few other features:
<ol>
<li> The ability to specify nonzero altitudes for rise and set--handy
if the visible horizon isn't level. For example, Mt. Whitney has an
altitude of approximately 10 degrees from most spots near Movie Rd;
typically, the Moon hits Mt. Whitney about an hour before and 10
degrees to the south of "official" moonset.

<li> The ability to search for dates on which Sun or Moon rise or set
meet certain criteria, such as rising or setting within a certain
azimuth range, or the Moon rising or setting with a certain phase, or
within a certain time of Sun rise or set. These can be combined with
nonzero rise and set altitudes; for example, you could find the dates
on which the Moon sets near Mt. Whitney with alpenglow on the
peak. You also easily could show that Dennis diCicco determined the
correct date (1 November 1941) for Moonrise, Hernandez, New Mexico.
</ol>
At first glance, the Rise/Set Options may seem a bit complicated,
especially when reading the Help section, but they actually are fairly
simple to use after a few tries.



Other Changes

The location database has been expanded so that it now covers 380+
locations, including most national parks in the United States and
Canada.

The handling of daylight saving time/summer time is more robust,
although the start and end times still are tied to U.S. rules (in the
southern hemisphere, these times are simply reversed). I've added most
of the common fractional-hour time zones.

Performance

Performance is fine when calculating rise/set times over the course of
a few weeks, but the program is slow when doing searches extending
over several years--such is the consequence of implementing
astronomical calculations in a script. A year's worth of rise/set
times takes just over 7 seconds on my 1.4 GHz Pentium 4. A 10-year
search of dates takes just under 60 seconds, and prompts a "slow
script" warning from Internet Explorer and Firefox unless the default
warning triggers have been changed. Nonetheless, it's faster (as well
as much easier) than grabbing the data from the USNO site and
rearranging and analyzing it.





Please feel free to leave any questions and comments here.

Giacomo GIRINO

great, great, great! So many times I've just been guessing at what time the moon would rise and in what direction etc. etc.
I always went on guessing based only on my experience but that works for the places I know well only and not too precisely either. I many times thought I should have worked out something like this calculator but I was just too lazy to.
Thanks Mr Conrad!

Lino (45°8'N, 8°31'E)

John_4185

great, great, great! So many times I've just been guessing at what time the moon would rise and in what direction etc. etc.

Pity. There are published tables.

Doug Dolde

"Pity. There are published tables." WTF is that supposed to mean? You must be a Pommie with a stick up his behind.

I think this is the best sun/moon calculator I have seen. Thanks.

Paddy Quinn

Jeesh - you sound like some kind of Aussie - keep the convict talk to yourself. As far as I know jj is all Yank?

BTW - there are other excellent online calculators of this sort online

Ralph Barker

Excellent addition to the site, QT, and nice job, Jeff.

Now, if we could just get one of these to interact with topo maps, and overlay the shadows in 3-D, we'd be all set. (lol)

Jeff Conrad

Don't laugh too hard, Ralph. In most cases, I wouldn't know what to do
with a Moon azimuth without a computerized topo map (though I wish they'd
give altitudes as well). I think the 3-D features of most such maps have a
way to go, but they still sometimes are helpful.

Several astronomy programs will simulate the passage of a celestial body
across the horizon, and allow this to overlay a photograph. The rub is
that you need a photograph of every view from every location that you want
to model. I use a program that generates a table of Sun and Moon positions
vs. landscape features; it's a bit short of VR, but the next step would not
be out of the question for someone good at graphics. Were there sufficient
demand, we might already be there.

John_4185

Now, if we could just get one of these to interact with topo maps, and overlay the shadows in 3-D, we'd be all set. (lol)

earth.google.com/
It interacts with GPS.

chris_4622

I've used this for sunrise information: http://www.hourworld.com/

chris

Jeff Conrad

If you need only information for the Sun, Wide Screen Software's SunPATH ($99)
looks as if it's very nicely done. It's available for the Mac, and using a
Mac emulator, for Wintel machines. John Cook posted

this link that has SunPATH on sale for $87 during September.

There are several native programs available for Wintel machines, such as
Fossil Creek's Heavenly
Opportunity ($25) or Digital Light &
Color's Ephemeris. Neither has all the features of the Sun/Moon
Calculator that I wrote, but they're much faster, and Heavenly Opportunity
has a much larger location database. Ephemeris is free, so the
cost/benefit ratio is hard to beat. Heavenly Opportunity allows searches
similar to those of my Sun/Moon Calculator, so it may be worthwhile for
those who do many searches in attempt to find the perfect photo op.
Neither program allows nonzero rise/set altitudes.