Re: Inaccurate starchart ?

Sune Storgaard wrote:
> Yes thats one of the few things im sure of.. There is a worldmap
where you
> can point on and then get the long/lat cordinates for that place, and
when i
> click on denmark, i get cordinates very similar to the exact ones i
entered
> myself.

The JPL Ephemeris generator is a reliable test benchmark:

http://ssd.jpl.nasa.gov/cgi-bin/eph

The following first ephemeris shows the span between May 12, 2005 at 21
UTC to May 13, 2005 at 02:00 UTC. This covers your first May 12 post
example. I'm not sure what your local time is in your example.

Target Body: Satellite Moon [Luna]
Observer Location: User Specified Location
Coordinates: 9°01'59.9''E, 56°34'00.1''N, 10 m

From: A.D. 2005-05-12 21:00 UT
To: A.D. 2005-05-13 02:00
Step: 30 minute

Date__(UT)__HR:MN Azi_(a-appr)_Elev L_Ap_Sid_Time
******************************************************
2005-May-12 21:00 Nm 285.4596 22.6149 12 59 01.6399
2005-May-12 21:30 Nm 290.9961 18.7868 13 29 06.5683
2005-May-12 22:00 Am 296.5099 15.0999 13 59 11.4966
2005-May-12 22:30 Am 302.0460 11.5876 14 29 16.4250
2005-May-12 23:00 Am 307.6417 8.2835 14 59 21.3534
2005-May-12 23:30 Am 313.3262 5.2213 15 29 26.2817
2005-May-13 00:00 Am 319.1215 2.4347 15 59 31.2101
2005-May-13 00:30 Am 325.0409 -0.0426 16 29 36.1385
2005-May-13 01:00 As 331.0894 -2.1783 16 59 41.0668
2005-May-13 01:30 N 337.2625 -3.9419 17 29 45.9952
2005-May-13 02:00 N 343.5468 -5.3065 17 59 50.9236

The JPL Ephemeris agrees with your software - about 320° az and 2°
alt. This agrees with your compass measurement of azimuth but is off
in altitude.

How did you measure the altitude of the moon? "[W]hile it looks more
like 20-30 to me, . . ." Two outstretched hands, with the fingers
spreadout, covers about 36°. A fist is 10°.

For your second May 13 example, you give:

> Odense 2005-5-13 16h31m ( TU + 1h00m )
> Sideral Time : 7h39m
> Hour Angle : 4h16m
> Azimuth :+259°21'
> Altitude :+29°47'

The GEOnet names server gives the following for Odense, Denmark:
http://gnswww.nga.mil/geonames/GNS/index.jsp

55° 24' 00" N 010° 23' 00" E

Using the JPL ephemeris generator reports on that location and time
reports the following for the time zone UT+1 (not UTC as in the
previous table):

Target Body: Satellite Moon [Luna]
Observer Location: User Specified Location
Coordinates: 10°23'00.0''E, 55°24'00.0''N, 10 m

From: A.D. 2005-05-13 15:00 UT+1
To: A.D. 2005-05-13 17:00
Step: 30 minute

Date_(ZONE)_HR:MN Azi_(a-appr)_Elev L_Ap_Sid_Time
******************************************************
2005-May-13 15:00 *m 139.8539 56.1811 06 07 13.2104
2005-May-13 15:30 *m 151.2483 58.5027 06 37 18.1388
2005-May-13 16:00 *m 163.7595 60.0594 07 07 23.0671
2005-May-13 16:30 *m 177.0136 60.7139 07 37 27.9954
2005-May-13 17:00 *t 190.3943 60.3993 08 07 32.9238

Note the local apparent sideral time is close, but both the alt and az
are way off. I have a hard time believing that Cartes du Ciel is that
far off.

Scanning the JPL ephemeris for Odense, Denmark for all of May 13 and
14, I donot find any alt and az that corresponds even closely to the
results you report.

My guess is that what you have entered for the geographic coordinates
of your hypothetical observing point of Odense, Denmark is off.

Hope the JPL ephemeris generator or the GEOnet names server helps in
working out what appears to be a data entry format problem. Try
entering lat and long in the form "ddd mm ss" instead of the decimal
form.

- Canopus56

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