Astronomical calculator program, by John Thorstensen.

*SELECT SITE* - Enter single-character code:
   n .. NEW SITE, prompts for all parameters.
   x .. exit without change (current: Kitt Peak)
   k .. Kitt Peak [MDM Obs.]
   s .. Shattuck Observatory, Dartmouth College, Hanover NH
   e .. European Southern Obs, La Silla
   a .. Anglo-Australian Telelescope, Siding Spring
   h .. Mt. Hopkins, AZ (MMT, FLWO)
   p .. Palomar Observatory
   t .. Cerro Tololo 
   r .. Roque de los Muchachos, La Palma, Canary Is.
   b .. Black Moshannon Obs., Penn State U.
   d .. Dominion Astrophysical Obs., Victoria, BC
   o .. McDonald Observatory, Mt. Locke, Texas
   m .. Mauna Kea, Hawaii
   l .. Lick Observatory
Your answer --> You have selected Roque de los Muchachos
(This can be changed later using the 's' [site] command.


DATE AND TIME SET AUTOMATICALLY USING SYSTEM CLOCK ... to
Sun, 1998 Apr 19, time  17 31 42.0 local time
(NOTE: time does NOT automatically update; 'T' reads clock again.)

COORDINATES SET TO ZENITH:   5 07 25.5,  28 41 56, epoch 1950.0

READY TO COMPUTE.  Use simple commands to set the date, time, RA
dec, and so on; then use other commands to compute and display
observability information.

NEW or RUSTY USERS: type 'f' (and return) for FAST guided tour.
FAST GUIDED TOUR: (type 'f' to see this again).

To explore this program quickly, try the following (in order):

--> Specify an evening date (e.g., 1995 March 22) and then display
    the almanac for that night by typing 
        y 1995 3 22   a 
--> Specify an ra and dec and then make an hourly airmass table
    by typing, for instance 
        r 15 28 27  d 12 13 14  h 
    (Notice how the date you specified earlier is still in effect.)
--> Specify a time (e.g., 4 50 00 AM local time) and display the
    circumstances at that instant by typing
        t 4 50 0  =
--> Type 'o' and follow the prompts to show observability
    through a season (tabulated at new & full moon).
--> Type 'l' to list the current input parameters and options.
--> Type 'm' to list planetary positions.
--> Type 'T' to set time & date to right now (+ settable offset).
--> Type 'x?' for eXtra goodies menu; log file, object lists etc..
--> Read the help texts; '?' prints a short menu, 'i' gives
    more complete information, 'w' tells you about inner workings.
    An upper-case 'Q' exits the program.
 Give a command: *** Almanac for the currently specified date ***:
Almanac for Roque de los Muchachos:
long.   1 11 31 (h.m.s) W, lat.  28 45.5 (d.m), elev.  2326 m
pseudo-Greenwich Daylight Savings Time assumed from 2 AM on
1998 Mar 29 to 2 AM on 1998 Sep 27; standard zone =   0 hrs W

For the night of: Thu, 1998 Apr 9 ---> Fri, 1998 Apr 10
Local midnight = 1998 Apr 9, 23 hr UT, or JD 2450913.458
Local Mean Sidereal Time at midnight =  11 00 24.8

Sunset ( 2326 m horizon):   20 41 GDT; Sunrise:    7 44 GDT
Evening twilight:   21 55 GDT;  LMST at evening twilight:    8 55
Morning twilight:    6 31 GDT;  LMST at morning twilight:   17 32
12-degr twilight:  21 26 GDT -->   6 59 GDT; night center:    2 13 GDT

Moonrise:   18 34 GDT   
Moon at civil midnight: illuminated fraction 0.966
2.0 days until full moon, RA and dec:  11 57 51,   1 41.8

The sun is down for 11.1 hr;  8.6 hr from eve->morn 18 deg twilight.
Bright all night (moon up from evening to morning twilight).

Type command, 'f' for fast tour, or '?' for menu:Suggestions or comments --> john.thorstensen@dartmouth.edu
Goodbye.