*** 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
1997 Mar 30 to 2 AM on 1997 Sep 28; standard zone =   0 hrs W

For the night of: Mon, 1997 Apr 28 ---> Tue, 1997 Apr 29
Local midnight = 1997 Apr 28, 23 hr UT, or JD 2450567.458
Local Mean Sidereal Time at midnight =  12 16 16.6

Sunset ( 2326 m horizon):   20 53 GDT; Sunrise:    7 25 GDT
Evening twilight:   22 10 GDT;  LMST at evening twilight:   10 26
Morning twilight:    6 07 GDT;  LMST at morning twilight:   18 25
12-degr twilight:  21 40 GDT -->   6 38 GDT; night center:    2 09 GDT

Moonrise:    1 58 GDT   
Moon at civil midnight: illuminated fraction 0.623
1.2 days before last quarter, RA and dec:  19 42 20, -17 06.9

The sun is down for 10.5 hr;  8.0 hr from eve->morn 18 deg twilight.
 3.8 dark hours after end of twilight and before moonrise.