*** 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: Fri, 1997 May 16 ---> Sat, 1997 May 17
Local midnight = 1997 May 16, 23 hr UT, or JD 2450585.458
Local Mean Sidereal Time at midnight =  13 27 14.6

Sunset ( 2326 m horizon):   21 04 GDT; Sunrise:    7 12 GDT
Evening twilight:   22 26 GDT;  LMST at evening twilight:   11 53
Morning twilight:    5 50 GDT;  LMST at morning twilight:   19 18
12-degr twilight:  21 53 GDT -->   6 22 GDT; night center:    2 08 GDT

Moonset :    4 26 GDT   
Moon at civil midnight: illuminated fraction 0.727
2.5 days since first quarter, RA and dec:  11 33 22,   1 56.2

The sun is down for 10.1 hr;  7.4 hr from eve->morn 18 deg twilight.
 1.4 dark hours after moonset and before beginning of twilight.