*** 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: Thu, 1997 May 15 ---> Fri, 1997 May 16
Local midnight = 1997 May 15, 23 hr UT, or JD 2450584.458
Local Mean Sidereal Time at midnight =  13 23 18.1

Sunset ( 2326 m horizon):   21 03 GDT; Sunrise:    7 12 GDT
Evening twilight:   22 25 GDT;  LMST at evening twilight:   11 48
Morning twilight:    5 51 GDT;  LMST at morning twilight:   19 15
12-degr twilight:  21 52 GDT -->   6 23 GDT; night center:    2 08 GDT

Moonset :    3 52 GDT   
Moon at civil midnight: illuminated fraction 0.638
1.5 days since first quarter, RA and dec:  10 47 27,   5 37.2

The sun is down for 10.2 hr;  7.4 hr from eve->morn 18 deg twilight.
 2.0 dark hours after moonset and before beginning of twilight.