*** 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: Sun, 1998 May 31 ---> Mon, 1998 Jun 1
Local midnight = 1998 May 31, 23 hr UT, or JD 2450965.458
Local Mean Sidereal Time at midnight =  14 25 25.7

Sunset ( 2326 m horizon):   21 12 GDT; Sunrise:    7 06 GDT
Evening twilight:   22 37 GDT;  LMST at evening twilight:   13 02
Morning twilight:    5 41 GDT;  LMST at morning twilight:   20 07
12-degr twilight:  22 03 GDT -->   6 15 GDT; night center:    2 09 GDT

Moonset :    2 09 GDT   
Moon at civil midnight: illuminated fraction 0.387
1.1 days before first quarter, RA and dec:   9 55 49,  11 14.2

The sun is down for  9.9 hr;  7.1 hr from eve->morn 18 deg twilight.
 3.5 dark hours after moonset and before beginning of twilight.