*** 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: Sat, 1998 May 23 ---> Sun, 1998 May 24
Local midnight = 1998 May 23, 23 hr UT, or JD 2450957.458
Local Mean Sidereal Time at midnight =  13 53 53.2

Sunset ( 2326 m horizon):   21 08 GDT; Sunrise:    7 08 GDT
Evening twilight:   22 31 GDT;  LMST at evening twilight:   12 25
Morning twilight:    5 45 GDT;  LMST at morning twilight:   19 40
12-degr twilight:  21 58 GDT -->   6 18 GDT; night center:    2 08 GDT

Moonset :   18 43 GDT   Moonrise:    6 14 GDT   
Moon at civil midnight: illuminated fraction 0.053
1.9 days before new moon, RA and dec:   2 23 05,   9 02.2

The sun is down for 10.0 hr;  7.2 hr from eve->morn 18 deg twilight.
Dark all night (moon down from evening to morning twilight).