earth sufficiently to destroy the visibility of stars, just as does
the scattered light of our daytime sky at the earth' s surfac~; and
(2) the astronauts are generally not well dark-adapted, as mentioned
in section 5 of this Chapter.
~!cntion has already been made of the dispersion in star visibil-
ity during satellite night because of the smudging of the windows,
Under the best window conJitions the astronomical sky is reported
to be similar to that from an aircraft at 40,000 ft. Under the
parti,~\llarl:' poor conditicns of Mercury 8, astronaut SchirrL!, who is
vcn falllLli:·ll' \\'ith the ,'oll:;;tellations, could not distinguish the Milky
"'av,
~Ieteors
In go'neral, meteors become luminous below lOG km., well below
an)' stahle orbit. Although organized searches for meteor trai.ls were
not part of the ccientific planning of the NASA programs, sporadic
obsvrvatiollS ycre made b)' the astronauts who reported that the meteor
trail:, could be readi 1y distinguisheJ from lightning flashes. Because
of their sporadic nature, these observations cannot be systematically
c~mrared with the ground-ohserved stati.stics of the known variation
of meteors during the y()i1l' as the earth crosses the paths of inte1'-
planetar:, dehris. Ilowevcr Gemini 5 was put into orbit shortly after
the peah of the :\ugust Leonid '~hower and ground observations of the
5hOl,'e1' \,ere confirmeJ in ~I rough wa~ when astronauts Cooper and Conrad
Ob~l"i'VC'd a slgnificant number of meteor flashes.
'111(' :::odiacal Light BDlld
T\~o factors tend to offset each other in the cbscrvati on of the
:.odiacal light band from a spacecraft. A favorable factor is that the
:odiacal hand gets \'cry rapidly brighter as it is observed as close
as SOllll' :; ° or 6° to tIll' sun, ns is possible from spacecraft in cun-
trast \"ith the t,dlight rpstriction on Lhe earth's surface of about 25°,
'111C ratio of briglltllcsS at an elongation of ~;o) bCi), to that at 25°,
B(.:S), is
earth sufficiently to destroy the visibility of stars, just as does
the scattered light of our daytime sky at the ea-.rth' s surfaC'c~; and
(2) the astronauts are generally not well dark-~dapted, as ment i oned
in section 5 of this Clwpter.
Mention has already been made of the dispersion in star visibil-
ity du-rin!1 satellite night because of the smudging of the windows,
Under the best window c0nditions the astronomical sky is reported
to be similar to that from an aircraft at 40,000 ft. Under the
I'arti,:ulal'ly poor conditj,'l15 of Mel'cury 8, astronaut SchlrriJ, who is
\'('r: fallllli:ll' \\'itll the c(lll:,tellations, couhl not distinguish the Milky
\~a \' .
~feteors
In g' debri!S. lIowever l~emini 5 was put into orbit shortly after
the peak of the ,\ugust Leonid "hower and ground observations of the
sho\,'er \,'cre confi rmed in ;1 rOllgh WIlJ when as t J'onlluts Cooper and Conrad
oh"e-i'v0d it Significant numher of Tn0teor flashes.
'111e :odiac_al Light BDlld
TI<lo factors tend to offset NICh other in the ebscrvation of the
2_odiacul light band from a ~pac0craft. /\ favorable factor is that the
:ollJacal band get" \'cry rapidly l.rightcr as it is observed as clo~c
a, SOIlll' :;0 or 6° to till' sun, llS is possible from spacecraft In CUII-
tl'C1st h'lth tht? t,dl\gilt rl'stl'iction on ellc earth'~ surface of aho\lt 25°.
'111(' ratlo of briglttncs~ at an dongation of ,jo) Iq!;) , to that at 2So,
Ill.'S), is