Weekly national intelligencer. [volume] (Washington [D.C.]) 1841-1869, 1847-07-24
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MARBuRG, ELECTORATE OF HEssE, J

A3RIL Ia, lS47.
ESTEEMED SIR Since the date of my last have been
oupied with the volume of your Astronomical Obserpa-
tos which you had the kindness to send me and
red to that might be acceptable you receive by let
ter in advance of its publication the contents of brief
tse which shall transmit NJ Schumacher in a few days
for publication in his Astronomische Nachrcht." This
will enable you commence observations in America this
year, should you find my correct the subject and
which, fear could be the if you awaited printed
copy of the paper
The subject is this am of opinion that
unwisely considering the solar paralax deduced from the
ans of Venus in l76 and 1869 sufficiently correct and
that they do avail themselves Of modern methods of
observation for the purpose of gradually acquiring more
knowledge of it. 1t true indeed that the oppos
tons of Mars long ago proposed for this purpose
not that any effective has been made Of them
since $751; although the Nautical Almanac has regularly fur
nished ephemers There is, however, third method,
which occurred years ago. and understand
why should have been entirely neglected. mean by
observations of Venus during the period of its reogade
ton, and more especially when the planet is stationary
At the conjuncons Venus offers excellent opportunities for
observation in its delicate and faint crescent form and from
what have been able to accomplish with my small instru
ment have every TO believe that most excellent
suits obanabe with meridian instruments observatores
IN opposite hemisphees, but lying nearly under the
Idlan Furthermore, Venus at that time about twice
near to the earth is Mars when opposition and obseva
tons upon have this very superior advantage, that it is not
absolutely requisite they should be simultaneous, nearly
simultaneous When too the planet stationary OBJ
servatons of one meridian may be readily referred another
by Interpolation without exposure error and it is this
time still the earth than Mars can be in the ia
voabe Finally, the distance of the planet from the
being about 29 mcromeca may be added to and connect
ed with meridian observations
Hence in my opinion our object should be to make fire.
quen meridian observations of Venus about the periods when
stationary, and endeavor obtain in all parts of the ear
more especially by voyage careful micrometrica observa
tons Let suppose traveller place of the southern
hemisphere TO observe it evening time T.
ring to projected point Of the heavens A. and that it also
observed the meridian during adjacent days. obsera
tory OF the northern hemisphere the meridian of the earth
in whose plane projected Venus found to be the time
will be readily ascertained from its known right ascenon
Corrected by the observations at b. This terrestrial meridian
will also be ntersected by the parallel of the observatory
point c. where simultaneous meridian observation has not
indeed been made but planets place may be found for
Interpolation from the observations B. BY this inerpoated
observation let Venus be placed the point of the heavens
Then evidently the celestial AC is the of the
angle under which the known places and appear to We
nus, and from this angle the horizontal paraax of the planet
must be deducbe, the advanageousy the the
terrestrial line AC approaches diameter Of the earth
also imagine that will be of great advantage astrono
will unite in making careful meridian observations and
promoting micromeca the stationary pc
RODS to the greatest possible extent For the latter
observations is however, necessary that only the
should be previously considered but the attending ccum
Stances and list Of fixed for comparison especial
y selected This will doubt be done should
nes be inclined adopt my proposition but send you what
have found for ls47, promising that have made partial
examination for both ls47 and ls49 and that the local
tonary point Of the latter year offers much greater facilities
than the present.
The next eastern stationary period of Venus, in right
eeso, will occur the 10Th September and about the mid
die of the space between Virgins and ! Cwpi The
stars in that vicinity to be found in the Berlin Academy
charts and which have been frequently Observed fol-
lows the R. A. all referred to the equinox Of 1900