Scientific American Supplement, No. 530, February 27, 1886Various
Science
Scientific American Supplement, No. 530, February 27, 1886
Various
Science -- Periodicals
In the latter part of the paper alluded to above, I stated the
speculative basis upon which I restricted the stellar region to be
examined; also the fact that between November of 1877 and March of 1878 I
was engaged in a telescopic scrutiny of this region, employing the
twenty-six inch refractor of the Naval Observatory. For the purposes
contemplated I had no hesitation in adopting the method of search whereby
I expected to detect the planet by the contrast of its disk and light
with the appearance of an average star of about the thirteenth magnitude.
A power of 600 diameters was often employed, but the field of view of
this eye-piece was so restricted that a power of 400 diameters had to be
used most of the time. I say, too, that, "after the first few nights, I
was surprised at the readiness with which my eye detected any variation
from the average appearance of a star of a given faint magnitude; as a
consequence whereof my observing book contains a large stock of memoranda
of suspected objects. My general plan with these was to observe with a
sufficient degree of accuracy the position of all suspected objects. On
the succeeding night of observation they were re-observed; and, at an
interval of several weeks thereafter, the observation was again
verified." Subjoined to the original observations are printed these
verifications in heavy-faced type.
In conducting the search, the plans were several times varied in slight
detail, generally because experience with the work enabled me to make
improvements in method. Usually, I prepared every few days a new zone
chart of the region over which I was about to search; and these charts
while containing memoranda of all the instrumental data which could be
prepared beforehand, were likewise so adjusted with reference to the
opposition-time of the planet as to avoid, if possible, its stationary
point. The same thing, too, was kept in mind in selecting the times of
subsequent observation. Notwithstanding this precaution, however, it
would be well if some observer who has a large telescope should now
re-examine the positions of these objects.
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