moment, however, that the outer edge passed off the
disc of Jupiter, its outline became perfectly visible against the
black background of sky. What was still more novel was the occultation
for some little time of a star, apparently of the tenth magnitude, not
by the planet but by the satellite, almost immediately after it passed
off the disc of the former. Whether the star actually disappeared at
once, as if instantaneously extinguished, or whether, as I thought at
the moment, it remained for some tenth of a second partially visible,
as if refracted by an atmosphere belonging to the satellite, I will
not venture to say. The bands and rings of Saturn, the division
between the two latter, and the seven satellites, were also perfectly
visible, with a distinctness that a much greater magnifying power
would hardly have attained under terrestrial conditions. I was
perplexed by two peculiarities, not, so far as I know, hitherto
[5]
mentioned by astronomers. The circumference did not appear to present
an even curvature.
I mean that, apart from the polar compression, the shape seemed as if
the spheroid were irregularly squeezed; so that though not broken by
projection or indentation, the limb did not present the regular
quasi-circular curvature exhibited in the focus of our telescopes.
Also, between the inner ring and the planet, with a power of 500, I
discerned what appeared to be a dark purplish ring, semi-transparent,
so that through it the bright surface of Saturn might be discerned as
through a veil. Mercury shone brightly several degrees outside the
halo surrounding the Earth's black disc; and Venus was also visible;
but in neither case did my observations allow me to ascertain anything
that has not been already noted by astronomers. The dim form of Uranus
was better defined than I had previously seen it, but no marking of
any kind was perceptible.
Rising from my second, or, so to speak, midday rest, and having busied
myself for some little time with what I may call my household and
garden duties, I observed the discometer at 1h. (or 5 P.M.). It
indicated about two hundred terrestrial radii of elevation. I had, of
course, from the first been falling slightly behind the Earth in her
orbital motion, and was no longer exactly in opposition; that is to
say, a line drawn from the Astronaut to the Earth's centre was no
longer a prolongation of that joining the centres of the Earth and
Sun. The effect of this divergence was now perceptible. The earthly
corona was unequal in width, and to the westward was very distinctly
brightened, while on the other side it was narrow and comparatively
faint. While watching this phenomenon through the lower lens, I
thought that I could perceive behind or through the widest portion of
the halo a white light, which at first I mistook for one of those
scintillations that had of late become scarcely discernible. But after
a time it extended visibly beyond the boundary of the halo itself, and
I perceived that the edge of the Sun's disc had come at last into
view. It was but a minute and narrow crescent, but was well worth
watching. The brightening and broadening of the halo at this point I
perceived to be due, not to the Sun's effect upon the atmosphere that
produced it, but chiefly to the twilight now brightening on that limb
of the Earth's disc; or rather to the fact that a small portion of
that part of the Earth's surface, where, if the Sun were not visible,
he was but a very little below the horizon, had been turned towards
me. I saw through the telescope first a tiny solar crescent of intense
brightness, then the halo proper, now exceedingly narrow, and then
what looked like a silver terrestrial crescent, but a mere thread,
finer and shorter than any that the Moon ever displays even to
telescopic observers on Earth; since, when such a minute portion of
her illuminated surface is turned towards the Earth, it is utterly
extinguished to our eyes by the immediate vicinity of the Sun, as was
soon the case
disc of Jupiter, its outline became perfectly visible against the
black background of sky. What was still more novel was the occultation
for some little time of a star, apparently of the tenth magnitude, not
by the planet but by the satellite, almost immediately after it passed
off the disc of the former. Whether the star actually disappeared at
once, as if instantaneously extinguished, or whether, as I thought at
the moment, it remained for some tenth of a second partially visible,
as if refracted by an atmosphere belonging to the satellite, I will
not venture to say. The bands and rings of Saturn, the division
between the two latter, and the seven satellites, were also perfectly
visible, with a distinctness that a much greater magnifying power
would hardly have attained under terrestrial conditions. I was
perplexed by two peculiarities, not, so far as I know, hitherto
[5]
mentioned by astronomers. The circumference did not appear to present
an even curvature.
I mean that, apart from the polar compression, the shape seemed as if
the spheroid were irregularly squeezed; so that though not broken by
projection or indentation, the limb did not present the regular
quasi-circular curvature exhibited in the focus of our telescopes.
Also, between the inner ring and the planet, with a power of 500, I
discerned what appeared to be a dark purplish ring, semi-transparent,
so that through it the bright surface of Saturn might be discerned as
through a veil. Mercury shone brightly several degrees outside the
halo surrounding the Earth's black disc; and Venus was also visible;
but in neither case did my observations allow me to ascertain anything
that has not been already noted by astronomers. The dim form of Uranus
was better defined than I had previously seen it, but no marking of
any kind was perceptible.
Rising from my second, or, so to speak, midday rest, and having busied
myself for some little time with what I may call my household and
garden duties, I observed the discometer at 1h. (or 5 P.M.). It
indicated about two hundred terrestrial radii of elevation. I had, of
course, from the first been falling slightly behind the Earth in her
orbital motion, and was no longer exactly in opposition; that is to
say, a line drawn from the Astronaut to the Earth's centre was no
longer a prolongation of that joining the centres of the Earth and
Sun. The effect of this divergence was now perceptible. The earthly
corona was unequal in width, and to the westward was very distinctly
brightened, while on the other side it was narrow and comparatively
faint. While watching this phenomenon through the lower lens, I
thought that I could perceive behind or through the widest portion of
the halo a white light, which at first I mistook for one of those
scintillations that had of late become scarcely discernible. But after
a time it extended visibly beyond the boundary of the halo itself, and
I perceived that the edge of the Sun's disc had come at last into
view. It was but a minute and narrow crescent, but was well worth
watching. The brightening and broadening of the halo at this point I
perceived to be due, not to the Sun's effect upon the atmosphere that
produced it, but chiefly to the twilight now brightening on that limb
of the Earth's disc; or rather to the fact that a small portion of
that part of the Earth's surface, where, if the Sun were not visible,
he was but a very little below the horizon, had been turned towards
me. I saw through the telescope first a tiny solar crescent of intense
brightness, then the halo proper, now exceedingly narrow, and then
what looked like a silver terrestrial crescent, but a mere thread,
finer and shorter than any that the Moon ever displays even to
telescopic observers on Earth; since, when such a minute portion of
her illuminated surface is turned towards the Earth, it is utterly
extinguished to our eyes by the immediate vicinity of the Sun, as was
soon the case
Similar Books
