126 
CELESTIAL DAY OBSERVATIONS. 
Observations 
upon the 
planet Venus 
in the day- 
time. 
greater distance from (he sun than Venus j since his light is 
so faint as to be scarcely perceptible when more than 20' from || 
the sun, while that of Venus is distinctly seen amidst the full (! 
splendour of the solar rays. With a power of 60 I have dis- 
tinguished the belts of Jupiter before sun-set, but could never ^ 
see any of his satellites till the sun was below the horizon. ^ 
RIy observations on Saturn in day-light have not been fre- |j 
quetit. Have seen his ring severat times before sun-set with a ||| 
power of 60 ; but his great southern declination, and conse- 
quent low altitude, for a considerable time past, have been un- 
favourable for such observations ; and therefore no general 
conclusions can be deduced from them. The southern decli- 
nation of Mars having of late been greater than even that of 
Saturn, has also prevented any satisfactory observations on him, 
when the sun was above the horizon. With respect to Mer- 
cury, I have seen him several times after sun-rise, and before 
sun -set, about 10 or 1 1 days before and after his greatest elon- 
gation, with a power of 45. I once or twice looked for him 
about mid-day, but did not perceive him. 1‘lie air, however, 
at the times alluded to, was not very clear, and I was not per- 
fectly certain that he was within the field of the telescope ; 
and therefore I am not convinced but that, with a moderately 
high power, he may be seen even at noon-day. 
Such, then, are some of the observations 1 have made on 
the heavenly bodies, in the day-time, and the conclusions, 
which may be deduced from them. I have been induced to 
communicate them from the consideration, that the most mi- 
nute facts, in relation to any science, are worthy of being 
known, and may possibly be useful. They may, at least, gra- 
tify the astronomical tyro with some information which he 
will not find in the common treatises on astronomy. Besides 
those already stated, the following general conclusions may be 
noted. ] • That a celestial body may be as easily distinguished 
at noon-day as at any time between the hours of nine in the 
morning and three in the afternoon, except during the short f 
days in wntter. 2. They are more easily distinguished at a li 
high than at a low altitude ; in the afternoon than in the morn- | 
‘"g. I 
