426
Kometen.
1828 :
Mean time Bremen
Appar. _/R
Appar.
Déclin.
Nov.
3.
12 h
8'
—
343°
7'
44"
+
24°
10'
6'
55
4.
12 h
ir
—
CO
J—a
O
57'
52"
+
23°
45'
17'
55
5.
ll u
40'
—
340°
46'
52"
+
23°
20'
33'
55
9.
ID
13'
59"
336°
5'
54"
+
21°
29'
19'
55
10.
ID
38'
50"
334°
55'
16"
+
20°
58'
2'
55
25.
7 h
23'
20"
319°
27'
4"
+
12°
48'
35' 1
55
27.
7 h
16'
8"
317°
32'
2"
—
—
—
Dec.
1.
7 h
11'
17"
313°
45'
3"
+
9°
16'
31'
55
1.
8 h
36'
21"
313°
41'
35"
—
—
—
55
6.
6*
28'
14"
308°
56'
36"
+
6°
10'
9'
55
9.
6 b
7'
48"
305°
54'
59"
+
4°
10'
14'
55
10.
6*
35'
19"
304°
51'
21"
“T
3°
28'
13'
55
15.
5 h
38'
44"
299°
17'
2"
—
0°
14'
15'
The first observations owing to the faintness of the comet, are
uncertain. The comet was a very diffuse and feeble nebula, whose
middle it was difficult to estimate with any certainty; after the end
of November it was easier to observe. I purposely used, for these
observations, the same telescope and magnifying power with which I
observed it in 1795, 1805 and 1825, that I might, as far as recollection
would enable me, assure myself whether, in the thirty-three years past,
it had undergone any change of appearance not dependent on its difference
of situation with respect to the sun und earth; but the bad weather,
and a sky scarcely ever free from haze, prevented my forming any
tolerable judgment on this point. In the year 1805 only did I see
any tail distinctly to this comet; this time, and in 1795, I could perceive
no trace of any. Perhaps however, after the 10 th December, when it
approached its perihelion, it may have exhibited a tail, and I am very
desirous to get information on that point. On the 15 th , when I last saw
it, it was very hazy.
This appearance of the comet has, it seems to me, established two
important points: 1 st , That it has no light of its own, and shines only
by the reflection of that of the sun; 2 al 9 That this comet actually does
suffer a resistance in that part of space wherein it moves. 1 ) The Ephe
meris of Encke, calculated on the hypothesis of such resistance, indi
cates only a small and nearly constant error, giving the AH only about
2' or 3', and the declination 1' too small: On the other hand, that of
Damoiseatt, who supposes no resistance, gave a very variable error,
which, after the middle of November, increased to an uncommon extent. 9
9 Vergl. Astronomisches Jahrbuch fur 1826, S. 133 f., wo Encke diese von
Olbers schoii damals ausgesprochene Ansicht weiter ausflihrt. Sch.