ASTRONOMISCHE NACRRICHTEN.

7.3 8.0 9.1 9.2 8.7 7 . 7

NZ 2438.

21h50m138 + 3'2818 2 1 56 1 7 + 3 41 .6 2 2 5 5 5 + 7 3.2

I I 3 + 7 37.6

23 56 + 8 34.5 16 19 + 8 33.8

~ ~~~~~~~~

Schreiben von Dr. I). Gill, Director der Konigl. Sternwarte am Cap der Gutmen Hoffnung, an den Herausgeber.

9.1 30 7 9.2 I 2 2 34 I 1

It is proposed to carry out a series of observations of the Minor Planets V i c t o r i a and S a p p h o for deter- mining the Solar Parallax by Galle's method in the months of July, August,. September and October of the present year.

The necessary extra- meridian observations will be made at Dunsink, Strassburg , Berlin, Bothkamp , Leipzig, Kiel*), Upsala, Moscou and Clinton U. S. in the Northern Hemisphere, and at Melbourne, Rio de Janeiro, Cape of Good Hope (2 telescopes) and Natal in the Southern He- misphere.

From the clearer skies of the Southern Hemisphere it is believed that a f d l y corresponding number of obser- vations will be secured there, notwithstanding that the number of cooperating observatories is smaller than in the Northern Hemisphere. It is therefore hoped that @her Northern observatories beyond the above-named (whose cooperation is already promised) will also take part in the work.

The necessary programme for the extra meridian ob- servations has been already circulated. The only alterations which have resulted from the criticism of Astronomers are the following:

I. The use of clock work is to be optional, and the observer, if he prefers it, may employ the older method of observing differences of Declination, in which the telescope remains at rest whilst the planet and stars of comparison transit the field. When from errors in the places of the comparison stars, or from errors in the tables of the planets, any distance between the planet and star of com- parison is found to exceed six minutes of arc, that distance is not to be measured, but the whole of the observers attention should be given to measuring the distance from the other comparison star, and to measures of the scale value stars.

The more immediate object of this notice is to re- quest the cooperation of powerful meridian instruments in determining the tabular errors of the motions of the planets.

Good meridian observations of the RA. and Decl. of V i c t o r i a and S a p p h o at all observatories provided with sufficiently powerful Meridian-Instruments, are required on every available opportunity between the under mentioned dates :

2.

+ 8 3.3 -k 7 26.7

*) Ich habe eine Mitwirkung der Kieler Sternwarte iioch nicht zugesagt, hofle aber, dass eine solche doch Statt finden wird. Es miissen in der nlchsten Zeit noch einige Aenderungen an der Auktel- lung des Refractors vorgenommen werden , die indessen hoffentlich rechtzeitig beendet sein werden. A>.

Bd. 102.

; I ;:; c 7 . 7 d 7 . 1

V i c t o r i a 1882 July 1 5 to Sept. 26 S a p p h o Sept. I to Oct. 22.

17h39m46s 40 10 40 23 40 54

Together with each observation of a planet, three of the following comparison stars should be observed, and to make all the series of observations strictly intercomparable, it is desirable that all the comparison stars mentioned below should be observed at least four times each in both RA. and Decl.

Comparison Stars for V i c t o r ia .

e

I S t a r 1 Mag. RA. 1855.0 IDecl. 1855.0

8.4 1 41 1 5

W, 2 1 h 1 1 7 5 1302

22h 1 0 2

313 2 1 2

498 63 1 719

Correction to 1882.0 + 1 ~ 2 1 ~ 81 + 8:o

Comparison Stars for S a p p h 0. W, 2 3 h 9 8 ~ DM. + 7'5100 W, 2 3 h ~ 2 0 3 DM. 3-12'8 W, 0 ~ 1 2 8

254 384

Correction to 1882.0 + 1 ~ 2 6 ~ C(r +9:3,

M e r i d i a n o b s e r v a t i o n s of t h e f o l l o w i n g s t a r s a r e a l s o r e q u e s t e d .

Stars for investigating the distortion of the field.

Decl. 1882.0

+ 5O46:o + 5 44.6 1- 5 42.4 + 5 49.3 -I- 5 44.2

14

2 1 I 2438 2 1 2

June 1 5 15.9 16 16.4 I 7 '5.9 18 15.9 I9 '5.9 21 15.4 22 14.9: 23 15.9 : 24 15.4 25 14.9 26 15.4

2 12.3 3 11.3 :* 4 11.8 * 5 10.3 * 6 9.8 *

July I 14.3

9 12.2 * '3 '4.9 *

S c a l e v a l u e s t a r s . For V i c t o r i a .

1882.0 7.8 22h24m33s +Ioo 4:4 7.8 25 53 + I 0 9.5

I4 15.4 I 5 15.4 1 7 15.4 18 16.4: 19 16.9 : 21 17.4 23 18.0 24 18.0 27 18.0:

Aug. I 18.0 2 18.0

I 1 18.0 * 13 18.0 * 21 1 6 7 22 16.7 23 15.7 : 2 5 '5.9

3 18.0 *

28 15.9 :

For S a p p h o . 1882.0 8.5 o 10 35 + I I 17.0

8.5 1 1 34 + I I 23.2.

It is earnestly hoped that all observatories possessed of sufficiently powerful Meridian-Instruments will cooperate in this work.

Royal Observatory Cape of Good Hope 1882 May 25.

Dnvid Gill.

Observations of Variable Stam in 1881. By Edw'in F. Sawyer.

The following observations of variable stars were made during the year 1881, at Cambridgeport, Mass. U. S. A. The observations were made by Argelander's method of step estimations, and his comparison stars were used although their light values were in the majority of cases indepen- dently determined from my observations, and the correspon- ding light of the variables deduced from these. I have thought it best as in former communications of this kind to give (in the case of variables of short period) their light values for each evening rather than attempt to deduce their times of max. and min. A low power opera-glass was used throughout the series. 4 n ++ is used to denote moonlight.

Light Aug. 29 15.7 *

31 15.7:" Sept. 7 15.4 *

8 15.4 * 13 15.8 :* I 7 14.3 18 13.8 19 12.8 20 13.0 21 12.6 25 12.6 26 12.3 30 12.6

30 15.7 :*

Oct. 3 13.8 * 6 15.4" 5 15.4 *

Light

I I 16.4 14 17.2

1 5 17.2 : 16 17.2 19 17.2 : 20 17.2

21 16.0 26 16.0

Nov. 1 1 15.8 14 15.8 1 5 15.8 16 15.8 20 15.4

26 14.9 * 28 14.9 *

Oct. 10 16.6 :*

22 15.4

I, i g h t S c a l e .

f Scuti = 26.9 K rn = 23.7 h x = 20.0 g )) = 18.0 c m = 13.8 m w = 11.8.

3. g H e r c u l i s . Observed from June 1 5 to Nov. 29. Maxima are in-

dicated as occurring about July 25 and Nov. 12, and a mi- nimum about Sept. 23.

4 a n d 5, @ P e g a s i a n d a C a s s i o p e i a . The former star was observed from Sept. 18 to Dec. 2,

and the latter from Sept. 18 to Dec. 12, but not the sligh- test change of light could be detected in either star.

6. x Cygni . A very good series of observations of this interesting

variable was obtained from June 15 to Sept. 18 and indi- cates a maximum as having occurred about July 14. The following. are the' light values for each evening expressed in Argelander's scale :