Page:Memoir and correspondence of Caroline Herschel (1876).djvu/88

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Caroline Lucretia Herschel.
[1786.

By the naked eye the comet is between the 54 and 53 Ursæ Majoris and the 14, 15, and 16 Comæ Berenices, and makes an obtuse triangle with them, the vertex of which is turned towards the south.

Aug. 2nd, 10 h 9'. The comet is now, with respect to the stars a and b, situated as in Fig. 4, therefore the motion since last night is evident.

10 h 30'. Another considerable star, c, may be taken into the field with it by placing a in the centre, when the comet and the other star will both appear in the circumference, as in Fig. 5.

These observations were made with a Newtonian sweeper of 27-inch focal length, and a power of about 20. The field of view is 2° 12'. I cannot find the stars a or c in any catalogue, but suppose they may easily be traced in the heavens, whence the situation of the comet, as it was last night at 10h 33', may be pretty nearly ascertained.

You will do me the favour of communicating these observations to my brother's astronomical friends.

I have the honour to be,
Sir,
Your most obedient, humble servant,

Carolina Herschel.
August 2nd, 1786.
Slough, near Windsor.

MISS HERSCHEL TO ALEX. AUBERT, ESQ.

Slough,August 2, 1786.
DEAR SIR,—

August 1st, in the evening, at 10 o'clock, I saw an object very much resembling (in colour and brightness) the 27 of Mr. Messier's Nebulæ, except this object being round. I suspected it to be a comet; but a haziness came on before I could convince myself of its having moved. I made several figures of the objects in the field, whereof I take the