ON THE PLANET VESTA. £&> 



ing power in the 13-feet reflector. In both these telescopes 

 its image was, without the least difference, that of a fixed 

 star of the Oth magnitude with an intense radiating light ; 

 so that this new planet may with the greatest propriety be 

 called an asteroid. An asteroid. 



April 2<3th in the evening at 9 o'clock, true time, 1 sue- Measured, 

 ceeded in effecting the measurement of Vesta, with the same 

 power of 288, by means of the 13-feet reflector, with which 

 that of Ceres, Pallas, and Juno had been made; and when 

 viewed by this reflector it also appeared exactly in the same 

 manner. Of several illuminated disks, of 2-0 to 0*5 decimal 

 lines, which I had before made use of for measuring the sa- 

 tellites of Saturn and Jupiter, the smallest disk only of 0'5 

 lines could be used for this purpose; by it the rounded nu- 

 cleus of the planet Vesta, when the disk was at the distance 

 of 6iro lines from the eye, appeared at most of the same 

 size, and I must even estimate its diameter as £ smaller. If 

 therefore, we attend, not to the full magnitude of the pro- Tts apparent 

 jection, but the estimation just mentioned, it follows by cal- diameter only 

 culation that the apparent diameter of the planet Vesta is ^t of'the 4th 

 only 0*488 of a second, and consequently only half of what satellite of Sa- 

 I have found to be the apparent diameter ofthefourtl\ salel- turn * 

 lite of Saturn. 



This extraordinary smallness, with such an intense, ra- 

 diant and unsteady light of a fixed star, is the more remark- 

 able, as, according to the preliminary calculations of Dr. 

 Gauss, there can be no doubt that this planet is found in the n is between 

 same region between Mars and Jupiter, in which Ceres, Mars and Junt. 

 Pallas, and Juno, perform their revolutions round the sun ; 

 that, in close union with them, it has the same cosmological 

 origin; and that as a planet of such smallness and of so very 

 intense light, it is comparatively near to the earth. This re- 

 markable circumstance will no doubt be productive of im- 

 portant cosmological observations, as soon as the elements 

 of the new planet have been sufficiently determined, and its 

 distance from the Earth ascertained by calculation. 



I/ilienthal, May 12, 1807- 



VI. 



