

Difference from 





Greenwich. 



very clear 



5 39 



04.3 



ditto. 



5 39 



12 



ditto. 



5 39 



02 



504 Eclipses of Jupiter' 's Satellites: [Not- 



VI — Eclipses of Jupiter's Satellites. 



[Observed at Chuprah, Lat. 25° 47' 26" N., Long. 5h. 39m. 7s. E. by Mr. Walter 



Ewer.] 



Mean Time. 

 h. m. s. 

 2nd October, Emersion of Sat. II. at 7 57 56.3 

 - 3rd Ditto, Emersion of Sat. I. at 9 53 50 

 19th Ditto, Ditto at 8 13 32 



Troughton's 5 feet achromatic, power about 200, aperture 3.8 inches. This teles- 

 cope has been 25 years in the country, and is in excellent order. 



Observatio?is in Calcutta. 



lQth October, 1832. — On this day by the Ephemeris the whole of 

 Jupiter's satellites were to be eclipsed, and of the phenomena no less 

 than four out of six, viz. two immersions and two emersions, should 

 have been visible at Calcutta. The weather having been unusually 

 fine and clear for some days past, it was thought to be a good oppor- 

 tunity for trying the power of the superb reflecting telescope, lately 

 presented to Mr. James Calder, by Sir John Herschell : — one of 

 the last made under his father's directions. The following gentle- 

 men undertook to make simultaneous observations with their own 

 telescopes, by way of ascertaining the extent of uncertainty in the use 

 of different instruments under precisely similar circumstances : Captain 

 D. Ross, Marine Surveyor General, at his residence in Chowritighee, 

 and his assistant Lieut. Lloyd, with a second telescope at the same 

 place; Captain Wilcox, Mr. Logan, and Lieutenant Waugh, at the 

 Surveyor General's office, in Park Street ; Mr. H. Barrow, H. C. Mathe- 

 matical instrument maker, in Loudon Street, Chowringhee ; and Mr. 

 Gray, at his observatory in Garstin's Buildings; while Lieut. Pember- 

 ton with his own telescope, Mr. Gordon with his, and myself at the large 

 reflector, should make the observation at Mr. Calder's residence in Es- 

 planade-row. 



The evening proved hazy, and it was only at intervals that Jupiter 

 could be seen to advantage ; still, however, with all three telescopes, 

 and particularly with the large reflector, the belts and satellites were 

 distinctly visible through the haze. The immersion of the fourth 

 satellite expected at 8h. 17m. 30s. was not visible on account of the mist 

 — indeed the satellite had disappeared several minutes previously, or 

 when we first stationed ourselves at our glasses. The emersion of the 

 same at llh. 3m. 20s. and the immersion of the third at l6h. 48m. 9s. 

 were likewise lost from the same cause ; so that the emersion of the first 

 satellite, was the only one we were fortunate enough to obtain. The 

 sky too was less hazy at that moment, and the belts were distinctly 



