3f90 Astronomical Lifonnation, 



from which the hmar distances are computed, have been re- 

 calculated for tlie beginning of the year 1820. At the bottom 

 of that little table we observe a short note, which may be cor- 

 rect ; but which the practical astronomer will be cautious in 

 adojiting generalljj', luiless the grounds on whidi it is founded 

 are distinctly stated. 



6. M. Harding has just completed the last Number of his 

 Himmehchay-tcn : it only remains now to form a catalogue of 

 all the stars, which are inserted therein ; without which help, 

 tlie work will lose much of its utility. 



7. Dm'ing the present year, the German astronomers have 

 been engaged m determming the difference of the longitudes 

 of their observatories, by observations of the transit of the 

 moon over the meridian, and certain fixed stars which differ 

 very little from her in right ascension, and are nearly in tlie 

 same apparent parallel of decUnation. A catalogue of some 

 hundreds of such stars, as are thus favourably situated, has 

 been from time to time published in the foreign journals. This 

 method is exceedingly simple ; and attended with very little 

 trouble or inconvenience : and, by thus knowing before-hand 

 the stars which have thus been agreed on, the practical astro- 

 nomer is almost sure to find some corresponding observationsj 

 fi-om which he may deduce the required results. As the transit 

 of the moon's lunb generally forms one of the objects in an 

 active observatory, the adoption of this method cannot be at- 

 tended v>ith much additional trouble : since it is merely required 

 to devote a few minutes before and after the passage of the 

 moon, to the observations of the proposed stars : and this may 

 frequently be done without moving the telescope. We in- 

 tended to have given the catalogue tor the ensuing month, for 

 the use of observers in this country: but such a measure would 

 answer no good purpose unless some public, or other well 

 known observatory, would undertake to make corresponding 

 observations. 



8. Mr, Dollond is about to construct a sextant on the prin- 

 ciple proposed by M. Amici, as mentioned in our last Num- 

 ber : and there is no doubt that, in his hands, it will receive 

 all the improvenmnt of which it is capable. 



9. M. Rumker has commenced his astronomical observa- 

 tions at New Soutli Wales. One of his first objects was to 

 determine the obliquity of the ecliptic, from observations of 

 the sun near our winter solstice, with one of Reichenbach's 

 circles. The quantity which he has deduced is 23°. 27'. 44",5 

 for the mean obliquity on January 1, 1822; which differs only 

 0",3 from the value deduced from Besscl's observations, in the 

 north of Europe. 



10. M. Eiikc's computationb of the comet, whose elements 



we 



