October 3, 1912] 



NATURE 



141 



OUR ASTRONOMICAL COLUMN. 

 Amrono.mical Occurrences for October: — 

 Oct. 3. i8h. om. Mercury in superior conjunction 

 with the Sun. 



4. gh. 25m. Neptune in conjunction with the 

 Moon (Neptune 5° 46' S.). 



9. 3h. om. Uranus stationary. 



10. 2h. om. Sun eclipsed, invisible at Green- 

 wich. 



,, iih. 36m. Mercury in conjunction with the 

 Moon (Mercury 1° 35' N.). 



,, I7h. lom. Mars in conjunction with the 

 Moon (Mars 1° 44' N.). 



12. 4h. 6m. Venus in conjunction with the 



Moon (Venus 2° 52' N.). 



13. i6h. 51m. Mercury in conjunction with 



Mars (Mercury 0° 11' S.). 



14. 6h. 15m. Jupiter in conjunction with the 



Moon (Jupiter 5° 2' N.). 

 17. 22h. 40m. Uranus in conjunction with the 



Moon (Uranus 4° 35' N.). 

 19. bh. om. Neptune at quadrature to the Sun. 

 22. 2ih. om. Uranus at quadrature to the Sun. 

 27. 23h. 9m. Saturn in conjunction with the 



Moon (Saturn 6° 26' S.). 

 31. I5h. 12m. Neptune in conjunction with the 



Moon (Neptune 5° 43' S.). 



Gale's Comet 19120. — Dr. Ebell's elements and an 

 e.xtended ephemeris for comet igi2a appear in 

 No. 4602 of the Astronomische Nachrichten. 



Ephemeris \2h. (M.T. Berlin). 



1912 a (true) i (true) log r log A 



Oct. 3 ... IS 24-0 



5 ... 15 28-6 



7 - 15 327 



9 •■■ 15 36-5 



II ... 15 400 



13 ■•• 15 431 



-3 343 

 - I 107 



+ 1 74 



+ 3 20 -2 



+ 5 27-5 



+ 7 29-6 ... 98740 ... 00600 



9'86i6 ... 0-0301 

 98653 ... 00454 



The calculated magnitude remains about 5*0 until 

 the middle of October, so that given a good clear 

 horizon the comet should not be a difficult object for 

 field glasses, or even the naked eye ; during the cur- 

 rent week it should be looked for almost due west. 

 On October 5, at about 7.30 p.m., it will lie about half- 

 way between 3 Libr;e and a Serpentis, and will form 

 the apex of an isosceles triangle, having the base, 

 a Coronse .Arcturus, about two-thirds the length of 

 the side. Its apparent path lies nearly along the line 

 joining 3 Librae to a point one-third the distance from 

 a to « Serpentis, a point which it will pass on October 

 II. .'\s may be seen from the ephemeris, the comet's 

 distance from the sun increases after October 5, and 

 its distance from the earth is also increasing, so that 

 it will not become any brighter ; at perihelion passage, 

 October 5, it. will be some 67'5 million miles from the 

 sun, and 99'4 million from the earth, while on October 

 13 these distances will be 6g'5 and 1067 million miles 

 respectively. The orbit of this comet is peculiar by 

 reason of its great inclination, 82°, to the ecliptic. 



Ephemeris for Tuttle's Comet. — In No. 4602 of 

 the Astronomische Nachrichten, M. N. Milicevic gives 

 an ephemeris for Tuttle's comet, based on the 

 elements, uncorrected for perturbations, published in 

 No. 3552 of the same journal. According to this 

 ephemeris, the comet should now be high up in Ursa 

 Major (October 6, a = 8h. 36m., 5=4-76° 19'), and 

 should travel southwards to ii=ioh. Sm., 8 = 70° 24"-' 

 on October 31. Its calculated distances from the sun 

 and earth on October 6 are 153 and 123 millions of 

 miles respectively. Discovered bv M^chain in 1790, 

 this comet was rediscovered bv Tuttle in 1858, and, 



NO. 2240, VOL. 90] 



having a period of about i3'7 years, was seen again 

 in 187 1, 1885, and May, 1899, so that it should pass 

 perihelion some time early next year. 



The L.wituue of the Khedivial Observatory .at 

 Helwan. — Some interesting facts concerning latitude 

 determinations are brought to light in a paper pub- 

 lished by Messrs. Wade and Knox Shaw in Bulletin 

 No. 6 of the Khedivial Observatory, Helwan. The 

 observations discussed were made (i) because observa- 

 tions made in September, iqo8, gave a value for the 

 latitude 3" lower than that formerly accepted, and (2) 

 because the observations at other geodetic stations 

 suggested a night-to-night variation, possiblv due to 

 some atmospheric variation such as the shifting of 

 the refractive zenith. They were also intended to 

 show whether any abnormal variation of latitude took 

 place from month to month. 



The instruments and observations are fullv dis- 

 cussed, Talcott's method having been employed, and 

 the final value for the latitude of the geodetic pillar 

 is given as 29° 25' 31-82" N. toTi". The authors 

 conclude that there is no very definite evidence for a 

 night-to-night variation, but there seems to be a 

 variation from month to month; thus August, igii, 

 shows the largest residual, 4-o"92", from the mean 

 value, although the probable error of the determina- 

 tion is small. .August, 1910, also gave an abnormal 

 value, and during the period July, iqio, to August, 

 191 1, the mean latitude actually varied from ^rS" 

 to 32-1". 



The Manchester .\stronomical Society. — The re- 

 port of this society shows that a vigorous interest in 

 astronomy is exhibited in the Manchester district, an 

 interest which would be welcome in other centres. 

 The membership for iqio-ii was 128, as compared with 

 q8 in igo3-4, and the average attendance at the 

 meetings was 72. Many interesting papers were read 

 and discussed, the lecturers including Father Cortie 

 and Mr. T. Thorp. On alternate Wednesdays the 

 Godlee Observatory is open to members for practical 

 work. 



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