on a new variable star in sagittarius

2 19 Nr. 1622. 220

Die Strahlenbrechung vergriisaert den Sonneiihalbmesser und verschieht clen hiiher gelegenen Kern riiinder stark, was aber durch die Hiihenparallaxe ausgeglichrn wertleii tliirfte. Der Strahlenbrechung kiinnte aber zugeschrieben werdeii, class je nach der Griisse cles Fernrohrs tler Sonnenhalbmesser i n - sofern griisser gesehen wiirtle, a l s von jeneni friiher erwahnten xuatten Saum , ,der ahgewandten Seite zugehiirend, mit einern grosseren Fernrohr etrvas iiiehr als nut eiiieni kleineren Fernrohr sichtbar wiire. Die nicht erreichhare absolute Voll- komnienkeit d e s Fernrohrs, nainentlich in Betreff der Achro- masie, mag den personlichen Fehler tler Einstelliing vermehren. Die Einstellung bei unrichtigeni Positionswinkel vergrossert allenial die Distannen, intlessen scheint dies hier ohiie Ein- fluss gewesen zu sein, !la die herechneten uiid beohachteten Posifionswitikel geniigend iihercinstimmen ; cler hei Mar, 3 I

vorkomniende Unterscliied = 1' mag eineni Schreihfehler zuzuschreiben sein , andererseits kann fiir dafi dem Sonoen- rande parallele Geliiltle die Distanz noch riclitig beobachtet sein, rrenn aucli cler Positionswinkel oiclit genau dem MitteG punkte d e s Kerns augehbrt.

Der Sonnenhalbniesser ist nach deni Nautical Almanac etcvas gr6sser a ls der Halbmesser des Berliner Jahrbuches, welcher fiir die heiclen letzten Tabellen allein henutzt 1st. Dieser Einfluss ist f3r p > 60' hiichst unbedeutend, denn zu clen AD wiirtle bei Anmendling des Halbmessers nach deni Nautical Alnianac iiur hinzutreten - t L . (1 - sin p ) , wo i i clen Uiiterschiecl awischen dem Nautical Alnianac und dem Berliner Jahrbuch betleutet.

A s c l a m , 1866 Dec. 20. G. Sporer.

On a new Variable Star in S a g i t t a r i u s . By Mr. AdoZphus Qwil.Zing.

I n July last year 1 succeeded in proving a s ta r to lie variahle which we had suspected here to he so for a long time previous, The star iti question is 6293 of the British Asso- ciation Catalogue, the place of which for 1865 is:

R. A. = 181"r3"30", N. P. D = 106'21'.

The s ta r forms an object of our present Working-Cata- logue a t the Radcliffe Observatory and was looked for, for the first time, by Yr. Lucns in 1862 Sept. 5 and 19. On both nights no object was visible in the assigned place, s o d Mr. LUCUS observed on bath these nights another star, British ,Assoc. Catal. 6294, t h e place of which for 1865 is R.A = 18"23"'31', N. P. D = 108'30' and he than wrote down *the following note i n the Catalogue ,,B, A. C. 6293 Not Been 1862 Sept. 5 , 19. Is this s tar variable?" The s ta r was not looked for in that year again, nor in the following year. In 1864 however 1 looked for the s tar on 3 nights, and not finding it visible, oliservecl also B. A. C. 6294 instead of it, noting a t the two first eveninge, July 14 and Aug. 18, ,,B. A. C. 6293 not visible." Last year however, a n July 29, when looking for the s t a r , I was surprised at finding i t of coiisiderahle hr.ightness, but as the state of the s k y w a s very had un tbat night, 1 did not attempt to

estimate its hrightaess, antl nierely noted clown ,,looked about 9 niag." On Aug. 16 however I found it to be 7"7, and wrote t h e following note ,,Decidedly a Variahle star." On Aup. 22 the sky w a s very hazy, and I did not begin m i i n d i n g .niagnitudes for soiiie time after I bat1 observed he variable etar, hut fiorling B. A. C. 6294 loakiiig about the 61h niag., which I thought a t the tiwe to be i ts proper

- hrightness (the s tar is rather brighter than 6 mag.) I noted B. A. C. 6293 to he of 9"O hut put a ? t o . i t , showing that I felt very uncertain about it. On the 24th Aug. 1 observed the variable again, and estimated it to be of 7m5. I than intended to watch the s ta r , but other work prevented m e from doing so, and my attention w a s not drawn to the s t a r again, before it came round anew to the Meridian this year, when 1 observed it on 3 nights: Aug. 4, 8, 9 calling it on Aug. 4 7"'6 and on Aug. 9 7"4. A s I did not find time for watching the s ta r , 1 wrote to m y friend and relative Mr. Julius Schmidt, at Athens, asking him, i f time would permit him to do so, to take t h e variable under his patronage. According to his las t letter the variable was about the niiddle of September of 9 '" tO .

The star has been observed b y Piazzi 8 times, and he calls it 8". A t Madras it bas been observed 4 times, antl Taylor calls it 6"7. The star has also lieen observed lry Lalancle (31186), and he calls it 8" Argelander observed only B. A. C. 6294 (2. 391, 169) and, going i n the direction of the variable s ta r , would not have passed it over, if it had been ;it that time hright. Tlie star h a s also been observed twice in Washington in 1860 and it is called on Aug. 8 of 6 '" i ; a t Greenwich B. A. C. 6294 has been often observetl hut not the variable star. Finally the s ta r is neither i n Baily's Mayer nor in Goultl's d'Agelet, though both M q c r and d'Agelet have observed B. A. C. 6294. Professor Argelnizder, I hope, will give the variable s t a r its proper denotiiination.

Adolp hits Quiding. R a d cl i f f e Ob s e r v a t o r y, Oxfor . t l , 1866 Dec. 4.