[vsnet-chat 4402] Star's designation.

[Afoevb@aol.com]

In [vsnet-chat 4395] Re: TMZ etc... orthography, Mr. Katsura Matsumoto asked 
: "I've known that reverse orders of alphabetical characters such as "BA", 
"CB", "ZA"... are never assigned for the names, but I don't know the history. 
 What was the reason for it? Best regards, Katsura"
F. Argelander assigned the letter R to the first variable star discovered in 
a constellation. Some people claims that the letter R was choosen because the 
most variable stars discovered by Argelander were long period variables, 
therefore red stars (in German ROT, in French ROUGE, in English RED). The 
answer is in an article written by Argelander in 1855 (3. May). Argelander 
wrote "I name R the star in Virgo whose variability was discovered in 1809 by 
Harding ... I think, given their originality, these stars allowed to expect 
the honour  to have a specific name ... In order to avoid a mix-up with the 
alphabetical designation used by Bayer, I choosed to use only the last 
letters of the alphabet". In his catalog Uranometria (1603), Bayer used the 
Greek letters from alpha to omega, alpha for the most bright star, beta for 
the seond in brightness (but, today, beta Cygni is less bright as gamma, 
delta and epsolon Cyg!), then the small Latin letters, and finally the 
capital Latin letters. In the constellation Cygnus the last designed star by 
Bayer was the famous star P Cygni and, in a second edition, the star Q Cygni 
(*).
In his meeting from 23 August 1867, the general assembly of the 
"Astronomische Gesellschaft" decided to use the mode of designation 
recommended by Argelander, except for the stars wich appears in Bayer's 
catalog (delta Cephei, chi Cygni, for example). The allocation of letters 
must follow the date of discovery, R for the first variable discovered in a 
constellation, then S, T ... Z, then RR, RS .. RZ, etc until ZZ. The 
combination RA, RB, SA, SB, was not utilised to "avoid a possible confusion 
with Bayer's designations" !  Later, to standardize, the combinations BA, CA, 
CB, etc.. were also avoided. The lettre J was newer used in order to avoid 
confusion with the lettre I. 
The combination V and a number (V335 Sgr in 1929) was suggested, around 1880, 
by the french astronomer Charles Andre. The suggestion was approved by the 
american astromer Chambers and the danish astronomer Nijland wich gave his 
name to this combination.
The Harvard number is a group of 6 numbers; the first four represents the 
hour and the minuts in alpha, the last two the degree in delta for the 
equinox 1900. But if the seconds in alpha exceeds 57, the minut is increased 
to on. Why ? I do not know.
Chambers designed the variables by a number wich is the tenth of the seconds 
in alpha for the exquinox 1900 ! Thus X And was numbered 650 (00h 10m 50s = 
650 seconds) and Y Cas 8629 (23h 58m 10s). 
(*) In GCVS Q Cygni is catalogued as a nova Na (mv 3.0 to 15.6), wich 
appeared in 1876. Beyer saw this star : a recurrent nova ?
Regards
Emile Schweitzer
AFOEV

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