APOD: Art And Science NGC 918 (2009 Nov 12)

[bystander]

A-Z: 1-26
aa-az: 27-52 (1*26)+... [(a-z) (1-26)]
ba-bz: 53-78 (2*26)+... [(a-z) (1-26)]
...
za-zz: 677-702 (26*26)+... [(a-z) (1-26)]

nc = (14*26)+3 = 367

Don't know what they will do for 703.
Perhaps aaa (1*26^2)+(1*26)+(1).

[TheBigHenry]

Apologies for being late to the discussion, but where does the number '26' come from??? I understand the 10, with 'J' being the tenth letter, and 'S' is the nineteenth, of course, but I cannot figure out where the 26 is coming from..?

26 letters in the alphabet

Supernova discoveries are reported to the International Astronomical Union's Central Bureau for Astronomical Telegrams, which sends out a circular with the name it assigns to it. The name is formed by the year of discovery, immediately followed by a one or two-letter designation. The first 26 supernovae of the year get designated with an upper case letter from A to Z. Afterward, pairs of lower-case letters are used, starting with aa, ab, and so on. Professional and amateur astronomers find several hundreds of supernovae each year (367 in 2005, 551 in 2006 and 572 in 2007). For example, the last supernova of 2005 was SN 2005nc, indicating that it was the 367th supernova found in 2005.

Okay, so every SN discovered after one designated with a capital letter 'Z' would automatically get multiplied by 26?????

I know I'm not as smart as many of the posters here, but no where in that wiki link does it spell out or clarify the 'equation' for naming SN's. (either that, or I'm even more dense than I thought! )

Try as I might, I don't see how 367 was arrived at, in the final example. Would someone mind spelling it out for me? (In small words - ) And for the record, I understand that 'n' is the 14th letter of the alphabet, and 'c' is the 3rd.

Thank you, once again, in advance.....

A thru Z is equal to 1 thru 26 (decimal);
aa is 27 (decimal);
ab is 28 (dec) etc.

and in general: nc = (26)n + c = (26)(14) + 3 =367

[orin stepanek]

1 to 2 per day

Ya! Thanks Art! That's what I wanted to type. My error! Guess I was in too big a hurry to go to Omaha this morning; and did a poor Job proofreading.

Orin

[orin stepanek]

Is this NGC 981 or 918???

Oh Oh! Another typo! I'll correct it. I guess someone already has.
Orin

[Indigo_Sunrise]

A-Z: 1-26
aa-az: 27-52 (1*26)+... [(a-z) (1-26)]
ba-bz: 53-78 (2*26)+... [(a-z) (1-26)]
...
za-zz: 677-702 (26*26)+... [(a-z) (1-26)]

nc = (14*26)+3 = 367

Don't know what they will do for 703.
Perhaps aaa (1*26^2)+(1*26)+(1).

Thank you bystander. This explanation is very helpful!
8)