Then they start over with AA-AZ, BB-BZ, etc. all the way to QZ (skipping the J's).
This allows for 334 names. After the letters are used up the stars are
simply named V335, V336, V337 and on and on.

As if that weren't confusing enough, there are now a host of other prefixes
and numbers assigned to variable stars and objects. The following is a guide
to help the reader understand what these names mean and where they came
from.

NSV xxxxx - These are stars in the Catalog of New and Suspected Variable
Stars, produced as a companion to the Moscow General Catalog of Variable
Stars (GCVS) by B.V. Kukarkin et al. All stars in the NSV have reported but
unconfirmed variability, in particular, lacking complete lightcurves. Some
NSV stars will eventually prove truly variable; others will be spurious.
Information about this and the General Catalog of Variable Stars can be found at:
http://www.sai.msu.su/groups/cluster/gcvs/gcvs/intro.htm

Many stars and variable objects are assigned prefixes based on astronomer,
survey or project names. Many are temporary designations until they are
assigned a conventional name in the GCVS.

Markarian xxxx - These are active galaxies from lists published by the Russian
astrophysicist B.E. Markarian. Markarian looked for galaxies that emit
unusually strong UV radiation, which comes from either pervasive
star-formation HII regions or from active nuclei. In 1966, Markarian published
'Galaxies With UV Continua'. Around that time, he started the First Byurakan
Spectral Sky Survey (FBS), which is now completed. In 1975, Markarian initiated
a Second Byurkan Survey (SBS). The SBS was continued by his collaborators after
his death. For more information see 'Active Galactic Nuclei', by Don Osterbrock,
http://nedwww.ipac.caltech.edu/level5/Osterbrock3/Oster_contents.html ]

HadVxxx - This represents variables discovered by Katsumi Haseda. Haseda's
most recent discovery was Nova 2002 in Ophiuchus, V2540 Oph.

LD xxx - Variables discovered by Lennart Dahlmark, a Swedish retiree living in
southern France are given this prefix. Dahlmark has been conducting a
photographic search for new variable stars; discovering several hundred to
date.

TKx - TK stands for T.V. Kryachko. The TK numbers of new variables continue
a numbering system first introduced in Kryachko and Solovyov (1996). This
acronym was invented by the authors.

3C xxx - These are objects from the Third Cambridge (3C) catalog (Edge et al.
1959), based on radio-wavelength observations at 158 MHz. There are 471 3C
sources, numbered sequentially by right ascension. All 3C sources are north
of -22° declination. The 3C objects of interest to variable-star observers
are all active galaxies (quasars, BL Lacs, etc.).

Another group of objects is labeled with the prefix O, then a letter, then a
number (OJ 287 for example). These objects were detected by the Ohio State
University radio telescope "Big Ear" in a series of surveys known as the
Ohio Surveys.
http://www.bigear.org/ohiosurv.htm

The project website url is:
http://www.aerith.net/misao/

Many variables are named with prefixes associated with surveys or
satellites, combined with the coordinates of the object.

FBS hhmm+dd.d - Stands for First Byurakan Survey and the coordinates of the
object. The First Byurakan Survey (FBS), also known as the Markarian survey,
covers about 17,000 square degrees.

SBS hhmm+dd.d - Indicates objects discovered by the Second Byurakan Sky Survey,
plus the coordinates of the object.

ROTSE1 Jhhmmss.ss+ddmmss.s - The Robotic Optical Transient Search Experiment (ROTSE) is dedicated to the observation and detection of optical transients on time
scales of seconds to days. The emphasis is on gamma-ray bursts (GRBs), the
most powerful explosions in our Universe. Objects detected by this survey are designated with positions to 0".1 precision.

http://www.umich.edu/~rotse/

XTE Jhhmm+dd - These are objects detected by the Rossi X-Ray Timing Explorer
Mission. The primary objective of the mission is the study of stellar and
galactic systems containing compact objects. These systems include white
dwarfs, neutron stars, and possibly black holes.
http://xte.mit.edu/

ROSAT is an acronym for the ROentgen SATellite. ROSAT was an X-ray
observatory developed through a cooperative program between Germany, the
United States, and the United Kingdom. The satellite was designed and
operated by Germany, and was launched by the United States on June 1, 1990.
It was turned off on February 12, 1999.

Prefixes for x-ray sources detected by ROSAT include, 1RXS, RXS and RX. The
J2000 coordinates for the source are then stated according to the accuracy
of the X-ray position and the density of stars in the field.
arcsecond accuracy ---> RX J012345.6-765432
tenth-arcmin accuracy ---> RX J012345-7654.6
arcmin accuracy ---> RX J0123.7-7654

Distressingly, these can all refer to a single object!

TAV hhmm+dd - The Astronomer Magazine, in England, has a program that
monitors variable stars and suspected variable stars. TAV stands for The
Astronomer Variable, plus the 1950 coordinates.

TASV hhmm+dd - TASV stands for The Astronomer Suspected Variable, plus the
1950 coordinates.

The Astronomer Variable star page can be found at this url:
http://www.theastronomer.org/variables.html

PKS hhmm+ddd - This was an extensive radio survey (Ekers 1969) of the
southern sky undertaken at Parkes (PKS), Australia, originally at 408 MHz and later at
1410 MHz and 2650 MHz. These sources are designated by their truncated
1950 position.
For example 3C 273 = PKS 1226+023. This is still the most common, and
useful, system of naming quasars.

SDSSp Jhhmmss.ss+ddmmss.s - In October 2001, the first results of a new survey
done using the Sloan Digital Sky Survey were published. In this paper, 19 new and
3 previously known CV systems were identified. The positions of the CVs are
given in the names. SDSS-(Sloan Digital Sky Survey), p- (preliminary astrometry), Jhhmmss.ss+ddmmss.s (the equinox J2000 coordinates).

The complete survey is expected to locate at least 400 new CVs. The abstract
and full paper can be read starting at
http://xxx.lanl.gov/abs/astro-ph/0110291

There is a CDS Web page where you can find details about
specific acronyms.
http://vizier.u-strasbg.fr/cgi-bin/Dic

My sincere thanks to Brian Skiff for his guidance and help in preparing this
article.