The object was found in the following catalogues:
  1. The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version)

  2. SKY2000 - Master Star Catalog

  3. Smithsonian Astrophysical Observatory Star Catalog

  4. The Washington Visual Double Star Catalog, 1996.0

  5. Combined General Catalogue of Variable Stars (Vol. I-III)

catalogues and names g1Sgr, W Sgr, HR 6742, HD 164975, SAO 186237, WDS 18050-2935A
constellation Sagittarius

data from The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) (Hoffleit+, 1991)

note (category: star names): Although HR 6742 and 6746 are named gamma1 and gamma2 Sgr, respectively, more often 6746 is simply called gamma Sgr and the Greek letter is omitted for HR 6742.

position, motion, parallax:

position (J2000) RA: 18h 5min 1,3sec DEC: -29 34' 48''
position (J1900) RA: 17h 58min 37,9sec DEC: -29 35' 4''
proper motion (J2000) RA: 0,013 arcsec/a DEC: 0 arcsec/a
radial velocity -28 km/s
note: spectroscopic binaries
note: orbital data avaible
rotational velocity 25 km/s (uncertain) (variable)


visual magnitude 4,69
(V on UBV Johnson system)

spectral / color information

spectral class F4-G1Ib
B-V-magnitude 0,78
U-B-magnitude 0,52
R-I-magnitude 0,45

variability information

variable star identification W Sgr
note (category: variability): ADS 11029A, CDelta 4.30 - 5.08V, 7.594710d. Period changes. Spectrum and magnetic field variable. One component of SB.

double/multiple star system information

number of components of multiple star system 4
separation 0,1 arcsec
mag difference (of double or brightest multiple) 0
note (category: double and multiple data): ADS 11029A is speckle interferometric double, sep. 0.116". Visual companions, 13.5v at 33" and 13.5v at 48".
note (category: spectroscopic binaries): 80y, K 2.65k/s, V0 -27.7k/s, asini 60.

data from SKY2000 - Master Star Catalog (Myers+ 1997)

position, motion, parallax:

position (J2000) RA: 18h 5min 1,222sec DEC: -29 34' 48,25'' 0,19 arcsec source: 16
proper motion (J2000) RA: 0 arcsec/a DEC: -0,001 arcsec/a source: 25
radial velocity -28 km/s source: 25
galactic coord. (B1950) longitude: 1,58 latitude: -3,98
GCI unit vector (J2000) X: 0,019049 Y: -0,869458 Z: -0,493639


visual 4,29 (observed) source: 30
photovisual 4,7 source: 16

spectral information:

spectral class F8 source: 96
Morgan-Keenan F4-G1Ib source: 25
B-magnitude 5,47 0,05 B-V-magnitude 0,78
U-magnitude 5,99 0,05 U-B-magnitude 0,52

variability information:

source of data: 30
variability type 111
var. amplitude 0,85
var. period 7,6
var. epoch 2443375
19. August 1977, 12:00:00 UT
next max light 2451628,6
25. March 2000, 02:24:00 UT

double/multiple star system information:

source of data: 19
separation between brightest and second brightest component 0,1 arcsec
position angle 153


16 PPM North and PPM South Catalogs and PPM Supplement
Roser, S., and U. Bastian, "Catalogue of Positions and Proper Motions," A&AS, Vol. 74, p. 449, 1988, and Bastian, U., et al., "Catalogue of Positions and Proper Motions - South," 1993
19 WDS Catalog
Worley, C.E., and G.G. Douglass, Washington Catalog of Visual Double Stars 1996.0, United States Naval Observatory, 1996
25 Bright Star Catalogue, 5th edition
Hoffleit, D. and Warren, W.H. Jr., The Bright Star Catalogue, 5th Revised Edition, Version 2, 1994
30 GCVS, 4th edition
Kholopov, P.N., et al., General Catalogue of Variable Stars, fourth edition, Moscow: Nauka Publishing House, 1985-88
96 SAO or HD/HDE Catalog
Reference from Value 1 or Reference from Value 2

data from Smithsonian Astrophysical Observatory Star Catalog (SAO Staff 1966; USNO, ADC 1990)

position and proper motion:

position (J1950) RA: 18h 1min 49,519sec DEC: -29 35' 3,04'' 0,021 arcsec
position (J2000) RA: 18h 5min 1,277sec DEC: -29 34' 48,09''
proper motion J1950 (FK4) RA: 0,0011 arcsec/a DEC: -0,001 arcsec/a 0,004 arcsec/a in RA
0,004 arcsec/a in DEC
proper motion J2000 (FK5) RA: 0,001 arcsec/a DEC: 0 arcsec/a
source of proper motion data Determined by source catalog


visual 4,3 (accuracy: 1 decimal)
source of visual magnitude data Source cited in source catalog introduction.

spectral information:

spectral class F8p
source of spectral data Taken from the Henry Draper Catalogue or no spectrum in source catalog.

remarks for duplicity and variability

Variable star in visual magnitude in source catalog


source catalogue GC, catalogue number: 24605
Durchmusterung CD-2914447
Boss General Catalogue 24605
Henry Draper Catalogue 164975

data from The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996)

position and proper motion:

position (J2000) RA: 18h 5min DEC: -29 35'
proper motion (J2000) RA: 0,004 arcsec/a DEC: -0,003 arcsec/a

double/multiple star system information:

component year number of measures position angle angular separation magnitude of 1st component magnitude of 2nd component spectral class(es) discoverer code
Aa 1976 1 153 0,1'' - - F4-G1Ib BLM
Aa-B 1897 2 234 32,9'' - 13,5 - SEE 346
Aa-C 1897 2 100 47,8'' - 13,5 - SEE 346

discoverer information:

discoverer code discoverer reference
BLM Morgan, B. et al
SEE 346 See, T.J. -


note Gamma (1) Sgr. A is the Cepheid W Sgr, spectrum also variable. It is a long-period spectroscopic binary and speckle and occultation pair.

data from Combined General Catalogue of Variable Stars (Vol. I-III) (Kholopov+ 1998)


position (J1950) RA: 18h 1min 49,5sec DEC: -29 35' 3''

variability informations:

variability type DCEP pulsating variable star
magnitute at max. brightness 4,29
magnitute at min. brightness 5,14
photometric system visual, photovisual or Johnson's V
epoch for maximum light [JD] 2443374,77
19. August 1977, 06:28:48 UT
period [d] 7,59503
next maximum light [JD] 2451622,97258
19. March 2000, 11:20:31 UT
rising time 32 % of period

spectral information

spectral class F4-G2Ib


to a study the main characteristics of the star was determined by the authors themselves
to a chart/photograph Vol. I GCVS (see Kholopov et al. 1985-1988)


ID in the GCVS catalogue 72/6
constellation Scorpius
notes on existence The star is equivalent to '0720007 X'.
There are notes in published catalog.

variability type description

variability type description
DCEP These are the classical cepheids, or Delta Cep-type variables. Comparatively young objects that have left the main sequence and evolved into the instability strip of the Hertzsprung-Russell (H-R) diagram, they obey the well-known Cepheid period-luminosity relation and belong to the young disk population. DCEP stars are present in open clusters. They display a certain relation between the shapes of their light curves and their periods.