eta Cygni

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

position, motion, parallax:

position (J2000)	RA: 19h 56min 18.4sec	DEC: +35° 5' 0''
position (B1900)	RA: 19h 52min 33.2sec	DEC: +34° 49' 3''
proper motion (J2000)	RA: -0.032 arcsec/a	DEC: -0.027 arcsec/a
radial velocity	-27 km/s
rotational velocity	<19 km/s
trigonometric parallax	0.015 arcsec
galactic coordinates	longitude: 71.02°	latitude: 3.36°

note (category: dynamical parallaxes):

0.035".

magnitude

visual magnitude

3.89
(V on UBV Johnson system)

spectral / color information

spectral class	K0III
B-V-magnitude	1.02
U-B-magnitude	0.89
R-I-magnitude
IR-note	object is infrared source (NASA merged infrared catalogue, Schmitz et al., 1978)

variability information

variable star identification

12586

double/multiple star system information

number of components of multiple star system	5
separation	46 arcsec
mag difference (of double or brightest multiple)	7.7
component ID	AC

note (category: double and multiple data):

AB CPM. B, 12v at 7". Other components optical.

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

position, motion, parallax:

position (J2000)	RA: 19h 56min 18.376sec	DEC: +35° 5' 0.34''	±0.06 arcsec	source: 15
proper motion (J2000)	RA: -0.0026 arcsec/a	DEC: -0.027 arcsec/a		source: 25
radial velocity	-27 km/s			source: 25
trigonometric parallax	0.015 arcsec		±0.002 arcsec	source: 25
galactic coord. (B1950)	longitude: 71.02°	latitude: 3.36°

magnitude:

visual	3.89 (observed)	source: 25
photovisual	4	source: 2

spectral information:

spectral class	K0		source: 96
Morgan-Keenan	K0III		source: 25
B-magnitude	4.91 ±0.05	B-V-magnitude	1.02
U-magnitude	5.8 ±0.05	U-B-magnitude	0.89

double/multiple star system information:

source of data: 19

separation between brightest and second brightest component	7.4 arcsec
magnitude difference between brightest and second brightest component	8.1
position angle	208 °

sources:

2	HD and HDE Catalogs
Cannon, A.J., and E.C. Pickering, Harvard Annals, Vols 91-99, 1918-24, Cambridge, Massachusetts: Harvard University; Cannon, A.J., Harvard Annals, Vol. 100, 1925-36, Cambridge, Massachusetts: Harvard University; and Cannon, A.J., and M. Walton Mayall, Harvard Annals, Vol. 112, 1949, Cambridge, Massachusetts: Harvard University
15	FK5, FK5 Extension and FK5 Supplement
Fricke, W., H. Schwan and T. Lederle, "Fifth Fundamental Catalogue (FK5), Part I. The Basic Fundamental Stars," Veroff. Astronomisches Recheninstitut, No. 32, Heidelberg, Germany, 1988, and Fricke, W., H. Schwan, and T.E. Corbin, "Fifth Fundamental Catalogue (FK5), Part II. The FK5 Extension," Veröff. Astronomisches Recheninstitut, No. 33, Heidelberg, Germany, 1991
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
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 (B1950)	RA: 19h 54min 25.726sec	DEC: +34° 56' 58.24''	±0.005 arcsec
position (J2000)	RA: 19h 56min 18.385sec	DEC: +35° 5' 0.31''
proper motion B1950 (FK4)	RA: -0.0027 arcsec/a	DEC: -0.026 arcsec/a	±0.001 arcsec/a in RA ±0.002 arcsec/a in DEC
proper motion J2000 (FK5)	RA: -0.0024 arcsec/a	DEC: -0.028 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	4 (accuracy: 2 decimals)
source of visual magnitude data	Taken from the "Henry Draper Catalogue".

spectral information:

spectral class	K0
source of spectral data	Taken from the Henry Draper Catalogue or no spectrum in source catalog.

catalogues

source catalogue	FK4, catalogue number: 1521
Durchmusterung	BD+34 3798
Boss General Catalogue	27622
Henry Draper Catalogue	188947

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

position and proper motion:

position (J2000)	RA: 19h 56.3min	DEC: +35° 5'
proper motion (J2000)	RA: -0.032 arcsec/a	DEC: -0.027 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
AB	1879	12	208°	7.4''	3.89	12	K0III	BU 980
AC	1879	6	327°	46''	3.89	10.5	-	HJ 1455
AD	1879	6	169°	49.7''	4	10.5	-	HJ 1455
AE	1898	2	247°	61.7''	3.89	11.5	-	BU 980
AE	1924	2	246°	60.2''	3.89	11.5	-	BU 980

discoverer information:

discoverer code	discoverer	reference
BU 980	Burnham, S.W.	-
HJ 1455	Herschel, J.	-

notes:

note

Eta Cyg.

data from Combined General Catalogue of Variable Stars (suspected variables) (Kholopov+ 1998)

position:

position (equinox 1950.0)

RA: 19h 54min 25.7sec

DEC: +34° 56' 58''

variability informations:

magnitute at max. brightness	3.88
magnitute at min. brightness	3.93
photometric system	visual, photovisual or Johnson's V

spectral information

spectral class

references

to a study

1791D (designation: ETA CYG)

miscanellous

There are notes in the published catalog (Kukarkin et al.(1982)).

catalogues and names	h Cyg, NSV 12586, 21 Cyg, HR 7615, HD 188947, SAO 69116, BD +34 3798, FK5: 1521, WDS 19563+3505A
constellation	Cygnus