Field list for NGC1647 area-wide v4.8-7.0 magnitude charts 

Star_No#		The ordinal star number, assigned by RA, used in this chart or table. 
Id 		Catalogue name cross-references. 
		Flamsteed or Henry Draper star catalogue cross-reference id
Alt_Name		Catalogue name cross-references.
		Tycho2 star catalogue cross-reference id 
Type		Simbad object-type codes. Simbad object type coding abbreviations 
		can be found at http://simbad.u-strasbg.fr/guide/chF.htx. 
		"*" stands for "single star"; 
		"PM*" means high proper motion single star. 
m_v_rnd		Visual magnitude (m_v), adjusted using Tycho-2 equation to 
		translate Tycho-2 B and V to the Johnson ubv system 
		V magnitudes to the visual system.  The Johnson V magnitudes 
		where further converted into visual system magnitudes using 
		Stanton 1999.  Rounded.  Because the stars in this catalogue 
		are bright and not reddened, there is no difference between the 
		Johnson V and Stanton visual magnitude values for these stars. 
		Therefore, catalogue plots Johnson V values. 
m_v_se		Standard error of m_v_rnd in visual system.  Assumes a standard 
		error in naked eye estimation of m_v of 0.2 mags. 
RAJ		Right ascension 2000 epoch
DecJ		Declination 
Angle2NGC1647	Computed angular distance in degrees to open cluster NGC1647

Transformations applied: 

Johnson ubv V magnitude adjusted per Stanton 1999 equation 14:
m_v = V + 0.210(B-V)  

Tycho2 ubv V magnitude transformed to the Johnson ubv system: 
Per Note 7 to the Tycho-2 readme file for field V_T (Tycho photographic V magnitude) 
states -
    Blank when no magnitude is available. Either BTmag or VTmag is
    always given. Approximate Johnson photometry may be obtained as:
    V = VT - 0.09 * (BT - VT)

References: 

Photometry for NGC1647: 

Hog, E. et al. 2000.  The Tycho-2 Catalogue of the 2.5 million brightest stars. 
Astron. Astrophys. 366,L27 (photographic in Tycho ubv system)  

Turner, David G. 1992.  Galactic clusters with associated Cepheid variables III. 
NGC 1647 and SZ Tauri.  Astron.J. 104(5):1865  (photoelectric and photographic 
in Johnson ubv with average se of 0.03 for photoelectric and 0.01 for photographic) 

Francic, Stephen P. 1989.  Mass functions for eight nearby galactic clusters.  
Astron.J. 98(3):888 (photographic in Johnson ubv) 

Transformation of Johnson V magnitudes to visual magnitude system: 

Stanton, Richard H. 1999.  Visual magnitudes and the "average observer": 
The SS Cygni field experiment.  JAAVSO 27:97 (conversion equation to adjust 
Johnson ubv photometry to the visual system, i.e. - the human eye sees fainter 
for reddened stars than Johnson ubv filtered light)  

Transformation of Tycho2 V magnitudes to the Johnson ubv system: 

Bessell, M. July, 2000.  The Hipparcos and Tycho Photometric System Passbands.
PASP 112:961 

Supplemental worksheet supporting charts, in Excel 2000 format (763kb):
http://members.csolutions.net/fisherka/astronote/observed/NGC1647/NGC1647_v48_70_stars.xls