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Date and Time of the Query: 2019-04-25 T09:51:07 PDT
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Diameter data point(s) for object NGC 4918

Diameter Data --- Published and Homogenized (arcsec) Units

  Published UnitsHomogenized Units
No.Observed Passband
REFCODE		Major Axis
(2a)		Major Axis UnitsMinor Axis
(2b)		Minor Axis UnitsAxis Ratio (b/a)Major Axis Unc.Ellipticity
(1 - b/a)		Eccentricity
[(a/b)2-1]/
[(a/b)2+1]		Position Angle
(deg)
[published]		Reference LevelFrequency (Hz)Major Axis
(2a)
(arcsec)		Major Axis Unc.Axis Ratio (b/a)Ellipticity
(1 - b/a)		Eccentricity
[(a/b)2-1]/
[(a/b)2+1]		cos-1(b/a)
(deg)		Position Angle
(deg)
[J2000]
1 K_s (2MASS isophotal)
20032MASX.C.......:		 16.1 (a) arcsec ... ... 0.500 (b/a) ... ... ... 85
[J2000]		 20.0 K-mag arcsec^-2^ 1.38E+14 32.20 ... 0.50 0.50 0.60 60 85
[J2000]
2 K_s (2MASS "total")
20032MASX.C.......:		 27.5 (a) arcsec ... ... 0.500 (b/a) ... ... ... 85
[J2000]		 Diameter for "total" magnitude 1.38E+14 55.00 ... 0.50 0.50 0.60 60 85
[J2000]
3 RC3 D_25, R_25 (blue)
1991RC3.9.C...0000d		 1.00 log(2a) + 1 ... ... 0.34
log(a/b)		 0.10 ... ... ... 25.0 B-mag arcsec^-2^ 6.81E+14 60.00 15.50 0.46 0.54 0.65 63 ...
4 RC3 D_0 (blue)
1991RC3.9.C...0000d		 0.96 log(2a) + 1 ... ... ... ... ... ... ... 25.0 B-mag arcsec^-2^ 6.81E+14 54.70 ... ... ... ... ... ...

Detailed Information for Each Entry

 No. 1
                                Published Units:                    Homogenized Units:

Reference Code                : 20032MASX.C.......:
Published Object Name         : 2MASX J13015062-0430020       
Frequency Targeted            : K_s (2MASS isophotal)         
Major Axis (2a)               : a = 16.1       arcsec               2a = 32.20 arcsec
Uncertainty                   : ...                                 ... 
Minor Axis (2b)               : ...                                 2b = 16.10 arcsec
Uncertainty                   : ...                                 ...
Axis Ratio                    : b/a = 0.500                         b/a = 0.50
Uncertainty                   : ...                                 ...
Ellipticity                   : ...                                 1 - b/a = 0.50
Uncertainty                   : ...                                 ...
Eccentricity                  : ...                                 [(a/b)2-1]/[(a/b)2+1] = 0.60
Uncertainty                   : ...                                 ...
Cos-1(b/a)                    : ...                                 60 deg
Position Angle [Equinox]      :   85   deg [J2000]                  85 deg [J2000]
Uncertainty                   : ...                                 ...
Significance                  : No uncertainty reported
Diameter Reference Level      : 20.0 K-mag arcsec^-2^         
Frequency                     : 2.17         microns                1.38E+14 Hz
Frequency Mode                : Broad-band detector (e.g. photographic plate)

Measurement Mode               
    Detector Type             : Maps (e.g., 2MASS, VLA, Sloan)
    Fitting Technique         : Ellipse fitting to image
    Measured Quantity         : Isophotal diameter
    Qualifiers                : A radius is given in DIA_MAJ, not a diameter
Coordinates Targeted          : 195.460907      -4.500543    (J2000)
Qualifiers                    : From new, raw data
NED Comment                   :                                         


 No. 2
                                Published Units:                    Homogenized Units:

Reference Code                : 20032MASX.C.......:
Published Object Name         : 2MASX J13015062-0430020       
Frequency Targeted            : K_s (2MASS "total")           
Major Axis (2a)               : a = 27.5       arcsec               2a = 55.00 arcsec
Uncertainty                   : ...                                 ... 
Minor Axis (2b)               : ...                                 2b = 27.50 arcsec
Uncertainty                   : ...                                 ...
Axis Ratio                    : b/a = 0.500                         b/a = 0.50
Uncertainty                   : ...                                 ...
Ellipticity                   : ...                                 1 - b/a = 0.50
Uncertainty                   : ...                                 ...
Eccentricity                  : ...                                 [(a/b)2-1]/[(a/b)2+1] = 0.60
Uncertainty                   : ...                                 ...
Cos-1(b/a)                    : ...                                 60 deg
Position Angle [Equinox]      :   85   deg [J2000]                  85 deg [J2000]
Uncertainty                   : ...                                 ...
Significance                  : No uncertainty reported
Diameter Reference Level      : Diameter for "total" magnitude
Frequency                     : 2.17         microns                1.38E+14 Hz
Frequency Mode                : Broad-band detector (e.g. photographic plate)

Measurement Mode               
    Detector Type             : Maps (e.g., 2MASS, VLA, Sloan)
    Fitting Technique         : Ellipse fitting to image
    Measured Quantity         : Isophotal diameter
    Qualifiers                : A radius is given in DIA_MAJ, not a diameter
Coordinates Targeted          : 195.460907      -4.500543    (J2000)
Qualifiers                    : From new, raw data
NED Comment                   :                                         


 No. 3
                                Published Units:                    Homogenized Units:

Reference Code                : 1991RC3.9.C...0000d
Published Object Name         : NGC 4918                      
Frequency Targeted            : RC3 D_25, R_25 (blue)         
Major Axis (2a)               : log(2a) + 1 = 1.00                  2a = 60.00 arcsec
Uncertainty                   :   0.10                              15.50 arcsec              
Minor Axis (2b)               : ...                                 2b = 27.42 arcsec
Uncertainty                   : ...                                 ...
Axis Ratio                    : log(a/b) =  0.34                    b/a = 0.46
Uncertainty                   :   0.08                              0.09
Ellipticity                   : ...                                 1 - b/a = 0.54
Uncertainty                   : ...                                 ...
Eccentricity                  : ...                                 [(a/b)2-1]/[(a/b)2+1] = 0.65
Uncertainty                   : ...                                 ...
Cos-1(b/a)                    : ...                                 63 deg
Position Angle [Equinox]      : ...                                 ...
Uncertainty                   : ...                                 ...
Significance                  : Mean error
Diameter Reference Level      : 25.0 B-mag arcsec^-2^         
Frequency                     : 4400         A                      6.81E+14 Hz
Frequency Mode                : Broad-band detector (e.g. photographic plate)

Measurement Mode               
    Detector Type             : Photographic plate, print, or film
    Fitting Technique         : Eye estimate
    Measured Quantity         : Isophotal diameter
Coordinates Targeted          : 130150.8        -043004.    (J2000)
Qualifiers                    : Homogenized from previously published data
NED Comment                   :                                         


 No. 4
                                Published Units:                    Homogenized Units:

Reference Code                : 1991RC3.9.C...0000d
Published Object Name         : NGC 4918                      
Frequency Targeted            : RC3 D_0 (blue)                
Major Axis (2a)               : log(2a) + 1 = 0.96                  2a = 54.70 arcsec
Uncertainty                   : ...                                 ... 
Minor Axis (2b)               : ...                                 ...
Uncertainty                   : ...                                 ...
Axis Ratio                    : ...                                 ...
Uncertainty                   : ...                                 ...
Ellipticity                   : ...                                 ...
Uncertainty                   : ...                                 ...
Eccentricity                  : ...                                 ...
Uncertainty                   : ...                                 ...
Cos-1(b/a)                    : ...                                 ...
Position Angle [Equinox]      : ...                                 ...
Uncertainty                   : ...                                 ...
Significance                  : No uncertainty reported
Diameter Reference Level      : 25.0 B-mag arcsec^-2^         
Frequency                     : 4400         A                      6.81E+14 Hz
Frequency Mode                : Broad-band detector (e.g. photographic plate)

Measurement Mode               
    Detector Type             : Photographic plate, print, or film
    Fitting Technique         : Eye estimate
    Measured Quantity         : Isophotal diameter
Coordinates Targeted          : 130150.8        -043004.    (J2000)
Qualifiers                    : Homogenized from previously published data
NED Comment                   : Extinction and inclination corrected.

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