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Date and Time of the Query: 2019-04-25 T22:42:36 PDT
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Diameter data point(s) for object NGC 2491

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.......:
10.7 (a) arcsec ... ... 0.620 (b/a) ... ... ... 85
[J2000]
20.0 K-mag arcsec^-2^ 1.38E+14 21.40 ... 0.62 0.38 0.44 52 85
[J2000]
2 K_s (2MASS "total")
20032MASX.C.......:
20.4 (a) arcsec ... ... 0.620 (b/a) ... ... ... 85
[J2000]
Diameter for "total" magnitude 1.38E+14 40.70 ... 0.62 0.38 0.44 52 85
[J2000]
3 r (SDSS Isophotal)
2007SDSS6.C...0000:
22.91 (a) arcsec 12.80 arcsec ... ... ... ... 78.5
[J2000]
25.0 mag arcsec^-2^ 4.77E+14 45.82 ... 0.56 0.44 0.52 56 79
[J2000]
4 r (SDSS Petrosian)
2007SDSS6.C...0000:
3.02 (a) arcsec ... ... ... 0.306 ... ... ... ... 4.77E+14 6.05 0.61 ... ... ... ... ...
5 r (SDSS deVaucouleurs)
2007SDSS6.C...0000:
1.8871 (a) arcsec ... ... 0.504 (b/a) 0.016 ... ... 77.9
[J2000]
... 4.77E+14 3.77 0.03 0.50 0.50 0.59 60 78
[J2000]
6 r (SDSS Exponential)
2007SDSS6.C...0000:
1.2378 (a) arcsec ... ... 0.518 (b/a) 0.006 ... ... 80.1
[J2000]
... 4.77E+14 2.48 0.01 0.52 0.48 0.58 59 80
[J2000]


Detailed Information for Each Entry

 No. 1
                                Published Units:                    Homogenized Units:

Reference Code                : 20032MASX.C.......:
Published Object Name         : 2MASX J07582739+0759018       
Frequency Targeted            : K_s (2MASS isophotal)         
Major Axis (2a)               : a = 10.7       arcsec               2a = 21.40 arcsec
Uncertainty                   : ...                                 ... 
Minor Axis (2b)               : ...                                 2b = 13.27 arcsec
Uncertainty                   : ...                                 ...
Axis Ratio                    : b/a = 0.620                         b/a = 0.62
Uncertainty                   : ...                                 ...
Ellipticity                   : ...                                 1 - b/a = 0.38
Uncertainty                   : ...                                 ...
Eccentricity                  : ...                                 [(a/b)2-1]/[(a/b)2+1] = 0.44
Uncertainty                   : ...                                 ...
Cos-1(b/a)                    : ...                                 52 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          : 119.614113      7.983858    (J2000)
Qualifiers                    : From new, raw data
NED Comment                   :                                         

No. 2 Published Units: Homogenized Units: Reference Code : 20032MASX.C.......: Published Object Name : 2MASX J07582739+0759018 Frequency Targeted : K_s (2MASS "total") Major Axis (2a) : a = 20.4 arcsec 2a = 40.70 arcsec Uncertainty : ... ... Minor Axis (2b) : ... 2b = 25.23 arcsec Uncertainty : ... ... Axis Ratio : b/a = 0.620 b/a = 0.62 Uncertainty : ... ... Ellipticity : ... 1 - b/a = 0.38 Uncertainty : ... ... Eccentricity : ... [(a/b)2-1]/[(a/b)2+1] = 0.44 Uncertainty : ... ... Cos-1(b/a) : ... 52 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 : 119.614113 7.983858 (J2000) Qualifiers : From new, raw data NED Comment :
No. 3 Published Units: Homogenized Units: Reference Code : 2007SDSS6.C...0000: Published Object Name : SDSS J075827.37+075901.7 Frequency Targeted : r (SDSS Isophotal) Major Axis (2a) : a = 22.91 arcsec 2a = 45.82 arcsec Uncertainty : ... ... Minor Axis (2b) : b = 12.80 arcsec 2b = 25.60 arcsec Uncertainty : ... ... Axis Ratio : ... b/a = 0.56 Uncertainty : ... ... Ellipticity : ... 1 - b/a = 0.44 Uncertainty : ... ... Eccentricity : ... [(a/b)2-1]/[(a/b)2+1] = 0.52 Uncertainty : ... ... Cos-1(b/a) : ... 56 deg Position Angle [Equinox] : 78.5 deg [J2000] 79 deg [J2000] Uncertainty : ... ... Significance : No uncertainty reported Diameter Reference Level : 25.0 mag arcsec^-2^ Frequency : 6290 A 4.77E+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 : 119.6140752986 7.9838155646 (J2000) Qualifiers : From new, raw data; DIA_MAJ or DIA_MIN modified from published data NED Comment :
No. 4 Published Units: Homogenized Units: Reference Code : 2007SDSS6.C...0000: Published Object Name : SDSS J075827.37+075901.7 Frequency Targeted : r (SDSS Petrosian) Major Axis (2a) : a = 3.02 arcsec 2a = 6.05 arcsec Uncertainty : 0.306 arcsec 0.61 arcsec Minor Axis (2b) : ... ... Uncertainty : ... ... Axis Ratio : ... ... Uncertainty : ... ... Ellipticity : ... ... Uncertainty : ... ... Eccentricity : ... ... Uncertainty : ... ... Cos-1(b/a) : ... ... Position Angle [Equinox] : ... ... Uncertainty : ... ... Significance : Based on count statistics only Diameter Reference Level : ... Frequency : 6290 A 4.77E+14 Hz Frequency Mode : Broad-band detector (e.g. photographic plate) Measurement Mode Detector Type : Maps (e.g., 2MASS, VLA, Sloan) Fitting Technique : Profile fitting to image Measured Quantity : See comments Qualifiers : A radius is given in DIA_MAJ, not a diameter Coordinates Targeted : 119.6140752986 7.9838155646 (J2000) Qualifiers : From new, raw data; DIA_MAJ or DIA_MIN modified from published data NED Comment :
No. 5 Published Units: Homogenized Units: Reference Code : 2007SDSS6.C...0000: Published Object Name : SDSS J075827.37+075901.7 Frequency Targeted : r (SDSS deVaucouleurs) Major Axis (2a) : a = 1.8871 arcsec 2a = 3.77 arcsec Uncertainty : 0.016 arcsec 0.03 arcsec Minor Axis (2b) : ... 2b = 1.90 arcsec Uncertainty : ... 0.00 Axis Ratio : b/a = 0.504 b/a = 0.50 Uncertainty : 0.003 0.00 Ellipticity : ... 1 - b/a = 0.50 Uncertainty : ... ... Eccentricity : ... [(a/b)2-1]/[(a/b)2+1] = 0.59 Uncertainty : ... ... Cos-1(b/a) : ... 60 deg Position Angle [Equinox] : 77.9 deg [J2000] 78 deg [J2000] Uncertainty : ... ... Significance : Based on count statistics only Diameter Reference Level : ... Frequency : 6290 A 4.77E+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 : Half-light ("effective") diameter Qualifiers : A radius is given in DIA_MAJ, not a diameter Coordinates Targeted : 119.6140752986 7.9838155646 (J2000) Qualifiers : From new, raw data; DIA_MAJ or DIA_MIN modified from published data NED Comment : Effective (half-light) radius
No. 6 Published Units: Homogenized Units: Reference Code : 2007SDSS6.C...0000: Published Object Name : SDSS J075827.37+075901.7 Frequency Targeted : r (SDSS Exponential) Major Axis (2a) : a = 1.2378 arcsec 2a = 2.48 arcsec Uncertainty : 0.006 arcsec 0.01 arcsec Minor Axis (2b) : ... 2b = 1.28 arcsec Uncertainty : ... 0.00 Axis Ratio : b/a = 0.518 b/a = 0.52 Uncertainty : 0.003 0.00 Ellipticity : ... 1 - b/a = 0.48 Uncertainty : ... ... Eccentricity : ... [(a/b)2-1]/[(a/b)2+1] = 0.58 Uncertainty : ... ... Cos-1(b/a) : ... 59 deg Position Angle [Equinox] : 80.1 deg [J2000] 80 deg [J2000] Uncertainty : ... ... Significance : Based on count statistics only Diameter Reference Level : ... Frequency : 6290 A 4.77E+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 : Half-light ("effective") diameter Qualifiers : A radius is given in DIA_MAJ, not a diameter Coordinates Targeted : 119.6140752986 7.9838155646 (J2000) Qualifiers : From new, raw data; DIA_MAJ or DIA_MIN modified from published data NED Comment : Effective (half-light) radius

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