CCD Characteristics


ST-9E CCD

        Gain                                              1.74 e-/adu
        Readnoise                                     ~13.0 e- with T_CCD = -10 deg C
        Bias Level                                     100 adu = 174 e-
        Dark Count Rate                           0.95 adu/sec = 1.65 e-/sec
        Full-well capacity                         180000 e- , 65535 adu - bias level and dark count
        Pixel size                                       20 micron x 20 micron
        Pixel scale                                     0.809"/pix
        Size of Science CCD                     512 pix x 512 pix
        Science CCD Field of View          6.9' x 6.9'
        Size of Tracking CCD                   190 pix x 162 pix
        Tracking CCD Field of View        2.6' x 2.2'

Imaging Mode:

Photometric calibration of the telescope + ST-9E CCD + VI filters was performed in June, 2008, just after the mirrors had been realuminized. Stars in the open cluster NGC6633 were observed and compared with Stetson's photometric standards. Results are shown below. The formulae allow one to estimate the apparent magnitude of a star (v,i) based on its standard magnitude (V,I) in a given exposure time (t). Note that the zeropoint of the scale is m_zpt = 25 mag, and it corresponds to a flux of 1 adu = 1.74 e- such that:

m = 25 - 2.5 * alog10 (flux / 1.74 e-)

where m = v or i, and

v = V - 0.188 - 2.5 * alog10 (t/180 sec)
i  =  I  - 0.418 - 2.5 * alog10 (t/180 sec)

Filter         Average Flux (e-/sec)        Surface Brightness of the Night Sky w/o Moon, but in hazy conditions
                 from an M=15 mag star                  (mag/arcsec^2)            (e-/pix/sec)

   V                         115                                        16.89                           13.28
    I                          142                                        17.41                           10.14


ST-8E CCD

Gain                              2.68 e-/adu
Readnoise                     18.6 e- with T_ccd = -10 C
Full-well capacity       16383 adu   (unbinned), 32500 adu   (2 x 2 binning)
Pixel size                      9 micron x 9 micron (unbinned)
Size of Detector          1534 pix x 1020 pix (unbinned)
Pixel scale                    0.728"/pix  (2 x 2 binning)
Field of View              9.3 arcmin x 6.2 arcmin   (2 x 2 binning)

Imaging Mode:

Photometric calibration of the telescope + ST8 CCD + BVRI filters was performed on Nov 13, 1999 when 12 standard stars in 4 Landolt fields were observed. From  32 to 42 separate observations were made in each filter. The derived calibration equations listed below convert instrumental magnitudes (bvri) to standard magnitudes (BVRI). They are valid for stars with -0.04 < (B-V) < 1.06 and  1.20 < airmasses < 1.73. Note that the zeropoint of 25 mag corresponds to a flux of 1 adu/sec = 2.68 e-/sec.

   v = V +  5.479 (+/- 0.033) +  0.023 (+/- 0.049) * (B-V) + 0.397 (+/- 0.086) * (X-1.25)
   b = B +  6.263 (+/- 0.028)  - 0.209 (+/- 0.038) * (B-V) + 0.610 (+/- 0.072) * (X-1.25)
   r =  R + 5.064 (+/- 0.014)  +  0.065 (+/- 0.020) * (B-V) + 0.359 (+/- 0.036) * (X-1.25)
   i =   I +  5.919 (+/- 0.014)  -  0.018 (+/- 0.019) * (V-I)  +  0.225 (+/- 0.032) * (X-1.25)

Filter          Average Flux (e-/sec)        Surface Brightness of the Night Sky for New Moon Phase
                 from an M=15 mag star                  (mag/arcsec^2)            (e-/pix/sec)

   U                          15.                                       16.5                             5.9
   B                         125.                                      17.9                           13.9
   V                         158.                                      17.5                           29.9
   R                         229.                                      17.0                           65.5
    I                         111.                                       14.8                         249.0

The New SBIG Self-Guiding Spectrograph (w/o binning):

Dispersion                        1.067 Angstrom/pix = 0.1186 Angstrom/micron
Resolution                        TBD
Wavelength Coverage      1637 Angstrom

The Old Spectrograph (w/o binning):

          Dispersion                       4.1 Angstrom/mm = 0.37 Angstrom/pix
          Resolution                        1.4 pix = 5.7 Angstrom
          Wavelength Coverage      570 Angstrom
 

ST-7 XE ABG CCD used w/ the 8" Meade Telescopes

        Gain                             ~ 2.3 e-/adu
        Readnoise                    ~15 e-
        Full-well capacity         50,000 e- (unbinned)
        Maxium A/D Counts    ~ 20,000 to 30,000 adu
        Pixel size                      9 micron x 9 micron
        Pixel scale                    0.800 "/pix
        Size of Detector           765 pix x 510 pix
        Field of View              10.2 arcmin x 6.8 arcmin

ST-6 CCD used on the Finder/Guider Telescope

Gain                              6.7 e-/adu
Readnoise                     30 e-
Full-well capacity        400000 e- = 65535 adu
Pixel size                      23 micron x 27 micron
Pixel scale                    4.0 "/pix x 4.75 "/pix
Size of Detector           375 pix x 242 pix
Field of View               25.0 arcmin x 19.2 arcmin

ST-6 CCD used on the 24" Telescope

Gain                              6.7 e-/adu
Readnoise                     30 e-
Full-well capacity        400000 e- = 65535 adu
Pixel size                      23 micron x 27 micron
Pixel scale                    0.98" x 1.1"
Size of Detector           375 pix x 242 pix
Field of View               6.1 arcmin x 4.6 arcmin

The following photometric data were determined from observations of 10 standard stars in the Landolt SA 92 field on August 28, 1996:

Filter          Average Flux (e-/sec)       Surface Brightness of the Night Sky for Full Moon Phase
                     from an M=15 star                  (mag/arcsec^2)            (e-/pix/sec)

   B                         174                                      18.81                             5.84
   V                         235                                      18.23                           13.4
   R                         260                                      17.40                            31.9


Last updated on Oct 9, 2007