iTelescope - T21 - Deep Space - Utah

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Location Information

Observatory: Utah Desert Remote Observatory at Great Basin Desert, Beryl Junction, Utah, USA
MPC: U94 

Telescope:  0.43-m f/6.8 reflector + CCD + f/4.5 focal reducer

Timezone:  UTC Minus 7:00. Daylight savings time is observed 

Minimum Target Elevation: 15º all azimuths except noted. 23º elevation for azimuths 50-130º. 

N 37° 44’ 16"    Decimal: 37.7378 North

W 113° 41’ 51"  Decimal: -113.6975 West

Elevation: 1,570 meters / 5150 ft

Operational Notes

Deep Field. Hybrid Missions. Typically used for Photometry and Imaging. FITS and TIF file formats. Dark Frame calibration data is available for  60, 120, 180, 300, 600  second exposures. Binx1 - Binx2.  Raw data can be found at

  • T21 is fitted with a 0.66 Focal reducer. Recommended Maximum Exposure 600 seconds.
  • The Planewave Ascension 200HR mount is so accurate whilst tracking that iTelescope Admin have disabled active guidance, with a corresponding decrease in session setup time when imaging. 
  • T21 is a 'Full House' telescope system. It can Image deeply and do powerful science. 

Instrument Package

CCD:  FLI-PL6303E  CCD camera

QE: 68% Peak

Gain: 1.16

Full Well:  ~100,000e-  Non Anti Blooming Gate (NABG)

Dark Current:   ~.005 e-/pixel/sec. @ -45º C

Conversion Factor (Gain): 1.13

Pixel Size:  9um Square

Resolution:  0.96 arc-secs/pixel

Sensor:  Frontlit 

Cooling:  Set to -35ºC default 

Array:  3072 by 2048 (6.3 Megapixels) 

FOV:      32.8 x 49.2 arc-mins

Astrodon LRGB 50mm unmounted, Astrodon Ha, SII, OIII, (all 5nm), 50 mm unmounted, Astrodon UBVRI John/Cousins

Position Angle: 359º


Telescope Optics

OTA: Planewave 17" CDK 

Optical Design: Corrected Dall-Kirkham Astrograph 

Aperture: 431mm

Focal Length: 1940mm (0.66 Focal Reducer)

F/Ratio: f/4.5 

Guiding: Active Guiding Disabled 

Mount: Planewave Ascension 200HR


Transformation Coefficients

VPHOT system –


Tub= 1.035; standard deviation= .010

Tbv= 0.974 ;  standard deviation= .012

Tvr=  1.077 ;  standard deviation= .011

Tri=    1.009 ;  standard deviation= .018


Tv=    0.012 ; standard deviation=  .006

Tr=   -0.048; standard deviation= .015

Ti=    -0.063; standard deviation= .004

Tb=  -0.009;  standard deviation=  .014


These use the following definitions (lower case are instrument magnitudes; upper case are reference magnitudes of NGC7790 from Arne Henden’s standard field available at


Tv= slope of (V-v)/(B-V)

Tr= slope of (R-r)/(V-R)

Ti= slope of (I-i)/(R-I)

Tb= slope(B-b)/(U-B)