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Lowell Observatory - Anderson Mesa Station

Latitude and longitude: 35°05′49″N 111°32′09″W (+35.0969, -111.5358)
Elevation: 2,163 meters (7,096 ft)
Site manager: Stephen Levine
Internet access:
Weather statistics:
Typical good seasons:


Wright 28 (W28) Donated by the late Paul Wright

Type:  Celestron C11 Schmidt-Cassegrain
Aperture: 280mm
Focal length: 1717mm
F-ratio:  6.13
Focuser:  Moonlite ( motorized focuser, 2” diameter drawtube.


Pointing accuracy is  typically 1 – 2 arcminutes 'in the blind', but after a plate solve/reslew pointing error is reduced to 20 arc seconds or less. Maximum unguided tracking restrictions, if any:  60 seconds
Computer:  PC/Win XP
Software:    Maxim for CCD/filter wheel control.  TheSky6Pro/TPoint for scope control and pointing model.  FocusMax for focuser control.  ACP and ACP Scheduler for overall system operation.
Telecope Advocate:  Sara Beck

Typical seeing:  2.8 arc seconds FWHM
Best seeing:  2.0 arc seconds FWHM
Scattered light:  After flat fielding, photometric errors are at the 1 – 2% level across the entire field.  (Arne has verified this with raster scan multi-image tests.)
Image defects:  None

Filter wheel:  SBIG CFW-10
Filters:  C B V R I  Ha  Sii  Red645NM  Sloan g'   Sloan r'
Exposure ratios/filter:  C=0.25  B=3.0  V=1.0  R=0.55  I=1.1  HA=14  Sii=15  Red645NM=13  Sloan g'=1.1  Sloan r' =0.55  (Note – if your target is a very red star, expect to shorten R and I exposures and lengthen B exposures...assuming V exposures remain constant.)
Pixel count:  765 x 510
Pixel scale:  1.08 arcsec/pixel
Field of view:  14 x 9 arc minutes
Gain: 2.5e-/ADU
Readnoise: 19e-
Full well:  Above 44,000 ADU response is not linear
Cosmetic defects:  None
Dark current: 1e-/sec/pix at 0C typical
Read time:  3 seconds
Shortest exposure:  0.11 sec
Compressed image size:  330KB

Typical images

Star Image Flat Bias Frame Dark Frame

Typical use of system 
Multi-filter 'snapshot' coverage once a night for many targets, or long time-series of a small number of targets, or a mixture of the two.

Miscellaneous notes 
Calibrated images are 16-bit, but can have negative values, and non-integer values.  You may have to set up your photometry software to specifically deal with this situation (some software deals with it automatically, some does not).

AAVSO 49 Bay State Rd. Cambridge, MA 02138 617-354-0484