Wallace 16" Telescope

picture of 16-in

General Information


The 16-in and its dome are located to the west of the main building.


Lhires III PF0001 spectrograph made by Shelyak Instruments.

*** Be really careful when changing gratings and changing micrometer settings, don't turn it past 0mm or 25mm!!!

OTA Ealing 16" aka Wallace 41cm
f/# 10.9
Diameter 406.4mm
Focal length 4429.8mm
arc seconds/mm ("/mm) at focal plane 46.56"/mm
Primary Instrument Lhires III Spectrograph w/QSI 683s CCD
Mount Ealing 16"
Typical pointing accuracy ~3 arcminutes
Max exp. due to tracking 5s wo/ autoguiding, 60mins with
PEC Enabled but not yet working
ProTrack N/A
Focuser Optec TCF-S3 Electronic Focuser
Filters n/a
Slit camera FOV ~3'
North Angle Selectable
QSI 683s CCD 8.3mp Kodak KAF-8300m sensor
Read out rates Dual read rates of 800kHz and 8MHz
Min / Max Exposure Times (sec) 0.12 / 3600
Max Counts Unbinned ~65k
Gain (electrons) High Gain 0.5 e-/ADU (800KHz)
Low Gain 1.1 e-/ADU (8MHz)
Pixel array  3326 x 2504 pixels
Imager Size: (WxH) 17.96mm x 13.52mm
Pixel dimensions 5.4 microns square
Temperature for operation -45 C from ambient
Peak QE ~57% @ ~540nm
Autoguider Yes
Celestron C8 f/10 D:203.2mm F:2032mm
FOV = ~ 8' x 6.1'

SBIG ST-i (KAI-0340) 648 x 484 7.4um
on Orion X-Y stage

Spectrograph Specs          
slit width at focal plane ~ 29um +/- 1um        
slit width in arc seconds ~ 1.35"        
Neon Sample Spectra 5800Å to 7500Å        
Grating (g/mm) 2400 1200 600 300 150
Dispersion (Å/pix) @ Halpha 0.082 0.180 0.443 0.825 1.650
Dispersion (km/s) 5 17 35 75 150
Spectral domain or FOV in Å 400 800 1400 ~2800 ~6000
Limiting magnitude S/N=100 5 6.3 7 10.4 12?
Micrometer settings
0-order line 15.20mm 6.65mm 2.2mm 1.5mm 0.65mm
User verified

Cheat Sheet 2400

600 Cheat Sheet






Originally designed as an instructional telescope, the 16-in and its dome were constructed in 1971. It was used by students in observing subjects until 1999.

The telescope drive has been completely refurbished by Alan Midkiff in 2008 and is now actively computer controlled using ComSoft's BBox and The Sky software.

During the summer of 2009 the Lhires III spectrograph was installed. Shortly there after, the ComSoft TCS computer blew up and was replaced. Students began using it for 410 projects Fall 2009.

During the spring of 2010 the optics were completely removed by Tim Brothers and Michael Person for recoating and polishing. It was reassembled that summer and is now restored to its original state. The secondary focuser was disabled in favor of an Optec TCF-S3 electronic focuser mounted on the rear of the telescope, right before the spectrograph entrance. Focus can now be controlled remotely through CCDSoft. The original autoguider platform has been replaced by a rigid system that has greatly improved the autoguiding capability of the C8 mounted on top of the 16" optics. An Orion X-Y stage is now used to select autoguiding targets.

The StellaCam3 video camera, which was often a source of trouble, finally died after 2 years of limited use. It was replaced with a Super Circuits pc165dnr camera.

WAO 16-in (41 cm) Telescope Information for Users from 1998.

During the summer of 2013 Tim Brothers, assisted by UROPs :, tore out the TCS control system and replaced with Sidereal Technology's Servo II brushed servo controller. With this upgrade, there are now axis limits, Home position sensors, improved autoguiding capability, more robust PEC functionality, reliability, one computer required instead of two to control and a factor of two improvement in pointing. In addition we added a new camera, the QSI 683s and a new autoguider camera, the SBIG ST-i.