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Grasslands Observatory : Operations

Looking North during the day At the gate looking South to the Observatory
  Earth's Shadow at sunset Late August early evening overhead Milky Way  
Achernar culminating on the Southern Horizon 4 Nov 2005, 11:20 pm MST; Altitude 1 deg, Azimuth 182 deg; Magnitude 0.54 Gacrux (the top star in the Southern Cross) culminating on the Southern Horizon 18 May 2007 9:40 pm; Altitude 0.5 deg, Azimuth 184 deg; Magnitude 1.65 The Grasslands Observatory 18 May 2007 Venus and the Moon 18 May 2007
Night at the Grasslands Observatory.
The Director of the Observatory is James McGaha who is a retired Air Force Major and a former C-130 pilot. He has a Master's degree in astronomy as well as an MBA degree. James directs the scientific program at the Observatory, which consists of asteroid astrometry, asteroid recovery, and asteroid discovery, as well as supernova photometry, and Tri-Color CCD Imaging.

Since 1995, the telescope and its associated instruments have been operated from the Control Room. This building is a small, one-room, well insulated house with lights, heat!!, a refrigerator, microwave, futon, chairs, and a Control Console for operating the telescope. The Control Console is connected by cables running through a metal conduit to the main Observatory Building. The Control Room Computer is networked to three computers in the Observatory Building, the Telescope Computer, the ACE Computer, and the Guider Computer.


The Control Room
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Control Room from Left to Right Control Console

The 24-inch f/5 telescope is fully computerized. It formerly had to be manually moved from position to position. Now, it is completely operated from the Control Room by a sophisticated control system installed by Astronomical Consultants & Equipment, Inc. (A.C.E.) of Tucson, Arizona. This system allows for accurate all sky pointing of the telescope, and it has a built in periodic worm correction encoder. It works in conjunction with an SBIG ST-402 ME CCD camera for long exposure guiding. In addition, a new mirror cell with built in tube fans was constructed for the telescope by A.C.E., and Losmondy mounting plates were installed on the telescope to carry a variety of instruments.

Ancillary equipment includes an 8-inch f/4 Meade LXD55 Schmidt-Newtonian telescope which has been mounted onto the side of the 24-inch telescope. Imaging through the 8-inch telescope is done with a Canon 20da digital camera back.  In addition, a Takahashi Epsilon 180 Astrograph is available for mounting on the 24-inch telescope.  Moreover, in early January 2007 a Celestron C-14 with exquisite optics was permanently mounted inside of the Grasslands Observatory building.  This telescope is used for visual observing and web cam imaging of the Moon and Planets. 

An Apogee AP7 CCD camera was used for imaging until September 2000. Among its accomplishments was the imaging of all 338 Arp Galaxies and tri-color imaging of all the Messier Objects. In September 2000, the AP7 camera was transferred to the 3towers Observatory in Tucson. It has been replaced by a Fingers Lake Instrumentation Dream Machine CCD. Prior to the AP7, an HPC-1 camera had been used, and some of its images are still posted on this web site. The HPC-1 was a very fine camera with 12 micron pixels and a 1024 x 1024 pixel array. Its quantum efficiency was good in the red and green portions of the spectrum, but it had a relatively low quantum efficiency in the blue portion of the spectrum. The Apogee AP7 camera has a very sensitive SITe 512 x 512 chip with 24 micron pixels. It was attached to an ISIS FW1 filter wheel containing an open slot, a clear filter, and standard R, V, B, and I (near-infrared) Photometric filters. Now, the Fingers Lake Instrumentation Dream Machine CCD camera is combined with a Finger Lakes CFW-1 Color Filter Wheel using Photometric R, V, and B filters. The AP7 gave a field of view of 14 minutes. The Dream Machine has a chip with a similar quantum efficiency as the AP7, but the chip is twice as large (1024 x 1024) and gives a nearly 28 minute field of view.

Focusing is performed with an Optec TCF (Temperature Compensating) digital electric focuser. At the Control Console, a Pentium 4 2.6 GHz Control Room Computer running under Windows XP is networked to the three computers in the Observatory Building, the Telescope Computer The ACE Computer, and the Guider Computer. The Observatory Building computers operate the telescope, the CCD camera, the filter wheel, the focuser, and other ancillary equipment. The Telescope Computer in the observatory consists of a Pentium 4 2.4 GHz system running under Windows XP. It operates the Dream Machine CCD camera and the filter wheel.  The ACE Computer is a Pentium (R) D CPU 3.20 GHz system that controls the telescope pointing and drive system using the sophisticated A.C.E. control system.  The Dream Machine CCD camera is controlled with MaxIm DL/CCD. The CCD is oriented on the telescope such that all images are displayed on the computer screen with the North to the top and East to the left.

A Pentium 4 2.4 GHz Guider Computer is also networked to the Control Room Computer, the ACE Computer, and the Telescope Computer. It runs the software and hardware for an SBIG ST 402 ME CCD camera mounted on a Celestron 8-inch f/10 telescope. The C-8 is attached to the 24-inch telescope, and the ST 402 ME guider is used for long exposures to correct periodic error drift and other drive errors. The Dream Machine CCD camera creates images that are over two megabytes in size. These are read from the CCD camera over the network directly to the Control Room Computer. In order to take the raw data home for processing, a CD disk writer on the Control Room Computer is used to make data disks for long term archival storage and for taking data home.


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Telescope at night Dream Machine CCD Camera Telescope with CCD Camera

tbh, Saturday 28 April 2007


Take Time to Smell the Flowers:

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This wild flower was photographed at 1:20am on 14 April 2001 by James McGaha with his new digital camera. We noticed the wild flower as we were returning from a night's observing run. The flower grew alongside the dirt road going back to the observatory building. It was visible in our car headlights. The entire 20 acres of property at the Grasslands Observatory was covered by these flowers. Mike Newberry of Mirametrics, Inc. (Mira) writes: "The flower James photographed is Oenothera caespitosa, or "evening primrose". "Caespitose" means growing in clumps or tufts. The flower opens in evening twilight and withers in morning twilight, lasting only 1 night. Other flowers or flowers on other plants will open the next night. It grows at 3000 to 7500' elevation in gravelly places. About 20 species of Oenothera are in Arizona."
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