The HAO consists of two telescopes in two separate observatory
structures: HAO#1 and HAO#2. But let's start the tour with this south-looking
view of my house from near the driveway entrance.
Notice the Sliding Roof Observatory (SRO) behind the house,
on the left (with brown canvas cover).
This view, looking west, shows both dome observatories. HAO#1
houses the Celestron 11-inch (CPC-1100) telescope and HAO#2 houses the Meade
14-inch (LX-200GPS). Both are controlled using buried cables.
Both domes are 8-foot diameter ExploraDomes. They are motorized
for azimuth movement only (no shutter motors). This picture was taken
before completion of HAO#2, and shows one of the two trenches open with
conduit in position. One conduit is for AC power and another is for control
cables. The left end of the house is my office (control room).
When this poicture was taken HAO#2 had a 11-inch Celestron inside (it
is now in HAO#1; HAO#2 now houses a Meade 14-inch). The optical backend
consists of a focal reducer lens, a 5-position filter wheel and a ST-8XE
CCD. More information is given in the "Hardware Specifications" section.
The HAO#2 dome is moved in azimuth by a motor/gear that I modified
to achieve 4 times better azimuth resolution. The original design used
a shaft painted white and black (total of 2 sectors) that were viewed
by an optical sensor; I moved the optical senor for a down-looking view
of an 8 sector black and white pattern. The quantization interval is 4
degrees, and this provides reliable slaving of the dome to the telescope
azimuth with no occasions of dome slit obstruction.
The control room has dedicated computers for the M14 (left)
and C11 (right). Each computer commands the telescope, focuser, CCD,
etc using serial and USB cables. Each computer has a dual DVI video card
for display on two LCD monitors. In this view both telescopes are observing
the same object, as seen by their respective left panel displays. The right
displays are usually used for display of TheSky/Six which assists in positioning
the main chip FOV so that the autoguider chip has a sufficiently bright
guide star. The M14 station includes a wireless audio.video camera display;
this provides audible and visual feedback of M14 movements.
Hardware Specifications
M14 (in HAO#2)
Meade LX200 GPS, a 14-inch Schmidt-Cassegrain telescope on an
equatorial mount (Meade Super Wedge).
CCD: SBIG ST-10XME (KAF 3200E main chip, TC-237 autoguide chip
next to main chip). The main chip has a 2184 x 1472 array of 6.8-micron
pixels (physical size is 14.9 x 10.0 mm). Gain is 1.3 electrons/ADU (unbinned).
Read noise = 8.8 photoelectrons. Full well capacity is 77,000 electrons.
External 10-position filter wheel for 1.25-inch threaded filters. Currently
filter set: CBB (clear with blue-blocking, 480 nm turn-on, Custom Scientific
brand) and u', g', r' and i' (the Astrodon SDSS set).
Available filters for this CCD/CFW: B (Astrodon),
V (Schuler), Rc (Schuler), Ic (Schuler), z' (Astrodon), NIR (Astrodon),
B, G, R (Custom Scientific pretty picture filters normally provided by
SBIG).
FOV with f/6.3 focal reducer: 20.4 x 13.7 'arc. Image scale =
0.56 "arc/pixel (unbinned). EFL = 2504 mm, f/7.04.
C11 (in HAO#1)
Celestron CPC 1100, a 11-inch Schmidt-Cassegrain telescope on
an equatorial mount (wedge).
CCD: SBIG ST-8XE (KAF 1602E main chip, TC-237A autoguide chip
next to main chip). The main chip has a 1530 x 1024 array of 9 micron
pixels (physical size is 13.8 x 9.2 mm). Gain is 2.7 electrons/ADU (measured).
Full well capacity is 100,000 electrons.
External filter wheel: 5-position, 1.25-inch threaded filters.
At the present time the filters in use are CCB (clear with blue-blocking),
NIR (near infra-red, turnon at 720 nm), V, Rc and Ic (Custom Scientific
Johnson-Cousin photometric filters).
FOV: 21.9 x 14.6 'arc. Image scale = 0.86 "arc/pixel. EFL =
2158 mm, f/9.32 (with a focal reducer ahead of the CFW).
Here are some useful filter passband shape plots.
SBIG's "pretty picture" B, G and R filter passbands.
Horizon
Looking south at mountains that are at 4.0 deg elevation on the
meridian (vertical red line). The star Canopus (declination -52.7 deg)
is transiting. Stars at declination -53 deg can be observed for more than
an hour either side of transit, although the air mass would be ~ 10 for
most of that time. Observations with the NIR filter would be subject
to an extinction of 0.75 magnitude at this air mass. Mexico is 7 miles
in this direction, so this sky is quite dark.
Directions to HAO
The HAO is located at West Longitude 110:14:16 and North Latitude
+31:27:08, at an altitude of 4670 feet. As the following map shows
the HAO is ~80 miles southeast of Tucson, 7 miles from the Mexican border.
Note that a street name has been changed from Janice to "Edward
V St."
When this picture was taken (for Google) only a sliding roof observatory
was located where HAO#1 now resides.
