H41 - ASO Petit Jean Mountain Facility

Updates and progress reports of the new facility
Started 14 March 2003

Last Updated - May 15, 2003

Conway County, Arkansas, home of Petit Jean Mountain, has now designated by the County Judge that ASO-H41 Petit Jean will be located at #10 OBSERVATORY HILL DRIVE on Petit Jean Mountain.

On Thursday, May 15, the signs went up.

In the meantime, there has been much progress with the observatory as nearly all landscaping has been completed, the lawn established outside and interior work progressing.

Among the interior work is the networking of the observatory's 4 computers to automate and remotely operate the telescope, the dome and the CCD imaging system and closed circuit TV's throughout the building.

In addition, installation of the office library and work space is progessing although not all of the holdings of the library will be placed in the observatory location.  The office/library area gives ample room for comfortable reading, writing and researching through books, computer files and records.

The dedication for the observatory is scheduled for EARLY JUNE and it is hoped that many of the friends of ASO will be able to attend and participate in this long-awaited event.

We thank our friends and supporters through the years for their attention and enthusiasm about our observatory projects, both on Petit Jean Mountain and Cascade Mountain.

Come see us.....

The Arkansas Sky Observatory Petit Jean Facility (Harvard/MPC H41) is nearing completion after one year of preparation and construction.  The above photo shows the completed exterior with some early landscaping as of May 3, 2003.  

Computers (4) have now been installed and the telescope automation is nearing completion; a unique attribute to the computerized system is the ability for the computers to accumulate, translate and convert data for immediate astrometry via the Harvard astrometric reporting that is the primary purpose of this facility.  Next week a series of photographs and explanatory text will be posted to demonstrate this totally unique CCTV Real Time imaging and reporting system, exclusive to ASO.

A dedication and open house for ASO Petit Jean is scheduled in the coming weeks and the date, time and location will be posted here with plenty of notice for those who have indicated they wish to attend.

In the three weeks since the 16" SCT's "first light" at this new facility, over 500 astrometric measurements and physical reports of over 28 different comets have been made to the Harvard/MPC as well as the Tokyo and Nakano Observatories of Japan.

There are still some minor dome operation bugs and some computer calibrations yet to be done, but thus far the total automation of ASO H41 is nearing completion.


April 15, 2003

Doc Clay at the controls of the telescope on the first night of operation...attempting to align and get the system calibrated.  As those who know, there were a few "dad-gum it's!" throughout the operation which greatly helped to move things along to perfection.

The 0.41m telescope and the imaging center in the observing room; this slave computer center inputs all data and images from the telescope and imaging equipment and transfers this data into the computer room for automatic processing.  Note that the walls in this room are not yet finished, this being one of the last needed final touches for completion of Petit Jean ASO.

Looking SE out of the Dome; note the large 6-foot industrial ladder behind the telescope that is used for an observing platform as an indication of scale.


We have been very busy and probably a bit neglectful the past two weeks getting ready for the groundbreaking of the NEW Petit Jean Mountain H41 (Harvard-MPC) station of the Arkansas Sky Observatory.

Sunset on a nearly completed Petit Jean Mountain Arkansas Sky Observatory, April 3, 2003

Exterior of ASO Petit Jean on April 5, 2003 with dome in full operation.

UPDATE:  MARCH 20, 2003 !!!
Please scroll to the bottom for all the latest postings of pictures as the Observatory progresses!!

Drawing of ASO H41; observatory has been built to conform with the rustic look and nature of surround Petit Jean Mountain

Wide field shot, showing the ASO "Sky Car" and the peak of towering Petit Jean Mountain

Arkansas Sky Observatory is being built in a hay storage area in the huge mountaintop ranch of Win Paul Rockefeller on Petit Jean Mountain, which rises like a Mesa some 1,200 feet above the surrounding Arkansas River Valley below.

We finally broke ground on Friday, March 14 and in only two days have made significant progress.  The huge cement pier required one FULL truck of cement....14,300 pounds; in the picture below, the cement has just been poured and skreeted awaiting the long anchors to attach the 700-pound telescope to the huge pier.

The pier - over 14,000 pounds of it - measures 6 feet long (north to south), 5 feet wide, and is buried 4 feet in the ground to dense bedrock below.  At ground level, the pier is reduced to steel-reinforced concrete 28" square rising two feet above the observatory floor to support the 400-pound steel telescope pier.  A false floor will elevate the observer to comfortable operational level when using the remotely operated telescope from the adjoining office area.

The following day, the cement slab for the observatory building was poured, being extremely careful to avoid any touching of the pier and the floor materials without a vibration-dampening barrier.

The observatory will be completed within the next 45 days, to include a completely automated robotic control via a heated and cooled control room; an adequate library and computer room will also be north of the main observatory.

The building is being constructed in native Cedar and Cypress siding; the observing room will feature an infrared-controlled motion dome which will move as the telescope slews.  Adjacent to the main building will be a 24-foot RV which will serve as a resting area and warm room.

The residence for the observatory is located about 1/4 mile north of this site for full time operation of the site during clear skies.

A custom Meade totally automated 16" Schmidt-Cassegrain powered by Project Pluto's Guide8 and the U.S. Naval Observatory A2.0 star catalog will be used for both comet and NEO astrometry and morphology studies, as well as for detailed study of Jupiter, Saturn and Mars.


The observatory slab was poured on March 18, on a very foggy morning on the mountain; by afternoon the skies had cleared to perfection and the framing had begun.

The huge concrete pier was freed of its form as it cured; levels indicated that the job was near perfect; a plumb line established with a LX 200 12" telescope the night before indicated that the bolt pattern for the 400-pound metal pier was dead on Celestial North.

Note that the 14,000+ pound concrete pier is isolated totally by a one-inch gap around all sides and beneath the huge slab by about 12" of earth and sand; this is for the best in vibration suppression.  The actual floor of the observing room will be elevated two feet to the top surface of this concrete pier once the building is completed inside; under this floor will provide ample storage spaces for equipment, cases and observatory urchins.

Framing was completed on March 19, awaiting the arrival of the 15-foot ceiling and roof joists; there will be two "peeking windows" (see drawing at front of update), heating and air located on the rear walls and a dividing wall between the large office, computer operation area, and observing room.

More details in TWO days....


The observatory's office and computer rooms roof rafters are installed on the north side of the observatory building (this picture is facing south-southwest; the 15' x 18' main observing room is visible through the door opening)

Another view of the roof going up in early stages, this facing near north. The 12-foot computer operated dome will be placed offset toward south, centered over the 16" Meade telescope in the large open roof area seen here.  For security reasons, there will be no windows nor doors in the observing room, other than those coming in from the main observatory entrance which is accessed via a steel security door.

This is a view of the north (center) and east (right) unfinished walls of the observatory's office showing the "Gunport windows" which are precisely high enough to look out of if vehicles approach during the night; these will be non-opening glass for security and lighting only.  They are small enough to prevent access.

The observatory is protected by many aspects of security:  

1) a special steel door was provided by a firm that contains internal security alarms and intrusion prevention; short of dynamite, this door will not be able to be removed once the external walls and metal door facings are installed;
2) the gunport windows prevent outside access;
3) heating and air system entry areas are security protected;
4) a full security system will protect vandalism and intrusion.
5) nearby outside security cameras monitor this immediate and surrounding areas for miles;
6) there is a series of three access gates to the observatory hilltop.

MARCH 24 - Dome support trusses and elevated flooring is installed:

The flooring of the 15-foot by 18-foot observing room is elevated 24 inches to provide optimum viewing and operation of the 9-foot tall 16" telescope; much design went into the support structure of 2 x 6 and 2 x 8 joists and stabilizing feet to allow solid flooring while not transmitting any vibrations to the massive pier.   A short staircase allows easy access from the main office into the observing room which will be kept both light- and temperature-isolated from the rest of the building when in use.

Showing the truss supports as they are separated from the 14,300 pound concrete pier.  Note that each corner flooring of the observing room is equipped with a "trap door" to allow easy access to the 2-foot storage area below the main flooring.

The tongue-and-groove 3/4" marine plywood is fitted onto the floor joists via both Liquid Nails glue and nails; this piece is seen with the cutout for the large 28-inch square pier, the top of which is precisely even with the flooring.  This will allow the 400-pound metal telescope pier to put the center of each fork tyne exactly 68 inches above floor level, providing a perfect height for operation, yet still give ample sky coverage to within 7 degrees of any horizon, and nearly horizontal viewing toward the crucial south.

The observing room was covered with a tarp after the dome support rafters were started and the floor was in place; the steps are leading up to the elevated floor and the sub-floor storage area is clearly shown; when completed, all walls will be finished with both red and white recessed lighting and the office and computer room will be separated from the observing area.

This is the beginning of the substructure for the dome over the observing room; the actual dome and its support ring will be recessed into the actual pitched roof; once operational the dome will be remotely control via infrared sensors for both azimuth and shutter operation.  NOTE:  The beams that are in place in this image are temporary and will be replaced with an actual heavy timber understructure to support the dome ring and rotation system; there will of course be no long central beam as seen in this image.  To complete the roof and eave system the temporary construction was necessary.

NOTE THE REASON WE ARE ON PETIT JEAN....check out those blue skies.

UPDATE March 25:

Prior to a major spring hail and thunderstorm moving in, the open roof of the observing room was tightly covered with a heavy tarp to protect the finished projects indoors; the office and computer rooms are now sealed against the elements.  Here the rough cedar siding and rough-cut cedar facia and all trim is being applied prior to the storm.

NOTE:  We are proud to state that JMH Commercial Contractors (Mr. Jim Henderson and crews.....) has been our contractor of choice in this project; the quality workmanship of this fine observatory is now beginning to resemble the craftsmanship of a quality piece of furniture with excellent precision and assembly throughout.

This wide shot of the observatory grounds shows the rolling pasture lands of Winrock Farms atop Petit Jean Mountain.  The blue tarp covers the open side of the building that will house the telescope and dome, which is scheduled to arrive on or about April 1.

The observatory will enjoy nearly obstruction free viewing in every direction, with the exception of north and the trees show; they do not, however, block higher than 30 degrees in that direction.  Being on the highest point on the north side of the mountain, ASO H41 looks out over the surrounding lands beautifully; note the crystal blue skies enjoyed virtually every clear day on this mountain.

Within only hours of starting, nearly 1/2 mile of pole and wire, cable and transformers were run to the observatory grounds by Arkansas Electric Co-op.  In two places, the large rock - common for this mountain - had to be dynamited to place poles.  This view is facing north, and the observatory drive is located at far end of Montgomery Trace road (the paved one in this picture) where it begins going uphill....the observatory drive is to the right, immediately ahead of the large green cedar tree in the distance.


The 900-pound dome was trucked into the mountain early this morning.  The dome ring is being carefully placed by JMH
Construction and the dome will be placed tomorrow....


UPDATE:  April 3,: The Dome is Installed at Petit Jean!

With six husky and able men available....and one pickup truck....anything is possible in Arkansas.  The dome is assembled on the ground, lifted to the rails of the construction pickup truck and then hoisted to roof level (next photo)

The dome is being readied for placement over the rollers of the base ring.

UPDATE April 5, 2003

The dome electrification (but not computer operation) was installed and tested (NOT without a few glitches, like all the windlass cable become unwound due to ambiguous instructions).  The shutter control and azimuth control now works without a hitch and is very quick and precise; here the large windlass operation for shutter opening and closure is plainly seen....this is one mechanism that we learned quickly must be intalled to perfection or there will be a tangled mess on the observing room floor and an open shutter for the remainder of the night should it not operate as designed.

The huge Meade-fabricated pier was too short (it stands 46" inches) for the overall design of the observing room and dome; thus JMH construction had a beautiful modification plate made (lowest section of pier in next photograph) to lift the pier to a total height of 64" from floor level; this will put the top of the telescope approximately 11.5 feet into the dome and the pivot point of the fork arms over 6 feet above.

The pier, with the lower extension, weighs close to 1,000 pounds; this does not take into account the 14,300 pounds of cement that it rests on.  The custom base was fabricated to dampen vibration within less than one second and allow for perfect alignment of the custom Meade-produced equatorial pier.  The fork arm assembly fits atop the tilted plate (precisely aligned to the latitude of Petit Jean Mt. ASO) and has been already adjusted for exact azimuth alignment for true celestial north.

The interior walls begin on Monday and work inside will begin to shape the future of ASO H41.  My hat's off to Wes, Aaron, Jim, John-Mark, Robert, Travis and Steve - the absolutely fantastic construction crew who have had a tremendous amount of input, design and engineering into making Petit Jean ASO a reality.

In addition, the crews of Arkansas Electric Co-op who ran the 1/4 mile of line and poles through the hardest rock in the south get a huge high five from Dr. Clay.

And....the folks on Petit Jean Mountain:  from Winrock International, to the residents, those at Winrock Farms....my sincere thanks for the warm reception, welcome and support that this project has received so far.

We are about to open the cosmos from another angle on beautiful Petit Jean Mountain!

More next week....

Dr. Clay

Stay tuned for information on the new Cascade Mountain Facility to be started soon.  It will house a full GOTO computer controlled 16" Newtonian on German Equatorial mount.  It's purpose will be for monitoring NEO's, comets, asteroids and variable stars, as well as planetary studies.

Back to ASO

Copyright Arkansas Sky Observatory 2003  [A.S.O.] All rights reserved. Revised: