This page provides more detailed information on the modifications, maintenance, and upkeep that have been performed since the observatory became operational in 2007.

The contents of this page are ...


April 2008 To reduce the amount of dust entering the building through the small clearance between the Dome Support Ring (DSR) and the observatory wall, I installed brush weatherstripping around the circumference of the DSR. Jerry Smith of Technical Innovations recommended the correct brushes and holders. This improvement significantly reduced, but did not eliminate, the entrance of dust, insects, and moisture.

July 2008 Noting that the daytime temperature inside the observatory can reach 109F, I installed a portable air conditioner inside the observatory. The air conditioner maintains the temperature below 96F.

April 2010 The observatory computer reached end of useful life, and was replaced by a new desktop computer with a dual core processor and Windows 7 Professional. The new computer has proved reliable for extended operation.

July 2010 Replaced the surge suppressor power strip at the pier station with a 475VA UPS. This protects the telescope from a loss of power, which would require realignment of the telescope if it were not parked when power was lost.

July 2010 Added a 4-port powered USB 2.0 hub to the pier station, allowing multiple ccmponents to share the single USB extension connecting the computer to the pier station. The USB hub is mounted on the side of the telescope base with adhesive-backed hook-and-loop tape.

July 2010 Installed a Santa Barbara Instrument Group (SBIG) ST-8300M CCD camera and took my first CCD astrophotos.

September 2010 Added a SBIG FW5-8300 filter wheel to the CCD camera and took my first color CCD astrophotos.

July 2011 Based on experience, replaced the rubylith filter on the monitors with a 3M privacy filter on the left (planetarium) monitor and a red acrylic filter from Astro Gizmos on the right (equipment monitoring) monitor. This combination seems to give the best balance between readable text and low monitor glare.

July/August 2011 Removed the original shelves over the South, West, and North outlet clusters, and installed custom wood shelves. The new shelves are sturdier, more functional, and more weatherproof than the original shelves.

November 2011 Upgraded the planetarium program from TheSky6 Professional to TheSkyX Professional.

October 2013 Added a paved walkway about 80 feet long from the maintained lawn to the observatory. This eliminates the need to walk across muddy ground during the winter, spring thaw, and after storms.

July 2015 Upgraded the observatory computer OS to Windows 10 Professional.

June 2018 Based on advice from Jerry Smith at Technical Innovations, added key-operated entry switch and indicator LED to outside observatory wall.

September 2018 The observatory computer again reached end of useful life after eight years. The major symptom was unreliable connections to peripherals. It was replaced by a Dell Inspiron 3470 with an Intel i3 processor and Windows 10 Professional. The new computer showed immediate improved performance.

November 2021 Resistance to dome rotation led to slippage of the drive rollers. Removed the conveyor brush weatherstripping and found that the dome rotated freely. The brushes had deteriorated, possibly due to heat and ultraviolet exposure, and were rubbing against the observatory wall. Installed a vinyl skirt in place of the brushes. The skirt allows free rotation of the dome and seems to prevent any entry of dust or moisture.

November 2021 Replaced south shelves with a Craftsman two-tier tool cabinet. The shelves had been extensively damaged by moisture entering under the dome support ring.


Periodic (Cleaning) A general cleanup, including a wipedown of the interior surfaces and vacuuming of the floor, is required a few times a year. The most serious dust buildup occurs on the base flange of the dome where it tends to settle when the high winds drive it under and around the dome flange. A wipedown with a wet cloth is sufficient to deal with this.

Insect intrusions are generally limited to a few small cobwebs, usually near the conduit penetrations at floor level. In general, yellowjacket nests have to be removed two or three times a year.

Periodic (Shutter Maintence) As instructed by the ProDome manual, I wipe down the shutter cable with an oil-soaked rag a few times a year.

Periodic (DDW) The DDW controller occasionally lost its training and reverted to its default settings. The DDW training calibrates the controller to recognize the azimuth corresponding to the home position, and the azimuth change for each pulse from the azimuth sensing wheel. This training is required to allow DDW to synchronize the dome with the telescope.

The immediate remedy for this problem is to retrain the controller, which only takes a minute or two. Since the problem emerged, the DDW controller has failed completely, and the circuit board replaced (see below), eliminating this problem as well

July 2010 (Collimation) The telescope required collimation for the first time. Collimation of the RCX400 is very convenient, since it is managed entirely from the hand controller. However, when the collimation was complete and I selected SET DEFAULT from the hand controller, the focus motors ran away and drove into the stops. I had to power down the telescope to stop the runaway, and when the telescope was powered up the alignment and collimation had to be repeated. It looks like trying to save the current collimation as a default is a bad idea. I have not determined if this is a problem for all RCX400s or a failure in my specific telescope.


March 2008 (Dome Rotation) The retaining nut for one of the dome support rollers fell off and had to be replaced. The retaining nut for another dome support roller had worked loose and was retightened.

June 2008 (Shutter Cable) The shutter cable developed some binding at the guide pulleys. The cause was that the pulley hubs had pressed into the plastic cable guides,allowing the pulley walls to bind against the guides. This may have been due to the plastic softening in the high summer temperatures. The problem was resolved by adding 1/4-inch stainless steel washers between the pulley hubs and the cable gudes, restoring the needed spacing.

June 2008 (Shutter Operation) The front shutter panel bound against the guide flanges during opening, due to uneven tension of the opening cable on the two sides of the shutter. Jerry Smith of Technical Innovations recognized the problem and provided two spacer blocks that mount on the guide flanges and keep the shutter panel properly aligned. Ultimately I installed two pairs of spacer blocks, and the problem has not recurred.

March 2009 (Shutter Lock) The security deadbolt that locks the shutter in the closed position became loose due to the lock nuts not holding in place. Since the deadbolt is redundant when the electric shutter drive is installed, I simply removed the deadbolt assembly.

August 2009 (Digital Dome Works) The DDW circuit board failed, apparently due to overheating of the drive transistors. This may have been due to inadvertent operation of a manual shutter operation switch during automatic shutter or dome operation; something the circuit is not designed to handle. Technical Innovations repaired the circuit board at a reasonable cost and returned it within 2 weeks.

March 2010 (Shutter Wiring) The shutter failed to open after several weeks of non-use. A portable battery pack was used to open the shutter partially using the emergency contacts included in the shutter design. The problem was minor corrosion on the stationary contact pads on the wall flange, that connect the DDW controller to the shutter shutter motor. The problem was eliminated when the contactor pads were cleaned.

August 2010 (CCD Camera) The power supply for the ST-8300M camera failed due to broken solder terminals on the DC connector. Returned to SBIG for warranty repair. When the power supply was returned, the DC connector failed again with intermittent shorting between the contacts due to loose wire strands. SBIG sent a new power supply. I repaired the original to maintain as a spare.

September 2010 (Weather Station) The weather station console communication to the outdoor sensors failed, probably during a lightning storm. Replaced the console and restored normal operation on November 2, 2010.

October 2010 (CCD Camera) The ST-8300M camera failed electrically. Also, the connection between the power supply and camera was not secure, in that it could be interrupted by motion of the DC cable. Returned camera, power supply, and filter wheel to SBIG for warranty repair. SBIG replaced the camera circuit board and replaced the power supply with a new and slightly different one.

February 2012 (Support Equipment) Replaced the AGM battery in the UPS for the observatory computer. The UPS failed when electrical service was lost during a severe wind storm with winds estimated at 75mph. The weather station was also put out of service, so no measurement of wind speed was recorded. The UPS was operational again after the battery was replaced. Other wind damage to the observatory was very minor, such as the bumper strip on the shutter end blown loose.

May 2013 (Weather Station) Weather console stopped reporting after an extended power failure that outlasted the UPS. Due to an injury I was unable to access the observatory until late June. Found the weather console powered up but in a failed state with every LCD field activated. The console recovered after being powered down for 30 seconds and then powered up.

November 2013 (Support Equipment) Replaced the UPS for the observatory computer. The previous UPS failed completely, for no apparent cause.

November 2016 (Weather Station) Retired the weather station due to physical deterioration and software failures under Windows 10.

September 2017 (Telescope) Reviewed telescope operation. Due to the communication problems the scope lost all of its setup information, including what kind of telescope it is, site and owner names, etc. Restored initialization settings and performed drive training and sensor calibration. All functions checked work correctly, with the exceptions noted below. In particular, goto, focus, temperature sensors, the OTA fan, dew heater, and RS-232 link work. The internal USB-Serial converter returns an initialization error code. The remaining three USB terminals (on the OTA back) operate, but remain unused because of reports that the hub can fail at low temperatures.

September 2017 (Serial Communications) The telescope responded incorrectly to links with TheSkyX, such as going into uncommanded download mode. The cause was assessed as serial communication errors. About half of the available serial ports from the PC failed to connect. Replaced the USB hub from the PC with StarTech ST4300USBM industrial model. The old hub was physically deteriorated and a suspect in the poor communication with the telescope. Replaced the USB-to-serial converters with StarTech ICUSB2324i industrial model, for the same reason. The telescope has responded properly since the changes.

September 2017 (Support Equipment) Replaced the louvered vent on the air conditioner exhaust. The louvers had fallen off and the plastic vent had deteriorated (from exposure to sunlight) to the point that it crumbled when removed.

September 2017 (Shutter Wiring) One of the phosphor bronze loops used as a sliding contact to provide power to the shutter motor broke due to metal fatigue. Redrilled the broken end and reinstalled the loop. The loop appeared to be catching an electrical terminal on a fixed contact, and repeated bending from this probably led to the fatigue. I relocated both sliding contacts outward about 1/2 inch to eliminate the problem.

June 2018 (Digital Dome Works) The DDW circuit board failed completely. Replaced it with a new Model 5 circuit board from Technical Innovations, with surface mount technology. All functionality seems to be restored.

June 2018 (Weather Station) The LaCrosse weather station and associated software no longer worked reliably with the observatory computer (See November 2016 entry above). An AcuRite Model 06004RM 5-in1 weather station had been installed for household use and operated without problem for at least two years. I built a C++ application to read the .CSV file maintained by the Model 02064CDI indoor display and upload the current weather conditions to the Conditions page of this website every 12 minutes. The 5-in-1 sensor has also been upgraded with a Model 06003 PRO+ sensor assembly and Model 06052M Remote Battery Pack.

June 2018 (Dome Rotation) Some of the side rollers that keep the dome flange from contacting the side wall were found jammed with desert dust. Continued dome operation against the increased resistance had caused some flat spots on the circular sides of the rollers. Replaced all 16 side rollers, and free dome rotation was restored.