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A visit was made to Las Campanas in the wake of a major lightning strike. Our step­ down transformer was replaced and everything to carne back to life. Some problems with the clutch mechanism surfaced, but were dealt with. A new water-cooling system that included a 44-gallon oil drum was installed...
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A visit was made to Las Campanas in the wake of a major lightning strike. Our step­ down transformer was replaced and everything to carne back to life. Some problems with the clutch mechanism surfaced, but were dealt with. A new water-cooling system that included a 44-gallon oil drum was installed. And finally, some changes were made to the temperature controllers.

A trip to Las Campanas was made between 1998 January 21 and February 2. The dome-motor mounting plate was tightened, the software was upgraded, the water cooling loop was reconfigured, the temperature readout system was changed, a sun monitor was installed, a new UPS was installed, and the clutc...
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A trip to Las Campanas was made between 1998 January 21 and February 2. The dome-motor mounting plate was tightened, the software was upgraded, the water cooling loop was reconfigured, the temperature readout system was changed, a sun monitor was installed, a new UPS was installed, and the clutch was modified.

The 60-foot tower services were restarted for the summer. The mechanical actuator for the east/west axis on the second flat had almost seized, and so this was disassembled and cleaned. Some diagnostic work was performed on the guider module which indicated a fault due to loose interface cards, parti...
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The 60-foot tower services were restarted for the summer. The mechanical actuator for the east/west axis on the second flat had almost seized, and so this was disassembled and cleaned. Some diagnostic work was performed on the guider module which indicated a fault due to loose interface cards, particularly the guider level threshold cards for both axes. No attempt has yet been made to secure the cards and improve their reliability.

A new fibre-based spectrometer was commissioned from 2017 May 8 to May 26. The system was initially commissioned using the light feed from the secondary cœlostat on the lower-level platform in the main observing room of the solar pyramid building. Limited operational time was achieved in this phase ...
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A new fibre-based spectrometer was commissioned from 2017 May 8 to May 26. The system was initially commissioned using the light feed from the secondary cœlostat on the lower-level platform in the main observing room of the solar pyramid building. Limited operational time was achieved in this phase due to bad weather. At the end of the site visit the whole system was moved into the apex of the pyramid sharing light from the primary cœlostat with the Mark-I spectrometer, and remains running in this configuration. Data from the spectrometer suffers from poor low- and high-frequency noise that are thought to be caused by the size of the solar image formed on the end of the fibre. The guiding performance of the Skywatcher mount was tested when operating via a Raspberry Pi single-board computer, and results are consistent with earlier tests at Mount Wilson. No issues are expected with the use of the low-power system.

The new fibre-based spectrometer was updated from 2017 September 1 to 11. The detector electronic noise and atmospheric scintillation noise were both measured. The scintillation noise was found to be approximately 105 times higher than the electronic noise, and so the system is dominated by atmosphe...
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The new fibre-based spectrometer was updated from 2017 September 1 to 11. The detector electronic noise and atmospheric scintillation noise were both measured. The scintillation noise was found to be approximately 105 times higher than the electronic noise, and so the system is dominated by atmospheric noise. It is unlikely that the LCD-based system switching polarisation states at 5 Hz will be able to equal the performance of a typical Pockel’s-cell-based system switching at 100 Hz. An overall reduction in noise power by a factor of almost 5 times is required to match the performance of Fred in Sutherland. This difference is of the order difference in scintillation noise between 5 Hz switching and 100 Hz switching. Two fibre-feeds were trialled. A 30 mm focal length lens to replace the exiting 80 mm, and so focusing a smaller image of the Sun onto the end of the fibre, and a telescope arrangement coupling quasi-parallel light into the fibre. The shorter focal length lens resolves both the low- and high-frequency issues experienced since initial commissioning. The quasi-parallel telescope fibre-feed suffers some Doppler-imaging problems and also produces higher noise levels due to the lower light throughput. The primary cœlostat mirror was replaced, and resulted in an increase in counts for Mark-I by approximately 3%. The PMT HV-PSU was replaced, removing a temporary 2kV unit and reinstating the normal 3kV supply resulting in a further increase in counts for Mark-I by approximately 18%.

A Skywatcher HEQ5-Pro motorised mount and Starlight Express Superstar CCD guide camera with OpenCV image processing were tested in use as a solar tracker. The best performance in RA and declination respectively was 0.00 ± 6.15 arcseconds and −1.32 ± 6.62 arcseconds. This compares favourably with dat...
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A Skywatcher HEQ5-Pro motorised mount and Starlight Express Superstar CCD guide camera with OpenCV image processing were tested in use as a solar tracker. The best performance in RA and declination respectively was 0.00 ± 6.15 arcseconds and −1.32 ± 6.62 arcseconds. This compares favourably with data captured on the standard BiSON mount in Carnarvon where the RA precision was measured to be 0.158 ± 8.434 arcseconds and declination −0.066 ± 3.823 arcseconds. The spectrometer was temporarily modified to accept a fibre-feed from the new mount. A low-frequency "footprint" was present in the data residuals that was not resolved, but otherwise results were as expected and comparable to the standard network performance. Two WiFi access points were installed, providing coverage over the whole tower.

The toroidal transformer power supply in the weather module failed and was replaced. The transformer failure caused the supply fuse for the main electronics rack to blow, additionally removing power from all other modules including the thermocouple sensor amplifiers within the Hannibal spectrometer....
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The toroidal transformer power supply in the weather module failed and was replaced. The transformer failure caused the supply fuse for the main electronics rack to blow, additionally removing power from all other modules including the thermocouple sensor amplifiers within the Hannibal spectrometer. Whilst the sensors were without power, the vapour cell oven became overheated and caused damage to the vapour cell. The cell was replaced with the last available spare. The two UPS devices were tested and both found to require new batteries.

Jabba was offline due to an internal water leak destroying the main power and signal pass-through PCBs at the rear of the spectrometer. Repairs were completed, including new PCBs and cabling, to bring Jabba back online. The aft starboard Peltier-effect thermoelectric coolers were replaced. Mark-V an...
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Jabba was offline due to an internal water leak destroying the main power and signal pass-through PCBs at the rear of the spectrometer. Repairs were completed, including new PCBs and cabling, to bring Jabba back online. The aft starboard Peltier-effect thermoelectric coolers were replaced. Mark-V and Jabba were removed from the mount. Mark-V has been moved into storage, and Jabba reinstalled in the electronics area at the rear of the dome fed by an optical fibre where it no longer requires water cooling. Additional repair work was completed to the mount RA drive transmission including replacing the stepper motor and gearbox, and also replacing the RA potentiometer encoder and signal cable. A new UPS was installed. Ongoing issues with the fibre conversion require further work.

Problems with the mount encoder position values and the RA drive were investigated and found to be caused by corrosion around the encoder header connectors on the PCB, and general dirt brought in by the cooling fan. The mount controller and RA motor were replaced with spares from Birmingham, resolvi...
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Problems with the mount encoder position values and the RA drive were investigated and found to be caused by corrosion around the encoder header connectors on the PCB, and general dirt brought in by the cooling fan. The mount controller and RA motor were replaced with spares from Birmingham, resolving all faults. The delta-B module was decommissioned.

The Peltier thermoelectric modules were replaced in the starboard scattering detector. The port detector modules were tested and confirmed operational. The water-coolant pump was found to have failed. A position encoder failed during the site visit, and temporary repairs were completed allowing norm...
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The Peltier thermoelectric modules were replaced in the starboard scattering detector. The port detector modules were tested and confirmed operational. The water-coolant pump was found to have failed. A position encoder failed during the site visit, and temporary repairs were completed allowing normal operation. Replacements for both the pump and encoder will be sent from Birmingham.

A major leak on the water-cooling loop inside the spectrometer caused serious damage to the printed circuit boards inside the rear connections box. The dome azimuth drive had problems with a damaged gearbox output shaft. Peltiers failed in two detectors. The linear polariser failed resulting in almo...
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A major leak on the water-cooling loop inside the spectrometer caused serious damage to the printed circuit boards inside the rear connections box. The dome azimuth drive had problems with a damaged gearbox output shaft. Peltiers failed in two detectors. The linear polariser failed resulting in almost zero ratio. Repairs were completed sufficiently to get the site back online and operational, but significant work is still required. The water-cooling loop can not be reactivated without major repairs to the spectrometer chassis. The data now show a strong low-frequency footprint caused by the use of a lens from a pair of polarising sun-glasses as a substitute polarising filter. A CCD-based guider monitor was used to assess the guiding performance of the mount.

The signal to noise performance of spectrometer-J (Jabba) has been deteriorating since it was installed in 2009 July. The fault was identified as being a failed Schott KG4 short-pass infra-red filter. Since KG4 has been discontinued and no spares are available, it was decided to simply remove the fi...
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The signal to noise performance of spectrometer-J (Jabba) has been deteriorating since it was installed in 2009 July. The fault was identified as being a failed Schott KG4 short-pass infra-red filter. Since KG4 has been discontinued and no spares are available, it was decided to simply remove the filter and run with only the Schott RG9 coarse red pre-filter installed. Additional work identified a failed rain detector which was removed and returned to Birmingham, with a replacement to be shipped out as soon as possible. The batteries in the UPS were also replaced.

The shutter motor keeps tripping out, and causing the dome to become stuck open. The dome and shutter motors were swapped over to eliminate a fault with the motor. It was discovered that there was no keyway on the shutter motor shaft which was allowing the motor to slip. A second fault was found on ...
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The shutter motor keeps tripping out, and causing the dome to become stuck open. The dome and shutter motors were swapped over to eliminate a fault with the motor. It was discovered that there was no keyway on the shutter motor shaft which was allowing the motor to slip. A second fault was found on one of the SSR relays in the relay box. A keyway was installed, and the faulty SSR bridged out. The shutter now operates correctly. Additional work was done on the weather arm, replacing the rain detector and repairing the anemometer.

Carnarvon was offline due to a shutter motor failure, and a computer failure. The shutter motor and reduction gearbox was replaced with the spare from the on-site shipping container. A new computer was installed. Further work was completed on the Jabba fibre conversion to resolve some ongoing issues...
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Carnarvon was offline due to a shutter motor failure, and a computer failure. The shutter motor and reduction gearbox was replaced with the spare from the on-site shipping container. A new computer was installed. Further work was completed on the Jabba fibre conversion to resolve some ongoing issues and return the instrument performance and data quality to expected levels.

I upgraded the autoguider and mount control system on this visit. I installed our first digital autoguider: the mount controller. I installed a new UPS, cured the step in Ivan, installed a new waterproof cloud detector, cleaned the rain detector, replaced the cups on the anemometer, and replaced the...
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I upgraded the autoguider and mount control system on this visit. I installed our first digital autoguider: the mount controller. I installed a new UPS, cured the step in Ivan, installed a new waterproof cloud detector, cleaned the rain detector, replaced the cups on the anemometer, and replaced the CPU fan in the computer.

The transmission-monitor photomultiplier tube is replaced by a new transmission monitor based on a photodiode. A temperature monitor is installed. It monitors the temperatures of the outside air, the upstairs room, the spectrometer baseplate, the interference filter, the scattered-light photomultipl...
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The transmission-monitor photomultiplier tube is replaced by a new transmission monitor based on a photodiode. A temperature monitor is installed. It monitors the temperatures of the outside air, the upstairs room, the spectrometer baseplate, the interference filter, the scattered-light photomultiplier tube, and the cell oven. It also monitors the right-ascension and declination guider error signals. A new BeebSub is installed.

Ian Barnes, Brek Miller, and Barry Jackson visited Carnarvon late in 2006. Jabba was removed from the mount, the weather cabling was replaced, all the dome roolers were replaced, the cloud detector LDR was replaced, some mount limit switches were replaced, the computer was replaced, the temperature ...
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Ian Barnes, Brek Miller, and Barry Jackson visited Carnarvon late in 2006. Jabba was removed from the mount, the weather cabling was replaced, all the dome roolers were replaced, the cloud detector LDR was replaced, some mount limit switches were replaced, the computer was replaced, the temperature onitor was reconfigured to monitor different things, the PMTEB was replaced, and the autoguider was realigned.

I had to make many repairs to the electronics, the damage looks like it was caused by a lightning strike. Work was hampered at first by high winds, and then by heavy snowfall. A small group of people were trapped on the mountain: The roads were out, the phone lines down, the electricity ...
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I had to make many repairs to the electronics, the damage looks like it was caused by a lightning strike. Work was hampered at first by high winds, and then by heavy snowfall. A small group of people were trapped on the mountain: The roads were out, the phone lines down, the electricity supply cut, and the Internet connection was not working. But through it all, not one single volcano erupted.

The main aims of this trip were to install the latest version of the Automatic Gain Control (AGC) circuit to try to improve the Narrabri Autoguider, to reconfigure the blind motor system and to install a "magnetic" Pockels cell. In the end, the latter was thwarted by an unexpected fault in the "velo...
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The main aims of this trip were to install the latest version of the Automatic Gain Control (AGC) circuit to try to improve the Narrabri Autoguider, to reconfigure the blind motor system and to install a "magnetic" Pockels cell. In the end, the latter was thwarted by an unexpected fault in the "velocity" Pockels cell driver. A few maintenance tasks were also achieved.