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Jim Wren has joined Andre Phillips and me at Siding Spring Observatory to install the first southern hemisphere ROTSE-III telescope.
The photo was taken shortly after Jim got the clam-shell working using the I/O box.
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The crane is in position to lift the telescope tomorrow morning. The CCD camera is in-transit, and will hopefully arrive early next week.
Progress today has included:
I took lots of photos like this one, to document the various bits and pieces of ROTSE-III hardware.
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After a satisfying day's work we were treated to some of Andre's excellent home-brewed beer.
Later in the evening Jim got his first view of the Magellanic Clouds.
At 8am we enlisted the help of the ANU and AAO staff to lift the ROTSE-III telescope box onto the back of an ancient truck.
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We then drove it to the ROTSE-III site, about 0.5km away, and Greg the crane driver lifted it out. That's Andre and Jim making fine adjustments.
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The telescope was lifted out of the box...
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and over onto the ground next to the enclosure, in preparation for installing the mirror. The mirror coating is looking rather the worse for wear, as you can see from the following images (which tend to exaggerate how bad it is).
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We drilled new holes in the baseplate that interfaces the mount to the pier, and then Greg the crane driver,
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and placed it in the enclosure
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where Andre and Jim settled it perfectly in place.
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We installed the corrector assembly, and I took a bunch of photos like these to document the process
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Other jobs completed today included:
After another round of Andre's beers, we retired for dinner, after which we were rewarded with the site of a kangaroo near the enclosure. Its rear-end is just visible in the right of this photo...
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Jim and I snuck around to get a better angle...
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but the roo was suspicious and bounded off.
Jim put in another couple of hours with the hardware, and was able to have the mount slewing under the control of the Windows NT box by 9:30pm. A persistent orange beetle was attracted by the lights in the ROTSE enclosure and drove Jim back to the safety of the APT control room, where we decided to call it a night.
All-in-all a very satisfying day, and we are all suitably exhausted.
We made a lot of useful progress today:
In the evening we noticed a nasty electrical burning smell. Investigation showed that it was coming from the RA motor, which was too hot to touch. Further investigation showed that the motor had been running at a duty cycle of 10%, due to the fact that the mount was not balanced. This was enough to overheat the motor, and it now has a fraction of its original torque.
So, we need a new motor. We also need some protection against this problem in the future, since it is clear that any out-of-balance condition, or cable snag, or wind loading, could cause the motor to be continually energised in one direction, leading to overheating. Andre and I had a similar problem with the APT, which we solved by (1) installing a much larger motor, and (2) by enabling I-squared-t heating protection in the PMAC servo-controller. A simple solution could be to place a resistor across the servo-amp output and monitor its temperature - if it exceeds a threshold delta-T above ambient, shut down the servo amplifier.
Jim spent most of the day working on installing new versions of RedHat Linux on the mount and camera computers. He had Vegemite on toast for lunch, and enjoyed it.
In the evening we were invited to a BBQ at Andre and Claire's house down near Coonabarabran. A very pleasant evening it was too.
Jim continued to work on the software.
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I worked on designing a new mounting bracket for a replacement RA motor. Yet another BBQ at Andre and Claire's house in the evening. Jim left ROTSE run all night, and the clam-shell closed on cue before sunrise.
24 hours and a 12-pack of Pepsi later, Jim was still hard at work.
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The ROTSE clam-shell opened up automatically at sunset. An historic moment.
Andre and I spent the day manufacturing the RA motor mount, using a variety of random materials we had in the APT building. We completed all the machining by 8pm, and an hour later we had an operational RA drive. You can see the PML pancake motor in the photo.
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We did a preliminary tune of the servo coefficients, and the motor seemed to work OK. Further tuning will have to wait until the CCD camera is installed, and the telescope is properly balanced.
The lights in the ROTSE enclosure attracted a swarm of insects which made working in there quite miserable. So we called it a night at 10pm.
The CCD camera is allegedly on the road, and is likely to be delivered tomorrow.
The following entries are by Andre (Michael has returned to Sydney).
The ROTSE camera was not delivered to SSO today, despite reassurances from DHL (in Melbourne) that it would be here as early as Monday morning. When it didn't arrive today Andre made a 'strongly worded' phone call to DHL, insisting they precisely locate the shipment. The DHL 'Lost Shipments' tracer was helpful, and telephoned back several hours later to announce that the camera was now located in the city of Dubbo, some 2.5 hours drive from SSO.
So this morning Jim and Andre drove to Dubbo and collected the camera.
We arrived back in the evening, during a thunderstorm periodically exploding directly overhead Coonabarabran township. Whilst Jim was making a cell-phone phone call, there was a flash and nearby thunderclap, and the cell phone went dead. It would appear that the town's cell-phone tower took a direct hit. Today was fairly warm and Jim and Andre slaked their thirst at Coonabarabran's Imperial Pub. While drinking a welcome beer, the town experienced a power outage, which lasted for the next hour or so. This outage also put the town's restaurants off-line, so we slipped by Andre's place for a sandwich.
Installing the camera onto the telescope was straight forward. There was uncertainty that the camera's power supplies could accept 240VAC mains power (an internal inspection of the supplies didn't solve the question), so they are currently being fed through a 240:115V step-down transformer. Unfortunately there appears to be something amiss with the supplies and/or camera. The symptoms include the CCD head's fan not working, and the lights on the 'gold box'... "not looking right" according to Jim. So for the time being Jim is disinclined to attempt a power-up of the camera.
The RA incremental encoder status LED was periodically flashing red, indicating it was out of spacing tolerance from the graticule strip. Some adjusting brought it back into line for most (but not all) of the RA swing.
The Mount covers were replaced and Jim went in search of an explanation behind the occasional weird wandering motion of the mount when it was commanded to move. Some of this behavior may be related to the replacement of the RA motor, and non-optimal servo constants entered into the mount computer GUI.
The weather remains overcast and the occasional lightning strike is flickering on the horizon. There is the smell of burning gum trees in the air, generated by bush several small fires started by today's numerous lightning strikes. There is one fire located on a hillside about 5km from SSO, which is casting an ominous red glow into the night sky. This fire has the potential to turn into something more sinister if tomorrow's weather should happen to be warm and windy. We'll know soon enough.
Today Andre removed the ROTSE camera and associated power supplies, controller box and cables, in preparation for shipping them to UNSW tomorrow for debugging in the astrophysics lab. The packing operation was expedited by recycling the neat-o [Bob Leach/LANL Packing?] made-to-measure padded boxes for the various camera components.
In view of the regular afternoon thunder-storming of the last few days, and because the UPS hasn't yet been installed in the ROTSE enclosure, Andre decided it was wise to leave everything powered down until his return from Sydney, on Boxing Day (or thereabouts).
Over the Christmas period Michael will work in the Camera, and upon his return, Andre will familiarise himself with the mount and its idiosyncrasies.
Andre drove down to Sydney today (a 7 hour trip) and delivered the CCD camera to Michael, who unpacked it in the Department of Astrophysics Lab.
Michael made some preliminary investigations of the CCD camera electronics. The power supplies are switch-mode, and do appear capable of running in 240VAC. One of the power supplies has a thermal cutout switch which is disconnected. Further investigations were hampered by a lack of documentation, and passwords to login to the camera control computer.
Andre installed the new APC Uninterruptible Power Supply today. This should help overcome the frequent power outages that plague the mountain. The UPS has enough grunt to run the entire system, and close the clam shell if necessary.
Andre also manufactured a blanking plate to attach instead of the CCD camera,to protect the optical assembly. He also loosened off the RA and Dec axes, in preparation for balancing the telescope tomorrow.
Andre did a very careful job of balancing the telescope today, and has left the Mount and Control computers and the clamshell I/O box powered up.
The maximum motor output has been set to 3.5 V in order to protect the motors. We will require a modification to the software to allow us to use larger voltages during slew operations.
Michael has set up the CCD camera in the lab, and it is ready to test. However, he isn't going to power it up until he has some documentation.
Andre conducted tests on the RA axis encoder (a Renishaw RGH22) to determine why it periodically failed. Measurements with a dial gauge indicated that the runout on the RA drive disk was sufficiently large (0.1mm) to be marginal for the encoder. Damaged or maladjusted bearings were suspected and a query note was sent to Alan Schier.
Suspecting that vibration of the telescope pier might also be contributing to the RA encoder mis-readings, Andre placed shims underneath the Rotse enclosure, directly beneath the telescope pier. The Rotse Downunder enclosure is supported by five concrete pillars; one at each corner and one directly underneath the pier. The support underneath the pier hadn't been correctly shimmed. This was corrected, although it appeared to have no effect on the RA encoder performance.
Michael has received some helpful documentation from Bob Leach, and is proceeding to diagnose the CCD camera. The symptom that we have at present is that the computer crashes whenever the device driver is asked to do a "mmap" (memory map). Michael has found a number of bugs in the device driver, but they probably aren't causing this problem.
Alan Schier replied with a very helpful discussion about adjusting the RA axis bearings. Andre performed the adjustment (it was a long way out), and the run-out is now +/- 0.02mm and is quite repeatable. The encoder is still flashing red, but it is now doing in a repeatable fashion, which gives hope that a small adjustment of its position will fix it.
Michael crashed the CCD Control Computer another 20 times today in
his attempts to diagnose the CCD problem. Putting the PCI card into
another computer delayed the onset of the crash to the second time that the
device was opened. This is beginning to look like a hardware problem.
Last updated 07-Jan-2003.
ROTSEIIIa commissioning Michael Ashley and Andre Phillips mcba@newt.phys.unsw.edu.au