When you want to see the stars, find someplace dark
Working atop The Mountain
Just checking to see if I got the wiring right. Some modifications to the telescope HBS, Hydraulic Bearing System, to allow for a slower startup. Some new hydraulic valves installed by Mark, a few new relays added by me, and the job is done. Hopefully less sputter and spitting on startup to keep the oil off the drive tracks. The system is a classic relay logic controlled setup, seriously old-school.
It is always a good day when I drive up the mountain to a broken telescope, then drive down leaving a working telescope. Easy to say, not always easy to accomplish, the simple statement obscuring a day of struggle to solve the problem and fix it.
The Keck 2 telescope drive is a complex beast of dozens of relays, miles of cabling, servo amplifiers and power supplies, plus several circuit boards designed and built in the 1980’s holding a bewildering array of arcane logic.
How many engineers does it take to change a light bulb?
This is one of those times. A nightlog coded as critical, the Keck 2 adaptive optics system has a slight problem, no output from the white light source, no calibrations, no science. Waiting until after 9am I call the support crew on the summit… Do you know how? No. I wrestle with the thought for a few moments. No avoiding it, I need to drive to the summit.
So how many engineers does it take to change a light bulb?
The Keck Adaptive Optics systems are workhorse scientific instruments. Equipment that has resulted in so many great astronomical discoveries. The AO systems have also seen a great deal of improvements and upgrades through the years. New computers, a new wave-front controller, guide star lasers added, new cameras, different science instruments, and much more.
Eventually I just get fed up with it and insist we spend some time getting rid of it. With no AO use scheduled for a while there is a chance to spend a couple days ripping out this pile of cruft. Identifying and removing unused boxes. Following cables to nowhere, wire cutters in hand to snip away the multitude of nylon zip-ties.
We remove three large armloads of cables and other gear, carring the pile down to the electronics lab for sorting through and disposal. Most of it is horribly obsolete, things like KVM’s for PS/2 style mice and keyboards, or cables for old Sun computers. Most of it will simply be thrown out. It feels so good to get it out of AO and to clean up the place a little.
I called this pile of junk cruft, a word that drew funny looks from my co-workers. You don’t know what cruft is? What sort of nerds are you? Sorry, cruft is what I have always called leftover technical junk.
Cruft is jargon for anything that is left over, redundant and getting in the way. It is used particularly for superseded and unused technical and electronic hardware and useless, superfluous or dysfunctional elements in computer software. – Wikipedia
It turns out that the word has a long history in engineering and computer science with a heritage that includes MIT and Harvard. It is indeed the proper word for the detritus that had been accumulating in the AO vault.
I have previously covered the importance of warping, tuning the Keck primary mirror segments for optimum optical performance. Warping has been my responsibility for some years now. Reading out the settings of the thirty strain gauges on the back of each segment is performed by a test fixture, a computer and a sensitive data acquisition system. Over the last year I have designed, built, and programmed a new test fixture.
As this is the third generation warping test fixture the name of the software is obvious… Warp3
I have been trying to get some good photos of both Keck lasers on the galactic center for some years. Other photographers have produced spectacular photos that have me seething with envy. Why can I not get equivalent photos? It is not like I have a lack of access. The answer is mostly bad luck and circumstance. I do work, this limits the nights I can make the attempt. On those times I have ascended the mountain to photograph I have been plagued by bad weather.
This year looked to be much the same. The night was set, I had volunteered to host several local photographers, we had film permits on-hand, an observatory vehicle reserved, all the arrangements made. The only issue? The Mauna Kea Weather Center forecast promised high clouds and fog for the night. I was bracing for yet another disappointment.
Getting rain or snow on the primary mirrors is bad.
The problem… You can have both rain and snow occur with low humidity. Moist air above the telescope can produce rain or snow which falls into drier air at the summit level. This can catch the operators by surprise, a situation we have observed on a number of occasions.
To help detect this you can deploy a precipitation sensor, something some of the neighboring telescopes have done. The engineers over at CFHT were kind enough to show me the units they had installed during their remote operation project.
Not that the project was finished there… The new sensor does not come with any sort of network interface. Rather surprising given that just about everything else Vaisala sells has either a serial interface or an ethernet interface. This sensor has just a couple simple outputs… A logic level indication of precipitation, an analog output representing roughly how much, and a frequency output representing the same thing. I needed to interface this unit to the network. As I have installed a terminal server in the rack below the weather mast, at the minimum I needed a serial port.
While I was at it there are a couple other little devices I want to install on the weather mast. These need a network interface as well. May as well put together another little PIC controller and assemble it all together in one neat little package. a few evenings of coding and I had my solution, an interface that allowed remote computer control and status read-back. How many microcontrollers do I have performing little tasks at the summit now? Quite a few.