Fabrication
Author: Andrew
An electrical engineer, amateur astronomer, and diver, living and working on the island of Hawaiʻi.
Scientists Discover Brightest Early Galaxy and Likely First Generation Stars
W. M Keck Observatory press release…
Astronomers using several of the largest telescopes on Earth and space have discovered the brightest galaxy yet found in the early Universe and have strong evidence that examples of the first generation of stars lurk within it. The results have been accepted for publication in The Astrophysical Journal.
A team — led by David Sobral from the Institute of Astrophysics and Space Sciences, the Faculty of Sciences of the University of Lisbon in Portugal, and Leiden Observatory in the Netherlands — peered back into the ancient Universe, to the reionization period approximately 800 million years after the Big Bang. Instead of conducting a narrow and deep study of a small area of the sky, the team broadened their scope to produce the widest survey of very distant galaxies ever attempted.
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Dome Control PLC Replacement
The time came.
It moved.
700 tons of steel and aluminum smoothly rotated until I hit the stop button.
Nothing crashed or seriously broken.
It even moved the right direction.
The risk of breaking something was a real possibility. A mistake here could leave the dome damaged for days or weeks and the telescope useless. I reviewed my plan one more time before starting. A fully written plan with a step by step testing method carefully thought out and reviewed by the other engineers in the department. The plan also had a whole section of “what can go wrong” risk analysis, with risk mitigation steps. What if the brakes release but the motors do not come on? What if the old controller fails when removed from the system?
After a fitful night’s sleep and a long ride to the summit the moment came when I brought the new controller online. Swapping out the connections with the old controller and applying power, the correct indicator lights came on. Even better, as I tested each of the controls in turn the dome and shutters operated perfectly. It worked from the control panel, from the radio controller, under computer mode from the control room. I even tracked the telescope and dome together for an hour without trouble. The tracking was excellent, within 0.1° the whole time.
New Moon
Keck Domes
Serious Apprehension
Today is the day I will close my eyes, cross my fingers, and press a button.
Further tests will open and close the shutters. If anything this part is even more worrisome. The controller is responsible for releasing the brakes on the shutters. If the brakes were to open without motor power the shutters will be able to simply run downwards.
Fortunately they will not fall, but they can run downwards to the hard stops rather quickly. There will be a tech stationed at the shutters with a finger poised over the e-stop button during these first tests. The button blows the dome main breaker, which removes power from the brakes, causing them to close.
A brain replacement is fraught with opportunities for error. Currently the old and new PLC’s sit next to each other in the cabinet, installed last week. Monday morning I will remove the old one and slave the I/O cards to the new controller.
Then the testing begins.
Ancient and Modern
On Time Again
So last month the observatory clocks decided is was 1995. A software bug interfered with proper decoding of the GPS time signal. For a few weeks we got by by kludging two of the old clocks together in a creative way to provide good time for the telescopes.
The new clocks are now fully online and operational. I ran one of the new time servers for a couple weeks while keeping the old time servers in place as a backup. These have now been removed, with a second new unit installed as an in-place spare.
Hopefully this will keep everything on-time for the foreseeable future. Two new precision clocks, Microsemi SyncServer S350’s, time accurate to microseconds.
Meantime there may be a fix for the old equipment, a new GPS module by Heol Design. We have one on order to try. It would be a shame to throw out these very nice clocks.
WHAC Visits Subaru
Over the past few years the West Hawaii Astronomy Club has visited nearly every telescope on Mauna Kea. One glaring exception to this is Subaru, the 8.2 meter telescope belonging to NAOJ.
Subaru is the only telescope with an active tour program. By making reservations ahead of time you can visit the interior of the facility with a guide. This made making the arrangements for a tour quite simple, even when the observatories are worried about events on the mountain. We did quite well for tour guides, Rieko Murai and Josh Walawender made the tour a bit better than the usual tour. Josh is well known to the local amateur community, bringing his own small telescopes to observe at the VIS.
The limit for any group visiting the telescope is eight due to practical considerations such as safety. Thus I had set up two tours, using both the 10:30 and 11:30 slots. This allowed most of the club an opportunity to visit the telescope. This did mean we were unable to enjoy the experience together. While we waited for our later tour I led a short walk to some interesting geologic features and one of the ancient ahu that are near the road.
Venus and Jupiter
Over the next two months the two brightest visual planets will dance in the sunset. Jupiter and Venus make for a brilliant pairing. With Venus shining at -4.3 and Jupiter somewhat dimmer at magnitude -1.9, the two are already quite obvious in the evening sky. Jupiter will swing just north of Venus approaching to within 0.3° on June 30th. The pair will separate slowly after that and disappear into the sunset glow together.
Around June 30th the two will be easily close enough to bee seen together in the low power view of amateur telescopes. It makes a fascinating sight to see the two planets together in the eyepiece.
As an added bonus the planet Mercury will join the pair around August 3rd, the trio forming a nice triangle of bright planets low in the sunset.