We have a lot of fun when the kids come to visit. We regularly offer tours of Keck to local school groups. When they come we lay in a schedule of activities… Solar telescopes, an IR camera demonstration, tours of our remote operations, the activities can vary depending on the grade level.
After the last tour we got a packet of thank you letters from one of the classes. These are just fun to read, it is great to see what the kids remember from their visit. A drawing of telescopes set up in the lawn caught my eye, I was responsible for running the solar telescope activity!
A thank you letter from a student after a tour of Keck Observatory
The New York Public Library has just published 187 thousand digital images online. The collection is staggering in its volume, a collection of images that ranges across the spectrum of American and even world history. One could publish an interesting blog simply mining this huge collection for the historical tidbits it contains. World events to restaurant menus, there is just so much there.
An eruption taking place in the Mokuʻāweoweo caldera of Mauna Loa. Credit: NYPL Image CollectionI did a few quick searches for interesting Hawaiian images. Most of the images showing the islands are either postcards or stereoscopic pairs. There are views of typical tourist scenes such as Diamond Head and surfing at Waikiki. There are quite a few images of the plantation era, sugar mills and such, as well as quite a few simple “pastoral” images with little context or interest.
In addition to the images there is a great deal of other material. Old engravings and illustrations, maps, even menus from restaurants dating back a century. I will have to refer to this collection when looking for illustrations in the future, there is a treasure trove of material here.
Most of the interesting images I found were stereoscopic pairs. Stereoscopic pairs were incredibly popular in the late 19th and early 20th centuries. While many might be familiar with the View-Master style stereo viewers of the 1950’s and 1970’s, the original version of this used a side-by-side print in place of a transparency.
I am no stranger to point-to-pointwiring. I routinely use the technique to build small circuit boards. Well done point-to-point is a permanent and reliable way to build a complex electronic device.
Welded point-to-point wiring on a complex circuit board
But then there is this circuit board assembly I came across… At first glance it looks like a wire wrap board. But there are no posts, the wires are flush to the board. Neither is it traditional point-to-point wiring, the wires are not terminated to solder pads beside the pins being connected. I had never seen a construction technique like this.
The board is an old PCB assembly found in a storage cabinet while clearing out the old junk that has accumulated about the observatory. No idea where it came from or what it was used for, the only clue is some writing on the box… “Keck level shifter”, Perhaps a piece of a detector controller? Someone clearly put a lot of work into the board at one time, now it sits in my office as unknown junk. It is the odd construction technique that caught my eye and led me to hang on to the board, at least temporarily. What is this?
A closer look under a microscope shows a connection clearly made by some sort of spot welder. There is a neat little hole through the insulation at each connection. Stripping back the insulation reveals a very neatly welded wire. Each wire is welded to the flat bottom of each pin socket. Every component pin is socketed, this includes all passives, which are mounted to headers and plugged in alongside the IC’s.
There are a number of advantages to this wiring method… The connections should be very reliable and robust, the weld is a nearly ideal electrical connection. As no connection pads are needed beside each socket the density is much higher using less circuit board real estate per component, you can cram more on the board. Interestingly the connection technique can be used without terminating the wire, daisy chaining to the next connection point.
There are disadvantages as well… The method clearly requires some sort of welding equipment with perhaps an automatic wire feeder and cutter, a built-in microscope for positioning the weld, and more. Clearly an expensive piece of kit. No components can be present during welding as they may suffer damage from the high electrical currents needed for spot welding, thus everything must be socketed. All those little sockets are expensive! Rework or repair would need to be done with more traditional soldering techniques.
I would love to see the machine that did this board assembly. Maybe even a chance to use it. More information on the process seems difficult to find on the web without a trade name or other keyword that would clearly identify the process.
Not that these welded wires would be of much use today. The technique is clearly ideal for complex digital circuits of the style and speed that was common through the 1980’s to around 2000 or so. After that the prevalence of surface mount technology and the abandonment of the DIP package would doom the method. Modern high speed circuits benefit greatly from the more controlled traces of a printed circuit board and would not fare well on a welded wire board. In these days of easy computer layout and cheap printed circuit boards welding would not be my fabrication method of choice.
Welded point-to-point wiring on a complex circuit board
Detail of a connection in welded point-to-point wiring on a complex circuit board
Detail of a weld in welded point-to-point wiring on a complex circuit board
Component side of a welded point-to-point circuit asembly
My slide digitizing project is now producing data by the gigabyte. As expected I am filling up the drives on my desktop computer. Not that there was a lot of space available in the first place, less than 50Gb was clear on the primary data drive. Time to buy a new hard drive! At least when I built the computer I bought a gaming cabinet with plenty of drive bays.
The hard drives of my desktop computer, Darker View is in there somewhere.I face the agonizing decision… When dealing with critical data, what brand and model of hard drive do I buy? I make multiple copies, but still, a failure can cost me days of work between backups. What hard drive do I buy for my photos?
The reviews on Amazon and other retailers are nearly useless on hard drives. There will always be failures of devices like this, and angry buyers are very likely to leave negative reviews. Thus the data looks very skewed and it is hard to evaluate the reliability in any sort on meaningful way. Much less compare one drive to another.
There is real data! The cloud storage provider BackBlaze runs thousands upon thousands of hard drives. Obviously hard drive failure rates are of paramount importance to them and they closely track each type of drive they buy. Fortunately for the rest of us they publish this data and allow us to see what does, and does not work.
There are several obvious lessons in the data… Stay away from the 3Tb drive from Seagate and to a lesser extent the 3Tb drives from Western Digital. Several 4Tb models appear to be far more reliable. The failure rates on the worst drives can be upwards of 20% to 30% per year, while the better drives well under 5%. Those rates may seem high, you need to consider the hard use these drives get in a data center.
Based on this I have a new HGST 4Tb drive installed in my computer. All looks good so far, a trouble free installation and my photo collection copied over without issue. Now to see how long the drive lasts when I put some hours on it.
The Moon and Jupiter will rise together this evening of January 26th. The Moon will rise first, around 20:40HST, followed by Jupiter half an hour later at 21:25HST. Over the course of the night the Moon will slowly approach Jupiter, closing to about 4° by dawn.
The following evening, January 27th, the order will be reversed, with Jupiter rising first at 21:21HST and the Moon rising twenty minutes later at 21:40HST, with about the same separation of 4°.
With a few public outreach events this last week I had a few opportunities to hold my phone up to the eyepiece and shoot a few shots of a waxing Moon. The iPhone 5S does have a notably better camera than my old 3S. The afocal method does provide some nice snapshots of the Moon.
As usual I demonstrated the technique to our viewers, showing them how to use their phone to shoot the Moon. The result? Big smiles and happy folks, thrilled to have some great Moon photos of their own.
The Moon approaching full, afocal photograph with an iPhone 5S and a small refractor
All five planets that are visible to the unaided eye can be found in the dawn for the next few weeks. Jupiter, Saturn, Venus and Mars have been visible in the dawn for some time now. Arriving late to the party is Mercury, just rising out of the glow of dawn. Mercury is headed for maximum elongation on February 7th, rising to 24° ahead of the rising Sun. The line of planets will persist for a week or two after that as Mercury drops back into the glow of dawn after elongation.
False dawn, actually zodiacal light, rising over Mauna KeaHighest in the sky is Jupiter, shining at -2.3 magnitude and rising before 10pm. Mars rises next, around 1am, seen as a ruddy red object, much dimmer at +1 magnitude. Saturn will rise around 3:30am in Scorpio near Antares, shining at +0.5 magnitude. Venus rises around 4:45am and will be quite obvious, the brightest of the five at -4 magnitude. Last will be Mercury, currently rising just before 6am and shining at +1.2 magnitude. It will rise earlier and earlier as it approaches maximum elongation, rising at 5:20am on February 7th. As Mercury reaches it highest it will be only 4° from Venus.
Together the five planets neatly outline the ecliptic, the plane of our solar system revealed by simply connecting the dots across the sky. As dawn approaches, but before the start of twilight around 6am, look for the zodiacal light, the bright glow of interplanetary dust also seen along the ecliptic.
Caltech researchers have found evidence of a giant planet tracing a bizarre, highly elongated orbit in the outer solar system. The object, which the researchers have nicknamed Planet Nine, has a mass about 10 times that of Earth and orbits about 20 times farther from the sun on average than does Neptune (which orbits the sun at an average distance of 2.8 billion miles). In fact, it would take this new planet between 10,000 and 20,000 years to make just one full orbit around the sun.
This artistic rendering shows the distant view from Planet Nine back towards the sun. The planet is thought to be gaseous, similar to Uranus and Neptune. Hypothetical lightning lights up the night side. Credit: Caltech/R. Hurt (IPAC)The researchers, Konstantin Batygin and Mike Brown, discovered the planet’s existence through mathematical modeling and computer simulations but have not yet observed the object directly.
“This would be a real ninth planet,” says Brown, the Richard and Barbara Rosenberg Professor of Planetary Astronomy. “There have only been two true planets discovered since ancient times, and this would be a third. It’s a pretty substantial chunk of our solar system that’s still out there to be found, which is pretty exciting.”
Brown notes that the putative ninth planet—at 5,000 times the mass of Pluto—is sufficiently large that there should be no debate about whether it is a true planet. Unlike the class of smaller objects now known as dwarf planets, Planet Nine gravitationally dominates its neighborhood of the solar system. In fact, it dominates a region larger than any of the other known planets—a fact that Brown says makes it “the most planet-y of the planets in the whole solar system.”
Batygin and Brown describe their work in the current issue of the Astronomical Journal and show how Planet Nine helps explain a number of mysterious features of the field of icy objects and debris beyond Neptune known as the Kuiper Belt.
“Although we were initially quite skeptical that this planet could exist, as we continued to investigate its orbit and what it would mean for the outer solar system, we become increasingly convinced that it is out there,” says Batygin, an assistant professor of planetary science. “For the first time in over 150 years, there is solid evidence that the solar system’s planetary census is incomplete.”
