Month: August 2019

Yesterday was … challenging. We emptied the entire observatory, including removal of the telescope from the Dec arm to make way for the sanding and washing of the terrazzo floor. The original contractor failed to apply the correct seal, using wax instead of polyurethane or epoxy. Over the past three weeks, the wax has collected dirt to the point of being impossible to remove.

While this was happening, I set up shop on a table outside and rebuilt a 5″ reflector, removing and cleaning, then collimating both mirrors.

When I learned that the contractor who was to have applied the sealant today had not read the back of the can nor measured the floor before providing his quote, hoping to use just 5 liters instead of the minimum 15 for the 70 square meters, Thomas and I raced to town, arriving just 8 minutes before the shop closed in order to purchase an additional 3 containers.

Today I will apply the “sandstone sealer” with hope that this successfully completes the floor and we can move in permanently first thing Sunday morning.

Today was a slow day focused on just two objectives: getting the RA gearbox to chatter less, and learning to use the CCD camera software.

We have known that the RA gearbox “chatters” quite a bit, the sound of the meshing of the teeth of the stepper motor axle gear to one of the two former planetary gear boxes (the planetary function reduced to a simple rotation). When I loosened the mounting bolts and manually hold the drive gear, it was perfectly quiet.

What’s more, the RA axle gear has two sets of teeth, a larger, outer set and an inner, smaller set–the design of that particular axle fitting as provided by Alan of AWR Technlogy, England.

While Dan and I had believed the inner, smaller gear of this one-piece configuration was not touching the outer of the two planetary gears, a close inspection demonstrated otherwise. So, we set to filing the inner teeth down to a smooth surface to make certain there was no undesired, secondary contact (it sounds more complicated than it really is).

Elineema, Eliatosha, and I borrowed a file from the kitchen staff (who use it to sharpen knives) and in roughly 30 minutes had the inner axle smooth. Upon reassembly, the chatter was notably reduced, but remained. Further testing found the position of the stepper axle 0.5mm too high such that the teeth of the axle gear do not fully set into the brass teeth of the first RA gear. I am going to consult Dan on whether it is ok to leave this as-is, or find a way to reduce the gap.

At the same time, Zacharia worked on the control software for the Orion CCD camera. It is a finicky, clearly incomplete piece of software that works irregularly, at best. We attempted to set the white balance and contrast, as instructed, but for the most part, are unclear if it is working.

Tomorrow a contractor comes to clean, wet sand, and apply a coat of epoxy to the floor. Finally, we will have the floor we intended with a beautiful shine that is easy to clean. Shoes off policy from here on out!

While I was in town, all five astronomy ambassadors Eliona, Elineema, Eliatosha, Zacharia, and Pendaeli dove into a book of Messier deep sky objects, making a list of those we should be able to see from our location at 3.25 degrees south of the equator. They then prepared a whiteboard sketch of the Earth to determine the most likely maximum view of the night sky, in order to give bounds to their continued Messier object search.

We also installed a DC power switch and cabling to the 12V car battery that operates our telescope. It looks quite nice and very professional.

And to top it all off, we enjoyed the presence of Thomas Mbise, chairman of the board of the Office for Science, Education, and Observation (OSEO) that manages the Mt. Meru Astronomical Observatory and a delegation of six individuals from Seattle, Washington who represent the Ailanga School Project that has supported the Ailanga Secondary School for more than 15 years. It was a true joy for us to share the fruition of our hard work with everyone this evening.

Today was the day, for me, that felt like our Observatory is truly operational. Congratulation to everyone who has contributed this past three and a half weeks!

Today we discovered the reason why we have play (“slop”) in the RA axis. The friction clutch has four through-holes that pass four bolts from the outer most plate through the large RA gear and to a fixed back plane attached to the RA armature. Springs provide the tension. The through-holes are a bit too large. So when RA motion is engaged, <1mm on the plate translates to ~5mm travel at the telescope before a solid connection is made. While this does not affect the guided function of the RA motor, it makes for frustrating manual centering. We went to Usa River to try and find a thin sleeve or bushing, but came back empty handed. We will take the outer clutch plate to the Arusha Technical University and use their mill to prepare a more sophisticate interface between the plates to eliminate the RA axis play.

Yesterday saw the attachment of new red carpet to the top of the two mobile work benches (built from the shipping crates) and the “carpeting” of the computer workstation too. The observatory is really coming together –looking so smart! with intent to seal the floor this weekend with an epoxy finish.
 
 
 

Movie nights at the Mt. Meru Astronomical Observatory!

We are watching the COSMOS series with Neil deGrasse Tyson. For the first episode we enjoyed the company of four Ambassadors to the observatory and a dozen students, all but one girls. Last night, we had standing room only with more than sixty students in the Observatory. It was awesome!

The first episode tells the story of Bruno, a priest who conceived of a universe far larger than that accepted in his time. He shared his vision for the Sun at the center of our solar system, and many other suns with worlds like our own. In this vision, he celebrated the Creator as that of a much larger, much more dynamic universe than simple celestial spheres. For his refusal to recant, he was burnt alive by the Inquisition.

This opened a powerful, engaging conversation for why those in power are often afraid to lose their position, from government leaders to local politicians to teachers too.

The second half places the history of the universe on a one year calendar, from Big Bang to the evolution of the human species in the final one minute. This invoked a series of questions about the birth of stars and formation of solar systems and planets.

The second episode was entirely about evolution, starting with the domestication of wolves to become every breed of dog today, and then a whirlwind tour of the “tree of life”, mass extinctions, and our own shared ancestry with chimpanzees. While the students do learn about evolution in this local school, it is primarily taught as a function of history, not a function in motion now.

I gave examples of evolution as we see it in hospitals across the world with “super bugs” and growing resistance to antibiotics. We discussed our own species as one of the most homogeneous on the planet, all of us nearly identical despite the incredible diversity of our visual appearance as s function of gene expression, not divergence of the DNA itself.

Zacharia, an Ailanga teacher and Astronomy Ambassador and I fielded the questions proposed by the students, for a conversation that could have easily continued to the midnight hour.

My favorite part of that evening was when Carl Sagan’s original 40 second animation of the evolution of species, from single cell organisms to homo sapiens caused everyone in the room to gasp. The resulting questions ranged from “Is there any species that is not evolving now?” to “Are viruses living or dead?”

This is exactly why we pursue astronomy as an entry to science education—it invokes questions about physics, biology, chemistry, and the evolution of life itself.

With my family Lindah and her son Liam, Bernard and Truphena again in their home in Nairobi Kenya, I returned my focus to the setting the telescope in its final position. I was joined by Telescopes to Tanzania Ambassadors Eliatosha, Elineema, Eliona, Pendaeli, and Zacharia, and Ailanga students David and [need to recall names] for this effort.

While we had three times before attempted to find polar north using “high noon” and the shortest shadow of the sun as defined by the Heavens Above website, we feel it is important to obtain this vector by our own accord. However, after three weeks we have not been granted a full hour of sun thirty minutes before and thirty minutes after the calculated high noon of 12:38-12:40 pm.

Once again we set our home built sundial (broom stick mounted on a sheet of plywood, bailing twine in tension holding the vertical position) and made certain it held 90 degrees all around.

We waited with pen and tape measure in hand … and waited … and were able to obtain six readings from 12:21 to 12:56 pm, but were missing those needed at the crucial 5 minutes to either side of 12:38 pm.

Between measurements, we conducted a series of linear approximations, starting both before (under) and after (above) the desired 12:38 pm, resulting in 0.9-1.1 mm change in the length of the shadow per minute. We fully understand that this is not a linear function, rather that of a parabolic arc, but for this brief period we were able to determine if 12:38 was likely to have produced the shortest shadow.

As we found the rate of change of the shadow to be similar both before and after the estimated high noon, we decided to fix the base of the telescope on a line parallel to that of 12:38, as captured the day prior.

We then spent nearly two hours leveling the telescope, using metal bars and washers as shims. The result is the top of the steel pedestal to be level within 0.1 degrees on all four sides, and exactly 90 degrees on the south face (the other faces are those of a trapezoid as the pedestal is wider at its base than the top).

If I could recall the names of my geometry and trigonometry teachers, I would reach out to each of them with deep gratitude, for nearly every theorem I memorized has come into play this past two weeks. But it is the Ailanga students who have come to the rescue with fresh recollection of the proper calculations for missing angles using sin and cos functions.

We carefully reassembled the telescope (for the fourth time). At the point of attaching the head we realized we had no easy way to make certain the head was parallel to the newly oriented base. We estimated, at first, but once the weights were attached, realized we could use the distance from the edge of the weights to south face of the pier as the Dec arm to provide a nearly perfect parallel identity.

However, last night we noted a drift in what appears to be both the Dec and RA. Before we shut down the observatory, we measured the equatorial axis alignment, and it had sunk from 3.3 to 3.0 degrees, the effect of the metal settling under the burden of the mass of the full assembly. Today we will easily correct this angle and tonight determine if our drift is reduced.

We now have two spotting scopes, one a battery powered “bull’s eye” without magnification, and the other an Orion magnified spotting scope with cross hairs. Both are now aligned with the primary tube, only a minor adjustment to be performed tonight for spot-on accuracy.

Not much to report this past two days, as I was mostly away from the observatory spending time with my visiting daughter and son from Kenya.

We got the TV and whiteboard hung and disassembled the telescope again to perform what we hope to be the final high-noon drop shadow test to determine polar north and south. With this, we will align the base of the telescope, set the bolts once and for all, and then make fine adjustments with the head.

But alas, no sun at noon for several days. Maybe our luck will change on Sunday …

Yesterday saw a multitude of tasks. I worked with students to mark the spots on the wall West wall where the new TV and white board will be mounted. Another group working with Ambassador Eliatosha disassembled an AWB Galileo reflector telescope, cleaned the primary and secondary mirrors, and reassembled it fully while another, in parallel, cleaned and rebuilt a Celestron refractor.

It is imperative to take note that none of these students have ever done anything like this before, most having never used a hex wrench or screwdriver. Without instruction, without any guidance on my behalf (other than how to clean mirrors with distilled water, and lenses with a special cloth), they were 100% successful. The capability of this next generation of Tanzanian’s is extraordinary. To not grant them to use their minds to the fullest is to waste a generation.

Ezikiel, Eliona, and I continued our work on aligning the base (as we have known it was not correctly installed). We spent most of the day transposing and comparing two triangles that share a common hypotenuse, built from the shadow of the sun at zenith (“high noon”). This method for finding polar north can be done by building a sundial or using this website (https://heavens-above.com/) to mark the shortest shadow and then lay down a parallel line. The equatorial axis must be parallel to this line, if it is to be parallel to the Earth’s axis.

We yet have quite a bit of work to do before this observatory is considered operational and the Ambassadors can be fully trained.