Germination of Dandya thadhowardii (?), a Mexican species of Themidaceae

Late last year I encountered seeds of a genuinely esoteric species of bulb from Mexico on offer on the web. It is actually a corm (a thickened underground stem that resembles a bulb). Since it is a Summer growing species related to Bessera, I decided to delay planting the seeds until I also planted my Bessera elegans corms for their growth season.

I believe it may be Dandya thadhowardii, though the species identification may have to wait a few years until the plants reach flowering size.

The seeds were planted on May 11th, and were all ready sprouting in the last week of May, though more seedlings have appeared in the past days. This photo is from June 3rd. I have been unable to locate any published photos of seedlings of this genus, so this photo may be the entire internet's worth of photos of germinating seedlings of this genus.

What strikes me about these is their very ordinariness. The California genera in the Themidaceae include Brodiaea, Dichelostemma, Triteleia, Dipterostemon, Androstephium, Bloomeria, and Muilla. These seedlings on basic appearance could be in any of those genera - a very familiar sight to us (we like the native bulbs and tend to start them from seeds). More famous kin from Mexico include Behria, Bessera, and Milla.

Some of these species are flowering in the mountains and coastal areas of California now and in weeks to come, as they often flower after the grasses dry. My son and I often go seed and lizard hunting together - he is very good at spotting many of our local species as seed heads, in some cases better than finding them as flowers!

One of these genera is Muilla. Muilla maritima is abundant in local populations in the San Gabriel and Verdugo Mountains (as well as much of California, for that matter). The flowers are easy to miss as they are lovely but pale and small, the seed pods are larger than the flowers and full of shiny black seeds - this species is easier to spot in seed than in flower!

Another one of my favorite local Themidaceae has recently been moved to a genus all its own:  Dipterostemon. Below is Dipterostemon capitatus, one of the cheerful and often abundant flowers of late Winter and Spring. When I was a kid growing up near Jet Propulsion Labs, the ones of these I grew at home often started to flower before Christmas.

 

Learning the plants that make up the thin green layer on our world can be a wonderful way to see the world in finer detail. Sports are often more fun when you know the players - landscapes have different sorts of players, knowing them can make a simple walk in the hills richer and a lot more fun as well. 

Maybe I'll make botanical Trading Cards....

 

Restoring an original Celestron NexStar 5

Late in 2019 my son and I bought a damaged original NexStar Celestron 5 from someone who had one that had fallen over. This was the very first of the NexStar telescopes, Celestron's first attempt to field a GoTo telescope that knew how to orient and align itself, and then how to find objects in the sky, all by itself.

Not all that many were made before it was replaced by an improved version, the NexStar Plus, a line of telescopes that are made to this day.

This being a relatively rare machine that was rapidly replaced by Celestron with newer and better telescopes, they no longer any sort of support for the model. We were on our own to get the machine up and running.

My son recently turned seven, so this seemed like a good opportunity to show how to figure out what was wrong and to repair it. While there are integrated circuits on the main board, they are modest and there are plenty of discrete components making probing and debugging relatively tractable.

In fact, the wiring can be traced just by holding the main circuit board up to a bright light.

What were the symptoms? The telescope would power up, and immediately start slewing in Azimuth. Altitude was fine, but with or without the hand controller attached the telscope just started moving at maximum speed clockwise (when viewed from above). The hand controller was erratic as well and the case showed signs of being crushed. The screen was intact, but flickered and was unreadable. The tripod had a broken support strut, and the focuser on the tube assembly had a great deal of play - to the point of wondering if it was doing anything at all.

Four related but separate problems.

The tripod we dealt with temporarily with a cable tie. The problem was the spider that holds the legs in  equilateral triangle had one broken coupling where they all meet in the center. Not elegant, we will machine or 3D print something better eventually.

The focuser likewise was a fairly simple fix: the screws were loose.

The main board was the hard part.

The main board had a single failed chip. It was the motor driver chip for the Azimuth motor. Finding it was accidentally easy - I happened to tap it while explaining to my son what some of the chips did (we looked the part numbers up online, I don't have this in my head...). When I tapped it, it burned my finger. This is an unsubtle clue to a problem.

That lead to grabbing the thermal camera and collecting more information. Fortunately, it was the only thermal anomaly on the board: apparently one of the motor driver H bridges had failed to being constitively on.

Using a SEEK thermal camera, this is what the board looks like after being turned on for about ten seconds:

The good news: only one conspicuously hot chip. The better news? It is a chip that we could still purchase. The chip is a Texas Instruments / L293DNE that we were able to buy from Digikey (not an endorsement, just the place we found them in stock). The Celestron NexStar main board has two of these in 16-pin DIP packages. One controls the azimuth motor (turns the telescope to different points of the compas) and one controls the altitude motor (raises and lowers the tube). Our failed chip was the azimuth drive.

The first task was to desolder the chip. Since the chip was dead, the legs could be snipped off next to the chip body and the chip removed. Then the pins can be desoldered one at a time. That would have been simpler than what we did, which was a classic chip extraction. After an hour of playing with desoldering wick, we had the chip out!

After the chip was extracted, we ran a very small drill bit through the holes to make certain they were clear (they are plated through, so do not use a bit that is even terribly close to the size of the hole or you will break circuits). We managed to cut one trace on the board as well, which we fixed with a solder bridge.

With the new chip installed, we are approaching readiness to reassemble and test the telescope! My son did all the soldering to reinstall the chip and most of the desoldering. He is proud of being able to fix his telescope.

When the whole thing was assembled, the telescope works, though the hand controller is often illegible. That is our next project!

First Bruschetta of the Season

It all begins with a tomato - a real, ripe, perfect one. In this case, we used our first ripe tomato of the season.

While suffering a bit from an earlier attack by inchworms, it tasted wonderful.

The pole beans are also from our garden, though they are not part of our Bruschetta....

Ingredients:

• Tomato
• 1/4 yellow Onion
• Basil
• Olive Oil
• Black Pepper
• Salt

Separately, make some toasted thin slices of Ciabatta bread... I tend to eat Bruschetta on crisp thin toasts.

Wash the tomato and remove any blemishes. Dice reasonably finely, usually about a quarter inch dice is good. Place in a glass bowl.

Dice the onion (you will want about 1/4 as much as you have tomato) into chunks half the size of the tomato chunks or smaller.

Place in glass bowl atop tomato chunks.

Wash the basil and pat dry. Mince at least as finely as the onion. Place on top of Onion and Tomato. Now drizzle some olive oil over the stack and gently mix. Add the salt and ground black pepper, stir gently to mix, cover with a towel, and allow the flavors to mingle for at least fifteen minutes.

Serve by spooning onto thin, crispy toast and eating!

For our family, this has become a ritual preparation marking the start of Summer, or at least the season of the Tomato.

Giant Puffball Mushrooms in Chaparral

While Spring is usually considered the time for wildflowers in the deserts of California, they are not the only things you can find in Spring.

How about football sized mushrooms? Even if these particular ones were a bit smaller than typical, they are still wonderful things to encounter while wandering in natural areas this time of year!

There is a tremendous excitement to finding these unexpectedly along a trail or while exploring. These can be found in almost any part of the state, generally around the time the Dichelostemma capitata are finishing their bloom period.

My son found these - Puffballs as a group contain some of the most numerous edible mushrooms in our yard (note - never eat wild mushrooms - join a local mycological society if you really want to explore this. The Mycological Society of San Francisco is a great one at mssf.org ). Hence the excitement when an unexpected "old friend" showed up along our path!

Turns out it hasn't been a great year for Calvatia booniana, as these were all ready getting ready to ripen their spores, and the mushrooms themselves are smaller than often encountered with this species. Still adds a flair of the hunt to any hike!

Wild Snapdragons of the Chaparral

California has a famously diverse flora, including the genus containing the domestic snapdragons, the genus Antirrhinum. The genus can be found across Europe, North Africa, and North America. California's species are in full bloom in the Chaparral (the bushy vegetation you find covering the coastal mountains on their lower slopes, generally).

We found two species recently that delight us whenever we stumble across them.

Antirrhinum multiflorum (above) is a perennial - a plant that lives for several years rather than just living within one growing season. The good news is if you find it, it will likely be there, and bigger, each year for several years. My son is always on the lookout for these, and found today's first one! These can grow to six feet tall, though normally are between two and four feet tall. The plants are sticky, so better to look than touch!

Antirrhinum coulterianum (above) in contrast is a fire-following annual, meaning it lives for a single year (actually about 6 months), sprouting, flowering, and setting seed in a span of less than a year. This plant is in a rush to grow, since Spring rains are fickle an it cannot trust the moisture will last. It doesn't grow a strong enough stem to face the wind - notice the twisting branches below the flowers? These "tortile branchlets" twist and turn through nearby plants to help keep the raceme of flowers standing tall. There is a second twist, in that this is a fire following specialist. Often, these plants are completely absent from the chaparral. They are waiting as seeds for the right conditions. Those conditions happen in the fall after a chaparral fire burns through the hills - all the soot, charcoal, and other remains of the fire trigger the seeds to germinate, after having waited for decades in the soil. You can generally find them for just a few years after a fire burns the chaparral off the hills, then they are gone again until the next fire cycle. Chaparral is a unique vegetation type evolved to burn completely several times a century.

You can play with Real Dough as well! Sweet Bread Snails!

Who knew you could play with real dough just as well as the toy variety?

My son called my Sweet Hawaiian bread "boring", so he helped make it more interesting. Notice the eyestalks! I started making spiral buns and he decided some of them needed bodies to become snails!

This is the recipe from a few weeks ago (link) on this blog, with the exception that the recipe was made more flavorful:

* Fresh grated ginger increased from 1 teaspoon to 1 tablespoon
* 2 tsp. of ground Cardamon added

Otherwise they are the same as before - though we forgot to brush them with egg whites before baking, so the crust isn't shiny.

Have fun!

City Lights and Spectroscopy

Ever look out at the city at night wondering what the technology behind the glittering lights might be? I do...

Turns out there is a simple way to find out what is making the light. This picture was taken through a 1000 lines-per-millimeter diffraction grating (the cheap kind from Rainbow Symphony that come in a 35mm slide frame). I placed it in contact with the camera case and parallel to it, then adjusted the rotation of the grating until the spectra were generally directly over the light source creating them.

The verdict?

This view of Los Angeles has a remarkable diversity of lighting technologies on display. One to the left of center stands out to me, as unlike most of the spectra in view (which are continuous stripes of color), this one is made from distinct spectral lines (not all colors of the rainbow are present).

 

Line Spectra are like fingerprints for atoms and molecules: the light is made of just a few select colors at characteristic wavelengths. Each line relates to a very specific transition in the orbiting electron clouds of specific atoms. In many cases the complete list of elements in a sample can be teased out of a careful examination of the spectrum.

The temperature of the plasma (assuming the emissions are coming from an electrically charged hot gas, as in a mercury vapor or sodium vapor light) can also be determined by understanding how much energy is released in each transition. There is a simple relationship for the average kinetic energy of atoms moving in a gas and their temperature:

K = (3/2)*(R/N)*T = (1/2)*m*v*v

Note that R=8.314J/mole-K, N=6.022x1023 particles/mole, T is temperature in Kelvins. K is the average kinetic energy of the atoms moving in the gas, with m being the mass of a given atom, and v being the root-mean-squared velocity of the atom.

There are several good sites discussing the kinetics of gasses. NASA has a nice one where you can select your grade and the material is selected appropriate to your grade level. See https://www.grc.nasa.gov/www/k-12/airplane/kinth.html

A variant of this thinking lead to Einstein's first Nobel Prize, which is for the Photoelectric Effect (light striking a metal causes no emission of electrons if the photos are below a certain energy, while above this threshhold the energy of the electrons emitted increases with increasing photon energy).

Incidentally, this is where "Absolute Zero" comes from - at Zero degrees Kelvin, all motion stops. (there are semantics about whether spreading of wavefunctions via the Heisenberg Uncertainty Principle amounts to some form of motion, for example).

We were just looking at pretty colors, right? Turns out it is a great entry point to explore some amazing physics and how our universe works.