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Author Archives: gfbrandenburg

Are we alone – 2?

14 Tuesday Oct 2025

Posted by gfbrandenburg in astronomy, astrophysics, History, Math, nature, science, Uncategorized

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aliens, civilization, evolution, exoplanets, life, philosophy, science, science-fiction, space travel, Speed of light

Someone else’s take on this topic.

If aliens could travel at a fraction of the speed of light, why haven’t they colonized our Galaxy by now?

We’ve all been brainwashed by years of Star Wars, Star Trek, Marvel Universe, Avatar, etc, to think that space should be teeming with intelligent civilizations, most of them vaguely like ourselves, working with and against each other to carve up the galaxy. As a result, it’s easy to overlook the huge assumptions embedded in your question.

  • Habitable worlds exist. Do they? It seems overwhelmingly likely, given that there are probably a trillion planets in the Milky Way alone, but for now we don’t know. Perhaps there are many near-miss planets like Venus and Mars, but extremely few true Earth analogs. For instance, life might require a particular rock/ice ratio, a large moon, and a specific style of plate tectonics. That level of specificity seems unlikely to me, but that’s just my random opinion. Until we find another planet with truly Earthlike conditions, we cannot say for sure that this is true.
  • Alien life exists. Does it? Honestly, we have no idea. There are many strong arguments suggesting that the fundamental biochemistry of self-replication is practically inevitable given the right conditions. But we don’t know how common those conditions are (see above), and even then we don’t know if there is some extremely low-probability gap that hinders the emergence of even simple microbial life.
  • Intelligent life exists. Does it? This one is a complete unknown. Keep in mind that there was no intelligent, self-aware life on Earth for 99.999% of its existence. Maybe the emergence of intelligence here was a rare fluke, unlikely to be reproduced anywhere else. Rat-level intelligence seems to have existed for at least 200 million years without any indication that higher level intelligence would confer a big evolutionary advantage. (There are all kinds of speculations about why intelligent life could not emerge until now on Earth, but these are just-so stories, trying to paint an explanation on top of a truth that we already know.)
  • Intelligent species want to “colonize” the galaxy. Do they? Life does have a tendency to explore every available ecological niche, and humans sure do like to spread out. From our example of one Earth, it seems likely that this is a general tendency of life everywhere, but we are doing an awful lot of extrapolating here. Maybe other types of intelligence have other motivations that have nothing to do with expansion.
  • Intelligent species become technological species. Do they? It’s certainly true for humans, but dolphins have a high level of intelligence and they are not trying to build spaceships. Crows, chimps, and bonobos are also capable of simple tool use, but they don’t appear to have experienced any evolutionary pressure to become true technological species.
  • Technological species can travel a significant fraction of the speed of light. (I assume you mean something like more than 1% of light speed.) Can they? Extrapolating from human technology, that seems extremely likely. Then again, the fastest spacecraft we have ever built would take about 300,000 years to reach the next star. Nobody is going to be colonizing the galaxy at that rate. You have to accept that speculative but unproven technologies are both feasible and practical for more advanced technological civilizations. Maybe intelligent life is out there, but in isolated pockets.
  • Intelligent, technological, space-faring species survive for a long time. Do they? Oh boy, we have no idea at all if this is true. Earth is 4.5 billion years old. Life has been around 4 billion years. Land species have been around 400 million years. Rat-level intelligence has maybe been around 200 million years. Our species has been around for about 100 thousand years. We have been capable of spaceflight for less than 100 years. It may seem inconceivable that humans could go extinct—but even if we last another 100,000 years, that may not be nearly enough time to spread across the galaxy, even if we develop the means to do it and maintain the will to do it. If intelligent species typically last less than 100,000 years, thousands of them could have come and gone in our galaxy without us ever knowing.

So there’s not one answer, but a whole set of overlapping possible answers why we don’t see evidence of any alien civilizations around us. And that doesn’t even consider more exotic possibilities, such as the idea that they might be here but just undetectable to us or deliberately hidden from our primitive eyes.

Are We Alone?

16 Tuesday Sep 2025

Posted by gfbrandenburg in astronomy, astrophysics, education, History, science

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astronomy, exoplanets, life, nasa, National Capital Astronomers, NCA, Rob Zellem, science, solar systems, space, UMCP, Universe, University of Maryland

Dr Rob Zellem posed this question last night (9-13-2025) to NCA members and visitors at their monthly meeting at the University of Maryland Observatory.

Are we alone in the universe, or are there exoplanets with life of some sort, and even some advanced civilizations out there?

Dr Zellem said the correct answer right now is, maybe. We just don’t have enough data to tell.

He reminded us that Giordano Bruno and Isaac Newton both correctly predicted that other stars would have planets around them. We now know that just about every single star is born with a retinue of planets, asteroids, dust, and comets, so there are at least as many planets as there are stars in our galaxy and all the others as well. Previous speakers to NCA have noted that many of these objects end up getting flung out into the vast frozen emptiness of interstellar space in a giant random game of ‘crack the whip’. No life can exist out there.

My calculations here: It is estimated that there are literally trillions (10^12) of galaxies, each with millions (10^6) or billions (10^9) of stars. Let’s start with our own galaxy, the Milky Way, with maybe 200 billion stars (maybe more). I will assume that life needs a nice, calm, long-lived G class yellow star, which only make up 7.6% of all stars. Roughly 50% to 70% of those stars are in binary systems, which I fear will reduce the chances of having a planet survive in the Goldilocks zone. Perhaps one-third to two-thirds of those G stars have a planet in their habitable zone. We have no idea how likely life is to get started, but after reading Nick Lane’s The Vital Question it sounds pretty complicated to me, so I’ll use a range of estimates: somewhere between 10% and 80% of them develop some form of life. We know that on Earth, the only form of life that existed during the vast majority of the existence of the Earth was unicellular microbes. Four-footed tetrapods like ourselves have only occupied about 1% of the life of our planet, and we humans have only had the telescope for just over 400 years, out of the 400,000,000 years since four-footed animals evolved, which is one in a million. Low estimate:

If my low-end estimates are correct, then there are about five or so exo-planets somewhere in our galaxy with a civilization formed by some sort of animal that can look out into outer space. High estimate:

In that case, there are well over a hundred civilizations in our galaxy — but the Milky Way is huge, hundreds of thousands of light-years across! Most of our exoplanet detections have been within the nearest 100 light years, and we have no way of detecting most exoplanets at all because the planes of their orbits point the wrong way.

NOTE: Jim Kaiser pointed out that I made a dumb mistake: a hundred billion is ten to the 11th power, not ten to the 14th power. Fixed now.

Even so, Zellem pointed out that thanks to incredible advances in sensitivity of telescopes and cameras, we are now closer than ever to being able to answer the title question: Are We Alone.

Plus, any amateur astronomer can take useful measurements of exoplanet transits with any telescope, and any digital camera. Following the directions on NASA’s Planet Watch webpage, you can take your data, in your back yard or from a remote observatory, process it the best you can, send it in, and be credited as a co-author on any papers that are published about that particular exoplanet. Then, later, a massive space telescope can be aimed at the most promising exoplanets during their transits. Astronomers can use their extremely sensitive spectroscopes to detect the atmospheres of those bodies and look for signs of life. They do not want to waste extremely valuable telescope time waiting for a transit that doesn’t recur!

Some day we will be in a situation where scientists will be able to say that based on their measurements, the signal indicates a very good chance of life at least a bit like ours, with similar chemistry on some planet. They will also state what the chances are that they are wrong, and indicate what further steps could be made to disprove or confirm their claim.

Zellem noted that both the Doppler-shift method and the transit methods are quite biased in favor of large exoplanets that are close to their suns.

I asked the speaker how likely it would be for observers from some exoplanet to detect the planet Mercury, but couldn’t do the math in my head and didn’t have paper and pencil to write anything down at the time. But now I do.

The closer Mercury is to the Sun, the larger the possible viewing angle.

Using a calculator to find the arc-tangent of that ratio (865,000 miles solar diameter, divided by the smallest and also by the largest distances between them, namely 28,500,000 and 43,500,000 miles) gave me an angle between 2 and 3 degrees, depending. So there is a circular wedge of our galaxy where observers on some other planet might view a transit of our innermost planet. Where is that wedge in our galaxy?

The following sky diagram has the Ecliptic in pink. Only observers within a degree or so of that curvy line could detect that Sol has planets.

So what fraction of the sky can ever hope to catch a transit of Mercury? Only about 1% or 2% of the sky — not much.

Turning things around, this means that we can ourselves only detect, via transits, a very small portion of all extra-solar planetary systems – those whose planes are pointing almost directly at us, and those with large planets that are very close to their stars. (Any planet so close to a star is not a very good candidate for life, in my opinion.)

The biggest obstacle is the sheer distances between stars. At the speed of our very fastest space craft (the Parker Solar Probe), which only goes 0.064% of the speed of light, it would take about 6250 years to reach our closest stellar neighbors near Proxima Centauri. One way. Which probably explains why, if all these other civilizations do exist, we do not appear so far to have been visited by any other extraterrestrial civilization.

At the meeting, someone in the audience was pretty sure that yes, we have already been visited by aliens. I talked with him outside after the meeting. His main evidence was a 2020 New York Times article concerning the upcoming release of classified data about mysterious flying objects (now called UAPs rather than UFOs). In the article, one Eric Davis claimed (without producing any evidence) that some items have been retrieved from various places by the US military that couldn’t be made here on earth. That is of course true of every single asteroid or meteorite ever discovered, since we can’t reproduce the conditions in which they were formed, so his claim is not very helpful. No technological devices clearly of alien manufacture have ever been publicly produced by him or anybody else for testing.

(It’s pretty obvious that American and other military forces spend a lot of money producing objects that go very fast and are highly maneuverable — and which they want to keep secret.)

There are in fact many, many unsolved mysteries in science (eg, the nature of dark matter and dark energy, and exactly how the nucleus arose in eukaryotes). Many of the unidentified sky or water phenomena that have been witnessed do not have clear explanations so far, but the simplest explanation is usually the correct one. Reputable scientists require a lot more than hearsay evidence before they make bold claims.

Thank you for a great talk, Rob Zellem!

Amazing Astrophotos by 19-year-old Venezuelan Immigrant at Art All Night – Mt Pleasant (DC)

13 Saturday Sep 2025

Posted by gfbrandenburg in astronomy, education, science, teaching, Telescope Making

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astronomy, DC, District of Columbia, DIY, dobsonian, Mount Pleasant, National Capital Astronomers, NCA, Optics, Telescope, Telescope Making

Last night was the opening of an exhibit called Second Sunset in an alley off Mt Pleasant Triangle in NW DC. Great astrophotos by 19-year old Gael Gomez, his neighbor Adam Green, and NCA VP Bryan Vandrovec! The images are huge – four to six feet across, and printed on durable sandwiches of aluminum and plastic, so they will survive outside for months. They were printed by Jason Hamacher of Lost Origins Gallery, located about a block away, aided in part by the Smithsonian’s Folk Life Festival.

It coincided with the 3rd annual Art All Night – Mount Pleasant, so a LOT of people were out having a good time, listening to a live Colombian band and visiting dozens of vendors and exhibits under tent covers on the Triangle.

So when Gael and Guy Brandenburg (NCA president) brought out their telescopes on the other side of Mt Pleasant Street, once we could actually see a few stars, we had long lines of people waiting patiently to look at double stars, Saturn, the ISS, and the Moon, and then discussing what they had seen, right up until 11:30 PM. We all had a blast!

If you can’t read the text, it says, “The Art of DIY Telescopes, Sidewalk Astronomy, and Astrophotography: The Debut Exhibit of the Mt Pleasant Sidewalk Astronomers”. As well as “Lost Origins Outside” and “November 12 to November 9, 2025.”

Captions are coming for all of the photos, explaining how they were made and what they depict, as well as a sign explaining the National Capital Astronomers which has been running the DC DIY telescope workshop since World War 2, in which both Guy and Gael made their first telescopes.

How to make a spectroscope – cheap!

04 Friday Jul 2025

Posted by gfbrandenburg in astronomy, astrophysics, education, Optics, Telescope Making

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cheap, grating, sidewalk astronomy, spectroscope

Making a spectroscopeDownload

Some surprises with new astro gizmos

24 Friday Jan 2025

Posted by gfbrandenburg in astronomy, education, Optics, Telescope Making

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astronomy, Astrophotography, ATM, celestron, dobsonian, Optics, science, space, StarSense, Telescope, testing

Astronomy is moving so fast, it’s amazing.

We only truly discovered the nature of galaxies, of nuclear fusion, and of the scale of the universe a mere century ago.

Dark matter was discovered by Vera Rubin just over 40 years ago and dark energy a few years later, just before the time that both professional and amateur astronomers began switching over to CCD and later CMOS sensors instead of film

The first exoplanet was discovered only 30 years ago, and the count is now up to almost six thousand of them (as of 1/21/2024).

While multi-billion dollar space telescopes and giant observatories at places like Mauna Kea and the Atacama produce the big discoveries, amateur astronomers with a not-outrageous budget can now afford to purchase relatively small rigs armed with excellent optics and complete computer control, and lots of patience and hard work, can and so produce amazing images like the ones here https://www.novac.com/wp/observing/member-images/ or this one https://www.instagram.com/gaelsastroportrait?igsh=cjMzYWlqYjNzaDlw, by one of the interns on this project. Gael’s patience, cleverness, dedication and follow-through are all praiseworthy.

However, it is getting harder and harder every year for people to see anything other than the brightest planets, because of ever-increasing light pollution; the vast majority of the people in any of the major population centers on any continent have no hope of seeing the Milky Way from their homes unless there is a wide-spread power outage. Here in the US, such power outages are rare, which means that if you want to go out and find a Messier object, you pretty much cannot star-hop, because you can only see four to ten stars in the entire sky!

One choice is to buy a completely computer-controlled SCT like the ones sold by Celestron. They aren’t cheap, but they will find objects for you.

But what if you don’t want another telescope, but instead want to give nice big Dobsonian telescope the ability to find things easily, using the capabilities inside one’s cell phone?

Some very smart folks have been working on this, and have come up with some interesting solutions. When they work, they are wonderful, but they sometimes fail for reasons not fully understood. I guess it has something to do with the settings in the cell phone being used.

The rest of this will be on one such solution, a commercial one called StarSense from Celestron that holds your phone in a fixed position above a little mirror, and you aim the telescope and your cell phone’s camera at something like the top of a tower far away. Then it uses both the interior sensors on your cell phone and images of the sky to figure out where in the sky your scope is pointing, and tells you which way to push it to get to your desired target.

When it works, it’s great. But it sometimes fails.

You have to buy an entire set from Celestron – one of their telescopes (which has the gizmo built in) along with the license code to unlock the software.

You supply the cell phone.

The entire setup ranges in price from about $200 to about $2,000. You cannot just buy the holder and the code from them; you must buy a telescope too. I already had decent telescopes, which I had made, so I bought the lowest-priced one. I then unscrewed the plastic gizmo, and carved and machined connection to a male dovetail slide for it. I also fastened a corresponding female dovetail to each of my scopes. The idea was to then slip this device off or onto whichever one of my telescopes is going to get used that night, as long as I that has a vixen dovetail saddle, and put inexpensive saddles on several scopes I have access to.

Here are some photos of the gizmo:

NCA’s current interns (Nabek Ababiya and Gael Gomez) and I were wondering about the geometry of the angles at which StarSense would aim at the sky in front of the scope. My guess had been that Celestron’s engineers would make the angles of their device so that the center of the optical pencil hitting the lens dead-on at 90 degrees, and hence coning to a focus at the central pixel of the CMOS sensor, would be parallel to the axis of the telescope tube.

We didn’t want to touch the mirror, because it’s quite delicate. But as a former geometry teacher, I couldn’t leave this one alone, so along with Gael and Nabek I made some diagrams and figured out what the angles had to be if the axis of the StarSense app’s image were designed to be precisely parallel to the axis of the telescope.

In my diagram below, L is the location of the Lens, and IJCK is the cell phone lying snug in its holder. The user can slide the cell phone left and right along that line JD as we see it here, or into out of the plane of the page, but it is not possible to change angle D aka <CDE – it’s fixed by the factory molds to be some fixed angle that we measured with various devices to be 19.0 degrees.

Here is a version of the diagrams we made that showed what we predicted all the angles would be so that optical axis OH will be parallel to the tube axis EBD, and that lens angle ILH is a right angle. We predicted that the mirror’s axis would need to be tilted upwards by an angle of 35.5 degrees (anle HBD).

To our surprise, our guesses and calculations were all wrong!

After careful measurements we found that Celestron’s engineers apparently decided that the optical axis of the SS gizmo should instead aim the cell phone’s camera up by 15.0 degrees (angle BGH below). The only parallel lines are the sides of the telescope tube!

We used a variety of devices to measure angle FBD and MNC to an accuracy of about half a degree; all angles turned out to be whole numbers.

Be that as it may, sometimes it works well and sometimes it does not.

Zach Gleiberman and I tested it on an open field in Rock Creek Park here in DC back in the fall of 2024, using the Hechinger-blue 8 inch dob I made 30 years ago and still use. We found that SS worked quite well, pointing us quite accurately to all sorts of targets using my iPhone SE. The sky was about as good as it gets inside the Beltway, and the device worked flawlessly.

Not too long afterwards, I decided to try out an Android-style phone (a REVVL 6 Pro) so that I wouldn’t have to give up my cell phone for the entire evening at Hopewell Observatory. I was unpleasantly surprised to find that it didn’t work well at all: the directions were very far off. I thought it might be because the scope in question had a rather wide plywood ring around the front of its very long tube, and that perhaps too much of the field of view was being cut off?

Why it fails was not originally clear. I thought nearly every modern phone would work, since for Androids, it just needs to be later than 2016 and have a camera, an accelerometer, and gyros, which is a pretty low bar these days. However, my REVVL 6 Pro from T-Mobile is not on the list of phones that have been tested to work!

Part of my assumption that the axis of the SS gizmo would be parallel to the axis of the scope was an explanation that StarSense on had such a large obstruction in front of the SS holder, in the form of a wide wooden disk reinforcing the front of a 10″ f/9 Newtonian, that the SS was missing part of the sky. We now know that’s not correct. It’s an interface problem (ie software) problem.

We think.

Success with digital measurement of parabolic telescope mirrors

02 Saturday Nov 2024

Posted by gfbrandenburg in astronomy, astrophysics, Math, Optics, science, Telescope Making

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astronomy, ATM, data, FigureXP, foucault, measurement, millies-lacroix, paraboloid, Telescope

Alan Tarica, Pratik Tambe, Tom Crone and I have been pulling our hair out for a couple of years, trying to use cameras and software to measure the ‘figure’ of the telescope mirrors that we and others produce in our telescope-making class.

There has been progress, and there has been frustration.

I think we finally succeeded!

Some of the difficulties have been described in previous posts. In brief, we want our mirrors to be really, really close to a perfect paraboloid. There are many ways of doing those measurements and seeing whether one is close enough, but none of those methods are easy!

(By the way, one needs the entire mirror to be within one-tenth of a wave-length of green light of that ideal paraboloid! That’s extremely tiny, and equivalent to the thickness of a pencil over a ten-mile diameter!)

I think I can finally report a victory. My evidence is this graph that I made just now, using data that Alan and I gathered last night with our setup, which consists of a surveillance camera coupled to an old 35mm SLR film camera lens, which is mounted on a linear actuator screw connected to a stepper motor controlled by an Arduino and a Python app developed by Pratik.

Something seemed to be always a bit — or a lot — ‘off’.

Until today, when I converted everything to millimeters and used the criterion set out by Adrien Millies-Lacroix in an article he wrote in Sky & Telescope back in 1976.

The blue dots just above the x-axis are the measurements for this one particular mirror with a diameter of 8″ and a radius of curvature of 77 inches.

The dotted blue curve in the middle of the image is the best-fit parabola for those dots. Notice that the R-squared value (variance) for that curve is not great: 0.3599.

But that variance isn’t important. What is important is the green and orange blobs and curves above and below the blue ones.

The green and orange curves are the upper and lower allowable limits for the measurements of this particular mirror, using the

Clearly, the blue dots are all well within the green and orange curves.

Which means that this mirror is sufficiently parabolized.

The fact that the blue dots don’t fit the dotted line perfectly, and behave pretty oddly at positive or negative 80 millimeters, both agree with the fact that we can see on the photos that the surface of this mirror is rather rough, as you can see in the images below. Note also that the image labeled ‘Step 6’ found not one, but two null zones on the right, indicated by two vertical blue lines.

So, finally, we have an algorithm that gives good measurements! What I still want to do is to automate all the spreadsheet calculations that I just did today. Perhaps we can upload them to something like FigureXP by Dave Rowe and James Lerch.

Thanks very much to all those who have helped, whom I should look up and name here.

Caveat: This method can give really ridiculous measurements close to the center and close to the edge.

PS: if anybody wants the raw data, just email me at gfbrandenburg at gmail dot com.

Free Open House at Hopewell Observatory in Northern Virginia, October 26 or 27

16 Wednesday Oct 2024

Posted by gfbrandenburg in astronomy, Hopewell Observatorry, Optics, Safety, science, Telescope Making

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astronomy, dobsonian, Hopewell Observatory, observatory, OnStep, space, Telescope

Come to Bull Run Mountain for a free night under the stars looking at a variety of targets using the telescopes at the Hopewell Observatory on Saturday, October 26, 2024. If it’s cloudy, we will try again on the next evening, Sunday the 27th.

You are invited, but will need to RSVP and, in this litigious age, must agree to a waiver of liability for anything that might happen up there, like tripping over rocks and trees. The waiver also includes detailed driving directions.

Click here for the RSVP form: 

But if you take the risk you can view, for free, Venus, Saturn and its rings, Jupiter and its moons, Uranus, Neptune, the current comet Atlas, the Milky Way, and a whole bunch of nebulae, galaxies, Messier objects, and beautiful double stars.

We suggest arriving near sundown, which will happen near 6:15 PM. It will get truly dark about an hour later. You can stay until midnight, if you like.

There are no street lights near our observatory, other than some dimly illuminated temporary signs we put along the path, so you will probably want to bring a flashlight of some sort. In the operations cabin we have a supply of red translucent plastic film and tape and rubber bands so that you can filter out everything but red wavelengths on your flashlight. This will help preserve everybody’s night vision.

Hopewell is located on the first ridge of the Appalachian mountain chain that you see as you drive west from the DC beltway, near Haymarket. Our elevation is about 1100 feet, and we have much less of a problem with dew than other observing spots in northern Virginia. The last two miles of road are dirt and gravel, and you will need to walk about 200 meters/yards from where you park. Some parts of the road are pretty rough, so don’t drive anything with low clearance underneath. Our parking spaces are pretty limited, so consider car-pooling if possible. Handicapped persons or telescopes can be dropped off at the observatory.

We do have electricity, and a heated cabin, but since we have no running water, we use bottled water, hand sanitizer, and a pretty nice outhouse. We will have the makings for tea, coffee, and hot cocoa in that cabin.

If you like, you can bring a picnic dinner and a blanket or folding chairs, and/or your own telescope or binoculars, if you own one and feel like bringing them. We have outside 120VAC power, if you need it for your telescope drive.

At this time of year, the bothersome insects have mostly gone dormant, but feel free to use your favorite bug repellent, (we have some). Remember to check yourself for ticks after you get home.

We have a variety of permanently-mounted and portable telescopes of different designs, some commercial and some made by us. Two of our telescope mounts are permanently installed in the observatory under a roll-off roof. One of the mounts is a high-end Astro-Physics mount with a 14” Schmidt-Cassegrain and a 5” triplet refractor. The other mount was manufactured about 50 years ago by a firm called Ealing, but the motors and guidance system were recently completely re-done by us with modern electronics using a system called OnStep. We didn’t spend much cash on it, but it took us almost a year to solve a bunch of mysteries of involving integrated circuits, soldering, torque, gearing, currents, voltages, resistors, transistors, stepper drivers, and much else. We could not have completed this build without a lot of help from Arlen Raasch, Prasad Agrahar, Ken Hunter, and the online “OnStep” community.

We also have two home-made Dobsonian telescopes (10″ and 14″ apertures) that we roll out onto our lawn, and have been lent a pair of big binoculars on a parallelogram mount.

The location of the observatory is approximately latitude 38°52’12″N, longitude 77°41’54″W.

Click here for the RSVP form to get detailed directions. You must sign the waiver to visit. If we cancel on Saturday the 26th because of bad weather, we will notify you by email and will try again on Sunday the 27th.

An amazing little telescope

06 Tuesday Aug 2024

Posted by gfbrandenburg in astronomy, astrophysics, Optics, science

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alt-az, astronomy, electronics, focus, Hopewell Observatory, light pollution, optical tube assembly, Optics, refractor, solar system, Telescope, Washington

Look what this little thing can do that I’ve always failed at myself, even with an entire observatory at my disposal: take decent astrophotos.

Here it is on a home made tripod, taking photos of the sun. Notice the reflective solar filter. Here are two images:

The device woke up, and after less than a minute of self’s-calibration, it pointed very accurately at the sun and focused itself perfectly. It produces a continuous feed; I even did 100 frames of a time-lapse. It’s all stored on my cell phone but I can share the photos or even live views with folks nearby.

And from night time spots here in DC and NOVA:

This can take tolerable astrophotos even when surrounded by streetlights!

.

Recent Photos at Hopewell

04 Thursday Jul 2024

Posted by gfbrandenburg in astronomy, Hopewell Observatorry

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astronomy, ealing, Ealing mount, Hopewell, Hopewell Observatory, Moon, planet, solar system, Telescope

These were made by Gael Gomez, a recent HS grad who visited on Monday, July 1.

The Ealing mount, looking south
The Milky Way — which doesn’t look this great to the naked eye
Dumbbell Nebula
Waning crescent Moon
M13, great Hercules globular cluster
Saturn, seen edge-on

No Night-time Golf Driving Range or Mass Tree-Cutting in Rock Creek Park!

03 Friday May 2024

Posted by gfbrandenburg in Uncategorized

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Dark Sky, Golf Course, light pollution, National Park, nature

Have you ever visited the golf course at Rock Creek Park in Washington, DC? Despite driving around it thousands of times, I never walked on it until today. Yesterday, I gave insufficiently-informed testimony against a proposed redevelopment of the golf course. Here is what I said, and what I should have included as well.

Hello. My name is Guy Brandenburg. I am a DC native and the current president of National Capital Astronomers, or NCA, a local educational and scientific non-profit astronomy club. I also teach at a school that is directly across 16th Street from the Rock Creek Golf Course!

I and every member of NCA that I’ve spoken to are opposed to installing a brightly-lit night-time golf driving range there.

Right now, the golf course is one of the most nearly pristine areas of the District of Columbia. Installing a illuminated, night-time golf driving range will have a very severe impact on all night-loving creatures in that part of the park. Those creatures include not only insects, birds, four-footed mammals and plants, but also humans nearby.

One special reason for my testimony is that members of my club have been, literally, holding “Exploring The Sky” sessions for the public inside Rock Creek Park, every month except winter, in conjunction with National Park Service Rangers stationed at the Nature Center and Planetarium, for over 75 continuous years, only a short distance from this driving range.

The field where we show planets, stars and galaxies to the public, at no cost, including on Saturday, May 4, two days from now, if the weather is clear, is located just south of the intersection of Military Road and Oregon Avenue – roughly 4200 feet (less than a mile) away from these new lights. Despite today’s testimony by Jamie Herr about the lights, I fear that those new lights will make observing the sky from our site nearly impossible and also affect residents along upper 16th street.

[Addition: My fear was justified. Physics says no such lights exist. Photons go on forever in straight lines unless absorbed, bent, or reflected; they don’t stop after 50 yards! Also, the developers are flat-out lying when they assure the readers that Dark Sky International (DSI) has already approved this lighting plan! I know some of the DSI activists here in DC, and they are hopping mad about this!]

[Addition: I challenge the National Links Trust to show us an example of a night time illuminated golf driving range with this magical 50 yard lighting, anywhere in the world!]

A brightly-lit installation in Rock Creek Park completely contradicts the policy that induced the Park Service to turn off all of the street lights on all of the roads in the park, many years years ago.

I wish more publicity had been given to this night time illumination plan. Previously, I had only heard about the cutting of mature trees. More review of this issue is needed by the local and national DSI.

Yes, I’m biased: I love being outside in a field at night during clear weather. One of my first dates with my wife, over 40 years ago, was a night-time stroll on a moonlit golf course in College Park, serenaded by owls.

Night time is the only time that people can see into the deep universe with their own eyes and see the Milky Way and the stellar furnaces that produced the very molecules that we are all composed of. But wasted, useless lighting at night (or WULAN) – like what I fear this proposed driving range will cause- make it impossible for people to see any of this. As an aside, even if there are habitable planets somewhere, the laws of physics and the vast distances mean there is no way at all to ever reach them. There is no planet B. We do not need to pave over, poison, and light up all of this planet, and especially not this lovely national park!

The current state of this little-used golf course is actually quite lovely. It’s a series of open meadows in the heart of the Nation’s capital, surrounded by large trees. Not being a golfer, the only changes I would recommend would be to remove the invasive alien vines that are smothering so many of those trees.

Let us not bulldoze and light up this lovely set of meadows, and let us review the lighting proposal again.

Guy Brandenburg

[Final addition: The current golf course is an amazing gem, hidden from almost everybody! Until today, I never, ever visited the place, and didn’t know anybody who had. I never even knew where it was until about a week ago, and only today (May 3, 2024) did I at last step on its grounds, though I’ve driven right by it many thousands of times and am a DC native!!!

I am amazed.

The golf course is composed of huge trees that surround amazingly beautiful and almost bucolic meadows! Right in the middle of DC! Much like the Arboretum but wilder, and much nicer than, say, the Franciscan Monastery or Howard Divinity School, or the Old Soldier’s Home!

I was flabbergasted! This golf course incredibly beautiful – in a way that most hyper-manicured golf courses are NOT.

I do think that the landscaping and vegetation need a LOT of serious gardening work, especially since there are lots of really nasty, invasive, alien vines there like English ivy and ‘tear thumb” (persicaria perfoliata). As I strolled and took photos on the ‘back nine’, I saw not a single person for 20 minutes.

As a long-time gardener and one-time farmer, I have a lot of horticultural suggestions for improvements, but the idea of cutting over a thousand big trees, simply because they overshade some of the grass, is obscene! Frankly, that shade makes those lanes much nicer to walk along if it’s hot and sunny — unlike the unshaded National Mall where it gets hot as hell!

But basically, the RCGC s very beautiful as it is, even without any improvement! I even found a pond filled with cattails and bullfrogs, and thickets with lots of wineberries, raspberries and blackberries, blooming right now.

I wish I had known about the place earlier, when I was raising my kids and grandkids! I encourage everyone to go visit, whether you play golf or not! (I do not, but I can see how it might be a great thing to do on this mostly-natural set of meadows, instead of the totally artificial and highly-poisoned typical US golf course.)

Yes, it needs a lot of serious gardening help, but let us not commit obscenities by cutting over a thousand big, beautiful hardwood canopy trees and lighting it all up with a driving range! ]

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