August Newsletter

I am going to attempt to revive the monthly newsletter, if I can find time to create it.  The August newsletter is attached here:

AUG2018 GMAC Newsletter

If you would like to write an article for a future newsletter, please send it to me.

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McMath-Hulbert Observatory Debriefing

Brief History of the Solar Observatory

The McMath-Hulbert Observatory (MHO), was founded in 1930 by three amateur astronomers, Francis McMath, his son Robert McMath, and Henry Hulbert, with the goal of enhancing their clever development of time lapse astrophotography, for outreach purposes. It soon garnered the interests of the University of Michigan and evolved into a world-class solar observatory, operated by the U of M through 1979. It is now in private ownership, nonfunctional, but largely intact.

McMath-Hulbert Observatory Then and Now

General Motors Astronomy Club Visits MHO

On Saturday, July 28th, 2018, nine members of our club toured all three towers of the historic observatory, and learned a great deal about the history and technical capability of the facility.  We would like to extend a special thanks to Jim Shedlowsky for donating his time and sharing his knowledge.

Since solar observatories are such complex systems, I had a few gaps in understanding after the tour, so I did a some follow-up research and found many published papers referencing the McMath-Hulbert Observatory, and was able to answer some of the questions that stumped us on the tour.  The information below is a mixture of what I learned on the tour and what I gleaned from the published papers.

The Oldest Telescope

The tour began in Tower 1, the smallest of the observatory buildings and the first one  built, more than 85 years ago, in 1930.  It was in this building, in 1934, where the very first “movies” of a solar prominence was filmed, using a 10.5-inch equatorial refractor, married to a custom-made motion picture camera, called a spectroheliokinematograph.  Much of the original equipment here is still intact, although somewhat deteriorated by the passage of time.

Our group was also led to the basement of Tower 1, where we saw the electrical control room, which included a number of devices to convert the DC power available at the time, into the AC power used to supply the observatory.


Inside a Tower Observatory

Upon entering Tower 2 of the observatory, our group was amazed at the sheer size and complexity of the equipment we found, complete with 1940’s era wiring and gauges and a steel staircase,

winding 50 feet up to the observatory dome, reminiscent of both an underwater submarine and Frankenstein’s laboratory, at the same time.  After puzzling at what all the dials, switches, and gauges were for, I jokingly asked, “Where is the instruction manual?”

Tower 3, also known as the McGregor Building, was the last one built and also the largest at the observatory.  It came complete with 2-story offices, laboratory, and machine shop.  In this last part of the tour, our group enjoyed inspecting the darkroom facilities, old photographic glass plates, mirror plating vacuum chamber, and peering up into the 70-foot steel tower.   Throughout the 1940’s and 50’s, light from the sun was collected from this tower and redirected into an giant vacuum spectrograph, used by scientists to further our understanding of our closest star.

A bit puzzling, was a sign on a hallway door stating “DANGER 50,000 ANGSTROMS”, which left us wondering what was so dangerous about angstroms.  Honestly, I didn’t know what an angstrom was, until I looked it up later and found that it is a unit of distance, equal to one-tenth of a nanometer.  Although not obvious to the casual 21st-century observer, it seems this sign is warning of the dangers of infrared light, which has a wavelength of 50,000 angstroms, but it is still not clear what the danger is, exactly.


Coelestat vs. Heliostat

One of the unanswered questions that came up on the tour, was regarding the operation of the mirror systems at the observatory and how they are able to track the sun.    It turns out, this system of moving mirrors is called a “coelostat,” which is distinctly different from a “heliostat.”

McMath-Hulbert Observatory, Tower 3

Diagram of the mirror system in Tower 3 of the McMath-Hulbert Observatory, which reflects and diffracts sunlight, for the purpose of imaging solar phenomena in various wavelengths of light.

A heliostat is a moving mirror that reflects the suns light toward a fixed target, such as an imaging device or an energy absorbing device, in the case a of solar-thermal farm.  The problem with using a heliostat in a solar observatory, is that the image of the sun produced by the device rotates at a rate of one revolution per day, due to the rotation of the earth.  The solution to this problem, is the coelostat, which is a system of two mirrors (like the ones we inspected in the top of Tower 2) that move in unison to produce a stationary image.  I imagine this would be very useful when attempting to precisely measure the velocity of a solar prominence, for example.

Both Tower 2 and Tower 3 of the McMath-Hulbert observatory are fitted with a coelostat system of mirrors.


Further Reading and Published Works

As a result of my follow-up research, I have compiled 11 published works (which I found online) into a “book” attached here:  McMath-Hulbert Technical Papers_GoodallCompilation2018

This document has very detailed information on the operation of most parts of the facility, and some of the scientific discoveries resulting from the work of Robert McMath and his associates.

A printed copy of this book will be provided to the McMath-Hulbert Astronomical Society to be used for reference in future work, and as a token of gratitude for reaching out to our club.  Anyone wishing to find out more about the observatory and future tours, can visit the McMath-Hulbert Observatory website at


Clear Skies,

Jim Goodall
President, GMAC

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Rent a Telescope!

Our club now has a telescope for rent as well as binoculars.  Visit our Online Store to check availability today.

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Peregrine Falcon Viewing & Star Party

The General Motors Astronomy Club will be joining the Warren Peregrine Falcon Group next Thursday, June 14th, for some birdwatching and stargazing. Feel free to bring a chair, binoculars, and a telescope, if you have one. We will be sharing our telescopes to view the birds and then enjoying the night sky afterward, if the weather is nice. Light pollution might be an issue in Warren, but Jupiter should be easily visible after sunset. Hope to see you there!

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New Club Logo !

The club would like to extend a special thanks to our Senior Astronomer, Tony Licata, for his artwork, which was chosen as the official logo of the General motors Astronomy Club.  Tony has been a dedicated member of the club since it was founded last year we sincerely appreciate his contributions.        

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M51 – The Whirlpool Galaxy

A spiral galaxy, visible to telescopes under dark skies, can be seen in close interaction with it’s smaller neighbor, NGC5195.  The distance to this galaxy pair is estimated at 23 million light years.

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M27 – Dumbell Nebula

Image by Jim Goodall

A planetary nebula, the remains of an exploded star, in the constellation Vulpecula.

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We are on Facebook!

Come check us out!!! Follow us on Facebook to stay current with events and news.

Comments Box SVG iconsUsed for the like, share, comment, and reaction icons

1 month ago

David Lester Jarrett

So a couple of questions about membership renewal.
1) Currently the website shows 2019 renewal option, with a discounted price of $16. Is this the correct option for renewing for 2021?
2) Should I also renew the Junior Astronomer package for my son? Is there something new in that package vs the 2019-20 kit he already has?
Thanks! Hopefully with a Covid vaccine soon to be available, we will be able to more actively participate in 2021!
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Comment on Facebook

Hi David, We are still working out the details for 2021 membership. Please stay tuned for more info. There will be events scheduled for the springtime to get us going again very soon. I too am looking forward to a post-covid world where we can gather without worries.

I too got some pics of the conjunction last nite. Here is one that highlights all the planets and moons together with no processing. Shows how really close the alignment is !! ... See MoreSee Less

2020 Great Lakes Star GazeSeptember 19, 2020

Description from Wikipedia:

IC 5146 (also Caldwell 19, Sh 2-125, and the Cocoon Nebula) is a reflection[2]/emission[3] nebula and Caldwell object in the constellation Cygnus. The NGC description refers to IC 5146 as a cluster of 9.5 mag stars involved in a bright and dark nebula. The cluster is also known as Collinder 470.[4] It shines at magnitude +10.0[5]/+9.3[3]/+7.2.[6] Its celestial coordinates are RA 21h 53.5m, dec +47° 16′. It is located near the naked-eye star Pi Cygni, the open cluster NGC 7209 in Lacerta, and the bright open cluster M39.[2][5] The cluster is about 4,000 ly away, and the central star that lights it formed about 100,000 years ago;[7] the nebula is about 12 arcmins across, which is equivalent to a span of 15 light years.[6]
When viewing IC 5146, dark nebula Barnard 168 (B168) is an inseparable part of the experience, forming a dark lane that surrounds the cluster and projects westward forming the appearance of a trail behind the Cocoon.
SGPro, PHD2, FocusLock
10" f/8 RC Telescope
Losmandy G11 mount
ZWO asi071mc PRO camera @ 0C, gain 300
48 x 10 minute subs
24 darks
50 flats
Stacked in Deep Sky Stacker (DSS)
Processed in PixInsight
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Our Mission

To further the interest and knowledge of the public in astronomy and to encourage youth education in the fields of Science, Technology, Engineering, and Math (STEM).

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