About Us

The Grand Traverse Astronomical Society is a nonprofit organization dedicated to to education and enjoyment of the night sky. Established in 1982, the GTAS has about 30 members from the Traverse City and the Grand Traverse area of northern Michigan. Meetings are held on the first Friday of every month beginning at 8 p.m. at Northwestern Michigan College's Joseph H. Rogers Observatory, though the August meeting is preempted by the annual picnic at another location.

Guests are always welcome to our meetings.

Over 750 attended the society sponsored Comet Hyakutake Watches March 23, and 24th, 1996. The farthest traveler came from Detroit to enjoy the dark skies and the spectacular comet through many telescopes. Comet Hale-Bopp attracted approximately 1,400 during the three scheduled viewing nights that were clear.

We've hit the road, so to speak, with outreach beyond the NMC Observatory since 2007. Since 2011 we've held monthly star parties at Sleeping Bear Dunes National Lakeshore from April to October with additional eclipse and meteor shower watches. We bring our telescopes and exhibits to several festivals around the area along with Friday Night Live in Traverse City. Since 2010 the society has been hosting monthly star parties at the Sleeping Bear Dunes National Lakeshore.

The GTAS belongs to the International Dark-Sky Association and participates in Project Astro.

Two of our members are also NASA/JPL Solar System Ambassadors.

Upcoming Meetings and Outreach Events

Note that outdoor events are held weather permitting

Friday, February 3, 2023

8 pm EST (UT - 5 hours): Regular Meeting - In-person at Northwestern Michigan College’s Joseph H. Rogers Observatory, AND via Zoom. Masks are recommended if attending in person.

Program topic to be announced.

9 pm EST (UT - 5 hours): In-person/Virtual Star Party if it’s clear.

Zoom instructions and a link will be provided here prior to the meetings.

Check here often for other events that may pop up during the month.

These articles are distributed by NASA Night Sky Network

The Night Sky Network program supports astronomy clubs across the USA dedicated to astronomy outreach

Spot the Messenger: Observe Mercury

David Prosper

Most planets are easy to spot in the night sky, but have you spotted Mercury? Nicknamed the Messenger for its speed across the sky, Mercury is also the closest planet to the Sun. Its swift movements close to our Sun accorded it special importance to ancient observers, while also making detailed study difficult. However, recent missions to Mercury have resulted in amazing discoveries, with more to come.

Mercury can be one of the brightest planets in the sky – but also easy to miss! Why is that? Since it orbits so close to the Sun, observing Mercury is trickier than the rest of the “bright planets” in our solar system: Venus, Mars, Jupiter, and Saturn. Mercury always appears near our Sun from our Earth-bound point of view, making it easy to miss in the glare of the Sun or behind small obstructions along the horizon. That’s why prime Mercury viewing happens either right before sunrise or right after sunset; when the Sun is blocked by the horizon, Mercury’s shine can then briefly pierce the glow of twilight. Mercury often appears similar to a “tiny Moon” in a telescope since, like fellow inner planet Venus, it shows distinct phases when viewed from Earth! Mercury’s small size means a telescope is needed to observe its phases since they can’t be discerned with your unaided eye. Safety warning: If you want to observe Mercury with your telescope during daytime or before sunrise, be extremely careful: you don’t want the Sun to accidentally enter your telescope’s field of view. As you may already well understand, this is extremely dangerous and can not only destroy your equipment, but permanently blind you as well! That risk is why NASA does not allow space telescopes like Hubble or the JWST to view Mercury or other objects close to the Sun, since even the tiniest error could destroy billions of dollars of irreplaceable equipment.

Despite being a small and seemingly barren world, Mercury is full of interesting features. It’s one of the four rocky (or terrestrial) planets in our solar system, along with Earth, Venus, and Mars. Mercury is the smallest planet in our solar system and also possesses the most eccentric, or non-circular, orbit of any planet as well: during a Mercurian year of 88 Earth days, the planet orbits between 29 million and 43 million miles from our Sun – a 14-million-mile difference! Surprisingly, Mercury is not the hottest planet in our solar system, despite being closest to the Sun; that honor goes to Venus, courtesy its thick greenhouse shroud of carbon dioxide. Since Mercury lacks a substantial atmosphere and the insulating properties a layer of thick air brings to a planet, its temperature swings wildly between a daytime temperature of 800 degrees Fahrenheit (427 degrees Celsius) and -290 degrees Fahrenheit (-179 degrees Celsius) at night. Similar to our Moon, evidence of water ice is present at Mercury’s poles, possibly hiding in the frigid permanent shadows cast inside a few craters. Evidence for ice on Mercury was first detected by radar observations from Earth, and followup observations from NASA’s MESSENGER mission added additional strong evidence for its presence. Mercury sports a comet-like tail made primarily of sodium which has been photographed by skilled astrophotographers. The tail results from neutral atoms in its thin atmosphere being pushed away from Mercury by pressure from the nearby Sun’s radiation.

NASA’s Mariner 10 was Mercury’s first robotic explorer, flying by three times between 1974-1975. Decades later, NASA’s MESSENGER first visited Mercury in 2008, flying by three times before settling into an orbit in 2011. MESSENGER thoroughly studied and mapped the planet before smashing into Mercury at mission’s end in 2015. Since MESSENGER, Mercury was briefly visited by BepiColombo, a joint ESA/JAXA probe, which first flew by in 2021 and is expected to enter orbit in 2025 - after completing six flybys. Need more Mercury in your life? Check out NASA’s discoveries and science about Mercury at solarsystem.nasa.gov/mercury/, and visit the rest of the universe at nasa.gov.

Mercury in morning twilight at 7:15 am, for Traverse City, MI, January 30, 2023. This is Approximately 50 minutes before sunrise. Mercury and the stars are shown somewhat brighter than they will actually appear at that hour. Altair and Antares will be visible, the dimmere stars may not be. Created using Stellarium.

Mercury is hot, small, and heavily cratered across its gray surface, as seen in this image from NASA MESSENGER. Mercury is the most heavily cratered planet in our solar system, since it lacks either a substantial atmosphere or geologic activity to erode surface features like craters - similar in certain aspects to the surface of our own Moon.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Source: https://solarsystem.nasa.gov/resources/439/mercurys-subtle-colors/


For Kids: NASA’s Space Place website

The Space Place is a NASA website for elementary school-aged kids, their teachers, and their parents.

It’s colorful! It’s dynamic!
It’s fun!

It’s rich with science, technology, engineering, and math (STEM) content!

It’s informal. It’s meaty. It’s easy to read and understand. It’s also in Spanish. And it’s free!

It has over 150 separate modules for kids, including hands-on projects, interactive games, animated cartoons, and amazing facts about space and Earth science and technology.

See this month's NASA Night Sky Network article at the bottom of the center panel on this page.

Also check out these two sites for kids: NASA's Climate Kids and NOAA's SciJinks

Bob Moler's Ephemeris contains audio mp3s of current Ephemeris programs; calendars of sunrise, sunset,moonrise and moonset for the Grand Traverse area of Michigan, and other locations in northern Michigan; plus a monthly star chart.

Also Bob's Ephemeris Blog with daily transcripts of and illustrations for his Ephemeris programs on Interlochen Public Radio. Wednesday’s program looks at where the bright planets are along with finder charts.

Northwestern Michigan College's Joseph H. Rogers Observatory

If you'd like to donate

From Article II, B of the Articles of Incorporation of the Grand Traverse Astronomical Society:

The Society shall operate a scientific and educational organization with the goal of increasing interest in, the knowledge and enjoyment of astronomy; cooperate with similar organizations; and cooperate with Northwestern Michigan College to increase the benefit of the college observatory to the community.

As you can see by the statement above the society is inexorably linked to the Joseph H. Rogers observatory. However in the past number of years members have been also taking telescopes out into the community, on sidewalks and street corners, and in the street on Friday Night Live, and to the Sleeping Bear Dunes National Lakeshore. We find that many folks in the area have never been out to the observatory. This way we are going to to the public. And having a huge telescope is really a great attraction, not to mention the superb views of the heavens it will provide.

We have purchased a 25 inch Dobsonian telescope with trailer to use and to take around for our outreach program. We have also purchased two solar telescopes to view the Sun's prominences and chromosphere.

We have recently purchased small telescopes to give to libraries for them to lend out. The first two recipients are Traverse Area District Library and Betsie Valley District Library. Enerdyne of Suttons Bay donated the second telescope..

You may contribute to the fund to help us upgrade and add accessories to the society's telescopes by mailing a check to the GTAS, c/o the society treasurer Gary Carlisle, 1473 Birmley Rd, Traverse City, MI 49686. We are a 501(c)(3) non profit organization. Donations are tax deductible.

Thank You!

Updated: 01/06/23 10:56:22 PM