Archive
05/26/2023 – Ephemeris – Sun & Star Party tomorrow at the Sleeping Bear Dunes National Lakeshore
This is Bob Moler with Ephemeris for Friday, May 26th. Today the Sun will be up for 15 hours and 11 minutes, setting at 9:15, and it will rise tomorrow at 6:03. The Moon, 1 day before first quarter, will set at 2:48 tomorrow morning.
Tomorrow, the Sleeping Bear Dunes National Lakeshore and the Grand Traverse Astronomical Society will host a Sun and Star Party at the Dune Climb area of the park. There will be a solar viewing period from 5 pm to about 7 pm. The society has two hydrogen alpha solar telescopes to view the Sun’s chromosphere and prominences. Plus, some members also have solar scopes and white light filtered telescopes to view sunspots on the face of the Sun. Night viewing will start at 9 pm, with the Moon and Venus featured, along with the brighter telescopic wonders of late spring. There will be a pass of the International Space Station from 10:11 to 10:18 pm. The rangers will have an alternate program if it’s cloudy.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
Addendum

A Sun Party at the Dune Climb. Credit: Eileen Carlisle.

Preparing to start the May star party, several years ago at the Dune Climb. A few of the telescopes are visible, including the GTAS 25″ “Emmettron” telescope at the far right background. Credit: Eileen Carlisle.
04/28/2023 – Ephemeris – International Astronomy Day is tomorrow
This is Bob Moler with Ephemeris for Arbor Day, Friday, April 28th. Today the Sun will be up for 14 hours and 6 minutes, setting at 8:43, and it will rise tomorrow at 6:36. The Moon, 1 day past first quarter, will set at 4:23 tomorrow morning.
Tomorrow is International Astronomy Day. The Grand Traverse Astronomical Society (GTAS) will celebrate the event with a Sun and Star Party at the Dune Climb area of the Sleeping Bear Dunes National Lakeshore. There will be a solar viewing period from 6 pm to about 7:30 pm or so, when the Sun will set over the dune. The society has two hydrogen alpha solar telescopes, and members have another two, to view the Sun’s chromosphere and prominences. Plus, other members have white light filtered telescopes to view sunspots on the face of the Sun. Night viewing will start at 9 pm with the Moon and Venus featured, along with the brighter telescopic wonders of spring. But only if the skies are clear or mostly clear.
The next GTAS event at the Sleeping Bear Dunes will be Saturday, May 27th, with a program like this Saturday’s. What we call a Sun ‘n Star Party.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT –4 hours). They may be different for your location.
Addendum
10/07/2022 – Ephemeris – Learn about the Sun tonight and view the Moon on Saturday
This is Bob Moler with Ephemeris for Friday, October 7th. Today the Sun will be up for 11 hours and 24 minutes, setting at 7:12, and it will rise tomorrow at 7:49. The Moon, 2 days before full, will set at 6:08 tomorrow morning.
Tonight at 8 pm, the Grand Traverse Astronomical Society will have an in-person meeting at Northwestern Michigan College’s Rogers Observatory. The meeting will also be available via Zoom. The program will be presented by Mary Gribbin who has been observing the sun through her special solar telescope. She’ll describe the features visible with a solar telescope. If it’s clear, there will be a star party following the meeting. The observatory is located south of Traverse City off Birmley Road, between Garfield and Keystone roads. A Zoom link is available at gtastro.org. There will be a Moon and star party at the Sleeping Bear Dunes, Dune Climb tomorrow starting at 8 pm. That may be our last of the year out there. 2023 promises to have a full slate of star parties out there.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.
Addendum
Excerpt from the Sleeping Bear Dunes National Lakeshore calendar posting:
“These events will be cancelled if the sky is not visible due to weather conditions. The decision to cancel is usually made either three hours in advance or by 4:30 p.m. the day prior to the event. Please call park rangers at 231-326-4700, ext. 5005, for a voicemail message with the decision. For the early morning and late evening astronomy events, bring a flashlight for the walk to and from the event. Park rangers and GTAS staff will wear red glow bracelets at the events. For more information about the Grand Traverse Astronomical Society, go to http://www.gtastro.org/.“
09/23/2022 – Ephemeris – Weather prospects look dim for a star party tomorrow night, but we won’t know for sure until we get closer
Update: The Star Party has been Canceled
Here’s a deep dark secret: Ephemeris programs are recorded the Sunday night for the week beginning Tuesday through the following Monday. However, the posting of the scripts here is generally done the night before the air date. From this vantage point, with the weather forecast not changing for the past week, it looks like we’ll be greeted with not only clouds but rain. The operative words in the post below are “weather permitting”, Which explains the headline.
This is Ephemeris for Friday, September 23rd. Today the Sun will be up for 12 hours and 7 minutes, setting at 7:38, and it will rise tomorrow at 7:32. The Moon, 2 days before new, will rise at 5:54 tomorrow morning.
Weather permitting, a star party will be held tomorrow night, Saturday, September 24th at Sleeping Bear Dunes National Lakeshore at the Dune Climb starting at 8 pm. The star party will be hosted by the Park Rangers and members of the Grand Traverse Astronomical Society (GTAS), who will bring their telescopes to view the heavens, including the planets Jupiter and Saturn plus the wonders of the summer Milky Way. The telescopes will be set up in the parking area closest to the dune. Saturn will be available immediately, while we wait for Jupiter to rise higher. As it gets darker, more and more wonders of the Milky Way will be seen. They include star clusters and nebulae, clouds of gas and dust from which stars form, and which are expelled in the process of star death.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.
Addendum
If you are not sure if it will be clear enough to hold the star party, please call the park rangers at 231-326-4700, ext. 5005, for a voicemail message with the decision. Alternately, gtastro.org, the GTAS website, will also display the status of the star party, and if it is canceled by 5 pm on Saturday the 24th.

This in the beginning of setup for the October 21, 2017 star party at the dune climb. Taken early, looking to the south-southwest, while there was enough light. The dune blocks up to 12 degrees from the southwest to northwest, but the rest of the horizon is quite low. Note the lone trees on the hill right of the top of the ladder. They are my targets to align my telescope’s finder. Once, while performing the alignment, a fog bank tumbled over that ridge and wiped it out for a time. It was eventually a good night.
We’ve had more than our share of iffy weather at or travelling to the site. A good share of GTAS members live in the Traverse City area, some 30 miles east of the park. More than a few of us, over the years, have driven through rain showers, on our way to the park, for a successful star party. Here’s a link to another night with iffy weather, this time with a lunar eclipse.
09/09/2022 – Ephemeris – Observe the Harvest Moon at the Sleeping Bear Dunes Saturday night (weather permitting)
Update 9/10/2022, 6 pm: The weather does not permit it! We’ll have another, again weather permitting, on September 24th. This time with dark skies and a look at the summer Milky Way, two days after the end of summer. (It still counts).
This is Ephemeris for Friday, September 9th. Today the Sun will be up for 12 hours and 49 minutes, setting at 8:04, and it will rise tomorrow at 7:15. The Moon, 1 day before full, will set at 7:14 tomorrow morning.
Tomorrow night, September 10th, there will be, weather permitting, a star party at Sleeping Bear Dunes National Lakeshore, this will take place at the Dune Climb. Actually, it will be mostly a Moon and planet party. The event will be made possible by the rangers of the park and the Grand Traverse Astronomical Society. The society’s and member’s telescopes will take over the parking lot closest to the Dunes. The event starts at 8 p.m., near sunset, while it’s still light out and the location can be found. The Moon will join the party, rising at 8:41 pm. Oh, and it’s a supermoon. There will be a short talk about Harvest Moon lore and why it was important. See if you can find the Man in the Moon and the Chinese rabbit pounding medicine.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.
Addendum
08/22/2022 – Ephemeris – Sleeping Bear Dunes Star Party tonight!
This is Bob Moler with Ephemeris for Monday, August 22nd. Today the Sun will be up for 13 hours and 43 minutes, setting at 8:36, and it will rise tomorrow at 6:54. The Moon, 3 days past last quarter, will rise at 2:43 tomorrow morning.
Weather permitting, a star party will be held tonight at the Sleeping Bear Dunes National Lakeshore at the Dune Climb starting at 8 pm. The star party will be hosted by the park rangers and the Grand Traverse Astronomical Society, who will bring their telescopes to view the heavens, including the planet Saturn and the wonders of the summer Milky Way. The telescopes will be setup in the parking area closest to the dune. While as twilight fades Saturn will be about the only object to view, as it gets darker more and more wonders of the Milky Way will be seen. They include star clusters of both kinds: young open clusters of a few hundred stars sparkling like diamonds and great, ancient globular clusters of hundreds of thousands of stars. Jupiter will rise later in the evening, around 10 pm.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.
Addendum
07/22/2022 – Ephemeris – Saturday, weather permitting, there will be a star party at Sleeping Bear Dunes
This is Ephemeris for Pi Day number 2, Friday, July 22nd. Today the Sun will be up for 15 hours and 1 minute, setting at 9:19, and it will rise tomorrow at 6:19. The Moon, 2 days past last quarter, will rise at 2:01 tomorrow morning.
What’s Pi Day number 2? In the European way to write the date: 22 July or 22/7, the improper fraction that approximates pi, the ratio of the circumference of a circle to its diameter.
On to astronomical matters: Tomorrow night July 23rd there will be, weather permitting, a star party at Sleeping Bear Dunes National Lakeshore, this will take place at the Dune Climb. The star party is made possible by the rangers of the park and the Grand Traverse Astronomical Society. The society’s and member’s telescopes will take over the parking lot closest to the Dunes The event starts at 9 p.m., while it’s still light out and the location can be found. The park rangers will leave at 11, while the society members will stay longer.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.
Addendum
Excerpt from the Sleeping Bear Dunes National Lakeshore calendar posting for August 23:
“These events will be cancelled if the sky is not visible due to weather conditions. The decision to cancel is usually made either three hours in advance or by 4:30 p.m. the day prior to the event. Please call park rangers at 231-326-4700, ext. 5005, for a voicemail message with the decision. For the early morning and late evening astronomy events, bring a flashlight for the walk to and from the event. Park rangers and GTAS staff will wear red glow bracelets at the events. For more information about the Grand Traverse Astronomical Society, go to http://www.gtastro.org/. “

Preparing to start a star party at the Dune Climb in a year before COVID. A few of the telescopes are visible, including the GTAS 25 inch “Emmettron” telescope at the far right. Credit: Eileen Carlisle.
Celestial events that night at the Dune Climb:
9:17 pm – Sunset (Sun will set behind the dune by around 8 pm)
9:57 pm – ISS* pass: highest 24° altitude in the north, moving from WNW to ENE.
10:00 pm – Brighter stars are visible. Telescopes can start to show the brighter binary stars.
10:20 pm – Saturn rises in the east-southeast. The sharpness of its image will improve as it rises higher in the sky.
10:33 pm – Nautical twilight ends. The brighter deep sky objects (DSOs**) become visible in telescopes. The Milky Way begins to show.
11:31 pm – ISS pass: highest 43° north-northeast, moving from NW to ENE
11:33 pm – Astronomical twilight ends. The sky is now completely dark.
* ISS – International Space Station. Start to look for it 2-3 minutes before this time. It will be at its brightest at its highest altitude.
** Deep Sky Objects – Telescopic objects beyond the solar system. They include star clusters, nebulae, and galaxies. Though that night, the only galaxy visible will be the Milky Way.
Click here for the definitions of the types of twilight.
09/03/2021 – Ephemeris – Tonight: Virtual Star Party via Zoom with the Sleeping Bear Dunes National Lakeshore
This is Ephemeris for Friday, September 3rd. Today the Sun will be up for 13 hours and 7 minutes, setting at 8:15, and it will rise tomorrow at 7:09. The Moon, 3 days before new, will rise at 4:01 tomorrow morning.
Tonight the Sleeping Bear Dunes National Lakeshore and the Grand Traverse Astronomical Society will host an online star party this evening starting around 9 pm via the Zoom app available for Android smartphones, iPhones and computers. Instructions for joining are on the society’s website, gtastro.org. Images will be captured live, if it’s clear, from Northwestern Michigan College’s Joseph H Rogers Observatory. The images will be pretty much what is seen at the telescope eyepiece, and definitely not Hubble Space Telescope quality, which take weeks to process. Visible will be the Venus, Jupiter, Saturn and wonders of the Milky Way, some really neat star clusters, and nebulae, that is clouds of gas and dust in the Milky Way.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.
Addendum
Also, the planets Venus, Saturn and Jupiter will be visible during the session.
This post is going out at Midnight the night before, and the forecast is for clouds. It is possible that we will reschedule for Friday the 10th. If so, I’ll have a post about it then.
10/16/2020 – Ephemeris – There’s an online star party tonight if it’s clear
This is Bob Moler with Ephemeris for Friday, October 16th. Today the Sun will be up for 10 hours and 55 minutes, setting at 6:55, and it will rise tomorrow at 8:01. The Moon is new today, and won’t be visible.
Tonight the Sleeping Bear Dunes National Lakeshore and the Grand Traverse Astronomical Society may hold the another of the park’s 50th anniversary online star parties this evening starting around 8 pm via the Zoom app available for Android smart phones, iPhones and computers. Instructions for joining are on the society’s web site gtastro.org and the Sleeping Bear Dunes Facebook page. The images will be captured live from Northwestern Michigan College’s Rogers Observatory south of Traverse City. If it is cloudy, the event will be rescheduled for Saturday night at 8 pm. Another backup night will be Friday the 23rd. The images will be pretty much what is visible at the telescope eyepiece, and definitely not Hubble Space Telescope quality.
gtastro.org will announce cancellations and alternate plans as soon as the decision to cancel is made.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Nights of star parties past
These pictures were taken before the star parties actually began and most of the crowds showed up, when there was enough light for photography. We don’t take flash pictures during the events.

Sleeping Bear Dunes National Lakeshore’s 40th anniversary cake lighting at the Stop 3, Pierce Stocking Scenic Drive (Dunes Overlook) October 21, 2010. This was the GTAS’ second star party with the park in the society’s now a bit over 10 year collaboration with the park. Credit: Eileen Carlisle.

Star Party at the Sleeping Bear Dunes National Lakeshore, Thoreson Farm August 2013. Credit Eileen Carlisle.

Preparing to start the May star party at the Dune Climb. A few of the telescopes are visible including the GTAS 25″ “Emmettron” telescope at the far right. Credit: Eileen Carlisle.

Star Party at the Dunes Overlook. Credit: Eileen Carlisle. We’ve since had to abandon hosting star parties here. A victim of our success, due to a lack of enough parking here and at Picnic Mountain next door.

A Star Party at Sleeping Bear Dunes National Lakeshore’s Platte River Point. Credit: Eileen Carlisle
09/25/2020 – Ephemeris – The Sleeping Bear Dunes National Lakeshore Virtual Star Party is tonight
This is Ephemeris for Friday, September 25th. Today the Sun will be up for 11 hours and 59 minutes, setting at 7:33, and it will rise tomorrow at 7:35. The Moon, 2 days past first quarter, will set at 1:51 tomorrow morning.
Tonight the Sleeping Bear Dunes National Lakeshore and the Grand Traverse Astronomical Society may hold the park’s 50th anniversary online star party this evening starting around 8 pm via the Zoom app available for Android smart phones, iPhones and computers. Instructions for joining are on the society’s web site gtastro.org and the Sleeping Bear Dunes Facebook page. Images will be captured live, if it’s clear, from Northwestern Michigan College’s Joseph H Rogers Observatory. The images will be pretty much what is seen at the telescope eyepiece, and definitely not Hubble Space Telescope quality, which take days to process. Visible will be the Moon, Jupiter, Saturn and later on Mars plus some really neat objects beyond the solar system. it all begins at 9 pm.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.