Welcome

OUR CLUB
The SAS was founded in 1975 to foster the development of amateur Astronomy in the east-central Michigan area. Members come from all walks of life and span a wide range of ages. Our activities include observing sessions, annual public star parties, and friendly meetings where we share our common interest and learn from formal presentations and each other. If you are interested in astronomy, please join us at one of our monthly meetings.

News

 NEXT CLUB MEETING: April 12, 2019
Friday April 12, 2019 
Bay City State Park 6pmApril's SAS meeting will take place at Bay City State Park
(3582 State Park Drive). 
​
Important news about the next meeting of the Sunset Astronomical Society,
Friday April 12, 2019 (mark it on your calendars!).
 
April 12 is Statewide Astronomy Night and our meeting will take place at the Bay City State Park (3582 State Park Drive Bay City, MI 48706).  (See MAP here)  The Park and the Delta College Planetarium are partnering together for Statewide Astronomy Night (SWAN).  A special public event is planned, and we need club volunteer help and time to help make it a big success and a lot of fun for everyone!
SCHEDULE:
  • 6:00pm  SAS members can arrive to set up
  • 7:00pm  Activities start inside the Visitor Center - PUBLIC WELCOME
                        (solar observing can start outside, weather permitting) - PUBLIC WELCOME
  • 8:00pm  Mike’s talk on basic astronomy & what's up in the sky tonight - PUBLIC WELCOME
  • 9:00pm  Night sky observing starts in the archery lot (weather permitting) - PUBLIC WELCOME
 
Sunset is at 8:14pm
Astronomical Twilight: 9:57pm (there will be a first quarter moon that night)
THANKS IN ADVANCE!!  Come join SAS for a fun night ... no telescope or binoculars are needed for the general public to come share club telescopes and view objects visible.
PLEASE ... those arriving late (past sunset) please use parking lights as you enter/leave the park at the south end of the Visitor Center to preserve night vision of those observing.  THANK YOU!!

MAY MEETING
The SAS May meeting will meet on SATURDAY May 11th instead of the normal Friday meeting.  The meeting will incorporate National Astronomy Day and will be held at the Delta Planetarium  (See Map)
  • 7:30pm:     Planetarium show about observing techniques (by Mike Murray)
  • 9:00pm:     Telescope Workshop - Club telescopes will be available for working with the public
  • 7:30-9:00pm:     Family & kid activities in lobby 
  • 10:00pm:    Observing on the deck of the planetarium (weather permitting)

meetings and observing events

Club meetings and observing events are listed in the club calendar on the "MEETING / EVENT CALENDAR" page . This calendar changes frequently with up to date status of meetings and events. Listed future events are tentative and subject to change due to weather and other conditions. 

SAS newsletters

Please view our newsletters for a wealth of information on club activities and important and interesting articles about astronomy.

recent activities

PictureThis artist’s impression shows a computer generated model of the Milky Way and the accurate positions of the globular clusters used in this study surrounding it. ESA / Hubble, NASA / L. Calçada
The Milky Way Contains the Mass of 1.5 Trillion SunsBy: Monica Young | March 18, 2019
Courtesy of Sky & Telescope Magazine's Weekly Guide to Astronomy

Astronomers are using Gaia and the Hubble Space Telescope to make the most precise measure of the Milky Way’s mass to date. The new result puts our galaxy on par with — if not more massive than — Andromeda Galaxy.
The mass of the Milky Way has long been debated, to the point that we don’t even know where it stands in the Local Group of galaxies. Is it the heavyweight champion, or does our sister galaxy, Andromeda, outweigh us?
Laura Watkins (Space Telescope Science Institute) and colleagues have used data recently released by the European Space Agency’s Gaia satellite, as well as roughly ten years of Hubble Space Telescope observations, to peg the motions of 46 tightly packed bunches of stars. Known as globular clusters, their orbits help pin down the Milky Way's mass.

Our galaxy’s gravitational pull determines the clusters’ movements, explains coauthor N. Wyn Evans (University of Cambridge, UK). If our galaxy is more massive, the clusters will move faster under the stronger pull of its gravity. The key is to understand exactly how fast the clusters are moving.
Many previous measurements have measured the speed at which a cluster is approaching or receding from Earth. “However,” Evans says, “we were able to also measure the sideways motion of the clusters, from which the total velocity, and consequently the galactic mass, can be calculated.”
The team finds a mass equivalent to 1.5 trillion Suns. The results will appear in the Astrophysical Journal (preprint available here).
A Tricky ScaleAstronomers have been fussing over the mass of the Milky Way the way parents fuss over their newborns. Understandably so: Just as a baby’s weight serves as an indicator of more important things, like their growth and well-being, the heft of our galaxy affects everything from our understanding of its formation to the nature of dark matter.
But while the pediatrician will usually tell you your baby’s weight to within a percent (equivalent to a tenth of an ounce if you’re in the U.S.), the Milky Way’s mass is known only to within a factor of two. Imagine putting your newborn on the scale, only to have the needle waver between 5 and 10 — is baby failing to thrive? Or doing just fine? The uncertainty would render the result meaningless.

INTERESTING?  Read more at Sky & Telescope's web page: https://www.skyandtelescope.com/astronomy-news/milky-way-contains-mass-trillion-suns/?k=vEnrofEgJvneaRhq1y9ryEhSEd9gsj%2BMsl6ZgLBIURM%3D&utm_medium=email&utm_source=newsletter&utm_campaign=sky-mya-nl-190322&cid=DM110178&bid=1085042875