April 2025 Meeting Notes

Bartlesville Astronomical Society Meeting Notes

April 7, 2025

Attendance: 

We had 14 members and 4 visitors in attendance this evening, in person and on Zoom.

Astronomical trivia—John G:

·       How many comets described and reported to the Minor Planet Center during 2025, as of our March 3 meeting?  17 (Denise had guessed 10)

·       What is the largest constellation by area?  Hydra, 1303 square degrees

·       What is the oldest named constellation?  Taurus.  17,000-year-old paintings in France’s Lascaux caves show a bull’s head with the Pleiades!

·       Who named the most constellations?  Ptolemy—he named 48 out of the 98 current constellations!

Astronomy 101—Gravity—Pat S:

·       The speed of light is constant.

·       Weight is equivalent to gravity.

·       Gravity makes clocks run slower, but gravity doesn’t warp time—the warping of time causes gravity.  Earth’s mass slows time.

·       There is a good PBS video on gravity.

We need more volunteers for Astronomy 101, 10-minute astronomy, to cover the months of May through December. 

·   Daryl offered to do 10-minute cosmology in October.

·   One of our guests this evening offered to do mythology in December.

Main presentation:  Marine Navigation and Astronomy by Daryl and Gil

·       Daryl and Gil gave us a very interesting presentation on how astronomy relates to marine navigation!

·       They discussed the parts of a sextant and brought one for us to pass around the room to hold and look at.  They also passed around a star wheel and showed us a ship’s compass.

·       To help you locate your position, you need an accurate table called an ephemeris.  An ephemeris gives the predicted positions in the sky at given times of objects like the sun, moon, planets, and stars.  To use an ephemeris, you need to be familiar with constellations and picking out stars in the night sky. 

·       You also need to know some other elements of astronomy to do celestial navigation, such as the Zodiac and the celestial ecliptic.

·       It’s hard to work out accurate time based on your longitude.  Gil and Daryl told how to find your latitude and longitude using the Sun.  You use a sextant, take readings, and write down the time.  To do this, you need to know when noon is.  The solar readings on a sextant will go higher and higher and then start going down.  The highest point is noon.

·       The three stars in Orion’s belt are nearly on the celestial equator, so that is a guide to the position of the celestial equator.

·       The sword of Orion points south.

·       An alternative to using Orion in celestial navigation is to use Polaris, the North Star.  The Big Dipper as well as Cassiopeia point to Polaris.  To find your latitude and longitude using Polaris with a sextant, you find the angle to Polaris at a given time.

·       The book Longitude, the True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time, written by Dave Sobel, discusses the work of John Harrison.  John invented the marine chronometer.  This instrument could tell the right time when at sea.

·       Daryl and Gil also discussed the use of the Nautical Almanac.  The Nautical ‘Almanac gives the dates and times of various positions of astronomical objects.

·       Gil and Daryl recommended a PBS show, Lost at Sea, the Search for Longitude.

Upcoming Club Events:

·       April 18, weather permitting, at Boy Scout Camp McClintock:  The Billion Light Year Club—to see Quasar 3C 273, 2.5 billion light years away.  This quasar is magnitude 12.9, located in the constellation Virgo.  It would appear as a faint star-like object.  Its photons have been traveling toward us 2-plus billion years.  Could we capture it with a Seestar? Alternate dates April 25 and 26.

·       May 3 is Astronomy Day—starting to plan something at the library

·       Next Club meeting May 5—special guest speaker arranged through the Night Sky Network, Dr. Liliya Williams, Professor, Minnesota Institute for Astrophysics. Her topic is “What we know and don’t know about dark matter”.

Upcoming Astronomical Events: 

Luann showed us a poster with these upcoming astronomical events--

·       April 5—Moon, Mars and Gemini.  Mars and the Moon will be about 2° apart in the late evening, high in the southern sky.

·       April 12—Full pink moon

·       April 22—Lyrid meteor shower

·       April 24—Venus at its brightest                               

·       April 25—Triple conjunction—Venus, Saturn and Moon

·       April 29—Four planets appear together—Venus, Saturn, Jupiter, Mars

Craig also said he would go to the sundial by the Price Tower on April 15 to observe noon on the sundial, which would actually be closer to 1 p.m. CDT. 

Treasurer’s Report – Evan Z:

·       Ending balance February 28, 2025:  $17909.96

·       Deposit $320.00 from Benevity Causes

·       Deposit $50.00 membership dues and donations

·       Deposit $44.57 Truity account interest

·       Expense $63.72 reimbursement to Denise for library display supplies

·       Ending balance March 31, 2025:  $18260.81

Club purchase of Seestar telescope:

The Club approved buying a Seestar telescope.  Craig advised delaying the purchase because a new version of the Seestar is scheduled to come out around June 1.

Steve Plank’s equipment:

Suzanne Plank said she could offer the Club some of Steve Plank’s equipment that she has.

Website:

John G discussed the website needing to be updated, and need a webmaster.  Pat S said that he has built some websites and would like to try to do something for us. The Club agreed that he should try this, and Gil offered to help.  Pat would like input from everyone on what they would like to see in our website.  Pat recommended looking at the Colorado Springs Astronomical Society website, https://csastro.org/, for ideas.

BAS needs volunteers:

We need volunteers for public star parties and other observing events.  All members are encouraged to help out with some of these events.  In addition to telescopes, help is needed with setup, answering general stargazing questions, conversing with and encouraging visitors, providing handouts and signup sheets. If you can help, contact jrgrismore@icloud.com.

Reminders:

BAS has equipment, books, educational materials and scopes available for loan to qualifying members.