October 2023 Meeting Notes

Bartlesville Astronomical Society Meeting Minutes

October 2, 2023

• Opening and Welcome

•     Thank you to Denise Gregg for Zoom setup.

•     21 in attendance this evening—13 members (including one new member who joined this evening!) and 8 guests, including our guest speaker for this evening!

• Observing and Imaging Reports

•     No reports from attending the Okie-Tex star party September 8-16

•     Craig showed four images from Sonny Manley—the Sun in brilliant orange, the Sun in grayscale, and Saturn and Jupiter.

•     Tallgrass Prairie—Craig and Denise checked this out for viewing Comet C/2023 P1 (Nishimura), but it was too light and hazy at sunset, even with the remote Tallgrass Prairie location.  They also checked it out as a potential viewing location for Northern Lights.  Tallgrass Prairie closes at 7 p.m., so we wouldn’t be able to go inside the park to view Northern Lights.  (Craig showed an image of Northern Lights taken at the entrance to Tallgrass Prairie in April 2023.)  The skies at Tallgrass Prairie did get dark—Craig showed images he took of Sagittarius, Scorpio, the Milky Way and Ptolemy’s Cluster.

•     Denise showed images she took of Starlinks at the August 19 Club star party at Jo Allyn Lowe, and of Comet C/2023 P1 (Nishimura) taken before dawn on September 9.

•    Astronomical News and Events

• Virgil Reese - Astronomy news – Virgil wasn’t in attendance this evening.

•    Anyone planning to go somewhere for the solar eclipses?

•    Broken Arrow Sidewalk Astronomers will be at the Discovery Lab at 3123 Riverside Drive on October 14 for the annular eclipse.  Their mobile observatory will be there.

• https://icarusshades.com - Andrew Oleson has solar glasses to sell

•    Annular eclipse on October 14, 2023:  We discussed having an event at the mall from 10:30 a.m.-1:30 p.m. (The eclipse begins at 10:23 a.m. and ends at 1:23 p.m.)   Five of our members who would typically help with such an event won’t be able to help.  Only three others present at the meeting or on Zoom would be able to help, so we decided not to have an organized event for the annular eclipse.  (We would have needed at least five-six people to help at such an event.)  [Note:  We did decide later to have an event at the mall.]

•    Total eclipse on April 8, 2024—Many Club members already have plans to travel to see this eclipse in totality.

•     We decided to have our October star party be the Observe the Moon event October 21.  We will have that at Jo Allyn Lowe Park and will start setting up equipment at 7 p.m.

•    On October 20, the Broken Arrow Sidewalk Astronomers are planning a trip to visit the Keystone Ancient Forest

•    Kalamazoo Astronomical Society news:

• Monthly meeting October 6

• Introduction to Astronomy class in January - Registration in November

• Eclipse series starting in November; one of the speakers will be Fred Espenak, who worked with Ken Willcox on the Totality book.

•    https://kasonline.org to register

• Denise reviewed upcoming meteor showers peaking in October and early November:

• Orionids--September 26-November 22, peak night Oct. 20-21, predawn.  Radiates from club of constellation Orion, north of bright, ruddy star Betelgeuse. 

• Southern Taurids--September 23-December 8, peak Nov. 6.  Peak time just before dawn.  Radiates from constellation Taurus.  (Taurus is NE from constellation Orion.)  This shower tends to be rich in fireballs.

• Draconids--October 8-9, peak October 8, late evening, 10 p.m.-midnight or a little past.  Radiates from constellation Draco.  Sometimes Draconids may be visible at nightfall through early evening.

• Andromedids--October 24-December 2, peak November 6, late evening 10 p.m.-midnight or a little after.  Radiates from constellation Andromeda.  Watch for possible outburst this year.

• Lambda Ursae Majorids.  October 18-November 7, peak October 28, predawn, best seen last hour before dawn.  Radiates from southern Ursa Major

• Kappa Ursae Majorids.  October 28-November 17, peak November 5, predawn, best seen last hour before dawn.  Radiates from SW Ursa Major.  The two Ursae Majorids showers are minor showers, but we think we saw meteors from one or both of these at a Club star party at Jo Allyn Lowe on October 29, 2021.

• Business

•    Minutes of previous meeting are posted online by Denise Gregg - Approved

•    Treasurer’s Report - Evan Zorn:

•    Ending balance August 31, 2023:  $13,897.77

•    September expenditures:

•     $27.77 solar filter for Club telescope

•     $70.56 for future speaker gifts from Amazon Marketplace

•     $74.95 for Zoom annual renewal

•     $176.00 for P.O. Box annual renewal

•     $411.00 for State Farm insurance renewal

•    The Club received a donation of $1,081.20 from Benevity Causes.

•    Ending balance September 30, 2023:  $14,218.69

•    Request for NASA speaker for November 6 meeting

•    We haven’t been notified of a speaker yet; Denise has tried to contact the person working on this multiple times.

• http://www.universe-of-learning.org

•    Committee Reports

•    Astronomical League news and activities - Denise Gregg: 

•    Denise got the annual email from the Astronomical League about free bulk shipping for Astronomical League calendars and handbook for 2024.  To get free shipping for a calendar, the Club would need to order six calendars at $19.00 each.  To get free shipping for a handbook, the Club would need to order 10 handbooks at $26.00 each.  No members present at the meeting in person or on Zoom were interested in doing a bulk order.  Calendars ordered are $21.00 each plus shipping, and handbooks ordered individually are $27.00 each plus shipping.  Here is the website page for ordering--https://store.astroleague.org/

•    Denise also mentioned that the 2025 Astronomical League convention, ASTROCON 2025, will take place June 25-28 at the Ruby’s Inn and Convention Center, located a few miles from the entrance to Bryce Canyon National Park in southern Utah.  The Astronomical League is putting out a call now for volunteers who would like to coordinate workshops for the convention.  The convention’s goal is to teach how to enhance one’s personal viewing experiences through workshops and evening viewing, plus opportunities to learn photography/digital imaging skills.  No deadline at this time for offering to volunteer.  Conference registration and booking of hotel is anticipated to start July 2024.  

•    Youth club (BYA) news - Rick Bryant—Rick was not in attendance this evening.  There was not a scheduled BYA meeting in September.  Rick has had to step down from leading the BYA due to health concerns in his family.  The youth group, which had a monthly attendance of 20-25 youth pre-pandemic, is now down to 2-3 families.  A volunteer to take over leading this group is needed.

•    FCC and mall storage room—Evan

•    We moved out of the First Christian Church to our new storage facility at the mall on September 29.  Thanks so much again to Gary who suggested contacting the mall about storage space; to Evan for setting this up, and to Craig, John B, John G and Denise who helped with loadout and setup at the mall.

•    We will look into getting shelving for our storage space.

•    Old Business

•     Library Telescope—Denise has not heard back yet on the application she submitted in July.

•    New Business

•    Elections

•    Slate of officers:

•    John Blaesi - President

•    John Grismore - Vice President

•    Evan Zorn - Treasurer

•    Denise Gregg - Secretary

•    Nominations from floor—Nominations for Club officers were solicited at the meeting and no members present in person or on Zoom were interested in being nominated for a position.

•    Duane Perkins will not run for re-election as an at-large Board member for 2024.

•    John Blaesi wouldn’t be an at-large member once he is President. 

•    Mall display area

•    We will have a display area inside the mall.  This area is about twelve feet wide, eight feet high and three feet deep.  Ideas are wanted for the display!  If you have any ideas, tell John Blaesi who will be forming a committee to work on this.  (Denise has decided not to head up the mall display committee.  She has volunteered to be on the committee; Andrew Oleson has also volunteered.)

•    The Club voted to spend up to $500.00 for materials to put in the display.  These could include—

•    A digital photo display, which we would see if we could update remotely (not sure if we could do that or not).  John B has priced this out—a 16-17 inch display would cost $200-300. 

•    A telescope, astroturf and a chair (to set the stage for night viewing)

•    Printing of moon posters and any other posters or pictures we would like to put in the display—a rough estimate of printing costs is $50-100.

•    We could possibly also use one of the mall kiosks for an additional display.

•    Binocular purchase program from Vortex Optics

•    50% of MSRP

•    Club - interest in loaning to members

•    Library?

•    OHSP?

•    Girl Scouts?

•    OHSP telescope?

•    OHSP dark sky

•    Club telescopes

•    Do we want to have a loaner scope or binoculars

•    Eclipse ambassador

•    Tonight’s Program - Byron Labadie:  “Understanding Optical Glass for Refractor Telescopes and Lenses”

•    Byron discussed how optical glass is manufactured and then evaluated for its quality.  (If optical glass is “pure”, it has a maximum impurity level of one tenth of one percent!)

•    There are various types of optical glass, including crown glass and flint glass. 

•    There are various types of optical lenses, including achromatic, apochromatic, doublet and triplet.

•    Optical coatings for lenses are used to enhance the transmission of light.  Optical coatings are typically made of combinations of oxides, metals and/or rare earth minerals.  The performance of these coatings depends on the number of layers of the coatings, their thickness and the refraction index between them.  

•    Byron described the process of manufacturing optical glass.  Raw materials are mixed until they melt into a liquid, typically at 2500 degrees F.  The glass goes through more heating and cooling processes as air bubbles are worked out, the glass is poured into molds and then readied to be cut into lenses. 

•    Lenses are then made using a high-speed cylindrical cutter with a round diamond blade called a curve generator.  Cut lenses are then checked with a spherometer.

•    Brands of optical glass are ranked based on their Abbe number.  The Abbe number, a measure of dispersion, is used to characterize the quality of optical glass.  Dispersion is the scattering of white visible light into its component colors (rainbow effect) and shows how much the refraction index changes with the wavelength of light.  Dispersion leads to undesirable chromatic aberration in lenses, which leads to blurring or smearing or color fringing around objects.  Higher Abbe numbers indicate low dispersion. 

•    The grinding process for lenses takes 1-8 hours.  Lenses are ground using a slurry that contains water and an abrasive to do the grinding. 

•    After grinding, lenses are cleaned and then polished.  The polishing tool is made of pitch.

•    Finished lenses are then evaluated using various indices and tools.

•    Thickness and diameter of finished lenses are measured with a Vernier caliper. 

•    Curvature of lenses is measured with a spherometer.

•    The Strehl ratio of an optical lens is a measure of the quality of its optical image formation.  The value of the Strehl ratio is 0 to 1 (1 is best) and the industry standard is a level of 0.8.

•    The aspect ratio of a lens is the proportion of the longest diagonal measurement across a lens surface, compared to the thickness of the lens.  An aspect ratio of over 5:1 isn’t desirable.

•    The clear aperture of a lens is the functional portion of the lens, over which the surface form is guaranteed.  An optical designer can, for example, specify that 90 percent of a surface must meet all required specifications. 

•    The flatness of a lens (part 1) is a measure of the deviation from a theoretically perfect plane surface.  Opticians use interferometers to measure subtle nanometer-scale differences between a known reference and an optical surface of unknown precision.  A lens requirement can be, for example, to have a distance of no more than 632.8 nanometers between the highest peak and the lowest valley across a usable clear aperture. 

•    The flatness of a lens (part 2) measures the overall curvature of a lens along its surface, taking into account any bowing or warping. 

•    The flatness of a lens (part 3) measures the fringes, the light and dark lines that are created when optics are tested against a known reference surface. 

•    Transmitted wavefront distortion is a measurement of the deviation of light when it passes through an optical lens, defined in terms of waves or fringes. 

• Adjournment

•    Next meeting November 6 at library, presentation TBD

• Thanks!

• Ice cream at Braum’s!!!

• Motion to adjourn