From The Director

by Rex Parker, PhD director@princetonastronomers.org

Escape from the Black Hole of Relentless News Headlines.  Though we had a couple of rainouts for May events, the lunar eclipse AstroVideo Live was saved by member Rich Sherman broadcasting from Florida May 15.  We’ll keep going with Public Open House each Friday night at the Observatory at Washington Crossing State Park.  Join the adventure of direct astronomy with excellent telescopes, along with your own family and friends – spread the word about our Friday night sessions. 

We want to see you in person at the next monthly meeting of AAAP.  The last meeting of the academic season will be held in person — for the first time since March 2020! 

June 14 meeting (7:30pm) in person at the Planetarium in Trenton The meeting will also be broadcast by You Tube and Zoom from location, although the main planetarium show on the dome cannot not be shown.  Planetarium Technician Bill Murray, AAAP member and Outreach Chair, will run the celestial show featuring a new state of the art computing and projecting system.  For more info see the Program Chair article below.

Then, just when we needed some positive science news to cut through the background of chaos and continually worrisome news reporting, the astrophysics world came through!  Over the past month we’ve seen breakthroughs in both solar system and deep sky fronts. These results from long-term projects reaching pivotal moments are even more amazing when you ponder the degree of difficulty of engineering and the depth of scientific questions being asked. 

The first-ever telescopic image of our Galaxy’s supermassive black hole, called Sagittarius A* in radio radio-astronomy, was just published from the multiyear collaboration called the Event Horizon Telescope.  This is a network of large radio telescopes linked together around the world.  A very long baseline interferometer, this is the time the black holes at the center of our galaxy could be resolved.  By coincidence, the angular size of these two black holes is similar, so the resolution of the Milky Way’s black hole is the same as M87’s, and the images look surprisingly similar.  In the image published by the group, gravitationally lensed emissions glow around a dark shadow which is the event horizon of our galaxy. This publication and a set of related papers can be read in the May 12 special issue of Astrophysical Journal Letters.

Boeing’s Starliner spacecraft returned to Earth May 25 after the first successful uncrewed test flight, with 4.5 days at the International Space Station.  It made a picture-perfect landing in the desert and met all the mission objectives, a very big deal to the future of NASA and planetary space travel.  The James Webb telescope successfully collimated its mirror and is now testing the science instrumentation, and it won’t be long until the first actual data streams come forth.  And Solar Orbiter’s new images of the sun are as dramatic as we were hoping.  Late in March, the ESA’s Solar Orbiter made its closest approach to the Sun so far, inside Mercury’s orbit, to about one-third of the Earth-Sun distance.  With the most complex science lab ever sent to the Sun, Orbiter observes solar events in multiple modes and wavelengths simultaneously.  The recent data, images, and videos are totally engaging and can be reviewed at the ESA Solar orbiter site.

George Abell’s Amazing List from Palomar.  In 1966 the American astronomer George Abell published a list of 86 likely planetary nebula based on discoveries before 1955 from the National Geographic and Palomar Sky Survey with the 48-inch Oschin telescope at Mount Palomar, California.  This telescope, sometimes referred to as the world’s largest Schmidt camera, was the forerunner of today’s deep sky surveys and conducted a dozen other surveys since 1995.  As a quick aside, the glass corrector plate has a 48-in aperture and the primary is a 72-inch f/2.5 mirror. It was originally designed to use 14-inch square photographic plates, each covering 6×6 degrees of sky, and since 2000 has used CCD detectors instead of film.  

Not as well-known as the Messier list (which includes many objects that are not planetaries), the planetary nebulae on Abell’s list are fainter and more challenging to observe.  But when accessible under the right conditions they can be wonderfully mysterious with beautiful color and structure.  Last month I was fortunate to remotely observe Abell PLN 35 in the southern hemisphere constellation Hydra, using a 24” Planewave Telescope in the Chilean Andes.  The nebula emits strongly in the ionized oxygen (O-III, blue) and hydrogen (H-alpha, red) bands, with shock-wave like regions of density.  Located about 1200 light years away and about 5 light years across, Abell PLN 35 has a magnitude value 12.7 and angular diameter ~12 arc-min. 

Abell Planetary Nebula (PLN 35) Imaged with CCD Camera and 24” Telescope in Chile.  True colors are based on R, G, B filters plus H-alpha (red) and O-III (blue) narrow band filters.  Angular size, 31×31 arcmin.  The bright star in the field is magnitude 8.4.  Astrophoto by RAParker

This entry was posted in June 2022, Sidereal Times and tagged , . Bookmark the permalink.

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