Amateur Astronomers Association of Princeton

by Rex Parker, Director

Upcoming events and ideas for AAAP members

• Night-sky refresher at Planetarium
• Changing of equipment at the Observatory
• Software tools for your consideration

A Rare Opportunity for AAAP Members ONLY
Night-sky refresher at the Planetarium – Yes, hands-on astronomy can be done right  despite the light pollution that we all lament!  AAAP is offering a “night sky refresher” opportunity for members wishing to better understand which deep sky objects are visible over the seasons, how to find and identify them, and how to more effectively show them to others. We’ll utilize the considerable strengths of the planetarium along with the expert knowledge of planetarium staffer and AAAP member Bill Murray. Depending on member participation, one or more dates are being arranged in the near future. We need your input, so please take this survey to help us determine best dates for the planetarium sessions.  https://www.surveymonkey.com/r/VDM9QZT

Take Advantage of the New Celestron-14 to Add Photography to Your Observing Skills
Changing equipment at the Observatory – We’re anxious to unveil the new Celestron-14 telescope now installed at the observatory (see photos in this issue). The advantage of the new telescope is Fastar capability.  Fastar is a design invented by Celestron where the secondary mirror is swapped for a special lens and camera mount to allow CCD imaging from the front end of the scope. This results in a very fast focal ratio (f/2.3) which gives a wide field and shorter exposure times for astrophotography, making the whole endeavor easier. We’ll be discussing how to take advantage of this, potentially acquiring a Fastar lens and an appropriate camera later this spring;  you could also use your own camera.  For a taste of what can be done in astrophotography, have a look at the website I recently developed to display my own deep sky images obtained right here in central New Jersey over the past year or two. (http://rexparkerpixels.com/)

The club’s original C-14 telescope had been at our observatory since the millennium turned, a source of pride to members and a wonder to thousands of visitors through the years.  Fittingly, it was sold this month to the North Jersey Astronomy Group, a well-established astronomy club with connections to Montclair State University. With NJAG, the telescope will continue its productive life for New Jersey amateur astronomers and public outreach.

In Search of Something in the Sky?
Software tools for your consideration – Even experienced astronomers need better tools to figure out which celestial objects are visible or best positioned on any given date and time. A number of good software programs are available to help do this.  Software Bisque’s TheSkyX is a truly outstanding planetarium and telescope control program that keyholders are familiar with, as TheSky v6 is currently in use at the observatory. Another program I would like to see more members using is SkyTools3, produced by Skyhound of Cloudcroft, NM.  SkyTools has an extensive database and integrates the core tasks of observation planning, charting, real time observing, and logging into a single tool. No matter the level of expertise, this program lets you get more out of observing, minimizing time spent at the computer and maximizing time under the night sky. There are different levels and costs of the software available.  Let me know if you’re already using this program. If you aren’t, I highly recommend you check it out on-line:  http://www.skyhound.com/order.html

In the News
Ancient Babylonians figured Jupiter’s position through integral calculus.  The current media fanfare about five planets in the early morning sky sets the stage for a remarkable archaeo-astronomy discovery which made the cover of Science this month (M. Ossendrijver, Science 351, issue 6272, Jan 29 2016).  Dr Ossendrijver of Berlin’s Humboldt University, an astrophysicist turned historian, studied clay tablets from the 4^th century BCE with weekly pilgrimages to the British Museum’s vast collection of Babylonian cuneiform tablets. A few tablets prescribed the drawing of trapezoidal figures along with a reference to Jupiter, which Babylonians favored as vehicle of their patron god Marduk. As described in the Science commentary on the paper, Ossendrijver received from a colleague photos of an uncatalogued tablet that seemed to depict some kind of astronomical calculation.  Alone in his office a few months later, he realized the blurry photos showed inscriptions identical to the trapezoid inscriptions he’d been studying.  He concluded that the trapezoid calculations were a tool for determining Jupiter’s displacement each day along the ecliptic over 60 days from when the planet first appears in the night sky before dawn.  This is when Jupiter’s apparent motion slows due to the combination of its orbit and earth’s, so that a graph of apparent velocity vs time slopes downward and the area under the curve is a trapezoid. The area under the curve gives the distance Jupiter moved along the ecliptic during the 60 days. This was the true “Eureka!” moment for Dr Ossendrijver, as he realized the ancient Babylonian astronomer-scribes had used the basic calculus operation of the integral nearly two thousand years before Newton and Gottfried!