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National Capital Astronomers

About NCA

NCA logoServing science and society since 1937. The National Capital Astronomers (NCA) is a non-profit, membership supported, volunteer run, public service corporation dedicated to advancing space technology, astronomy, and related sciences through information, participation, and inspiration, via research, lectures and presentations, publications, expeditions, tours, public interpretation, and education. NCA is the astronomy affiliate of the Washington Academy of Sciences. We are also members of the Astronomical League, in fact NCA members helped form the Astronomical League a long time ago.

NCA has for many years published a monthly newsletter called Star Dust that is available for members. Besides announcement of coming NCA meetings and a calendar of monthly events Star Dust contains reviews of past meeting and articles on current astronomical events.

NCA is a very unusual astronomy organization. All are welcome to join. Everyone who looks up to the sky with wonder is an astronomer and welcomed by NCA. You do not have to own a telescope, but if you do own one that is fine, too. You do not have to be deeply knowledgeable in astronomy , but if you are knowledgeable in astronomy that is fine, too. You do not have to have a degree, but if you do that is fine, too. WE ARE THE MOST DIVERSE local ASTRONOMY CLUB anywhere. Come to our meetings and you will find this out. WE REALLY MEAN THIS!

Our Meetings

Monthly Meetings with Educational Presentations are Free and Open to the Public

NCA has regular monthly meetings September through June on the second Saturday of the month. Most meetings are held at the University of Maryland Astronomical Observatory in College Park, Maryland (directions/map).

Public transportation: Directions/maps to the UMD Observatory
Inclement weather: In case of severe weather (tornado/snow/impassable roads), a notice will be placed on the Observatory Website on the day of the meeting. (Be sure to refresh/reload the page to make sure you are seeing an updated page.)

Meeting Schedule for 2017-2018

Next Meeting Date: Saturday, 12 May 2018

7:30 pm at the University of Maryland Observatory on Metzerott Road.

Stars Disrupted By Super-Massive Black Holes

Speaker: Dr. Nathaniel Roth, UMD

Abstract: Approximately once every ten-thousand years in a typical galaxy, the random perturbations of a star's path bring it near enough to the central super-massive black hole that the tidal forces from the black hole's gravity tear the star apart. As the stellar remains swirl around the black hole, they viscously heat and give rise to a flare of radiation known as a tidal disruption event (TDE). Predictions that such events should take place were made decades ago, but until recently the ability to detect them has been limited. Now, with the deployment of wide-field surveys searching for transient astronomical events, dozens of these events should be discovered each year. As TDE detections have begun to accumulate, a number of fascinating puzzles have arisen regarding the underlying emission mechanism, such as the origin of their unexpected brightness at ultraviolet and optical wavelengths. In this talk, Dr. Roth will review the history of TDE astrophysics and discuss how we can TDEs to learn about accretion onto black holes in extreme conditions. He will also discuss how we can use TDEs to study the demographics of super-massive black holes across the universe.

Bio: Nathaniel Roth is a Joint Space-Science Institute Fellow at the University of Maryland, College Park and NASA Goddard Space Flight Center. Prior to coming to Maryland he earned his PhD in physics from the University of California, Berkeley. He specializes in radiative transfer calculations that connect theoretical predictions of how light and matter behave near super-massive black holes to the data collected across the electromagnetic spectrum. Recently he has focused on understanding how accretion proceeds in the aftermath of the tidal disruptions of stars by these black holes, particularly by analyzing the optical and ultraviolet spectra from these events.

Weather-permitting, there will be observing through the telescopes after the meeting for members and guests.


Join Us for Dinner Before the Meeting

Telescope-Making and Mirror-Grinding

Telescope-making and mirror-making classes with Guy Brandenburg at the Chevy Chase Community Center, at the intersection of  McKinley Street and Connecticut Avenue, NW, a few blocks inside the DC  boundary, on the northeast corner of the intersection, in the basement  (wood shop), on Fridays, from 6:30 to 9:30 PM. For information visit Guy's Website  To contact Guy, use this phone #: 202-262-4274 or Email Guy.

Come See the Stars at Exploring the Sky 2018!

Exploring the Sky is an informal program that for over sixty years has offered monthly opportunities for anyone in the Washington area to see the stars and planets through telescopes from a location within the District of Columbia.
Sessions are held in Rock Creek Park once each month on a Saturday night from April through November, starting shortly after sunset. We meet in the field just south of the intersection of Military and Glover Roads NW, near the Nature Center. A parking lot is located next to the field.
Beginners (including children) and experienced stargazers are all welcome-and it's free!
Questions? Call the Nature center at (202) 895-6070 or check: Exploring the Sky @ Rock Creek. Download the flier!

Date Time Things of interest
7 Apr 9:00pm Orion nebula, Beehive cluster
5 May 9:00pm Jupiter, Beehive cluster
2 Jun 9:00pm Jupiter, M13
14 Jul 9:00pm Jupiter, Saturn, M13o
11 Aug 8:30pm Jupiter, Saturn, M13
1 Sep 8:00pm Jupiter, Saturn, Mars
6 Oct 7:30pm Saturn, Mars
17 Nov 7:00pm Saturn, Mars, Uranus, Moon
Exploring the Sky is a presentation of the National Park Service and National Capital Astronomers.

For NCA information by E-mail or phone

NCA Documents

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Updated by E. Warner on 7 May 2018.