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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.

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 2015-2016

Most meetings will be held at the University of Maryland Astronomical Observatory in College Park, Maryland.

Next Meeting Date: Saturday, 12 December, 2015

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

The progenitors of Type Ia supernovae, revealed by X-ray observations of supernova remnants

Speaker: Dr. Hiroya Yamaguchi (UMd, GSFC)

Abstract: Type Ia supernovae (SNe Ia) are widely believed to result from the thermonuclear explosion of white dwarfs. They are particularly important for astrophysics, as they are used as distance indicators (standard candles) in cosmology. They are also a major source of the iron-peak elements (i.e., Cr, Mn, Fe, Co, Ni) in our universe.

Despite decades of intense effort, however, many fundamental aspects of Type Ia SNe remain obscure. But X-ray observations of supernova remnants have now allowed us to accurately measure the abundances of heavy elements that were synthesized in supernovae. That provided a key for understanding the mechanisms of Type 1a supernova explosions, and how they produce heavy elements.

In this talk, I will present recent observational studies of Type Ia supernova remnants, made with the Japanese X-ray astronomy satellite Suzaku. Owing to Suzaku's high sensitivity, we successfully detected weak emission lines of the iron-peak elements from a number of supernova remants. From 3C 397, one of the brightest Type Ia supernova remnants in the Milky Way, we discovered extremely strong emission of Mn and Ni, for the first time. We measured the abundances of these elements; they are the highest reported in any Type Ia SNe/SNRs observations. We proved that these abundances can be achieved only by electron capture reactions taking place in the dense core of exploding white dwarfs. This indicates that the progenitor mass of this SNR had become close to the so-called Chandrasekhar limit, the maximum mass of a stable white dwarf. That answers the major long-standing question about the physics of Type Ia supernovae.

I will also discuss future prospects for the forthcoming X-ray mission, ASTRO-H.

Bio: Dr. Hiroya Yamaguchi is an Assistant Research Scientist at the University of Maryland, but usually works at the NASA Goddard Space Flight Center. He received a Ph.D. in Science from Kyoto University, Japan in 2008. Subsequently he held postdoctoral positions at RIKEN (Japan) and at the Harvard-Smithsonian Center for Astrophysics (Cambridge, MA). He is currently involved in developing software for the ASTRO-H mission, a joint US-Japan X-ray observatory to be launched in early 2016. His research is on supernovae and their remnants, on galactic chemical evolution, and on atomic processes. He is also familiar with X-ray detectors, as he was involved in detector development and calibration when he was a graduate student.

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 2015!

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.

Date Time Targets of Interest
18 Apr 8:30pm new moon
23 May 9:00pm 5-day moon
6 Jun 9:00pm no moon
11 Jul 9:00pm no moon
15 Aug 8:30pm 1-day moon
5 Sep 8:00pm no moon
17 Oct 7:30pm 4-day moon
07 Nov 7:00pm no moon
Exploring the Sky is a presentation of the National Park Service and National Capital Astronomers.

Star Parties

For NCA information by E-mail or phone

NCA Documents

NCA constitution and by-laws current as of August 28, 2005 they need some changes so we can continue to be a healthy organization.
NCA constitution and by-laws revision as of October 25, 2005 proposal.

HOME | Telescope Making Workshops | Exploring the Sky | Contact Info | Star Dust Archive | Links

Updated by E. Warner on 23 November 2015.