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      Volume 9 Issue 3 March 2017      

Wednesday, March 1st 7:00 pm.
Madelyn Helling Library
Community Room

NcA Logo

Our Starry Neighborhood in 3D
by David Buchla

The March meeting will be a presentation by David Buchla who will describe some of the features of the Orion Spur of our galaxy. In particular, he will show a three-dimensional model of the 39 nearest star systems to the sun and describe some of the interesting facts about these stars. Although the majority of the nearby stars are red dwarfs, there are some exceptions – for example Sirius.  Sirius is actually a binary star with a faint white dwarf companion, which was discovered in 1862 by Alvan Clark, the famous telescope maker. The brighter component is a type A star located just 8.6 LY from us. Although the dwarf (“Sirius B” or “The Pup”) is about the size of Earth, it is about as massive as our sun! A teaspoonful of white dwarf material would weigh several tons.

After looking at some of our closest stars, we will travel a little further out (primarily staying in the Orion spur) and visit some other stars and objects in the neighborhood. In this context, our “neighborhood” goes out about 5000 LY. Most of the objects visited will be shown in their place within the arm (or above or below) using two views. Within 1000 LY, we will find some open clusters and some Planetary nebula. The closest open cluster is the Hyades (in Taurus) and a little further out are the Pleiades (“Seven Sisters”). These two clusters are totally different from each other; we’ll look at the differences and see a few others before moving on. A little further out there are some interesting star forming regions including the famous Orion nebula, Cygnus X, and the Gum nebula. There are a few other neighborhood objects that will be looked at with a unique perspective in this presentation.

Bring a friend ... bring the kids!

President’s Rant

Hello Stargazers,

How about this weather? I do appreciate the much-needed precipitation, however, would it be too much to ask for one clear, moonless night? Perhaps we’ll have one soon.

On Monday the 20th, Bill Thomas and I braved the elements to go to Lonnie Robinson’s home in Citrus Heights for a meeting with the ATM connection. We met with telescope makers from the Stockton, Sacramento Valley, and Nevada County astronomy clubs to discuss Carl Zambuto’s method of figuring mirrors. Zambuto is a highly-respected mirror maker who has a large following of people who are using his methods. This was a very interesting discussion, a far cry from the method that we saw John Dobson use in the video that we watched a couple of meetings ago. Mirror making has really evolved from the “caveman” era. If any of you are interested in telescope making, speak to either Lonnie or Bill at the meeting March 1st.

March is the beginning of the club’s “busy season” of school-related events. I will leave the explanations to Dave Buchla. I would just ask that you volunteer to help with one or more events because they can be fairly intense with excited youngsters and we can always use one more person.

See you at the meeting.


Outreach - David Buchla

We are continuing to plan for our three events this spring that were announced last month. So far, nothing else has been added to the calendar.

Scotten School Science Night is on March 9; set up at 4 pm. The exhibits will be a little more interactive and we are planning to do star wheels, so help is appreciated in that activity and for observing the bright nearly full moon. The moon will be rising at 3:30 pm. It is 11 days past new. A few scopes outside are needed. We always have a lrge turnout for this event.

The STEM/STEAM expo at the fairgrounds is on March 25 from 9 am to 3 pm. Volunteers are still needed to help set up, take down and work with kids making star wheels. John Griffin is coordinating this event; let John or I know if you can help out.

The third event is Astronomy Day on April 29. John and I had a planning meeting with Yolande and we have lots of stuff planned. Alan Stahler has volunteered to take on publicity. John Griffin will make sure the outside stuff is coordinated, Rick Bernard is coordinating the entry area and I am going to focus on the community room. We have some new exhibits and we plan to have some very short talks in the new outside stage area. We also have a book discussion in the classroom along with some things that Yolande has planned for there and we will be doing star wheels in the children’s library. I will have a detailed plan to present at the March 1 regular meeting and would like to have a brief pre-meeting discussion at 6:45 pm in the entry area to go over plans. All members that can help on AD are encouraged to attend this. We’ll have a signup sheet for different activities. As in all outreach events, help is really appreciated on these events. To contact me for questions or to volunteer, click here:

Secretary/Treasurer - Dan St. John

March and April are full of activities which highlight our mission: 'Bringing Astronomy to the Public'.  Astronomy Day April 29th at the Library is our major outreach effort for the year, but also, on March 9th  (Scotten School) and March 25th (STEM/STEAM, Fairgrounds) many NC Astronomers will be contributing their time 'Bringing Astronomy to the Public'.

Your membership dues help make these efforts a great success.  Many members have already renewed their commitment to help us and as the year passess this number will continue to increase.  

I will again be collecting 2017 Dues/Donations ($20) at our March 1st meeting in the Library. So when you come to discover the amazing wonders of our Starry Neighborhood in the Orion Spur of the Milky Way, please bring your check (or CASH) and help us cover our expenses for Room Rent, Speaker Honorarium, Outreach Supplies and Miscellaneous Administrative Costs.

If you can't make our meeting, send your check to:

NC Astronomers, %Dan StJohn,
12296 Valley View Rd, Nevada City, CA 95959

a BIG Thank You to all our members who join and make our programs possible!

Solar Eclipse Provides Coronal Glimpse

by Marcus Woo

Visit to explore space and Earth science NASA Space Place Logo

On August 21, 2017, North Americans will enjoy a rare treat: The first total solar eclipse visible from the continent since 1979. The sky will darken and the temperature will drop, in one of the most dramatic cosmic events on Earth. It could be a once-in-a-lifetime show indeed. But it will also be an opportunity to do some science.

Only during an eclipse, when the moon blocks the light from the sun's surface, does the sun's corona fully reveal itself. The corona is the hot and wispy atmosphere of the sun, extending far beyond the solar disk. But it's relatively dim, merely as bright as the full moon at night. The glaring sun, about a million times brighter, renders the corona invisible.

"The beauty of eclipse observations is that they are, at present, the only opportunity where one can observe the corona [in visible light] starting from the solar surface out to several solar radii," says Shadia Habbal, an astronomer at the University of Hawaii. To study the corona, she's traveled the world having experienced 14 total eclipses (she missed only five due to weather). This summer, she and her team will set up identical imaging systems and spectrometers at five locations along the path of totality, collecting data that's normally impossible to get

Ground-based coronagraphs, instruments designed to study the corona by blocking the sun, can't view the full extent of the corona. Solar space-based telescopes don't have the spectrographs needed to measure how the temperatures vary throughout the corona. These temperature variations show how the sun's chemical composition is distributed-crucial information for solving one of long-standing mysteries about the corona: how it gets so hot.

While the sun's surface is ~9980 Farenheit (~5800 Kelvin), the corona can reach several millions of degrees Farenheit. Researchers have proposed many explanations involving magneto-acoustic waves and the dissipation of magnetic fields, but none can account for the wide-ranging temperature distribution in the corona, Habbal says.

You too can contribute to science through one of several citizen science projects. For example, you can also help study the corona through the Citizen CATE experiment; help produce a high definition, time-expanded video of the eclipse; use your ham radio to probe how an eclipse affects the propagation of radio waves in the ionosphere; or even observe how wildlife responds to such a unique event.

Otherwise, Habbal still encourages everyone to experience the eclipse. Never look directly at the sun, of course (find more safety guidelines here: But during the approximately 2.5 minutes of totality, you may remove your safety glasses and watch the eclipse directly-only then can you see the glorious corona. So enjoy the show. The next one visible from North America won't be until 2024.

For more information about the upcoming eclipse, please see:

NASA Eclipse citizen science page

NASA Eclipse safety guidelines

Want to teach kids about eclipses? Go to the NASA Space Place and see our article on solar and lunar eclipses!

Illustration showing the United States during the total solar eclipse of August 21, 2017, with the umbra (black oval), penumbra (concentric shaded ovals), and path of totality (red) through or very near several major cities. Credit: Goddard Science Visualization Studio, NASA

Click to Contact
President John Griffin
Vice President Rick Bernard
Secretary/Treasurer Dan St. John
Outreach Chairmen David Buchla

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First Wednesday Of The Month
Madelyn Helling Library
Community Room
980 Helling Way
Nevada City 95959

12296 Valley View Rd
Nevada City CA 95959

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