Annual Members-only Big Bash!!

Mark your calendar, collimate that scope and get something to throw on the grill! Star-BQ is almost here. Members may bring guests.

Friday, August 6:

Call to reserve a spot if you wish to camp overnight Friday and/or Saturday

Saturday, August 7:

Raffle & Barbecue, Solar Observing & Other events

Sunday, August 8:

Get some sleep after staying up all night, clean-up party

Contact Bob Lea, Walt Heiges, or Forrest Lockhart

(See Contact Page for their info)

 “Dawn: Ion Engines And Icy Asteroids.”

Dawn’s goal is to characterize the conditions and processes of the solar system’s earliest epoch by investigating in detail two of the largest protoplanets remaining intact since their formations. Ceres and Vesta reside in the extensive zone between Mars and Jupiter together with many other smaller bodies, called the asteroid belt. Each has followed a very different evolutionary path constrained by the diversity of processes that operated during the first few million years of solar system evolution.

 Visit http://dawn.jpl.nasa.gov/ to learn more about Dawn.

Dr. Kevin Grazier  

Friday, June 18, 2010 8:00 PM

at Sacramento City College

3835 Freeport Boulevard,

Sacramento, CA

Friday, May 21 @ 8:00 pm

Sacramento City College (SCC), in Mohr Hall Room 3

SCC is located at 3835 Freeport Boulevard, Sacramento, CA

SVAS general meetings are open to the public and are held on the third Friday of each month. See Meetings page for map & directions. ]]> http://www.svas.org/2010/05/meteorites-may-general-meeting/feed/ 1 http://www.svas.org/2010/05/may-speaker-cancels/ http://www.svas.org/2010/05/may-speaker-cancels/#comments Tue, 18 May 2010 04:22:43 +0000 lynda http://www.svas.org/?p=676 Dr. Kevin Grazier is once again unable to make the SVAS General meeting this coming Friday, May 21. Stay tuned as we confirm another speaker.

 Saturday, May 22, 11am to 3pm

ATM Boot Camp will be working with SVAS members desiring to build a new Dobsonian telescope or improve their existing one.  I would like to welcome new members who need help in selecting their first telescope.  We will be working on Lynda’s 12.5” DOB along with enjoying her progress articles in the SVAS newsletter.  Check out my ATM Boot Camp article “Let’s Build a Large Lightweight Dobsonian Telescope” also in the newsletter.  The last two parts will publish this month and next. These articles will give you an idea of what we will be doing.

 ATM (amateur telescope makers) Boot Camp” is the first of SVAS events designed to assist and work with our members on many topics of interest to the amateur Astronomer.  I am on the SVAS Boot Camp committee, and we are looking for more sponsors to present other topics like specialized observing, astrophotography, and new member introductory Boot Camps. Contact Lonnie @ lonrobie@surewest.net

 Yes, I know that there are numerous and wonderful objects in the universe.  With the invention of the telescope 401 years ago, and the subsequent failure to secure a patent on this new military device, our universe became visually accessible to anyone with a penchant for exploring new worlds.  That’s what excites us all about astronomy. We need to share that excitement with the public on Astronomy Day.  But don’t let the wonders of the universe mislead you into thinking that you must look outward to explore the universe.  Earth has a lot to teach us about the universe.

 For instance, we only recently realized how lucky we are to have Earth positioned just 90 million miles from a yellow dwarf star.  The mix of energy from the star and the availability of liquid water was the right combination to kick-start and support life here on Earth, at least as we know it.  The rarity of these conditions is becoming more apparent as we search for exoplanets.  The effort has turned up more than 400 other planets orbiting other stars.  But not one of these out-of-this solar system planets is within its star’s “green zone”.  Granted, the technology currently employed in the searches isn’t sensitive enough to detect earth-sized planets, but even the super-Jupiter and super-Earth sized planets already found lie outside the green zone.  So, Earth and all its life are now at least a 1 in 409 proposition — I’m counting Pluto.

 Maybe, different forms of life exist in the universe, or even in our own solar system.  Life that isn’t carbon-based and water-dependent is possible, and maybe even prevalent.  But then our form of life would be different, if not rare.   

 What if it turns out that life is everywhere throughout the cosmos?  Then there is the question of intelligent life.  Will the other forms of life that we find be smarter than us?  Or challenged?  So far, the efforts of SETI have concluded that any form of life within 60 light-years of Earth (60-yrs is how long we’ve been listening for radio waves from space) has yet to develop communication via the radio spectrum.

 And once found, how will we treat these other forms of life?  Will we have learned anything from our experience with life that once lived, and that now lives, among us; sharing our planet, our form, our fate?  Can we now cherish earthbound life as we would life found on another world? 

 Astronomy Day may never be as big as Earth Day, but they do complement each other.  Don’t they?

Ross Gorman, President

President: Ross Gorman
Vice President: Walt Heiges
Secretary: Charles Real
Treasurer: Kirk Alexander

Directors:
Molly Gallagher
Perry Preston Porter
Lynda Hall
Terry Sandbek
Forrest Lockhart
Gary Shuluk

The annual election of Officers and Directors takes place Friday, March 19 at Sacramento City College, Room 3 at 8:00pm. Only members in good standing as of the January general meeting will be given a ballot. All members and prospective members are encouraged to come to the meeting to learn about what is in store for the SVAS this year and to meet the people who make things happen for you.

http://www.newsreview.com/sacramento/content?oid=1380296

 Will Lynda ever finish hers?

by Lynda Hall

Thanks to Lonnie, I’ve been inspired to finish the mirror and scope I started   about 6 years ago at Cary Chleborad’s telescope workshops. I’m almost finished making my own mirror and am ready to start designing the scope itself.

   For those interested in the mirror-making process, I started with a beautiful 12.5” blank given to me by Forrest Lockhart. Cary gave me a 6” steel ring weighing at least 5 lbs and I went to work with the 80 grit aluminum oxide. You really have to put some weight into the rough grinding unless you want to spend a year doing it. It’s the hard part. I got in 3 hours at a workshop and let others have a go at it for about an hour. To measure the amount of glass I needed to grind out to form the required lens curvature for an f5.5, I laid a flat strip of (unbending) metal over the center of the glass and measured the gap between it (which represents the top of the glass when I started) and the new ground out bottom of the center of the mirror. This distance is known as sagitta and the sagitta I required was about 1/7”, or more conveniently– a nickel and a penny stacked together.

   I still needed a lot more grinding. So, the next day I worked at home for 8 hours until I could get the nickel and the penny under the “flat”. Ow. I didn’t work on the mirror again for a week. One more hour of grinding with silicon carbide and the rough grinding was done.

   The fine grinding requires much less force and went much more smoothly through the #120 grit (3 hrs); 40 micron (2 hrs); 15 micron (1 hr) and finally 3 micron (1 hr) sessions. At last, the mirror was ready for polishing with a cerium oxide  slurry and three hours later, I was ready for figuring.

Unfortunately, I ended up with a down-turned edge from too long a stroke somewhere in the process, and I am currently working on correcting that.

   Meanwhile, back to work on the scope design. Like Lonnie, I found the boxy traditional Dobs a bit, well– ugly and boxy. I’m also looking for something lightweight as I am a somewhat compact person. I chose the f5.5 ratio for the mirror as it provides the brightness and field of view needed to look at nebulae and galaxies  without having to worry too much about coma correction. It also provides a nice height for the eyepiece. Lonnie’s design is very similar to what I had in mind and I think I’ll use his as a basis for my own. Stay tuned to see how well  I meet Lonnie’s ATM challenge as I build my own light bucket.