My Favorite Things, Vol 1.4 – Online Class and Asteroids

[I’ll continue from my previous post next month since the stuff here is time sensitive.]

Robert Armstrong
I first met him as I started to become involved w/ the SJAA board. I quickly learned that there was wisdom in every thought and opinion he shared. When he spoke, everyone listened. His long standing support for the SJAA, his wisdom, and everything embodied by his presence will be missed.

Online Astronomy Class
Someone I work with referred me to coursera.com. All classes are free and if you take a class while it’s offered, you can earn a certificate. I found “Galaxies and Cosmology” given by a Caltech professor. This class already ended so I’m taking it self-paced. There are short quizzes mixed into the video lectures. This class has tests at the end of each week and no other assignments or final exam. You do need 1st year calculus to really understand the concepts.  (I missed this in the first short quiz: ∫¹₀ e^x dx. Sigh.)

Allergic to math (or at least calculus)? I’ve also sign up for “From the Big Bang to Dark Energy”. There is a “basic” track that requires just high school algebra/geometry and an “advanced” track for those who are gluttons for punishment  It runs for four weeks from 8/5 to 9/1  I’d encourage EVERYONE to sign up and get the certificate. You can always ping me for help. If you decide to jump in, do let me know!

Ceres and Vesta

S&T and other sources have noted that the asteroids Ceres and Vesta are now visible. They’ll both continue to be in the same binocular view for a while. I’ve seen them the past couple weeks and, courtesy of Tom Pillar, saw them at Rancho through his telescope in a 2° field of view. It turns out they’ll be closest together around July 4th. Because they’re small, you have to know exactly where they are. Otherwise there’s no way to distinguish them from stars.

If you haven’t seen them yet, you should! Being able to see both Ceres and Vesta in the same view is a rare occurrence. Although they’re both in the asteroid belt, their orbits are somewhat different. It turns out they get close to each other only once every 16 years. The next time they’ll be within 5° of each other will be Feb. 2030 and, drum roll please, the next time they’ll be within 2° is 2081!

So how do I know that? Did my Magic 8-ball tell me? Ha! Anyone who has known me a while knows that I make heavy use of Sky Safari. If you care to try the same exercise as I did, just follow along. This works well if you have the plus or pro version. If you have the basic version, you don’t have the capability to show field of view circles, so there’s no direct way to tell angular distance as asteroids fly by.  You can also do this with other software, but it’s MUCH easier if you have field of view circles.

Let’s set up field of view circles and turn off certain objects. In Sky Safari zoom in or out so your display is about 30° wide. You can search for Ceres or you can move your view so Mars is visible. As of this writing, they’ll be slightly above and to the left of Mars. Select Ceres and hit “Center”.

Go to “Settings” -> “Deep Sky Objects” and turn off deep sky objects. Similarly under “Solar System” turn off planets, but turn on asteroids, names, and at the bottom set the limiting magnitude to 11.0. To help you gauge the part of the sky you’re looking at, turn on constellation names. Also make sure your horizon is off (or on with either “Transparent With Line” or “Translucent Area”). [Note: All this is to prevent various objects from becoming distractions, like planets, as the whiz by at high speeds.]

Set one field of view circle to 10° and another to 4° and turn them both on. For Sky Safari version 3 go to “Display” and change the fields next to “Finder”, “Wide”, “Narrow”. For version 4 go to “Display”, turn on two “Custom Filed of View”, tap, and enter a new field of view. Hit “Done” to return to the view screen.

You should now see Ceres in the middle of the two field of view circles. Since we’ll have Ceres centered in the circles, anything inside the 10° circle will be at most 5° away, and anything in the 4° circle will be at most 2° away.

Select the “Time” menu set your time to 10pm. Select “Day”. Now hit the fast forward button. You’ll see Vesta move away and other changes as Sky Safari shows you how the sky changes as the days fly by.

You’ll notice the other (relatively) bright asteroids come and go. Eventually you’ll see Vesta swing into view around Feb. 2030. Hit the fast forward button again to stop and again to restart. Fast forwarding can take a long time, so you may want to bump up the numerical increment on the left to 10 or higher. If you’re running on a Mac (or other program on a laptop or desktop), the fast forward is faster (and looks smoother), so your increment won’t have to be as high. When something interesting comes into view, you can stop and bump the increment back down to one.

Here are the dates I found where Ceres and Vesta are close together:
2/2014 – 8/2014: ? (How close will they get?)
2/2030 – 5/2030: 3°
2047: ?
2065: ?
4/2081 – 6/2081: 1°, but visible only during pre-dawn hours

To find the exact angle between two objects, select the first object (if not already selected), select the second object, and hit “Info”. You’ll find the angle under “Angular Separation”. Be sure to reselect Ceres and center before restarting fast forward, otherwise Ceres will disappear from view.

Once you have this under your belt, you should be able to predict any imaginable event the solar system offers!