Tuesday, July 4, 2017

BACKYARD ASTRONOMY

The long weekend gave me the opportunity to go out with my telescope for the first time in eight months. I grew up in Cleveland, Ohio, so the sky that I am comfortable with is about the same as seen from the outer edge of a galactic arm.  Not many stars, but on a good night in the summer, you can find Homeward as steam from the teapot. In the winter, the stars are fewer but brighter: hot, young stars; with some red giants to remind us of our age.
 
Of course I keep a notebook.
I usually plan for each night I go out.
I typically record while viewing.
The night before last I was just getting familiar again with the process. All I lost in the grass was an eraser. Last night, for the first time, I watched a moon of Jupiter disappear behind the disk. It took about half an hour. I seldom display that much patience. I found a good lens (13 mm for 50x). At the end, I switched to higher power (6mm for 108x) just to see the last glimmer. I was surprised at how close the satellite got and still remained discernible. These old eyes still work.

When I came in and googled “moons of Jupiter tonight” I found a Sky & Telescope page that explained that Io was passing in front of Jupiter. 

As a member of the Austin Astronomical Society for two years, I did go out to their “Eagle Eye Observatory” at Buchanan Lake, about 80 miles from Austin. I earned a certification in telescope operations. I also took my own EQ-130 out there to see what I could see that I could not see from my backyard.  For the first time in my life, I viewed the entire Milky Way from horizon to horizon. But once the sky got completely dark, I had a hard time finding anything. “My God,” Dave said. “It’s full of stars.”  Fortunately, I was there with experts.

My telescope is a Celestron EQ-130 reflector (130 mm ~ 5.25 in). My wife and daughter bought it for me for my birthday in 2014. I shopped and they paid for it. I chose it because it seemed like a good midrange choice, similar to the Criterion 4-inch that I had from ages 10 to 17.  That device was much better by several standards.  (See my “Advice to New Astronomers” here.) 

When I got the telescope, I joined the Austin Astronomical Society and the International Astronomy Forum discussion board. There’s always lots of forums and blogs. The International Astronomy Forum felt best to me. I posted my complaints about my telescope there and got some replies. Going out to the Eagle Eye Observatory was evidence enough that the telescope’s optics were satisfactory. I just live in a city. So, the air is wavy and dirty. Nonetheless, I had to fix some mechanical problems.

On the Astronomy Forum, one of the posters told about the loss of his mirror. He thought that he was adjusting the azimuth when the telescope slid out of the cradle and hit the deck.  I knew why immediately: all of the knobs feel the same. It was a known problem in aviation. So, I fixed that. 

Beer bottle cap glued to knob.
(See "Drunken Astronomers" below.)
The first problem was losing one of the nuts off one of the C-clamps that hold the tube to the mount. It took several trips to Home Depot until I found hardware that would do the job and stand up to continuous use.  I will slide the tube forward or backward several times through the night, to balance it. Also, I take the ‘scope out and bring it in every night. (A couple of summer nights, wanting to go out again very late before dawn, I left it set up, and covered it with a plastic sheet.) And I have to be able to open and close the clamps without other tools.

The need for other tools comes from the fact that the azimuth is spring-loaded; it is not a worm gear.  So, with enough travel used, you have to go into it and with a hex wrench unscrew the bolt to allow further motion.  (With too much turning, it all comes out.)

Another thing that came apart in my hands was the 20mm ocular. About a month after I first used the ‘scope, I returned the motor drive unboxed, and I bought a set of lenses and filters. I thought that the filters would be compatible with the basic equipment. I unscrewed the 20mm eyepiece; and with a handful of little glass lenses I had a new problem. Fortunately, I got a pointer to a Celestron webpage from a poster to Astronomy Forum. Apparently, this is a well-known problem.

The first problem was losing one of the nuts off one of the C-clamps
that hold the tube to the mount.
It took several trips to Home Depot
until I found hardware that would do the job
and stand up to continuous use.
  
And it is easy to forget… The other night, I had that 20mm in my hand and was unscrewing it to put a filter in it… and I heard a little voice that I actually paid attention to… 

Orion Nebula
looks like this.
All of that aside, backyard astronomy has been my window to the universe. I own microscopes and hand lenses, but my Weltanschauung is mostly outward. The Orion Nebula, the Milky Way, Venus, Mars, Jupiter, Saturn, and the Moon are easy reminders of deep truths. The universe is more complicated than we know, but we can know it. Evidentiary facts have rational explanations: they are necessary truths. It is all at once very different from life on Earth, and yet very much like most of it: the same chemicals, molecules, atoms, particles, waves, and fields, agglomerated by mutual attraction into ponderable bodies, at once massive or weighable and worthy of and open to thought. 

ALSO ON NECESSARY FACTS

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