catching up

A couple of sessions I didn't set down yet:

Last Saturday 4/16 I used the 12.5-inch for a solar session.  Very large sunspot AR2529 was up, and I had nice views at 170x but with usual daytime mediocre (2 arc second) seeing.  It's a EKI class sunspot, and appeared like the Trifid Nebula.  One prominent filament arcing 2/3rds the way across the umbra, with shaggy extensions on the longer side of the arc.  It reached out and touched a smaller filament arc which was orientated in an opposite way from the major filament.  There was a third fainter arc reaching toward the base.  Two more very faint filaments arced in opposite directions to the east of this central pair.  The penumbra was irregularly shaped, and to the north there was a row of four smaller sunspots leading out of the umbra.  A very complex view.  When I saw photos of it later on they failed to capture the amount of detail I had seen -- perhaps the two secondary filaments were short lived.  AR2532, a CAO group, was on the opposite (eastern) side, and a small group of three umbrae with thin penumbrae.

We had poor transparency and seeing between then and now, so I spent my evenings preparing a 10" f4.7 Dobstuff I acquired used.  It is to be my "travel scope" to use on vacations and for outreach type of events.  I glued the primary to a floating 6 point cell which I modified from the original.  It's difficult to achieve balance with the 9x50 finder, so I will go without for now and have to rely on my Rigel finder skills.  All my eyepieces come to focus, so will need a night out with it to see how it performs.

Thursday night 4/27 the sky was just good enough to get out and I viewed through the 12.5-inch.  I planned to continue calibration of my astrometric eyepiece but seeing proved to be very bad.  I had a look at 90 Leonis, a close but easily split pair at 170x, a yellow-white A and a bluish-white B.  h4433 in Leo was a bright orange-yellow A with a much fainter blue B, widely separated, a beautiful sight.  The main event was an Io occultation behind Jupiter.  I saw Io pretty far out from Jupiter's limb at 9pm and went on to the doubles.  I came back to it at 9:25pm when Io was a hair split from Jupiter's limb; I watched as it sank to meet the limb, then appear as a bright pimple.  It disappeared at 9:30, exactly as the ephemeris predicted. 

Friday night was to be a busy place on Jupiter, with two moon transits and other nice events, but it was too cloudy to set up -- marine layer blowing in.