comet chasing

There being a break in our cloudy weather I prepared for an observing session during my lunch hour yesterday.  I wanted to give a try for 252P/Linear, which is now in Ophiuchus in the pre-dawn hours.  While printing the finder chart at cometchasing/skyhound.com I saw the other possible targets and printed those out too.  116P/Wild is in Scorpius and ought to be visible.  There were several evening comets and I convinced myself I could find those, even with the 1st quarter moon.  Not.

I used the 12.5-inch for these sessions.  I started out having a peek at Europa's shadow transit.  Seeing was not very good, with intermittent decent views at 277x.  The shadow was very small.  What was nice was three of the moons made a straight line toward the shadow, in a kind of exponential stack: Ganymede at the far edge of the field, lined up with Io about three times further in, then Europa half way between Io and the planet, and finally the shadow on Jupiter's surface, all in a straight line.  Calisto was way out of the field on the opposite side of Jupiter.  (UT 4/16/16, 3:45 or so).

When it was finally dark I tried for the comets.  C/2014 W2 (PANSTARRS) is in Draco, a fairly easy hop from Capella.  There were a couple hazy patches in the field but nothing certain.  It's 13.12 magnitude and 20.3 surface brightness -- and too close to the Oakland light dome.  Nearby C/2013 US10 Catalina should have been easier but it too was not found.  333P/Linear was even lower on the horizon and fainter at 13.42.  9P/Tempel behind Leo's rump was too close to the moon, 13.52.  81P Wild, which looks like a fun target since it is booking through Gemini's left foot, was not seen.  104P/Kowal is another fast mover, through the Hyades, but too low and blocked by a tree. 

So I occupied my evening looing at some double stars in Leo, 277x, with some nice surprises:

STT215: very close split (1.7" separation) near equal bright white stars

STT216: !! A white and bright (7.3), B red & much fainter (10.3), a close split (2").  Seeing needs to steady to see B

STF1448: An orange and blue pair.  Fainter than Alberio but just as pretty.

STF1447: Both white, A (7.5) 2x brighter than B (8.9).  Wide separation (4").  Is there a faint third? (no)

STF1487: Bright white pair (4.5, 6.3) wide sep (6")

STT105: very widely separated (11") orange pair.  Pretty bright (7.3, 8.3). 

S612: Very widely separated, split in finder (196"!); white A with a slightly red B

STT104: Very wide separation (208"!) orange pair.

Went to bed deciding to get up at 3:30am to have a try for the morning comets.  Clara woke me up at 3:00am, somehow knowing my intentions.  After she went back to sleep I went out.  I first tried 116P/Wild, which should have been a cinch to find off of Delta Scorpii, but I could never match the star field on the finder chart which what I was seeing in my finder scope -- too many stars on the finder chart to make sense of.  There's a straight trail of stars to the SW of delta which I found well enough, but I got lost from there.  I swept around the area with and without my comet filter but no luck.  It's mag. 12.91 & surface brightness 21.9, so maybe out of reach.  Seeing was not that good (Pickering 6) and even though it was pre-dawn there was light dome from San Jose, and moisture blowing in from the ocean.

I moved on to Ophiuchus to find 252P/Linear, and finally met with success, but disappointment too.  I found the comet but all I saw was a diffuse, irregular and rather large glow for a coma, brighter toward the center.  I could not discern a nucleus.  With the comet filter the glow became smaller but somehow more palpable.  The comet was then 6.73, coma diameter 35.1', surface brightness 23.1.  My SQML read 18.73.

After a look at the lovely large open cluster IC 4665, I moved on to the planets.  Mars was a surprise, a large disk with Syrtis Major jutting down darkly from Hellas, which appeared as a large elliptical ice cap.  It seemed the planet was tilted that I could see the whole of the circular cap.  Utopia was a less dark on the northern end, bordering a northern ice cap along the rim.  Nice view!  I tried a couple of filters but didn't like the artificial view.

Saturn was next, just a sweep of the telescope away.  Seeing was watery but there were some still seconds.  Cassini division was distinct, as were the bands and polar and equatorial regions; it always reminds me of a rugby shirt pattern.  What's exciting is I was able to see five of its moons!  Titan was far out, and in line with it were Rhea and Dione on either side -- these were always visible.  I caught and held Tethys with averted vision, and with time could have it direct vision.  I then had hints of Enceladus with averted when the seeing stilled.  It was an uncertain object but I added it to my sketch and I confirmed it this morning.  Score!

By then the sky was brightening and the traffic noise from 880 was noticeably louder, so I packed up.  I paused to look at the summer constellations just reaching meridian: Cygnus, Lyra, Sagittarius; things to look forward to.  The I went in and had a nap on the couch.