surprise shadow transit

I had high hopes for some observing last night, but a marine layer haze interfered with viewing, scattering the moon's light over the sky.  The moon was ~3 degrees from Jupiter, which was a nice view.  Jupiter itself shown nicely at 277x but seeing was not very good.  I noticed with surprise there was a shadow transit nearly over when I looked at around 9:20pm.  I saw Ganymede's shadow very low on the northern limb of the planet.  I should have looked at the ephemeris earlier, for I missed seeing Io's shadow by just 10 minutes!  Had I known it would be been a more exceptional night.  The moons are at an odd angle this time, crossing Jupiter along the north and occulting far to the south.  Callisto was making very rapid progress toward occultation.

My main interest was to see some doubles in Cvn.  I noticed two faint STFs very close to Cor Caroli, and wondered if they could be seen in the same FOV.  Cor Caroli was near zenith and it took me some time to figure out its orientation in relation to my charts.  I did find the STFs, but the haze and scattered light from the moon and average seeing conspired to fuzz the view.  I did not try a low enough power to get them in the same field -- I will need a moonless night.

Here are the doubles I recorded, the first two being close to Cor Caroli:

STF 1702: Orange and blue, faint, 0.5 delta mag, wide separation.  277x
12H 58M 31.97S +38° 16' 43.6" P.A. 82 SEP 36 MAG 8.72,9.41 SP G5V DIST. 44.21 PC (144.21 L.Y.)

STF 1688: Yellow A, orangish B, wide separation, both faint. AB pair seen, AC 13.44 mag, not see.  277x
12H 53M 35.26S +37° 58' 20.9" P.A. 344 SEP 14.1 MAG 9.24,11.06 SP G0 DIST. 318.47 PC (1038.85 L.Y.)

HO 256: 553x I can tell the airy disk is not clean indicating it's not single, but can't split for the seeing.  0.7".
12H 44M 08.82S +35° 46' 07.3" P.A. 117 SEP 0.7 MAG 7.3,9.55 SP KA5HF0V.. DIST. 88.57 PC (288.92 L.Y.)

At this point I switched from Carro Catalog objects to ones plotted in CDSA and went back to 277x:

STF 1723: Yellow and blue, around 5", 2 delta mag

13H 08M 13.49S +38° 44' 20.2" P.A. 11 SEP 6.1 MAG 8.67,10.08 SP G2IV-V DIST. 73.05 PC (238.29 L.Y.)

15 Cvn: Not clean diffraction; should be close pair but not split. [This is BU 608, and is the BC of the AB 17 CVN = EI 24.  It is 6.26/9.23 1.3" -- do deserving of a better night]

EI 24: Wide bright pair? [Yes, is 15 & 17 Cvn, 6.0/6.3, 278"]

h2639: Nice triple.  Orange-yellow A and bluish 2 delta mag B and C, wide sep.

AB: 13H 06M 13.50S +40° 55' 21.0" P.A. 159 SEP 37.2 MAG 7.48,11.23 SP K7III DIST. 819.67 PC (2673.76 L.Y.)

AC: 10.77 53.6".

At this point some definite clouds of marine layer started blowing in -- not just the persistent haze -- and it was time to wrap it up.  It was 11pm already -- only an hour and a half of usable observing time!