Neptune and Triton

by Bill Cone

Steve Gottlieb had showed me Triton, a moon of Neptune, this summer up at the Sierra Buttes, and I was interested to see if I could pull it in from my backyard in Moraga. Neptune right now is a pretty easy find, between Iota Capricorni and '29' Capricorn. After one attempt where I was fooled by a field star, I used Starry Night to very carefully plot the field size and angle of Triton relative to Neptune. It showed me that Triton was much closer to Neptune than what I had seen. On this night (10/8), Triton was lying 15" to the W. of Neptune, just a hair South of the ecliptic. I picked up Neptune in the finder, and at 145x it showed a small disc resembling a blue planetary, ironically enough, but no moon was visible. At 311x, I let it drift through the field a few times, and finally noticed a second faint dot with averted vision in the right spot, about 5 disc diameters away. If Neptune was drifting towards a 9 0'clock position in my eyepiece, Triton was leading it to the West at a 10 o'clock spot, just off the ecliptic. At 545x, I could see it without averted vision, though it was getting fuzzy. Seeing was pretty wobbly at times. I don't think I would've spotted it unless I had really been trying to hunt it down, and knew where to look.

Uranus is also conveniently placed, about a half degree S. of Lambda Aquarii, bigger disc, and more of a yellow green to my eyes. Both worth the trip. The arrival of the moon broke up the party..

All observed with Mariposa, an 18" Plettstone scope, Paracorr, 7mm Nagler, 4mm Burgess/TMB planetary.

-Bill Cone