by Jay Reynolds Freeman
I have been keeping late hours recently, and some times I set up a telescope in my yard in the wee small hours of the morning, for a look at this and that. The Palo Alto flats often have pretty good seeing, and the diffraction rings in my Vixen 70 mm f/8 fluorite have generally been visible, at appropriate magnifications, and very often steady.
I have the Vixen 70 on a light altazimuth mounting, much like the one I used to use for Refractor Red, so it is a one-hand carry to get it outside. The instrument is light enough that it is no problem carrying it down the block, to find a place where I can dodge trees and look at something close to the horizon.
My 8-24 mm Lanthanum zoom eyepiece is very useful for this kind of work. At its low-magnification setting, which gives 23x on the Vixen 70, the field is about two degrees, which is very useful for finding things, since the 6x30 finder's limiting magnitude is much restricted by city lights. The high end of its range is 70x, which is enough for a reasonable view of the Moon, or to show high-surface-brightness deep sky objects, like big globular clusters, to reasonable advantage, city lights notwithstanding. M13, M15, and M22 are subdued, but still impressive, from my yard with the little refractor. M57 shows as a tiny oval doughnut, and NGC 7009 as an almost round ellipse.
That's enough magnification for double stars as well, but for them a bit more is sometimes nice. I was out on the evening of August 20-21 with a 4 mm Meade Research-Grade orthoscopic, which gave 140x. Once the telescope had come to thermal equilibrium -- just a few minutes -- the view of Luna was spectacular. The Hyginus Rille was well placed near the sunset terminator, and the Straight Wall was beginning to brighten against the surrounding plain. I got nice splits of several double stars, notably zeta Aquarius, eta Cassiopeia and epsilon Lyra, then peeked over at Jupiter and Saturn, which had just cleared the tree line across the street. (I had actually walked to the corner for a view of these planets earlier, but they were down in the wiggly murk and besides, I started a neighbor's dog into barking. My neighbors are not nearly as interesting as the gas giant planets, but even so, I would not want anyone to think I was spying on them with a telescope.)
Jupiter was still very low, but even so, I could see several bands with hints of structure in them, and two moons, one -- I suspect Io -- very close to the following limb of the planet. Saturn revealed the Cassini division and the broad band in the northern hemisphere. I had looked at both of these planets late one night at the second Lassen trip this year, but they were down among the treetops then, and I could not see any detail. I guess they are officially back, now.