Last night, after a hazy and uncertain day, I was treated to a mostly clear sky. This was my second session with my new Orion 150mm Maksutov, which I'm still evaluating. Some high-power observations revealed that I need to adjust the collimation a bit, but it wasn't off by enough to disrupt my observing.
First up was a surprise pair: Gamma Herculis (3.8, 10.1, 43"). I had intended to use this star, which is not marked as double in my atlas, as a jumping-off point to get to my next target. Imagine my surprise upon seeing that pretty little speck of a secondary! I noted the PA as southwest, and the color of A as a creamy white. B gave me no color, but was a fine sight nonetheless. WDS lists an 8th magnitude D component at a separation of 8.3", which I didn't notice.
A short star hop away from Gamma was my intended target, STF 2052 (7.7/7.9, 2.5"). Even at 45x (3.3mm exit pupil), this object's duplicity was clear enough for me to estimate a PA along the NW/SE axis. At 72x (2.1mm exit pupil), they were split cleanly, although I still wasn't confident of which star was the primary. To the west was a silvery 8th magnitude star, and to the southeast a wide and dim double (I haven't so far found a designation for that pair in the WDS). Finally, at 120x (1.25mm exit pupil), I was confident that the western star was the primary. A was yellow, and B a darker orange.
Also in Hercules was WEB 6 (6.4/7.3, 153"). This one was mentioned in the forum by someone recently, but I can't remember who. Aubrey? Rich? Whoever it was, thanks for the recommendation! This is a wide but very pleasing pair set in a trapezoidal asterism. I saw A as light yellow and B as white.
Moving northeast into Lyra, I located STF 2362 (7.5/8.7, 4.4"). There are tons of doubles in this tight quadrant of the sky, so I was extra careful in my star hop, and double checked the data I had jotted down from WDS to make sure it matched what I saw in the eyepiece. And what a treat it is to look at: At 45x I saw A as a light greenish white, like a pale prasiolite gem, and B as blue-white, becoming grey-blue at 72x. I noted the PA as south. This is a beautifully tight and dainty pair at low and medium powers.
Nearby is STF 2362's twin, STF 2390 (7.4/8.6, 4.3"). This object is indeed very pretty, but just as remarkable as the double itself is its field: a stunning asterism of 6 brightish stars and several dimmer ones, forming a nearly straight line running southeast to northwest. It's almost like a miniature of Kemble's Cascade. Does anyone know if this asterism has a name?
My last Lyra pair was STF 2349 (5.4/9.4, 7.2"). At 45x I saw bright white A, and the irregular cigar-shaped smattering of field stars along the north-south axis. I got one very brief glimpse of a tiny B before bumping the power up. At 72x I could hold B consistently, and A turned a more pearloid off-white. A very fine unequal pair.
I ended the night with two spectacular Draco doubles, which I also sketched (if you feel so inclined, please visit the Sketching forum to see my work). First up was Omicron Draconis (4.8/8.3, 38"). The first time I observed this pair was in October of 2018, with my 80mm refractor. After revisiting it last night, I've come to the conclusion that this object isn't observed or talked about nearly enough!
A is the most astonishing shade of electrum I can think of. The hue is impossibly rich and lustrous. B is a curious star that shifts maddeningly from green to blue to purple to orange; as I wrote in the Sketching forum, it seems to average out at lilac or pale pink most of the time. In 2018, I saw exactly the same effect with my 80mm, and wondered how much of the shifting color was a product of my achromat itself. Re-observing with the 150mm Maksutov has not settled the issue one bit: this is a baffling and beautiful star.
Last, and least in magnitude if not beauty, was STF 2398 (9.1/10, 11"). This is another of the forum's recommendations, and despite its relative dimness is well worth a look. Both stars are M-type, and their color is quite noticeable, if somewhat subtle. A was very clearly orange, while B was just on the edge of colorless. With steady gazing at 72x, I could make out the auburn tinge in an otherwise dark grey speck. A thoroughly attractive pair.
That's all for now! As always, comments, corrections, and complaints are most welcome.
Edited by nerich, 02 June 2020 - 06:56 PM.