Spent some time last night splitting doubles in Leo. I used the Three-legged Newt on its AVX mount and two Orion Stratus eyepieces: 21mm (48x) 8mm (125x). It was a clear, mild night, with occasional light breezes, fair to good seeing, and a temperature at the start of 86°F (30°C). Most of the objects observed were rather subtle, with magnitudes that would have rendered them invisible in my suburban skies, even if the light of a waxing gibbous hadn’t been up there adding a generous contribution to the sky brightness. The computer in the mount came into its own, last night.
The first was κ Leonis, and it proved the most challenging due to a separation of 2.4” and a significant contrast in magnitude (4.5 vs 9.7). With the 8mm eyepiece I could, with patience and averted vision, see the companion star, a colorless fleck of light lost in the golden glow of the primary star any time unsteady air roiled the view.
3 Leonis was no challenge to split, 25” apart, but the eleventh magnitude companions was close to the practical limit of the Newt, especially with such a bright sky. The brighter of the pair (magnitude 5.8) was white with a slight yellow tint, and its companion was a barely visible, colorless hint of light. The 8mm eyepiece was especially useful for this one.
6 Leonis was restful, compared to the others, easily split (37.4”), with not much eyestrain involved when studying either component. The magnitude 5.2 star was a pleasant ruddy gold star, with a 9th magnitude companion that was rather faint, but distinctly blue in color. It was observable with the 21mm eyepiece, but the colors were better seen at higher magnification.
STT 102 was a truly subtle pair, but relatively easy to observe with either of the eyepieces I used. At a separation of 45.4”, splitting the two pale, white stars was no trouble. The brighter of the two is 7.9, with its neighbor all of 9.3. References on my desk ascribe a variety of colors to this pair. I saw white and gray-ish white.
7 Leonis was easy with the 21mm eyepiece, a bright white star touched with blue-gray companion 41” away. There’s a significant magnitude contrast, 6.3 vs 9.4.
STF 1399 was a pair of plain, white stars with a modest difference in magnitude (7.6 vs 8.4), 31” apart. Didn’t need much magnification to enjoy looking at this pair of look-alikes. The 21mm field of view included more stars than any of the previous observations – very attractive view.
STF 1431 took the more powerful eyepiece to split (3.3” apart), and that with a period of improved seeing conditions – that didn’t last, of course. The primary star (magnitude 7.8) and its 9th magnitude companion were both pale white. The view was dominated by 44 Leonis.
STF 1447 hinted at being a binary when seen with the 21mm eyepiece, and revealed its true nature clearly with the 8mm counterpart. At 4.4” apart, it took some patience to get a clear separation at times. The brighter star (magnitude 7.5) was a warm white with hints of gold to it. The 9th magnitude companion appeared a sort of cool, silvery blue.
STF 1448 was one of those pairs that could be split well enough with the 21mm eyepiece (11.1” apart). At magnitudes 7.5 and 9.6, that contrast was visible as well. What did not register clearly until higher magnification (8mm) was used, was the color contrast. This often happens with double stars. The primary (A) star had a pale but distinctly golden hue. Its companion was pure white.
The last one I observed was 88 Leonis, a 6.3 magnitude white gem with a pale blue 9th magnitude companion 15.4” away. An attractive pair, in a subtle way. Such subtlety was something of a theme last night. Understated gems of the Lion.