Dear fellow observers,
I have to confess that I generally do more astrophotography than visual observing. Yesterday, the bright moon would have interfered with deep-sky AP and the seeing forecast seemed to be favorable for visual observing, so I set up my TSA-120.
Indeed, during dusk, the seeing was quite good, therefore, I chose the moon as my first target. I had hoped to see the craterlets on the floor of Plato, but I could only detect the most prominent one at the very center of Plato. Quickly I moved to some binaries and started with Rigel. Normally not a big deal for a 4 to 5 inch APO, but we are at 53° N, where the maximum elevation of Rigel is about 28 degrees only. More often than not, bad seeing is unfavorable. When I started watching yesterday, the sky brightness was a tad too high, which prevented from seeing Rigel B. One hour later, the dim companion was easily visible already at medium magnification (90x).
Next target was the trapezium inside M 42. Although the seeing was still good and there was a lot of space beween the A, B, C and D components, I got the impression that the sky brightness, caused by the moon, was too high to see the fainter E and F components. There also was slight haze which did not help at all.
Unfortunately, temperatures started to drop fast, which resulted in deteriorated seeing. On the Pickering scale, it must have been 5 only. I could not remember ever having observed iota Cancri, so I moved to ths wide pair. Indeed, it is a spring version of Albireo, with striking color contrast. The nicest view is of course at low magnification (64x in my case). Another prominent one in the constellation of Cancer is Zeta. I was very amazed that I could split the Zeta 1 (or AB), where the separation at present is 1.1". The C component, which in reality is a binary or a triple itself, could of course be seen well at a separation of 7", if I am correct. It forms roughly an 120° angle with the connection line between A and B components. For this, I used a magnification of up to 180x.
After that I targeted my personal nemesis, eta Geminorum (Propus), which I never managed to split clearly. Even at highest magnification (432x), I could not detect it for sure because the first diffraction ring was always broken and speckles were dancing around. I doubt whether the companion of eta can be seen with 4 to 5 inch aperture, when the seeing is rated 5 on the Pickering scale.
One last try at Sirius B shortly after meridian transit was also unsuccessful. Nevertheless, I am quite happy having observed the nice objects in Cancer.