O∑403 Cyg

I only just had moved the 80ED outside when I checked the seeing this evening, so even though it looked a little worse then yesterday's, it may actually have been similar.

This evening I set up the 10" LX200GPS telescope to further explore the seeing. I had it cool down for at least 1.5 hours. I tweaked the collimation slightly, but it still isn't spot on.

I observed M13, resolving it for a large part, M57, in which I could not detect the central star, but only the one just outside the nebula and Epsilon Lyrae, which as expected could be resolved without problems.

Pushing the 10" using the SR4mm to a magnification of 625x, with ease it cleanly resolved both 0.8" separated magnitude 7.4 and magnitude 7.6 components of O∑403 Cyg. There was a third dimmer star approximately 10 arc seconds from this tight double star, which I later realized to be the magnitude 10.0 ∑2657 Cyg (separation 11.6"). No doubt I could have resolved double stars separated at the SCT's Dawes limit of 0.5" this evening.

Although the seeing was excellent, the star images did wobble around a bit, which I suspect was caused by the ALT-AZ tracking of the telescope and not by movement of the deck. I have to investigate that further.

I also experimented with the Barlow today. Using it behind the diagonal works for both the 80ED and the SCT. The 80ED setup becomes somewhat unstable with it though. Also with both telescopes it makes the view dimmer than expected, and I suspect significant light loss when using it (vignetting or reflections).

Incidentally the LX200GPS initially misbehaved this evening for the first time ever. With one of the two Pyramid power supplies its controller lighted up without displaying any text, but seemingly operating. Then when I switched to the other power supply, the Dec motor ran away at full speed upon initialization. Luckily I managed to turn off the telescope before damage occurred. After that the telescope behaved normal again, albeit the pointing accuracy was poor even after I had just aligned it using automatic alignment. Hence I didn't use the GOTO functionality this evening.

This evening also demonstrated that I like the quick grab-and-go setup of the 80ED really a lot more than the lug-and-slow setup of the LX200GPS. The LX200GPS really ought to be used with a permanent setup.