Jupiter and the full moon. 20th April.

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Having left the 7" folded refractor out of doors for several hours I started observing Jupiter before it was even getting dark. Initial impressions were of greater contrast in the two main belts than before but without any real detail. In other words they appeared darker but offered no insight into their real complexity. The Galilean moons were more rounded and differed more obviously in size than previously. 

The folded 7" refractor on the MkIV mounting taken by flash and brightened several stops.

There were fleeting moments when there was a hint of twisting and edge roughness in the belts but the entire evening passed without any real improvement as Jupiter climbed steadily higher. I tried the Fringe Killer filter and preferred the view without. Then the Yellow No8 and ND but again without any increase in detail. The odd thing was that I was using the 10mm eyepiece [and the 20mm with the Orion 2x Barlow] without loss of image quality. The image did not 'break down' at 216x as it had done on previous occasions. 

Attempts to capture afocal snaps were a complete waste of time. Jupiter was overexposed and misshapen by glare. The moons were just distorted blobs. The weakness of the OTA supporting battens may be the problem here. Touching the OTA produced flexure and caused brief vibration in the image. The 18mm, 3/4" birch plywood battens were only a temporary idea to get the OTA mounted. The top bars have to be rotatable to allow the OTA to be easily lifted on and off the MkIV's 60cm, 2' long cradle. Though there is no reason why I shouldn't beef up the lower crossbars for more stiffness.

The moon was full and blindingly bright as it rose behind the hedge. I tried a range of eyepieces once it was clear of obstruction but there was no great detail to be had. Perhaps the seeing was simply soft?  Jupiter reached just over 40 degrees altitude by 10.45pm while the Moon was considerably lower and further east by the time I packed up. The drives were working well all evening. Making centering at 216x much easier than tugging at the telescope with the clutches tightened.

I fiddled with the collimation using a torch to light the folding components but achieved little or nothing. It made no difference to the view of Jupiter. I am tempted to try some different coloured filters but have never really invested. A green, a blue or a red might be worth trying. At least I am getting telescope time and my practicing staring at fuzzy planets must good experience. Had there been fleeting moments of clarity it would have made it seem rather more worthwhile. 

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