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ZenithStar 71 ED Thermometer and Focus Rotation Issue

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Hi All,

I have a couple of niggles with my William Optics ZS 71mm, and can't find any answers on the interweb.  First problem is the thermometer is about 5 or 6 degrees C out.  Last night I was out and it was reporting -4 deg C, when the puddles on my patio were clearly still in liquid form!  The scope had been outside for about 2 hours, so should have settled by then.  Anyone know if there is a way to calibrate it without major surgery?  Not a big deal, just mildly annoying.

Second issue is the focus rotation.  When I unlock the rotation screw the focuser end becomes quite loose.  When rotating it feels like it's catching on something internally and can only be fully rotated if the focuser is pushed forwards into the tube.  There are a bunch of adjustment screws - the two big ones on top which adjust the friction on the focuser have been tightened enough that the focuser doesn't drop out when at Zenith with a DSLR attached, but not so tight that the micro-focuser can't operate.  There are a bunch of screws covered by tiny (5mm?) grub screws which I've not touched yet.  There are four on the top (where a finder can be attached) which are diagonally spaced, and one at the bottom near to the focus lock screw.  Does anyone know what each of these are for, please, and if they are safe to tinker with?  I'm assuming at least some are used to adjust collimation, so I don't want to mess with the wrong ones.

Thanks in advance,


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