Yep these GSO crayford focussers are not obvious at first.
If the bottom screw was hand tight, I suspect the tube was struggling to move. It is for locking the tube at focus point. Would be useful if you were trying to take photos through the focusser. Maybe useful to stop inexperienced people knocking the focussing knob and having it out of focus. BUT most people focus at slightly different places anyway. I always put a person's hand on the focus knob and say twiddle away until it is right for you. Many unscrew it right out and put it away somewhere - never use it and you don't want it falling out during bumpy transport to site.
Note that as the temperature changes, the performance of the Crayford changes - how it is working now in the warmth of the day may be different to what it was doing last night in the cool (well, it's all relative in Darwin
). Often through a night, one adjusts the tension screw a little to adjust for temperature change as well as for eyepiece weight.
Quote:
Originally Posted by Outbackles
Thanks folks for the speedy replies!
Erick, just checked and the bottom screw on the focuser was hand tight, I have loosend it. How loose should it be? what is the point in it?
Hope that is it !
I'm not sure I understand what it does as the tube appeared to be moving in and out anyway?
Hope that is it! Always the simple things to those in the know! but frustrating to the newbie.
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