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[TomT]

    Hi Tim:

    During fall 2019 I designed and built a new tube assembly for my 10 inch Newtonian optics.  It has some odd but useful features I'd like to share with other AU members who build telescopes. 
     
    Objectives of the design were as follows:
     
    1) Reduce weight and bulk of tube assembly & parts
    2) Make set-up assembly quick & simple in the dark
    3) Reduce tube currents and speed up cooling.
     
    The present configuration is the result of some trial & error.  Instead of a closed tube or open truss design it uses a rigid single-strut optical spar to hold the secondary and eyepiece assembly.   One bolt attaches the spar to the mirror box/altitude bearing assembly.  An adjustable counterweight makes use of a kid's lunch bag. The mirror box closes up to prevent condensation for immediate storage indoors after use on cold nights.  The tube works with a conventional Dob base which can ride on a commercial equatorial platform.  The focuser is a commercial 1.25"/ 2" inch 2 speed Crayford.
     
    Stray light is blocked simply by a removable baffle inserted into the focuser opposite to the eyepiece or camera.
     
    I use this scope with a ZWO CMOS camera operated and powered by a laptop computer.  This takes video clips, which I can stack using Registax, or still photos.
     
    I built this telescope using only hand tools (hacksaw and files) and a drill press. 
     
    Recently I took photos of this equipment set up in my back yard.  One photo is attached; showing the setup in use with the ZWO camera.  I have others showing more details and a stacked lunar image if there are questions.  I'm limited sending pictures with large megabyte contents.
     
    You're welcome to share this email and the photo with other AU members.
     
    Best wishes,
     
    Gail




I want to thank all you out there that are sharing your designs, builds , mirror results , images and everything in between. It is a true pleasure for me to send them along to you all and share. Thanks folks!


Stay safe everybody!!
Tim Crawford
Workshop Notes
Sent from my iPad