[M]: Focusing ETX w/201XT
| Subject: | [M]: Focusing ETX w/201XT |
| From: | Emery Hildebrand |
| Date: | Sun Sep 21 10:19:23 1997 |
>Also, I felt like I tightened the Losmandy rings up snug but the ETX
would slip to the rear when the scope was elevated straight up. The
tips on the adjustment bolts have nylon tips that are hard and seem to
be slick. I was afraid to tighten them real hard since I am afraid it
would put dents in the OT of the ETX. Anyone else have this and a
solution?<
You can cover the nylon tips with rubber tips that are available for
covering the end rails of wire closet shelving.
These rubber tips come in black or white and in sizes to fit 1/8" to 5/8"
diameter wire. Since they are rubber (some are pliable plastic) they will
grip well but youll need to tighten them to assure there is no flexure
from the rubber tips themselves. Youll need to get extras since these
will wear thru after repeated adjustments.
If the tips are a bit too large you need not glue them in place since they
will not fall off during normal use, and you will want to change them after
a couple of all-nighters worth of adjusting. To insure against denting the
tube you might even rubber-cement some small rubber disks to the OTA to
spread the load.
This combo has been adequate for holding a 4" SCT and a heavy 80mm
refractor without slippage. I usually leave the front 3 adjusting screws
tight and only adjust the rear three while locating a guide star. While
adjusting, the entire load is adequately supported by those front 3 screws.
Unitron had nice plastic rings around their guide scopes. These rings had a
groove in the center which would prevent the OTA from slipping out if the
screws were too loose. This is the best solution Ive ever seen for this
problem but I havent seen anything that could be adapted to work
similarly. I guess something could be fabricated out of strips of plastic ,
using a wide piece as the base and glueing two narrower strips atop that
with a gap between them. Perhaps someone with the right tools could
fabricate enough of these strips to equip a bunch of rings.... Ken Milburn?
Emery Hildebrand
would slip to the rear when the scope was elevated straight up. The
tips on the adjustment bolts have nylon tips that are hard and seem to
be slick. I was afraid to tighten them real hard since I am afraid it
would put dents in the OT of the ETX. Anyone else have this and a
solution?<
You can cover the nylon tips with rubber tips that are available for
covering the end rails of wire closet shelving.
These rubber tips come in black or white and in sizes to fit 1/8" to 5/8"
diameter wire. Since they are rubber (some are pliable plastic) they will
grip well but youll need to tighten them to assure there is no flexure
from the rubber tips themselves. Youll need to get extras since these
will wear thru after repeated adjustments.
If the tips are a bit too large you need not glue them in place since they
will not fall off during normal use, and you will want to change them after
a couple of all-nighters worth of adjusting. To insure against denting the
tube you might even rubber-cement some small rubber disks to the OTA to
spread the load.
This combo has been adequate for holding a 4" SCT and a heavy 80mm
refractor without slippage. I usually leave the front 3 adjusting screws
tight and only adjust the rear three while locating a guide star. While
adjusting, the entire load is adequately supported by those front 3 screws.
Unitron had nice plastic rings around their guide scopes. These rings had a
groove in the center which would prevent the OTA from slipping out if the
screws were too loose. This is the best solution Ive ever seen for this
problem but I havent seen anything that could be adapted to work
similarly. I guess something could be fabricated out of strips of plastic ,
using a wide piece as the base and glueing two narrower strips atop that
with a gap between them. Perhaps someone with the right tools could
fabricate enough of these strips to equip a bunch of rings.... Ken Milburn?
Emery Hildebrand
