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Light Shrouds for Strut Telescopes DISCUSSION: The question
about light shrouds often comes up with respect to an open-tube
telescope. Many believe that stray or ambient light causes
a problem when crossing the telescope's light path. Actually,
it is the light that is reflect back into the eyepiece that
is a problem. Light "crossing the light path" isn't much
of an issue. The 3-tube strut design has its own issues when
using a light-shroud, as the conventional light-shroud can
droop into the light-path itself obstructing the image. Here
are a couple of solutions I've found that correct this issue. |
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Made
from light weight breathable black fabric. Two ABS bands
prevent shroud from obstructing the light path. Upper and
lower draw strings. Blocks stray light & dew from reaching
the optics. Increased image contrast. Made in the USA!. Check
out their product at: Photo, with permission, of Carol Anderson's 16" Astro Tech Dob/Newtonian. |
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Embroidery
hoops are available in a variety of sizes and can be used to
keep the traditional light-shroud out of the light path. I've
seen these in sizes up to 18". Slide one or two of these over
the struts of the ota and tighten to keep the hoop in place. They are very inexpensive and are available in crafts stores such as Michaels and JoAnns. |
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Astro Engineering is a company in the U.K. with a unique solution. Although their shroud is made for the Meade Lightbridge telescopes, their products are no doubt available in other countries.
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| Photo to follow |
Here's an interesting idea from Don Wyman via Cloudy Night's forums. "Another solution is to use shock cord (bungee cord) as is used in collapsible tent poles. Just put some small hooks on the UTA an on the mirror box half way between the struts, then run the shock cord. It will hold the shroud out just like having 3 more struts." |
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Here's an interesting approach from Brian Reed via Cloudy Nights Forums. Used with permission. Brian says: "I finally got
around to making a shroud for my dob. I thought of useing cloth but
I am concerned it might sag with a long newt unless it was pulled
very tight, also I didn't want to take a chance of deforming the structure. |
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Here's a custom shroud for one of our 10" telescopes with ETT
option. The center ring of the ETT keeps the shroud neatly out
of the light-path. Notice there are "cut outs" for the Rigel
finder, focuser and alt-bearing clamps. |
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For more information about
your requirements: |
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