[tas-list] Re: Sun shields for a solar telescope

From: "charles jacobson" <jacobsonc@xxxxxxxxxxx>
To: <tas-list@xxxxxxxxxxxxx>
Date: Tue, 5 May 2020 21:11:59 -0700

Thanks Richard another great idea from you.  chuck

From: tas-list-bounce@xxxxxxxxxxxxx <tas-list-bounce@xxxxxxxxxxxxx> On Behalf
Of Richard Frederick
Sent: Thursday, April 30, 2020 12:16 PM
To: tas-list@xxxxxxxxxxxxx
Subject: [tas-list] Sun shields for a solar telescope

Here’s a follow up to my earlier post about the Solar Quest Mount that may be
of interest to someone looking for a project.

If you’re not using a solar scope the eyepiece shield part of this works great
for nighttime viewing.  Keep your non-viewing eye open.  No more squinting!
(Another nighttime shade of a different sort worth looking at is detailed in
Sky & Telescope, April 2017 in Jerry Oltion’s column. The “Dethloff eyepiece
shade.”)

An often overlooked but necessary accessory for a solar telescope is a good sun
shield—which in reality means two shields, a larger one at the front and
another at the eyepiece.  Conventionally you can cut a hole in a piece of foam
core and slide it over the barrel of the scope (somehow holding it in place)
and then put a cloth over your head.  I’ve tried numerous variations but after
getting the Solar Quest mount (now resting on a weighted Manfrotto 055 tripod
that gives a steadier platform) I decided to revisit the issue.  The main
challenge is finding a way to attach the shields to a telescope that has no
obvious mounting points.

A parts list:

1.  Foam core.  Black.  Approx 11x18.  White may intuitively seem better on the
sun side but is a glare bomb for anyone on that side of the scope.  A high
shade is good to get a little shade when not viewing.

2.  Velcro—sticky back and strapping

3.  Mending plates.  6 pieces.  (Hillman ½ x 5 ½”).  (Lowes)

4.  Sticky-back felt.  3 sheets.  9 x 12”.  Craft store.  Or Internet at the
moment.

5.  Cable Clamp Pro.  Large.  McLendons.  Or Internet.

6.  Dense foam.  A garden kneeling pad works.

7.  Packing tape.

8.  Machine screws & nuts.  8x32.

Photo 1.  Sun shields on a Coronado Solar Max 60.  The main shield attaches at
the front of the telescope’s clamshell mount, sliding about halfway over the
diameter of the tube.  The first step is to measure and cut the foam to fit
over the finder, tube and dovetail mounting bar.  This is the most time
consuming step and worth using some scrap matboard.

Photo 2.  Front of main shield.  An additional cut is made to allow reaching
over the telescope mount and adjusting the etalon tuner.  A piece of
sticky-back Velcro is attached to the top of the tube and a collar of 4 or 5
pieces of strapping Velcro attached to that, serving as a stop for the bottom
of the shield.  A piece of mending plate is taped to the shield, acting as a
further stop as it abuts a set screw on the dovetail mounting bar.

Photo 3.  Back of main shield.  A mending plate is bent and taped to the
shield.  It rests over sticky Velcro attached to the clamshell and is held in
place with a piece of strapping Velcro.  A small piece of Velcro on the bottom
of the mending plate keeps it horizontal. There’s a bit of play in all this—a
good thing when the wind is gusting.  The cutout to the right is for adjusting
the etalon.

Photo 4.  Support for the eyepiece shield.  A dense piece of foam (kneeling
pad) is cut to fit around the eyepiece holder above the diagonal.  It’s then
marked and cut to match the non-round jaws of the clamp.  Cut so there are
about six teeth of the clamp showing when tightened. An additional cut is made
to accommodate the eyepiece locking screw.  Mending plates are bent about 120°
and held to the clamp with 8x32 machine screws and nuts.  An additional mending
plate is needed on the right side.  (The eyepiece shield detailed in the Sky &
Tele article is made from a plastic bowl with felt wings.)

Photo 5.  Rear part of the eyepiece shield.  This is made with 2 pieces of 9x12
sticky-back felt.  (This is really sticky so watch out.)  Remove backing from
one piece and place mending plates about 2 inches out on each side of center.
(Hidden location shown in red.)  Remove backing and place second piece of felt
on top.  The mending plates can then be bent about 2 inches in to hold the felt
up.  The felt is held on the back with strapping Velcro over the uprights
coming off the Cable Clamp.  The felt is cut at bottom center to fit around the
eyepiece.

Photo 6.  Front part of eyepiece shield.  The front part is made of a single
piece of sticky-back felt, folded lengthwise and stuck together.  A hole is cut
about an inch down to fit over the eyepiece.  A few pieces of strapping Velcro
hold front and back part together.  As a shade for nighttime viewing cut the
eyepiece hole in the center.  There’s no need for the rear part of the shade,
or to cut a foam collar for the eyepiece.  Assuming an eyepiece diameter of
around 2”, half-inch sticky-back insulation foam can be applied to the inside
of the clamp jaws and it closes directly on the eyepiece barrel.  As when using
with a solar scope there’s no need to squint one eye closed and viewing is much
more comfortable.

[tas-list] Re: Sun shields for a solar telescope

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