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Dhinakar
Rajaram
Member:
Astronomers Without Borders
(AWB)
[email protected]
Points to be taken care off
Before we project or show sun we need to take
care of 1. Audience be properly educated on hazards of
direct viewing of sun.
2. Not to see the sun directly through an
unfiltered optical device. Ex: Cameras,
Telescopes & Binoculars etcetera
3. Advising on safe view methods and not to use
discarded X ray sheets, reflection on glossy
surface, through sun glasses etc.
•
Using Sun spotter technique
The Suns potter is a folded
achromatic refractor made of
Baltic birch plywood that projects
a 3 ¼ x 3 ¼ image of the sun on a
white piece of paper. It's designed
for use with small groups,
particularly with children. There
are a number of advantages to
using this type of a system for
solar viewing when you are
working in a group. The two
largest are probably that you
don't have to worry about the
filter coming off the telescope,
and that several folks can view at
once. It's easy to use, transport
and set up. So easy, that as an
educator, I would have no qualms
about giving it to younger
students to use on their own,
after appropriate instructions. It
can be setup in minutes and used
indoor or out. The instructions are
very simple and contain decent
lesson plans – mostly suggestions
for questions and projects, further
these can easily be adapted for
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any age group.
Projection of sun through the spotter
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Image of an active region as seen through the
spotter
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Sun spotter Specifications
Telescope type: folded-path refractor, F 11, altitude-azimuth design
Objective lens: 2-element achromatic, 700 mm FL, fully coated
Objective aperture: 61.7 mm diameter, stopped down to 57.0 mm
Mirrors: 50 mm x 50 mm x 10mm, two @ 25 mm x 25 mm x 5 mm ,
<1/4 wave
Field lens: 4-element, 12.5 mm FL Plössl, fully coated, 10 mm
aperture
Total path length: 875mm, fixed focus
Equivalent magnification: 56x
Approximate solar image diameter: 85 mm (3.25")
Field of view: .75° (1.5 solar diameters)
Pointing range: altitude 0°-30°, 30°-90° (reversed), azimuth 0°-360°
Pointing aids: 2.2 cm gnomon (±30°), 22 cm pinhole projections (±3°)
Frame material: 15mm 9-ply (cradle), 20mm 13-ply (telescope), Baltic
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plywood
Solar Projection
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SUN FUNNEL: A solar projection using tracing paper and a funnel by me
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A Projection contraption
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sun through binos on to a projected surface
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Kids were shown last Venus / mercury transit using projection!
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A cheap cctv camera can be used instead this costly camera to
record and project the sun on to a screen . Projected image in
next slide
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Projected sun image!
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Sun Gun - Solar Projection - The best
method
Sun Gun is a solar projection gizmo made by Mr. Bruce
Hegerberg, USA for safe projection of solar disk so that many can
see the events in sun also cheaper to make using few easily
available materials.
SUN OF A GUN ( scaled down edition)
The SUN OF A GUN is a smaller version of the of the SUN GUN will work with any
telescope. It consists of a black plastic 5 Kg black paint bucket , if not black paint the
interior flat black. A 2" insert male adapter, adapts polyethylene tubing to standard
female pipe thread mounted in a 2 1/4" hole in the centre of the bottom of the paint
bucket, with two 2" conduit lock nuts. One lock nut on the inside and the other on the
outside of the bucket. Drill a 1/8" hole ½" in on the hose end of the male adapter.
The adapter will slide over a standard universal camera adapter, using the eyepiece
retaining screw, on the camera adapter, to hold the 2" male adapter and the eyepiece in
place. A 15" square kadha cloth as it is cheaper. is mounted to the top of the paint
bucket with a 48" wire tie or a large rubber band. Lay the rear projection screen on top
of the bucket, polished side facing out. Connect the wire tie so it just fits over the rear
projection screen and the top lip of the bucket. Tighten the wire tie under the lip of the
bucket and adjust the rear projection screen tight across the top of the bucket, it should
look like a drum when done. Cut the excess screen off, leave ½" below the wire tie for
future adjustment. Loop a large rubber band through itself on to the handle,
hooking the rubber band over the finder will give it extra support. Use on a telescope
with a lens of 4" or less, or stop down a larger lens to 4" or less.
With the SUN OF A GUN use a 17mm or a 20mm eyepiece, with a # 12 eyepiece filter,
on a 4" SCT giving a 11" and a 10" image. If using a telescope with over a 4" lens stop it
down to 4" or less. On a 8 SCT, stopped down to 2", a 25mm eyepiece was used. Also
a #21 orange eyepiece filter can be used. Plossl eyepieces where used because they
deliver sharper and better color corrected images than Ramsden or Huygenian
eyepieces.”
Other safe methods to see sun
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Observation through filtered optics
and eclipse goggles
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Other contraptions for safe viewing of sun
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Projection of sun through a refractor telescope
Best method and easy to set up and photograph
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PIN HOLE METHOD
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Simple Pin hole method using a
used tin!
• Using a discarded cola tin
• Take hard bodied cola tin or a cardboard barrel
• Cut off the both ends, cover the holes on one end with
a thick paper or chart paper or card board while the
other end with clear smudge free tracing paper
• On the end with thick paper or board, make a pin hole
good enough to effortlessly allow the sunlight clearly
• View the sun via the tracing paper side, the paper will
act as an screen. One can easily see the solar disk with
spots and eclipse. Taller the can or barrel good the
image.
• If possible place the contraption on to a adjustable
holder to see freely
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Home made pin hole
camera
The Pinhole Projection Method
One safe way of enjoying the Sun during
a partial eclipse-or anytime--is a "pinhole
camera," which allows you to view a
projected image of the Sun. There are
fancy pinhole cameras you can make out
of cardboard boxes, but a perfectly
adequate (and portable) version can be
made out of two thin but stiff pieces of
white cardboard. Punch a small clean
pinhole in one piece of cardboard and let
the sunlight fall through that hole onto
the second piece of cardboard, which
serves as a screen, held below it. An
inverted image of the Sun is formed. To
make the image larger, move the screen
farther from the pinhole. To make the
image brighter, move the screen closer to
the pinhole. Do not make the pinhole
wide or you will only have a shaft of
sunlight rather than an image of the
crescent Sun. Remember, this instrument
is used with your back to the Sun. The
sunlight passes over your shoulder,
through the pinhole, and forms an image
on the cardboard screen beneath it. Do
not look through the pinhole at the Sun.
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A pinhole camera
made from an
discarded oatmeal
can. The pinhole is
in the centre. The
black plastic which
normally
surrounds this
camera has been
removed.
Thanks….....
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