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Materials Required
- Astrolabe master sheets
- RA and Dec grid xeroxed onto heavy paper
- Bright objects from Norton's Catalog
- Elevation guide - xerox onto heavy paper
- Overlay - xerox onto a transparency
- manila file folder
- glue stick and transparent tape
- scissors
- watersuluble transparency pens
- self-adhesive plastic transparent book cover (optional)
Step-by-Step Instructions
Preparation
- Cut out Elevation guide along the square.
- Trace the elevation guide square on the manila folder, and cut out 2
squares of the same size (one can be in 2 halves if there is not
enough space on the folder).
- Cut out the RA / Dec grid (this one has stars)
along the circle. Trace the circle onto the manila folder and cut out
a manila circle.
- Cut the transparency overlay diagonally at the corners, following
guiding lines, and ONLY along 1 side P the one which says "cut
this side only".
Assembly
- Glue the two RA/Dec circle onto the manila circle. I will either
make 2 circles and paste one on each side (so if you drop it in the
dark you don't have to worry about orientation), or I may customize
one side to include moving objects I intend to observe or my
favorites list.
- Crease the transparency along fold lines. Put glue on the
reverse side of the transparency on all parts outside the square.
Place the manila square on the outline of the square on the
transparency, and fold over the excess transparency on side 1 and glue
it down. Repeat the process for sides 2 and 3. Note: The
transparency may be a little hard to fold, and you may need to weight
it down with books until the glue dries.
- Glue the second manila square on the back of the first manila
square to hide the folded edges of the transparency. Put glue on the
back side (blank) of the elevation square and glue it to the manila
square. This should be oriented so when held the circle cannot fall out
of its pocket.
- Insert the circles into the pocket on the front side and the
astrolabe is ready to use!
- If you have the positions, RA and Dec of objects which change
position (e.g. bright comets, planets etc.) which you wish to
plot on the astrolabe, you would need to first laminate both sides of the
RA/Dec circle (clear plastic book cover material works well). Then you
can plot your object on the RA/Dec circle. Be sure to use water
soluble marker pens so you can wipe them off later as objects move.
- Tip: For greater durability you may want to laminate your circle with
transparent book covers.
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