Customizing A Baader Solar Filter Mount for Your Telescope

Standard Refractor Cell Mounting

Off-Axis Mounting for Reflectors and Schmidt-Cassegrain Telescopes

See a photo illustration of construction Here.

For your standard refractor, binocular, or Maksutov objective, you will center the filter material.  The collar may be made from cardboard, cardstock, or opaque flexible plastic.  The cap  material should not allow any light through either the hole around the Baader Material, or the edges where it connects to the collar.   You may need to run duct tape or electrical tape around the join, or make the end piece hang over the collar with flanges cut to bend over the collar and be  taped down.

 

For your standard Newtonian Reflector or Schmidt-Cassegrain, you will mount the filter material off-axis to avoid light blockage by internal components mounted inside the telescope tube.  The collar may be made from cardboard, cardstock, or opaque flexible plastic.  The cap  material should not allow any light through either the hole around the Baader Material, or the edges where it connects to the collar.   You may need to run duct tape or electrical tape around the join, or make the end piece hang over the collar with flanges cut to bend over the collar and be taped down.


    DUST CAP MOUNT

Images were submitted from Cindy who constructed her off-axis filter using her telescope's Dust Cap.
This is probably the most practical method to make a secure off-axis filter if you have the proper tools to make it and your telescope comes with a dust cap.

 

 

 

Picture 1

Using a 3.5" circular bit from Lowes to drill the hole, I actually just hand-rotated it and cut through the soft plastic without attaching it to a drill bit.  Pretty easy.  I used sandpaper to smooth the edges.

Picture 2

This is an 8" dust cap for the XT8. It's an older version that is flat on most of the top-perfect for an off axis solar mask.

Picture 3

The film was cut and taped in place over the hole.  I did not remove the film from the 2 sided card stock it came in.  That made it easier to keep it from getting smudged.

Picture 4

I cut a piece of white cardboard to mount over the top (outside) of the dust cap and taped it in place.  The white helps reduce turbulence from the added heat of a black cap.

Picture 5

The solar filter is lined up so that the filter is between two spider veins.  The cap is very snug on the OTA, but you may want to tape it on to be sure it doesn't accidentally fall off.  I used an old Telrad (got the idea from another amateur astronomer) to create a solar finder. The light falls through the hole drilled in the flat wooden piece that is parallel to the bullseye. This is to line up the 'scope without directly looking at the sun. 

Note:  You don't look through the Telrad, anyway.


Here is another illustrated example of mounting a Baader filter for your telescope main objective:

Homemade Solar Filter for Small Telescopes

By Steven Bellavia and Judith Guercio

 

These are the instructions for how to make a professional looking, but inexpensive, homemade solar filter for a small telescope.
We achieved a perfect fit for our Orion 80mm Short Tube Refractor.

Phase 1:  Gather the following items:

 

1.      3.5 inch Baader Solar Filter from www.dracoproductions.net

2.      4-inch PVC drain pipe cap, Bar code # 52063 40406:   ($1.72 at Lowes or Home Depot)

3.      A 3-inch hole saw

4.      Foam board, or oak tag or other stiff, paper or plastic that can be easily cut

5.      Double sided tape or transfer adhesive

6.      Self adhesive felt pads

 

Phase 2:  Preparing the Pipe Cap

1.      Mark the center of the PVC pipe cap. (One method is to trace the outside of the pipe cap onto a piece of paper.  Cut out the circle,
 and then fold it twice to form a pizza-slice shape.  Align the outer edge and the apex of the pizza slice points to the center).

2.      Using the 3-inch hole saw, cut a hole in the center of the PVC Pipe Cap

Note:  if desired, you can lightly sand and polish the cap for a professional look.  Now is the time to do that if this is desired.

Phase 3:  Mounting ring and solar filter material:

1.      Using the same hole saw (or a knife or razor) cut a 3-inch hole in the foam board (or oak tag, or whatever you were able to get).
  Then  cut a 3.5 inch diameter circle centered around the 3-inch hole:

2.      Apply the double side tape to JUST ONE SIDE of the mounting ring.

3.      Place the solar filter material on a nice, flat surface (table or countertop) with a clean, lotion-free tissue taped down underneath, onto the flat surface.

4.      Press the mounting ring carefully onto the solar filter material, to adhere the filter to the ring

5.      Cut out around the filter material

6.      Now place the double-sided tape onto the other side of the mounting ring

  

Phase 4:  Final Assembly

1.      Adhere the mounting ring, with solar filter to the inside of the pipe cap, carefully centering the hole in the ring
  with the hole in the pipe cap.

2.      Add felt pads to inside of cap to fit the barrel of your telescope

3.      You may want to add labels for safety. Safety is VERY IMPORTANT when viewing the sun!

 

ALWAYS place the filter at the FRONT of the telescope.

4.      Carefully slide onto telescope.  Make sure it is a tight fit and will not fall off.  If not, add thicker pads or stack them.

You are done!


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