Introduction: Make a Solar Filter for Your Camera or Binoculars

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Make a Solar Filter for Your Camera or Binoculars

The next Total Solar Eclipse over the Continental United States will be April 8, 2024. At that time a partial eclipse will be visible over most of North America. If you want to take some photos of the partial eclipse you will need a special filter for your camera. I made this filter for my camera and similar ones for my binoculars for the August 21st 2017 Solar Eclipse which was amazing and especially spectacular when viewed in the path of totality. Google '2024 Eclipse' for websites to learn more!

To safely view and photograph a partial eclipse you need special eclipse glasses or filters. This Instructable shows how to make a nifty filter for your point-and-shoot camera or for binoculars.

This filter is not only good for viewing partial eclipses, but also for viewing the sun's disk along with sunspots.

I took some photos of the sun and noticed sun spots. I looked at NASA's Solar Dynamics Observatory website and saw the same sun spots!


Solar Eclipse Glasses

3D printed filter holder

3D printed filter cutting template

3D printer and software

Box cutter or razor knife

Calipers (to measure camera lens barrel)

General Purpose Adhesive (glue)

Toothpick to apply glue

Camera or Binoculars wanting the filter :-)

Block of wood to cut on

Step 1: Start With Certified Eclipse Glasses

The filters used in this project are from inexpensive Solar Eclipse glasses that have been certified as safe for direct solar viewing. Do not use any type of glasses or filters that do not bear a certification for use to directly view the sun. These filters are black on both sides. Not silver. There has been some concern over filters that are silver on one or both sides. Look for certification information on the glasses.

Also note that the filter MUST be installed on the lens closest to the sun. It is is NOT SAFE to have the filter located next to an eyepiece or just in front of your eye. The filter must be installed so that it filters the sunlight as it enters the camera or binocular.

Some cameras have a separate viewfinder for composing your image. This filter arrangement will not provide safe viewing through a viewfinder. Do not look through the viewfinder eyepiece when using this filter.

Step 2: Measure Your Camera or Binocular

Measure your camera or binocular to determine the size the filter needs to fit onto. You will use this information to design a 3D printed filter holder that will fit snugly onto your camera or binoculars.

Step 3: Design a Filter Holder

Use Fusion 360 or a similar program to design a filter holder that will fit onto your camera or binoculars.

You need to take into account the diameter of the lens tube that you measured in the previous step and allow a slight gap between the finished part and the camera.

I designed in some tabs with gaps on each side into the perimeter of the filter holder to provide friction fit under tension when the filter holder was slipped over the camera or binocular lens.

On the inside of the filter holder is a rectangular recess that is designed to hold a piece of filter material cut from the eclipse sunglasses.

You will need to 3D print the filter holder. In addition to the filter holder it is helpful to design and 3D print a filter template that matches the recess for the filter in the filter holder. This template will be used when cutting out the filter material from the eclipse glasses.

I have attached example files of the filter holder and filter cutting template.

Step 4: Cut Out the Filter

Cut out the filter from the eclipse glasses. The filter material that is cut out should fit into the recess in the filter holder.

You can use the template to cut out the filter material if you chose to 3D print one.

Step 5: Install the Filter Into the Filter Holder

Check fit the filter material into the filter holder. Trim if needed. Note that the filter must fit edge to edge into the filter holder. There cannot be any gaps or blinding sunlight will slip past the filter.

Using a toothpick apply glue to the recess in the filter holder and place the filter material onto the glue to fasten it securely into the filter holder

Step 6: Install the Filter Onto Your Camera

Install the filter holder, with the filter securely mounted, onto your camera or binoculars.

(Remember to make two filter assemblies for binoculars ;-)

Make sure to only look into your binoculars if the filters are installed.


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