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Inexpensive solar filter


InQ
 

开云体育

It was about $40 for a square foot of Thousand Oaks solar film, and the embroidery hoop was $5. I used a 9" circle of film in an 8" hoop. It sits nicely inside the lip of my 8" sct. All it needs is a wedge opposite the screw. I intend to straighten the film out and use heavier cardboard for the flange. Even though this is proof of concept it is usable as it sits. Of course no clear skies of any kind soon :)

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Great design. At some point this year, I'll be buying a 3D printer. When I do, I'd be happy to print a custom sized hoop/ flange if you want something more exact.

Envirolaser does custom printing too but they're obviously more expensive to cover their time.?

On Thu, Apr 7, 2022 at 7:38 PM InQ <inq@...> wrote:
It was about $40 for a square foot of Thousand Oaks solar film, and the embroidery hoop was $5. I used a 9" circle of film in an 8" hoop. It sits nicely inside the lip of my 8" sct. All it needs is a wedge opposite the screw. I intend to straighten the film out and use heavier cardboard for the flange. Even though this is proof of concept it is usable as it sits. Of course no clear skies of any kind soon :)

May be an image of 1 person


Ingrid
 

开云体育

I got my hands on some leftover stiff pink insulating foam. I cut some rough chunks to be manageable, and stacked them on top of each other to be able to make a matched set. I taped them together with painters tape so they’d stay together while I cut them. ?I had access to a hot wire cutter, and cut two concentric circles in the double layer. The inner circle matched the outer diameter of my scope, and the outer one was an extra 2” on the radius to make a rigid doughnut (4” total extra diameter). Hint: cut the outer circle first, so you can use the same center reference for both circles.

I sandwiched the film between the two foam circles, and glued it in place. And then I coloured the whole thing black with a marker, so it wouldn’t look so obvious. I put black hockey tape around the outside edge to reduce any chance of the layers coming apart. Bonus: it hides some of the imperfections. Works like a charm, and fits snugly.

One thing I would change: I glued it on a table top. Turns out my bottom-of-the-line scope tube isn’t quite round, so the filter is perfectly flat… until I put it on the scope. I’d suggest anyone doing this glue it together while the ring is on the scope, and mark which way needs to be up.

?

From: [email protected] [mailto:[email protected]] On Behalf Of InQ
Sent: Thursday, April 07, 2022 19:38
To: [email protected]
Subject: [OAFs] Inexpensive solar filter

?

It was about $40 for a square foot of Thousand Oaks solar film, and the embroidery hoop was $5. I used a 9" circle of film in an 8" hoop. It sits nicely inside the lip of my 8" sct. All it needs is a wedge opposite the screw. I intend to straighten the film out and use heavier cardboard for the flange. Even though this is proof of concept it is usable as it sits. Of course no clear skies of any kind soon :)

May be an image of 1 person


InQ
 

开云体育

Thank you for this idea. Brilliantly simple. I have a second filter to build for a kid who got a small telescope (definitely lower end) for Christmas so I will probably redo mine at the same time.

On 2022-04-11 5:41 p.m., Ingrid wrote:

I got my hands on some leftover stiff pink insulating foam. I cut some rough chunks to be manageable, and stacked them on top of each other to be able to make a matched set. I taped them together with painters tape so they’d stay together while I cut them. ?I had access to a hot wire cutter, and cut two concentric circles in the double layer. The inner circle matched the outer diameter of my scope, and the outer one was an extra 2” on the radius to make a rigid doughnut (4” total extra diameter). Hint: cut the outer circle first, so you can use the same center reference for both circles.

I sandwiched the film between the two foam circles, and glued it in place. And then I coloured the whole thing black with a marker, so it wouldn’t look so obvious. I put black hockey tape around the outside edge to reduce any chance of the layers coming apart. Bonus: it hides some of the imperfections. Works like a charm, and fits snugly.

One thing I would change: I glued it on a table top. Turns out my bottom-of-the-line scope tube isn’t quite round, so the filter is perfectly flat… until I put it on the scope. I’d suggest anyone doing this glue it together while the ring is on the scope, and mark which way needs to be up.

?