Below: a photo guide on how to make a solar filter holder from cardboard - this is the cheapest and most universal method, applicable to any telescope, as well as all spotting scopes, binoculars and monoculars.

Tools and elements necessary to make the frame




(tools: compass, pencil, ruler and cardboard about 1-2 mm thick)






(paper knife and scissors)






(double-sided adhesive tape, good thick paper glue - we do not recommend regular office glue, clothespins, crocodile clips)






(Baader Solar Foil)






(handkerchief or plain fabric)


Making a tube clamp
To make the clamp, you need rectangular cardboard strips about 2.5 cm wide - they can be narrower or wider, depending on the need and the construction of the telescope tube.



(on the edge of the cardboard we measure the required width depending on the construction of the telescope tube - optimally it is 2.5 cm)






(on the opposite edge we mark the same width of the strip)






(we draw a line according to the measured width of the cardboard from edge to edge)






(cut a strip of cardboard along the line - this can also be done with scissors)






(we repeat the operation to obtain several strips of cardboard - the number of strips needed depends on the diameter of the telescope tube; for a tube with a diameter of approx. 13 cm and cardboard strips 43 cm long, the optimal number is 4 strips)






(we try on a strip of cardboard to the telescope tube; if we do not have a sufficiently "long" cardboard, we should glue several strips together)






(apply glue to one end of the strip)






(we wrap the tube and glue the two ends so that they overlap; we clamp them together)






(we spread glue on the surface of the second strip)






(we wrap and glue)






(you can use a clothespin)






(we repeat the operation by wrapping and gluing the next strips of cardboard, holding them with clips; then we have to wait for the glue to dry)





Making the foil frame (filter mounting frame)
We proceed to bind the Baader foil in cardboard.



(removed clamp - measure its diameter; in our case it is approx. 13.5 cm - we assume with a margin of 14 cm)






(we set the radius of the clamp on the compass, i.e. half of the established diameter - 7 cm)






(we draw a circle on the cardboard, preferably as close to the edge of the cardboard as possible, to save material)






(you will need two wheels)






(we measure the diameter of the telescope's aperture with a compass - in this case the aperture is 76 mm, so the measured radius is about 38 mm, i.e. 3.8 cm; it is worth giving a slightly smaller radius - e.g. 3.5 cm - then, additionally at the cost of theoretically minimal decrease in resolution due to the reduced aperture, the image contrast will improve, because we will significantly reduce reflections, i.e. reflection of light from the walls of the tube)






(we draw aperture circles, located centrally in relation to those drawn previously)






(using scissors, cut out cardboard circles along the outline)






(cutting)






(two cut out circles, now you can start cutting out the centers)






(it is best to cut with a sharp paper knife; if the knife is not new, it is worth breaking off the used end of the knife first)






(we separate the middle)






(alternatively, you can cut out the center with scissors, to do this, you need to cut the cardboard so that there is room to insert the scissors)






(cutting with scissors should be done in a spiral so that the cutting edge of the scissors gradually reaches the inner outline)






(two foil clamps cut out)






(we prepare pieces of double-sided adhesive tape. It is worth cutting one of the ends of the tape evenly first; alternatively, you can use glue instead of adhesive tape)






(instead of adhesive tape you can also use glue, but adhesive tape works much better)






(add the next pieces of double-sided adhesive tape evenly to the clamp)






(subsequent gluing stages, the optimal amount for this diameter is 8 pieces on one side of the clamp; for larger diameters we use more tape)






(stretch and stretch the tissue or fabric evenly - thanks to it you can lay the Baader solar foil flat and without stretching it)






(we put a piece of foil intended for the filter)






(we are trying on the foil clamp)






(we tear off the protection of the other side of the adhesive tape)




















(we stick it gently to the foil - of course, remember to remove the foil protection first)






(turn the whole thing over and, if necessary, gently level the other side)






(we glue the second part of the foil clamp evenly)






(cut off excess foil with scissors)






(ready foil frame - it is worth trying to make it so that the foil surface is as even as possible, and not too stretched; in our case it was only partially successful ;-D )





Gluing both elements and finishing





(ready-made frame elements: tube clamp and framed foil)






(if necessary, align the edges of the clamp)






(grease the edge of the clamp generously with glue)






(a lot of glue will fill the empty spaces that do not stick to the cardboard and will additionally strengthen the structure)






(glue the tube clamp to the foil frames as centrally as possible)






(the gluing area can be additionally filled with glue)






(ready glued tube clamp to the foil frame - the frame is almost ready)






(once the glue has dried, the protruding edge can be evened out with scissors)






(the telescope solar filter is now ready for use)


For safety reasons, it is a good idea to secure the filter from slipping off during observation with adhesive tape, securing the mount with tape to the tube, preferably in two places. It is also a good idea to paint the mount from the inside of the filter with black ink.




(Sun and spots - click to enlarge)