开云体育

开云体育

Last time I needed replacement caps for a Nagler, I contacted Televue directly and they mailed the needed caps back to me. I seem to remember thinking that the price was reasonable.

Bill

开云体育

When I acquired a number of used eyepieces - most without caps - I figured out how to make custom caps very cheaply, using yogourt tub lids, aluminum foil, and black hockey tape. I cut a circle from the lid about the same diameter as the end of the eyepiece I wanted to protect. I used a bit of aluminum foil roughly two inches bigger than the diameter of the eyepiece end. I used narrow black cloth tape (maybe 1" wide). I cut three strips of tape? and cut them even thinner lengthwise, maybe 1/3 the width. These strips should be the diameter of the eyepiece, plus almost 2x the width of the tape you are using. I cut another strip a bit longer than the circumference of the eyepiece, and wrapped it around the side of the eyepiece, sticky side out at the end I wanted to protect. I put the yogourt tub lid circle adjacent to the cylinder of tape, at the end of the eyepiece. I then wrapped the small bit of aluminum foil over the entire end, trapping the plastic and sticking the aluminum foil to the tape, making the cup shape. I did this with the eyepiece inside, to ensure the result had the right shape. I then reinforced this all, by laying the skinny strips one by one like spokes on the flat end (sticky side toward the foil), and attaching them down the sides. For my eyepieces, usually seven skinny strips were enough to cover up the aluminum foil, but you might need 8. I'd use the 9th skinny strip for the next cover. (YMMV, depending on how wide your tape is). I then took everything off the eyepiece, and trimmed off anything that poked down past the initial strip of hockey tape. I put it back on the eyepiece, and wrapped one last strip of tape around the circumference, trapping all the ends of the skinny strips, and giving a bit more reinforcement. If I goofed, and didn't line the two circumferential tapes up well enough, so that a sticky bit was uncovered, I just trimmed the bottom with scissors.

The result is a snug cap that slides on and off easily but not too easily, and keeps the dust off. This works best with eyepieces whose ends approximate cylinder sections. For the one eyepiece I have where the business end approximates a cone, I made the cap longer to get down to the more cylindrical part.

The tub lid section gives the cap shape, stops it from crumpling, and is a clean, safe surface for something near optics. The aluminum foil adds strength, and keeps everything together while you're adding the strips over the top. The cloth tape sticks, but is a bit repositionable, doesn't ooze adhesive, is very slightly stretchy, and is soft enough not to damage anything. Everything is cheap enough that you don't feel bad if you have to make another as part of your learning curve.

And in the dark, nobody notices that your cover is homemade. It was also a much faster way to protect my eyepieces than waiting for mail order.

-Ingrid