In 2016 I got to see the transit of Mercury thanks to a group of volunteer astronomers. The astronomer had a device attached to the telescope eyepiece that allowed the light to project onto frosted glass.

I’d like to get such a device for my own telescope for viewing the next two solar eclipses, but I don’t know what this device is called. I’ve Googled various things, but I’ve had no luck.

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    $\begingroup$ I used a sun funnel for the partial solar eclipse in 2017. It worked far better than I expected, even with my awful cheap old telescope. See here for a link: eclipse2017.nasa.gov/make-sun-funnel. $\endgroup$
    – Ed V
    Commented Sep 8, 2023 at 15:42

1 Answer 1


The device you saw was probably a "solar projection eyepiece". You can use any eyepiece for this, in theory, though eyepieces with cemented lenses can heat up in the sun and the glass can crack.
Personally I wouldn't feel comfortable using one of those with my telescope.


You can use solar film specially designed for looking at the sun, such as Baader's "AstroSolar Safety Film" which comes in a variety of sizes.

The link above is for just the film, but if you want to use it with a telescope then they also sell the film mounted in a frame which clips onto the front of your telescope.

Further down the line, if you get more into solar observation, then you may want to look into buying a Herschel Wedge which filters the light after it's passed through the telescope, so shows more detail.


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