I have a pair of binoculars with 10x magnification, 50mm objective diameter, and 6.5 degree (real) angular field of view.

I'm looking into buying solar filters for it (something like these) so I can view the sun. If I do so, will I be able to see most/many sunspots and planetary transits? Or is this simply not a powerful enough instrument to be worth investing in solar filters for it?

I like the idea of being able to check out the sun sometimes, but I don't know if I'm just getting way out of my league here and would need more complicated and expensive equipment to make it at all worthwhile. Thought I'd ask some experts before buying anything.

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    $\begingroup$ Just a warning - those look a bit cheap. If you buy them, check them in front of a strong lamp first and send them back if there are any pinpricks of white light showing through, or any gaps around the edges of the filter. $\endgroup$
    – Andy
    Commented Jul 5, 2016 at 17:15
  • $\begingroup$ Right. Solar stuff should be good quality. Any failure here can have nasty consequences. $\endgroup$ Commented Jul 5, 2016 at 21:52

1 Answer 1


You will definitely see some sunspots at 10x; in exceptional cases sunspots are big enough to be visible with the naked eye through the sunset haze near horizon, but many sunspots are visible in a small instrument like a 10x binoc with proper filtering.

The Sun is at low activity right now, but still a few sunspots are showing up once in a while. And the activity should increase gradually in the future.

Planetary transits - yes. However, the next transit of Venus will take place in a century or so. Mercury transits more often, and the filters will allow you to see it - a tiny dot on the face of the Sun. A bit higher magnification might be beneficial, but anyway even at 10x you should see the planet, even if it's rather small.

BTW, I recommend solar filters based on the Baader solar filter film (just google it). They are neutral-density (do not change the color of the image), and are recommended and have been tested with instruments from small binocs to dobsonian telescopes. Make sure the filters are firmly attached to the instrument, and are free of defects.


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