Archive

Posts Tagged ‘Filters’

06/27/2023 – Ephemeris – Preparing to view the upcoming solar eclipses safely

June 27, 2023 Comments off

This is Ephemeris for Tuesday, June 27th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:32, and it will rise tomorrow at 5:59. The Moon, 1 day past first quarter, will set at 2:21 tomorrow morning.

In preparation for the two solar eclipses that will be visible in North America in the next 10 months, I’m going to spend some time describing what the Sun is, and how it appears to us. First point: Never look at the Sun without proper and approved filters. Inexpensive eclipse glasses work fine for the partial phase of a solar eclipse. However, most features, like sunspots, are generally too small to be seen with them. Do not use these glasses with binoculars or a telescope. The plastic filters will melt through in a fraction of a second. Glass filters can shatter from the heat. The only safe solar filter for telescopes is one placed in front of the telescope tube, so it’s only exposed to ambient light and heat. If confused, just ask your local amateur astronomer.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.

Addendum

The eclipse glasses must contain a statement that it “Conforms to and meets the Transmission Requirements of ISO 12312-2, Filters for Direct Observation of the Sun.” Click or tap on the image to enlarge it.
This is a filter for a small telescope that must fit snugly in front of the telescope. I bought this for the 2017 total solar eclipse and have used it occasionally ever since. Note the tiny scratches. I will have to check it out to see if they affect the image. Even a tiny pinhole can ruin the view. It’s not that they are dangerous, unless it’s a really big one. A single pinhole can be covered up, but too many will ruin the view.
Categories: Ephemeris Program, Observing, Sun Tags: , , ,