Solar Glasses

The first thing you learn about astronomy is “never look at the Sun”, the reason you are told this is because it is very good advice. The Sun can cause some serious damage. But with solar glasses, you can safely see the Sun as much as you want!

When using Solar glasses it is also important to remember that not all are equal. Make sure that the black polymer that you are looking through is not scratched or punctured before using and make sure they are certified. Your eyes are on the line so it pays to double-check.

The Sun taken using my phone camera with some solar glasses over then lens. The solar glasses block all the light from the blue sky out but you can see the yellow disk of The Sun. Image credit: Holly

Solar glasses are most used during partial or total solar eclipses. This is because you can see the moon slowly covering up the sun darkening the day time or turning day to night in a total solar eclipse. During a solar eclipse, there are increased cases of eye damage due to looking at the Sun without the right equipment.

You do not want to be one of those people.

The next partial and total solar eclipses visible from New Zealand are:

20 Apr 2023 Partial Solar Eclipse

22 Sep 2025 Partial Solar Eclipse

22 July 2028 Total Solar Eclipse (from Otago the other parts of NZ will see a partial solar eclipse)

The sun spot is almost 12800 km across. Image from NASA’s Solar Dynamic Observatory captured on Oct. 23, 2014

But even when there aren’t any solar eclipses happening, you can see some big features on the Sun’s disk if you are lucky. Big sunspots will move around the surface of the Sun and they are big dark magnetic storms, you can sometimes see these using solar glasses. The best time for these sunspots is during a solar maximum. Unfortunately, we are in a solar minimum at the moment (2019-2020). The next solar maximum is expected to be in 2024 so in a few years, we should start seeing an increase in sunspots.

Other events that you can consider using solar glasses are transits. On the 12th of November 2019, Mercury passed in front of the Sun making a tiny black silhouette. Mercury could not be seen as a silhouette with solar glasses, to make the silhouette out you need some magnification so in these cases the best idea is to find an institution (museum, astronomy club, university etc) with a solar telescope to see Mercury blocking out a tiny bit of sunlight. From New Zealand the transit happened between 01:34 until 07:03 NZDT with sunrise happening at 6:06 am. Add to that the clouds that have been through most of the country, it was not easy to see Mercury this time.

Another cool trick is to put your solar glasses up against your phone camera if the glasses cover completely your camera lens then you can get an easy photo of the surface of the sun this way (see the first image).

Finally, something that I think is super cool is to watch the sunset (sunrise will also work) watching the earth spinning to reveal the sun is a sight to behold even without the solar glasses. With solar glasses, you can watch the disk of the Sun revealed / or hidden by the horizon so that is super cool.

So hopefully this has made you think of the Sun as a cool observing target that does not necessarily need expensive equipment.