HOW TO OBSERVE THE
SOLAR ECLIPSE SAFELY USING PROJECTION METHODS
On Friday 20th March, the UK will see the best
partial solar eclipse since 1999. From mainland UK, as much as 90% of the solar
surface will be covered by the Moon. The eclipse is taking place from around
8:30am until about 10:45am, with the maximum coverage being at around 9:30am
(exact times will vary depending on your location).
If you have left it too late to get hold of a solar filter
and want to safely observe the eclipse, then don’t panic! You can safely
observe the Sun using a couple of projection methods and all you need are some
simple household objects.
SAFETY NOTICE: NEVER EVER ATTEMPT TO LOOK AT THE SUN EITHER
DIRECTLY, OR THROUGH BINOCULARS OR A TELESCOPE WITHOUT THE CORRECT EQUIPMENT.
YOU WILL GO BLIND! SUNGLASSES ARE NOT SUITABLE – ONLY USE DEDICATED
ECLIPSE GLASSES FOR DIRECT OBSERVATION, AND A FILTER MADE FROM BAADER SOLAR
FILM OR SHOP BOUGHT SOLAR FILTER FOR YOUR TELESCOPE OR BINOCULARS. DO NOT
ATTEMPT TO PHOTOGRAPH THE SUN THROUGH A TELESCOPE OR BINOCULARS WITHOUT THE
CORRECT FILTERS IN PLACE– IT WILL BURN THROUGH YOUR SENSOR AND KILL YOUR CAMERA.
I will now explain how you can observe the eclipse using a
couple of different projection methods. First of all, you need a piece of white
card, or white paper glued onto a piece or card, or a piece of white board.
This will be your projection board. If you can, try to find a way of mounting
it onto a tripod or broom handle so it is free standing. It will help you
greatly later on if it can stand up by itself.
Next, you need something that has a small hole in it. To produce your own pin-hole projector, take another piece of card and make a tiny hole in it using a compass point or a pin. Place your projector board in direct sunlight, then hold the card with the hole in it in front of the projector board. Once you have the angle correct, you should see a small bright circle on the white card. You can move the pin-hold card forward and backward until you get a crisp disc. During a normal day the bright spot will be a circle, however, during the eclipse the bright dot will become a crescent at the Moon passes in front of the Sun. This method produces a very small projection but you will see a difference during the eclipse. The picture below shows a cloudy solar disc. You can also use other household objects to do this. As the photo below shows, you can use a kitchen colander to produce multiple projections, but any object which has lots of small holes in it will work. When the 2nd photo below was taken it was a cloudy day, but you can clearly see multiple bright spots. During the eclipse, each one of those spots will become a crescent.
Telescope projection method:
If you have a telescope or binoculars, you can also use them to project the image onto a piece of card.
SAFETY NOTICE – IF YOU ARE OBSERVING THE SUN USING A TELESCOPE, MAKE SURE YOU KEEP THE CAPS ON YOUR TELESCOPE’S FINDERSCOPE. EVEN THAT LOW MAGNIFICATION IS ENOUGH TO BURN YOUR EYES AND CAUSE PERMANENT DAMAGE
Begin by lining up your telescope with the Sun. Place your projection board behind the eye piece to help you get things lined up properly. If you are using a refractor, your projection board will be behind the telescope, but if you are using a reflector it will be at the side. When everything is in place, you will see a large bright disc on your projection board. Adjust the focus on your telescope until the disc is nice and sharp. You should easily be able to see any sunspots which are currently visible. During the eclipse, you will see the Moon passing in front of this disc causing it to become a crescent shape. If you want to take a photograph of the projection on the white board, it is safe to do so.
If you have a telescope or binoculars, you can also use them to project the image onto a piece of card.
SAFETY NOTICE – IF YOU ARE OBSERVING THE SUN USING A TELESCOPE, MAKE SURE YOU KEEP THE CAPS ON YOUR TELESCOPE’S FINDERSCOPE. EVEN THAT LOW MAGNIFICATION IS ENOUGH TO BURN YOUR EYES AND CAUSE PERMANENT DAMAGE
Begin by lining up your telescope with the Sun. Place your projection board behind the eye piece to help you get things lined up properly. If you are using a refractor, your projection board will be behind the telescope, but if you are using a reflector it will be at the side. When everything is in place, you will see a large bright disc on your projection board. Adjust the focus on your telescope until the disc is nice and sharp. You should easily be able to see any sunspots which are currently visible. During the eclipse, you will see the Moon passing in front of this disc causing it to become a crescent shape. If you want to take a photograph of the projection on the white board, it is safe to do so.
Binocular projection method:
Begin by placing your projection board facing the Sun. Point your binoculars at the Sun and angle them until you see 2 bright discs on your projection board. Adjust the focus of the binoculars until you get nice sharp discs. As with the telescope projection, you may be able to see sunspots using this method. During the eclipse, you will easily be able to see the Moon passing in front of the Sun. Once again, if you wish to photograph the image on the projection board, it is safe to do so, but you may need an extra pair of hands to hold everything in place if you don’t have a tripod for your binoculars!
Begin by placing your projection board facing the Sun. Point your binoculars at the Sun and angle them until you see 2 bright discs on your projection board. Adjust the focus of the binoculars until you get nice sharp discs. As with the telescope projection, you may be able to see sunspots using this method. During the eclipse, you will easily be able to see the Moon passing in front of the Sun. Once again, if you wish to photograph the image on the projection board, it is safe to do so, but you may need an extra pair of hands to hold everything in place if you don’t have a tripod for your binoculars!
I hope this blog helps you to be able to observe Friday’s
eclipse safely - let’s hope we get some clear skies. Good luck and happy
observing!
