Last minute tips for solar eclipse 20.3.2015

So, tomorrow, where weather permits, a solar eclipse will be visible in Europe, Northern Africa and in parts of Middle East, Central Asia and Western Siberia. The line of totality of this eclipse will be in Northern Atlantic Ocean. Only land areas, where a total eclipse can be seen are Faroe islands and Svalbard islands in the Arctic ocean. Everywhere else, the eclipse will be a partial eclipse. The maximum lenght of totality in this eclipse is 2m and 46s. The duration of the whole eclipse is roughly two hours. There’s plenty of information about the eclipse for example at site called solareclipse2015.org.uk.

Visibility map of solar eclipse March 20th 2015.
Visibility map of solar eclipse March 20th 2015.

How to observe the eclipse safely?

When observing Sun and the eclipse, you should do it safely and with safe methods! Do not ever attempt to look straight towards the Sun with naked eye or with telescope, not even if the eclipse is very deep at your location! Only during the couple minutes of totality it is safe to have a look at the eclipsed Sun with naked eye.

There are two safe methods for observing the eclipse: 1) observing with solar filter, 2) projecting method. Ideally, you should have a proper solar filter made specifically for solar observing. It can be a filter made of AstroSolar -film or it can be a filter made of special glass. AstroSolar -film is a cheap but safe alternative, and you can easily get started with filter of that kind. Four years ago I wrote a blogpost about how to easily make a solar filter for you of AstroSolar -film. With the method presented in that article, it is easy to make a simple solar filter for your telescope, binoculars or a camera lens. It is also possible to watch the eclipse with naked eye through the AstroSolar -film. At the homepage of sky and Telescope, there is a good article about how to safely observe the Sun, and how to observe the sun with projecting method. If you don’t have AstroSolar or any other proper solar filter available, you can use a welder’s glass for watching the solar eclipse. The welder’s glass should be properly dark for safe solar viewing. You can ask for welder’s glass at your local hardware store.

How to photograph the eclipse?

Now I’m going to give you couple of hints about how to photograph the solar eclipse. These tips are specifically for the ones who have an opportunity to photograph the eclipse through a telescope. First of all, you need a DSLR camera and an adaptor ring for your camera. You also should have a adaptor sleeve in your telescope with proper threads for the adaptor ring. You just simply remove the lens from the camera, and set the adaptor ring to the camera the same way you set a lens to the camera. Then just make sure, that the solar filter is in it’s place at the objective side of your telescope.

When the camera is attached to the telescope, aim the telescope roughly to Sun. Do not look through the finder for locating the Sun! Instead, use the image of the Sun for locating the Sun in field your telescope. For example, place a white piece of paper behind the finderscope so that you can see the shadow of the finderscope at the paper. If you can also see the projected image of the Sun at the paper, then just turn the telescope (around rectascension and/or declination axises) so that the image of the Sun s exactly at the shadow of the finderscope. Then the Sun should be in the field (assuming that your finderscope is in alignment with the telescope). Then use the ‘live view’ mode of your camera to make sure that the Sun is in the middle of the view and to make sure that it is focused. Focus normally with the focusing wheel of your telescope. In live view mode, you can zoom in to some sunspots or at the limb of the Sun to make sure, that the image is as well focused as possible.

When taking photos, use short exposure times. The exposure time can be as short as 1/800s – 1/3200s. Ideally, you should take some test shots before the eclipse for finding the best settings for your setup. Also during the eclipse, you can take series of photos with different settings and then choose the best shots afterwards. ISO value can be something like 100 to 400. As the white balace setting, you can use for example daylight or automate mode. And remember to use the manual (M) program for solar photography!

If you don’t have an DSLR camera, you can take photos through the ocular of your telescope with your compact camera or a camera of your smartphone. This method is simply known as digiscoping.

The partial eclipse of June 2nd 2011 observed and photographed by me in Utsjoki, Finland with digispocing -method.
The partial eclipse of June 2nd 2011 observed and photographed by me in Utsjoki, Finland with digispocing -method.

Briefly:

  • Exposure time: 1/800s to 1/3200s
  • ISO: 100 to 400
  • White balance: automate or daylight mode

Okay, so with these tips you should have better chances at succesfully observing and photographing the solar eclipse on 20th March 2015! I wish you the best of luck with observing this rare, natural phenomena!

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One week to solar eclipse

Observed object: Sun and sunspot group AR 2297
Date: 22.03.2015
Time: 10:15 UT
Observing site: Kuusamo, Finland
Instrument: Canon EOS 1100D, 4” refractor

Today when I’m writing this post, it’s exactly one week to go to the solar eclipse! Now weather has been really fantastic, days and nights have been clear and now the length of the day almost equals the length of the night! I’m just a bit worried about the timing of this period of clear skies, I’m now wondering, how long it lasts? Does it last until the eclipse day? Let’s keep our fingers crossed!

Yesterday (12.3.2015) I was practicing solar photography with my telescope here in Kuusamo. My telescope was f/9.8/4” refractor (102mm/1000mm). My camera is Canon EOS 1100D. I’m using solar filter made of Astrosolar -filter material. Yeasterday there was large group of sunspots, and it was so large, that it was well visible with naked eye too!

I noticed, that it is good idea to keep the exposure time as short as possible. The exposure time can be as short as 1/400 to 1/800 seconds or even shorter. Then camera “freezes” the turbulence of atmosphere better, and the sunspots become more clearly visible. ISO value can be something like 100-400. White balance should be on in daylight- or sunlight setting.

So, today I’m going to carry on the rehearsals. I just might report them here later, so keep on looking my blog! 🙂

Here you can see the results of the rehearsals of yesterday:

_MG_3919
Sun photographed 12.3. in Kuusamo, Finland with 4” refractor and Canon EOS 1100D.

Do it yourself -solar filter

When I purchased my new telescope, I also bought a sheet of Baader Astrosolar film for solar observations. I made a cheap and easy solar filter out of Astrosolar film and cardboard. In this post, I will show how to do a similar solar filter by yourself!

For making a solar filter like this you will need:
– 1 sheet of astrosolar film (for example size A4)
– 2 A4 size sheets of cardboard
– glue
– tape
– ruler
– drafting compass
– pencil
– scissors

Phase 1.
First, measure the inner diameter of your telescope. Cut large enough piece of Astrosolar film, it should be at least as big as your scope’s diameter is, but it is convenient to make it somewhat bigger.

Phase 2.
Cut one cardboard sheet in half, then determine the center point of both sheets. Then draw a symmetrical circle (as in picture 1.) around the central point and cut holes in the cardboards along the circle (as in picture 2.).

Phase 3.
Take the other cardboard form and cut it in half. Then put them side by side along their short side. Roll the cardboards into a tube (as in picture 3.) and try it on your scope. The cardboard tube should be tight enough to prevent the filter slipping of in windy weather. After you have tried the tube on your scope, glue the pieces of this tube together. You can use tape to make the seam stronger. Then cut ~1” long and 1,5” wide “winglets” with even spacing in the other end of the tube (as in picture 4.).

Phase 4. Open the winglets and put small drop of glue in the bottom sides of each winglet. Then attach one of the cardboards with hole in this tube with winglets (as in picture 5.). You can make the attachment stronger with tape. Then put this tube on board so that the cardboard with hole is on the top. Then put small amount of glue in it. Take the Astrosolar film, and put it carefully on the glued face of the cardboard (as in picture 6.). Then take the other cardboard with hole and put glue on it and place it on the Astrosolar film. Be very careful in this step to avoid any stains and wrinkles in the Astrosolar film (as in picture 7.)! Then you can tape the edges of the cardboard to make it stronger. And then you are finished!

Now you are ready to start your safe solar observing with your new DIY solar filter (which should look like the one in picture 8.)!