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5 astronomy projects you can do with the sun (part 2: record sun orbits)

Yesterday I had started with the series 5 astronomy projects you can do with the sun. Actually it should be a single article, but after I finished the first project, I saw how extensive it becomes.

So I just divided my project to describe the 5-projects into 5 articles. Today I would like to make you another project suggestion. Today I would like to introduce you to the Sun path bring closer.

Why it is exciting to look at the sun’s orbit? Well because it changes and we make it visible.

Since we move with our beautiful planet the earth around the sun and that 1 times in a year and we lie also still obliquely in the space, the apparent course of the sun changes over the sky.

Every one of you knows that. Why? Because everybody knows that the sun is longer in the sky in summer and shorter in winter. The sun’s position, i.e. the height above the horizon, is also greater in summer than in winter. Therefore you know it changes something.

But what changes? Before we go into this question and I give you practical tips to record these changes, here comes the hint for sun observation. Please take this seriously.

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Also I have to point out again and with emphasis that you can never , and I say NEVER , also not sometimes or once, but never with the telescope without sun filter looks into the sun. Also not with binoculars. Massive eye damage can occur and lead to complete blindness. So NEVER looking with the telescope into the sun without sufficient preparation and appropriate filters. After all, you want to do the hobby of visual astronomy, don’t you??

But now to the sun observation and how you can record the path of the sun in the sky.

I have created a small GIF animation of the sun at noon with the help of Stellarium. There you can see the sun positions over all 12 months.

This illustrates quite clearly that the sun’s orbit changes over time.

Now you may want to record this. For this I would like to give some suggestions.

You can record the apparent path of the sun in the sky in several ways. One way is relatively simple and should work with any good camera. Another one is very nice from the experimental point of view.

Way 1: Time lapse

What always goes as a way, of course, is time-lapse photography. Here you put the camera z.B. set up a Canon 600D DSLR camera at a fixed location and have it take a picture every 30 or 60 minutes.

Of course you have to do this over days, so that also the apparent orbits come out.

I have done this once exemplarily at the sun in Stellarium. Depending on the settings of the camera you will then get such a result:

Sun path across the sky

Here you can see a picture of the sun’s path across the sky. Unfortunately there is a lens effect in Stellarium. Therefore the horizon is bent downwards and the sun path is therefore quite straight.

There would change of course with a real admission.


The only problem you have now is the fact that you want to superimpose this sun track. So you need tracks of several days.

And so that you can tinker the whole thing together, you must not move the camera anymore.  So here is the big disadvantage of the whole story.

Of course you can choose some sunny days and leave the tripod instead of the camera at that place. Or you build an adapter plate and put the camera on it again and again. This should then also work.

If you have some photos of the trails together over the year, you can create great trails using the program StarTrails. Now not everyone wants to do without his camera. Nobody has to do that either.

But there is a second way and I would like to not only describe it to you, but also try it myself.

I found this way in the last Interstellarum (Review here in the blog).

Way 2: Solarography with a pinhole camera

The easier way of the two described here is to shoot with a pinhole camera.

You do not need much. The following components are completely sufficient to create the images from the video below

  1. A film can or any can which is closed darkly all around
  2. Aluminum foil (the best is the tea light foil – it is a bit thicker)
  3. A fine sewing needle
  4. PE paper (coated photo paper – best black and white)
  5. An astro lamp (red light)

What comes now is the production of the hole optics.

Step 1: Take the aluminum foil and cut a small square piece from the foil. With the tea light, the edge is well suited.

Step 2: With a sewing needle you poke a small hole into this foil. The hole should be approx. be 0,1mm large. This is not so easy to achieve. It is very important that the hole is evenly round. Also the degree on the backside of the foil has to be removed. The sandpaper should be fine and you do not exert pressure when removing it.

If you have a microscope at home, you can check the hole. It must not be frayed. Here the image is strongly dependent on the hole geometry.

Step 3: Now take the film can and poke or drill a hole in the side with a diameter of approx. 6 mm. Over it the aluminum foil with the small hole is stuck.

TIP: So that the pinhole camera does not disappear, one should tape off the aluminum foil if possible. Birds like shiny things and often peck at them with their beaks.

Step 4: When you have checked that the hole is not glued shut, you can cut the photo paper to size. This is now done in a dark room, because otherwise you expose the paper.

With the black and white photo paper you can use your astrolamp. This one does not react to red light. Cut a piece of 4x5cm and put it into the pinhole camera.

Now you are done with the construction of the camera. Now fix the camera outside or in the garden (attention, protect from animals) and then it is called wait.

Who really wants to record the course of the sun, needs mind. 6 months of patience. But since the production of the cameras is very easy and cheap, you can also make several cameras and then distribute them. So you can collect a camera month by month and see already results.

Step 5: After months of waiting, of course you want to finally see your result. But be careful. The paper is sensitive to light even after months and if you open the can under bright light, the result will deteriorate.

So always be careful when opening and removing. How such a story looks like, you can see in the video. In the interstellarum it is recommended not to use fixation. In the video one is used. Here you certainly have to try out a few things.

Here I have also picked out a video where someone describes how he makes the pinhole camera. Unfortunately in English, but the Germans seem to be less willing to film here.

That was it with my second part. In about. 6 months I will present the results of my pinhole camera and of course describe them here. Who of you will also build one?


This was now the second project proposal for the observation of the sun. So you should have in any case, in addition to photography, also a great project for the summer. Actually this project is really class suitable for schools.

Finally, you can build the pinhole cameras at the beginning of the school year and collect and evaluate the cameras at the end of the school year. If a teacher from Berlin is interested, please contact me.

Otherwise part 3 of this small series will be released soon. There it will also be about the sun track. But what that will be is still open. But it is definitely a long term project.

To the other parts in the project:

Related articles:

5 astronomy projects you can do with the sun (part 2: plot solar orbits) , 5.0 out of 5 based on 2 ratings

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