Equinox Solargraphy

[NedL]

Part I

Today I made a simple pinhole camera to try an idea I've had for a while. The idea is this: if a solargraphy camera is tipped up to aim at an elevation of ( 90 - latitude ) degrees, then on the day of the equinox, the sun should track a straight line across the middle of the paper. In the Summer, the sun will be above that elevation in the sky, and it will make sun streaks below that line in the camera. In the Winter, the sun will be lower in the sky, and will make sun streaks above that line on the photopaper. Since Thursday is the Summer solstice, now is a good time to start. I don't know what it will look like, but it might be kinda neat.

The camera took less than 2 hours to make and set up, so I thought I'd share how I did it.

It all started when my wife put a big tin can on the dining room tables and said "I'm sure you'll want this". It's about 10 inches tall:

and about 6-1/2 inches wide:

So it will hold an 8x10 piece of photopaper easily. I'd like to somehow put a drain in the bottom because condensation can be a problem in these. First step is:

( picked up 5 or 6 of these at Walmart a long time ago for less than $1 each )

Less than a minute later, we've made a good start:

While that was drying, I was trying to figure out some simple way to hold the paper so that water could get down to the bottom of the can, also I'd like the paper to be a little closer than 6.5 inches from the pinhole, so that there is a wider field of view. I noticed some hardware cloth sitting in the backyard waiting to be put away, and that lit the idea bulb:

that will form a paper holder that will allow air to circulate and keep the paper away from the walls of the can.

Proof of concept with a piece of 8x10 paper:

Looks like it will work! Then I trimmed the hardware cloth a little and wrapped it around a cylinder to get a nice smooth shape. It holds the paper nicely ( held in place by the folds at the end of the curved part ).

Next I marked where the pinhole and drain will be. Our latitude here is 38.3 degrees. I missed dot marking the angle by a tiny bit but I'm sure it will be fine:

Make the drain hole:

I started the hole from the outside but finished it from the inside so the "dimple" would guide water out of the can.

I decided to make a pinhole in thin aluminum rather than just poke a hole in the can. So now it's time to make a pinhole.
We need an aluminum can, old scissors, some fine ( #600 or finer ) emery paper, and a needle:

The pinhole is a little bigger than I wanted, but it will be fine, just chill!

Next I wanted something to block the light from the drain hole and keep the bugs out. Some black foam would be good.
Used Fuji FP-100c instant film cartridges have a little piece of foam that will be good for "reduce, reuse, recycle":

Now we're ready to make the camera!

Darken the back of the pinhole ( to prevent reflections ), and mount it w/ duct tape.
( Not shown, I also used the sharpie inside the can to darken the shiny edges of the hole the pinhole will be mounted over )

To be continued! In the next exciting installment we'll install the drain!

 

[NedL]

Part II

Now install the drain:

By the way, that foil tape stuff is awesome to have around for making pinhole cameras: it's waterproof, it sticks like crazy, you can form a tight seal by pressing on it, and it's 100% perfectly lightproof. Great way to seal edges when you need something to be light tight. And you can open it by slitting with your thumbnail. I also sealed the lid edges at the top of the can with it when I was done.

Then I went into the "dark closet" and put a piece of photopaper in the holder, and positioned it inside the can so that it was aimed at the pinhole.
I also put a tape "shutter" in place so that I can start the exposure Wednesday night.

Here I'm mounting the camera on a post. I put two small pieces of wood underneath so that the drain would not be obstructed:

Mounted with cable ties and leveled:

It's held pretty tight but there is a lot of leverage if you push on the end of the can, so I added that little crosswise piece of wood and I'll glue it in place tomorrow so it will dry before I open the camera.

you get the idea... I did this until the line was perfectly vertical:

Almost done, it just needs to have the cable ties trimmed and that last piece of wood glued:

And here's what it will see, looking due South:

Actually, I doubt the field of view will go all the way to those trees, maybe it will just get the treetops. Next year I'll figure out a way to make the FOV wide enough to see all the sun streaks and all the way to the horizon ( already got an idea about that... I shouldn't have centered the paper at the pinhole, because the FOV does not need to include anything past the zenith... so keep the pinhole aimed the same, but rotate the paper in the camera a little.... )

In six months, we'll see what happens.

 

[NedL]

Might paint the bottom of the can before Winter starts so that it doesn't rust.

 

[DWThomas]

Well at the least, you should get an award for patience! Anyway, I'll be looking for results in at Christmas time!

A drain -- not sure I would have thought of that, but I suppose it could prove necessary at the angle you're mounting that -- interesting.

 

[Agulliver]

I did a solargraph this time last year, made in minutes from a beer can. What I did was drink the beer, then use a can opener to remove the top. The I made a small pinhole which I covered with duck tape. In a changing bag I inserted a 5x sheet of photographic paper which when rolled inside the can left just enough gap for the pinhole to let in hight. Put the top back on and covered in three layers of duck tape.

Finally I duck taped this to the back fence in my garden, facing the sun and the rear of my home...removed the tape over the pinhole and left it for three months.

 

[NedL]

Yes, simple is good. Because I live near the ocean, the air often has a lot of moisture and condensation forms in a can at night when it gets cold. Sometimes the can has water all the way to the pinhole when I collect it. I used to make a lot of solargraphs with drink cans or bean cans or whatever.... So far I haven't thought of anything that is both simple AND will keep the water and bugs out.

 

[Agulliver]

Here's the result of my beer can.

 

[NedL]

Very cool!

You can see a few of mine here
And here's a solargraphy map.

The map is not totally updated, but you can click on any of the green or yellow markers, or on the placement name in the list, to see the result.
On some of them, if you click the picture, you can see a bigger version.
There used to be links to full sized images for all of them, but when they changed google maps, a lot of the links were lost.

Have fun!

 

[NedL]

Yesterday I painted the bare metal bottom of the can so that it won't rust.

 

[Jim Jones]

A pinhole camera with the pinhole in one side and the film wrapped around the opposite side can't cover a full 180 degrees. However, there is one variation that might do this: having the pinhole in the end, not the side of the cylinder. Long ago I improvised a camera from a Pringles potato chip can with the pinhole centered in the end and paper completely wrapped around the sides. Unlike NEDL's camera which provides fairly even exposure on much of the paper, about 10x the exposure at the end near the pinhole was required at the far end. This was accomplished by sliding a tube up over the outside of the Pringles can during exposure.

 

[NedL]

Solstice to Solstice.
The equinox is the perfectly flat line in the middle.

You can see our usual late summer foggy mornings, and the storms we had in October this year.
Paper is reloaded and it's out and ready to go until next June!

The drain worked pretty well... it was damp inside, but it wasn't full of water and didn't have water sloshing around in the bottom of the can.

 

[Theo Sulphate]

Awesome.

What paper/film did you use?

Is the drain just tape loosely over the drain hole? Can light get in from below?

 

[NedL]

Awesome.

What paper/film did you use?

Is the drain just tape loosely over the drain hole? Can light get in from below?

Hi Theo:
A piece of 8x10 inch Adorama VC RC paper.
The small drain hole has a small piece of foam over it, held in place by a piece of tape.
Idea was to make it light tight and still let water get through.

For many years, I've been in the habit of writing down a weather observation every day.
Now I think the big dark area in the lower half was caused by the smoke from the fires we had this year.

 

[NedL]

Solstice to solstice: 21 December 2018 to 21 June 2019
Tall grass grew in front of it this spring, interesting that its shadows show "behind" the winter sun streaks...

 

[awty]

Amazing. You must be a very patent man. Think I would want to take a peek.

 

[RalphLambrecht]

Part II

Now install the drain:

View attachment 202600

By the way, that foil tape stuff is awesome to have around for making pinhole cameras: it's waterproof, it sticks like crazy, you can form a tight seal by pressing on it, and it's 100% perfectly lightproof. Great way to seal edges when you need something to be light tight. And you can open it by slitting with your thumbnail. I also sealed the lid edges at the top of the can with it when I was done.

Then I went into the "dark closet" and put a piece of photopaper in the holder, and positioned it inside the can so that it was aimed at the pinhole.
I also put a tape "shutter" in place so that I can start the exposure Wednesday night.

Here I'm mounting the camera on a post. I put two small pieces of wood underneath so that the drain would not be obstructed:

View attachment 202601

Mounted with cable ties and leveled:

View attachment 202602

It's held pretty tight but there is a lot of leverage if you push on the end of the can, so I added that little crosswise piece of wood and I'll glue it in place tomorrow so it will dry before I open the camera.

you get the idea... I did this until the line was perfectly vertical:

View attachment 202603

Almost done, it just needs to have the cable ties trimmed and that last piece of wood glued:

View attachment 202604

And here's what it will see, looking due South:

View attachment 202605

Actually, I doubt the field of view will go all the way to those trees, maybe it will just get the treetops. Next year I'll figure out a way to make the FOV wide enough to see all the sun streaks and all the way to the horizon ( already got an idea about that... I shouldn't have centered the paper at the pinhole, because the FOV does not need to include anything past the zenith... so keep the pinhole aimed the same, but rotate the paper in the camera a little.... )

In six months, we'll see what happens.

please share when you have results.

 

[NedL]

Solstice to solstice again with the same camera. 22 June to 22 December 2019.
8x10 Adorama RCVC paper. This one came out very clean. Top inch or so is cropped.

Here's what it looks like before inverting the colors:

It's reloaded with unicolor positive paper... which makes nice soft pastel colors after inverting.

 

[NedL]

Solstice to solstice again, 22 December 2019 to 20 June 2020.
8x10 inch Unicolor positive color paper. I did not manipulate the colors except to invert them.

The can had a dent on the bottom and you can see something odd in the sun tracks just after the equinox.
One corner of the paper had come loose from the paper holder, so it could be that the paper curled due to changing temperatures and humidity, or maybe a turkey jumped on it or something like that ( we have lots of turkeys in our yard ).

( sorry for the scanner artifacts from my cheap scanner )

 

[NedL]

Another solstice to solstice image. Nice clean image on adorama 8x10 rc paper.

 

[Grandpa Ron]

I think you get an A+ for persistence and especially for making what initially sounded like a boring idea come to life.

Way back when you started and said you were going to take pictures of the sun crossing the sky, I just scratched my head and said "huh". But, after seeing the results, I have to say "wow" what a neat idea.

Congratulations and thanks for the pictures and explanations.

 

[NedL]

Thanks Grandpa Ron!

Kinda fun to think that every time the sun has gone across my backyard sky for the past 3 years, it's made a line on one of the papers in this thread.

Here's 21 December 2020 to 20 June 2021 on Unicolor positive paper again:

 

[Grandpa Ron]

Ned L,

While most folks see the lines on paper, for those of us that tinker in sundials, you can the line spacing in relationship to an Analemma pattern.

Cool stuff for us sky watchers.

Thanks

 

[NedL]

Ned L,

While most folks see the lines on paper, for those of us that tinker in sundials, you can the line spacing in relationship to an Analemma pattern.

Cool stuff for us sky watchers.

Thanks

Thanks!

I've had an idea for an analemma camera for years now... even got to the point that I gathered some of the parts but I never put it together. The idea is this:
Those plug in "lamp timers" have a motor in them that makes one revolution every 24 hours. My idea is to mount a pinhole can camera on top of one of those so that it rotates once per day. The entire thing would be rotating inside another can with a very thin slit in it. Once a day, at the same time, it would make an image of the sun... the whole thing could be mounted inside a big glass jar to keep the rain off... a practical problem is that it might need a UPS in case the power goes out. I got as far as finding an old timer that would work, and a huge glass jar that it would fit inside, but it's still sitting on my shelf waiting to happen Now that you've reminded me, maybe I'll try to put it together..

 

[Grandpa Ron]

Ned, you certainly got farther the I did. I was thinking of an electric/mechanical shutter tripped by a timer. Maybe the shutter from an old camera tripped by a selenoid.

However, your idea sound very interesting. I certainly would like to see the results.

Unfortunately I live in an area with several power outages a year so I would need a power-out reset. I would think it better to skip a day of two then print the wrong time.

Good Luck

 

[NedL]

No idea why, but this time the color of the paper was very different! 20 June 2021 to evening of 20 December 2021 ( Winter Solstice was this morning, the morning of December 21st ). This is the same 8x10 inch Adorama VCRC paper that I've used many times, and this time it is very grey without much ruddy or purple or peach. As always, this is a straight inversion of the colors, no other digital editing.

A turkey definitely jumped on it this time, the bottom of the can was dented and you can see where the image shifted when the can moved. I had to tighten up the straps when I put it back out. I filled it with the unicolor paper again, I kind of like the pastels...