First time solargraphy

Harmvw · Apr 19, 2024

Hi all,

This is my first post on here, I hope the location is right.

I dove in to the rabbit hole of solargraphy, the first time I saw a solargraph was during a visit to a observatory a couple a years ago.
Lately I saw another one at an other observatory and decided to try to make one myself.

Instead of using a "normal" (beer)can i used a spare piece of rainpipe, it is 80mm in diameter.
I made a large hole in it, in front of that i placed a piece of brass sheet metal with thickness 0.05mm.
In that i drilled a 0.3mm hole with the edges sanded down flat.
I glued the bottom an taped the top and bottom.
It looked like this.
I used glossy 18.7x24 ILFORD paper. (later I read that matt would have been better)

This was the mounted position.

After 8 days 2,5 sunny the others rainy, we took it down to see if it worked.

Well it worked, only it paper was pretty moist.

I was able to make a scan of the paper.
It looked nice.

I inverted en mirror it in photoshop.

Now it looks like this.

I was wonder if the ghost trails were because I used glossy paper.

And is this much condensation normal for 8 day outdoors, or is it due to the materials used?

Thanks for reading and possibly replying.

Harm vdw

koraks · Apr 19, 2024

Harmvw said:
I was wonder if the ghost trails were because I used glossy paper.

I think they're due to an internal reflection of some kind. This may even be a reflection against the edges of the pinhole itself.

Harmvw said:
And is this much condensation normal for 8 day outdoors

Given the humid weather we've had lately, I'm surprised you didn't have more problems with moisture.

Harmvw · Apr 22, 2024

koraks said:
I think they're due to an internal reflection of some kind. This may even be a reflection against the edges of the pinhole itself.

Oke, is there could also still have a reflection from the backside of the brass sheet metal, I have seen people coloring it black, so on the new one I will also do that.

koraks said:
Given the humid weather we've had lately, I'm surprised you didn't have more problems with moisture.

From the solargraphs I have seen on the internet i didn't see/read much about moisture. But for the next one I will try and find a beter/dryer location.
I made a 3d printed version for the next try.
It has a drain and ribs on the backside to let the moisture down the tube.
I will test it, to see if it works.
update will follow when the sun has shown itself for a couple off days.

koraks · Apr 22, 2024

Cool, very much looking forward to further attempts!

Harmvw said:
I made a 3d printed version for the next try.

Couldn't help noticing the open-frame power supply in the background, LOL! Convenient to keep around for hobby projects. Looks like we may share some interests.

Harmvw · Apr 22, 2024

koraks said:
Cool, very much looking forward to further attempts!

Couldn't help noticing the open-frame power supply in the background, LOL! Convenient to keep around for hobby projects. Looks like we may share some interests.

Well it's a replacement of a broken one in yet another hobby, it's an induction heater.

koraks · Apr 22, 2024

Ah, I see! Feel free to elaborate at some point about your other interests. Don't feel compelled, but I for one always enjoy hearing what people are up to!

Harmvw · Jun 3, 2024

Update:

I have 3D printed a small one for 8.9x12.7mm. It was in the full rain, and it was really rainy last month. I put it up on April 24th and took it down on June 2nd.

This is the result (flipt, rotated and inverted):

My aim was too low, so the path of the sun was mostly on top and out of view. The strange thing is the dark sides. I first thought it was due to the small size. Then I took down and scanned the large one. It was also aimed far too low and also had the same dark sides and top.
Result large one:

It was placed "dry" and the paper looked very nice.

Then I realized that it was probably the 3D design. Here is a close-up of the hole. I think it is far too small. On the inside the shape is the same.
I mean the hole in the tube not in the brass.
I think I have shadows/ obstruction of the tube.

If anyone has any extra ideas you may always share them.

koraks · Jun 3, 2024

Harmvw said:
This is the result (flipt, rotated and inverted):

'Access denied'

It would work best if you just copy-paste the photos into your post, please. Off-site links always create problems sooner or later. In this case it starts with permissions issues that need to be set manually, and then in a few months/years, the provider decides to change their URL system and all links break, leaving us with nothing.

DWThomas · Jun 3, 2024

I second Koraks' comment. Not being too fond of Google gobbling up everything in the IT Universe, I do not have, nor do I want, a Google account. But I do indulge in pinhole work and would be interested in seeing your efforts.

NedL · Jun 3, 2024

Welcome to photrio!
I think it's great! Hope you do some more.

I just got home an hour ago from hiking on a remote beach to pick one up!

Yes "ghost trails" can be caused by the shine from the inside of the rain pipe, the shine off glossy paper, or sometimes if water gets into the bottom of the can it will cause reflections like that. I spray paint the insides of my cans flat black and use "pearl surface" paper, but I think the ghost trails are kinda neat too...

My advice: don't worry about the size of the pinhole too much. If it's around .2 or .3 mm it will be fine. I punch a small hole in the bottom of the can and push a little piece of foam into it.... this blocks light but allows water to drain. In my location there is so much condensation that the can will sometimes fill all the way up to the pinhole if there isn't some way for it to drain

Here's one I picked up just a couple days ago: link to ipernity

On that one, the paper got damp then dried and curled... causing the "ghost image" because the curl changed the position of the paper. There are a few ways to prevent that ( something to hold the paper ) but I don't bother usually. I kinda like ghost images too. Go with the flow and have a nice surprise to open and see what you get!

Oh, and the little speckles are tiny bugs that got in through the pinhole! Happens on the ones I pick up in June, but not so much on the December ones.

Harmvw · Jun 4, 2024

koraks said:
'Access denied'

It would work best if you just copy-paste the photos into your post, please. Off-site links always create problems sooner or later. In this case it starts with permissions issues that need to be set manually, and then in a few months/years, the provider decides to change their URL system and all links break, leaving us with nothing.

DWThomas said:
I second Koraks' comment. Not being too fond of Google gobbling up everything in the IT Universe, I do not have, nor do I want, a Google account. But I do indulge in pinhole work and would be interested in seeing your efforts.

I have edited the post so now it also contains the pictures.

NedL said:
Welcome to photrio!
I think it's great! Hope you do some more.

I just got home an hour ago from hiking on a remote beach to pick one up!

Yes "ghost trails" can be caused by the shine from the inside of the rain pipe, the shine off glossy paper, or sometimes if water gets into the bottom of the can it will cause reflections like that. I spray paint the insides of my cans flat black and use "pearl surface" paper, but I think the ghost trails are kinda neat too...

My advice: don't worry about the size of the pinhole too much. If it's around .2 or .3 mm it will be fine. I punch a small hole in the bottom of the can and push a little piece of foam into it.... this blocks light but allows water to drain. In my location there is so much condensation that the can will sometimes fill all the way up to the pinhole if there isn't some way for it to drain

Here's one I picked up just a couple days ago: link to ipernity

On that one, the paper got damp then dried and curled... causing the "ghost image" because the curl changed the position of the paper. There are a few ways to prevent that ( something to hold the paper ) but I don't bother usually. I kinda like ghost images too. Go with the flow and have a nice surprise to open and see what you get!

Oh, and the little speckles are tiny bugs that got in through the pinhole! Happens on the ones I pick up in June, but not so much on the December ones.

The one with the ghost trails is also pearl paper. For the next test i am using semi-mat.
The 3d printed tube also has water drainage so that should not give any reflections and the tube is black, and the paper is held in place because of the design.

I was talking about the hole in the tube and not the hole in the brass, I have drilled the hole larger. And now i hope for a sunny week.

Your photo looks absolutely stunning, beautiful colors, do they come in through the hole? That's insane, are the speckels the bugs or places where they rested?

Thanks for the reactions

koraks · Jun 4, 2024

Harmvw said:
I have edited the post so now it also contains the pictures.

Thanks so much!

Good progress, too.

Harmvw said:
Then I realized that it was probably the 3D design. Here is a close-up of the hole. I think it is far too small. On the inside the shape is the same.
I mean the hole in the tube not in the brass.
I think I have shadows/ obstruction of the tube.

Really? I would expect that the roof overhang for the second attempt / large sheet was the main problem:

That would be smack in the field of view, wouldn't it?

Harmvw · Jun 4, 2024

koraks said:
Thanks so much!

Good progress, too.

Really? I would expect that the roof overhang for the second attempt / large sheet was the main problem:
View attachment 371504
That would be smack in the field of view, wouldn't it?

That could also be a problem indeed, but the small one also has it al around the picture. But that is also worth a test indeed.

koraks · Jun 4, 2024

Harmvw said:
the small one also has it al around the picture.

Yeah, but that one has it to the sides, which makes sense since the paper sites in a circle, so some parts will barely get any exposure. The top edge on the large sheet is likely caused by the overhanging gutter.

Harmvw · Jun 4, 2024

Now i look a the picture, you are probably right, you can already see the shadow on the wall, it is almost the same height as the tube.....

DWThomas · Jun 4, 2024

Harmvw said:
I have edited the post so now it also contains the pictures.

Thanks!

I think your analysis of the supporting hole being too small is quite likely good. Unlike lens-based designs that can sort of funnel light rays through an opening, a pinhole is just straight ray tracing and it is surprising how much peripheral "stuff" winds up getting in the way. I had to totally re-do a design of a sliding flap shutter after finding major vignetting.

I have sometimes found it useful to do a carefully measured scale layout of a cross section to look for possible interference. My pinhole cameras have been boxes targeted at regular photographs, no doubt your cylindrical "film chamber" can add some additional fun to that process.

Anyway, welcome to Photrio, it appears you are off to a good start. I look forward to the next round.

NedL · Jun 4, 2024

Ah now I see! Yes, that paper looks very clean! Nice! Agree w/ you and with Dave, it can be surprising how big that hole needs to be. Sometimes I tilt the camera while looking inside at the projection of the sun, to make sure the image will reach the corners of the paper.

In mine they are usually the actual microscopic insects stuck to the paper.. but I didn't look closely enough at this particular one to say for sure!

Have fun!

Harmvw · Jun 5, 2024

Update:
I have made the holes larger and now running a test week (if there are a few days with sun i hopefully know enough)
Here's the test setup:

koraks · Jun 5, 2024

Harmvw said:
if there are a few days with sun

Now that would be nice for a change...

Harmvw · Nov 2, 2024

Here is a small update.
The first part is the following of the last post.
The photo's are still not what i hoped for, but I learned more and 3d printed some new desigs.

It took a while before I had time to make a new stand and test the new stand and 3d print, with the following result.

That looks a lot better, so i directly tried a special version with a arduino in it. But it did not yet work as i hoped. I have still some stuff to find out.
The new one has some dark spots in it which i can not explain yet. So now i have the latest version installed and I will be waiting for a few weeks because of the time off the year and to get a clear picture.

I will be back when i have a update to share.

koraks · Nov 2, 2024

The dark stripes are puzzling indeed!
I quite like the color in the first few; reminds me a bit of aurora photos.

Synthon · Nov 2, 2024

Oh this is so nice, i just stumbled into this Forum for a thread about curtain speed testing with an arduino setup and now i see, there is also fellow solargraphers

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