How to Make a Pinhole Camera to Observe the Mercury Transit

[helicon]

I found this short video which describes a pinhole camera to observe an eclipse safely. This design also should work for Monday's transit of Mercury across the face of the sun. Should work and it means that you don't have to run out and buy a Lunt or Coronado to observe it. Enjoy!

[Michael131313]

Thanks Michael. Last solar eclipse I could see it on my patio floor through a hole in my laminate roof. Will try out the box. Wonder if the dot will be big enough to see?

[yobbo89]

That's nice and all, but if you have a lunt or a solar filter then lend someone a view of this rare event!!, welding lense are dirt cheap too

[Lady Fraktor]

Welding glass of #14 or #15 will work but do not use anything lighter.

** Welding glass is not a good substitute for extended solar viewing.**

[notFritzArgelander]

Thanks Michael. Last solar eclipse I could see it on my patio floor through a hole in my laminate roof. Will try out the box. Wonder if the dot will be big enough to see?

You have some control over that. To magnify, increase the distance from the pinhole and shade to the projection screen. Use a larger box.

[Michael131313]

Very good n_FA. Thanks.

[Thefatkitty]

Welding glass of #14 or #15 will work but do not use anything lighter.

** Welding glass is not a good substitute for extended solar viewing.**

I second that in big way. I took a full-time welding course years ago, and I remember the teacher stressing that point. He said the Sun is a lot bigger and brighter than any weld arc you'll ever see, not to mention it puts out light waves that an arc doesn't.
He also said if you do, limit it to under half a minute of viewing.

I don't have a thing to worry about, though. My forecast calls for snow all day...

Best of luck everyone!

[Lady Fraktor]

The only thing I use welding glass for is a light shield for my Telrad and that is more to not overheat the reticle in it.

[Gfamily]

Thanks Michael. Last solar eclipse I could see it on my patio floor through a hole in my laminate roof. Will try out the box. Wonder if the dot will be big enough to see?

I would be sceptical about that, as Mercury is small and diffraction will be significant if the pinhole is small, and blurring will be significant if it's larger

Mercury is the small dot in the lower right quadrant

[helicon]

I'm also planning to use a bigger box to cast a larger image. I'm hopeful it works, but who knows?

[Gfamily]

I also planning to use a bigger box to cast a larger image. I'm hopeful it works, but who knows?

According to Stellarium, Mercury will have an angular size of about 10" of arc - which is about 1/180th the size of the Sun.
I think (rough calculation) that if you make your box 2 metres long, the image of Mercury will be about 1/2 mm across, on a Sun image that's about 9cm wide.

On the other hand, there don't seem to be any Sunspots at the moment, so at least you should be confident that if you can see anything, it'll be Mercury.

Best of luck - let us know how you get on.
We're forecast broken cloud through the afternoon, so I may get the 8" SCT out and use the Baader film filter I used in 2016

[helicon]

Here's a link to a livestream of the transit starting tomorrow...you can watch it on your computer.

[jrkirkham]

I will be curious to learn if you were able to capture Mercury by projection. It seems so small.

I am also curious as to the telescope that Gfamily used for that picture? How much magnification was it?

We are predicted to have a cloudy morning and two inches of snow. I'm not going to take my telescope to work and try to catch it. I think I will take my Canon 80D with a 400 lens, a 1.4X teleconverter and a solar filter. That should give me a magnification of roughly 20X. I can set that up in my office and run out quickly if there is a break in the clouds. I don't know if that will be enough magnification for a capture, but it's worth a tree.

And if I miss it, hey, we're all astronomers here. That means we are accustomed to loading bunches of gear, driving long distances and lack of sleep all for the mere joy of watching clouds roll across the cold dark night sky.

[Gfamily]

I am also curious as to the telescope that Gfamily used for that picture? How much magnification was it?

As I recall it was my 8" f/10 SCT with an APSc sensor dSLR on the back.