I see there was a thread about this but it only touched briefly on how to view it safely. Does anyone have any secret do-it-yourself recipes? Most of what I’ve read has instructions for making a pinhole viewer but they all seem to call for boxes / tubes three feet or longer. I’ll be at a very crowded roof top patio bar so that’s not super practical. I’ve seen mention of welder’s glass (or maybe it was glasses?), though it’s been mentioned that might not be the safest. Where would one get such glass? Or for that matter, is there anything your average bear like myself could purchase at say, Home Depot, that would suffice? If anyone has any cheap, accessible ideas or even something home made that doesn’t take a rocket surgeon to fashion I’d be grateful.
Also, barring getting the proper eye protection, is it still as dangerous to watch as the sun sets? Can it even be seen then?
You need to check out the links in the other thread. But here is one method I have not seen mentioned. You can make a pinhole camera. But thats kind of a pain because the solar image size is a function of the distance from the hole to the piece of white whatever the sun’s image is one. Anything more than a few feet gets to be a pain in the ass.
But you can also make a pinhole mirror. So, you can have a mirror way out in your front yard projection an image of the sun onto a white screen say inside the hallway through your front door or into your garage and the throw distance will be something like 50 feet away, which would give an image a decent 5 inches across. And since you can view it in darker area it will be easier to see than out in the yard.
And the longer the throw the bigger the “pinhole” can be, resulting in greater resolution. Wikipedia has some info on how to choose the right pinhole size. Just figure out how far your throw distance is and go from there.
You’re forgetting one thing: you won’t be able to see anything without magnification. Venus will be just a tiny black circle against the sun, and without magnification all you’ll see is the sun.
Also, an image 5" across is considerable magnification, since the Sun spans only 0.5 degrees of arc in the sky. Venus will appear as a dark speck against the Sun in any case, though you might be able to detect some kind of halo from its atmosphere.
Yes, in this case, for a pinhole camera/mirror the “throw distance” is the “focal length”. I just played with a prism from a bincular, some tripods taped together, and some tape to make a crude pinhole 1/3 and inch across. Threw the image down the driveway, into the garage , through an open door and into the house a bit and got an “okay” image about 8 inches across. My pinhole probably wasn’t the optimum size.
IF the OP really wants to see this, go buy an elcheapo telescope and use the eyepiece projection method. Just don’t let the sun shine through the scope for very long at any one time or you might melt or break something. I did it yesterday with one and could see the sunspots fine. If I could see those I could see Venus I am sure. Go to the other thread for links on how to do that.
Oh, and for God’s sake don’t ever look through a scope at the sun (unless you have good filters and you KNOW you have good filters). Even to point it momentarily for eyepiece projection. You have to do the pointing blind so to speak.
Oh, and throw distance is distance from the pinhole/mirror to the thing the light is shining on. 56 inches gets you a sun a inch across. Twice as far, twice as big and so on and so on.
I just did a quick and dirty projection with 8 by 50 binocs with a white piece of paper handheld a few inches back. With the sun’s image being a few inches across I could easily see the sunspots that are on the sun now. Rig up something a bit more stable with a bit more throw and better shading of the piece of paper and I think it would probably work pretty well.
Any welder’s supply should stock #14 glass filter plates. They are available in several sizes. Apparently, anything below 14 presents a risk to your eyesite.
I use a piece large enough to cover one objective on a pair of 10x80 binoculars. Two pieces would be better. (one one each side)
Sadly, it will almost certainly be total overcast here for the entire event.
Cloudy here as well so I will once again be watching the CosmoQuest live star party where they will have commentary and live views through amateur telescopes across the planet. I watched this during the eclipse a couple of weeks ago and it was pretty good. Coverage begins at 2pm PT, about four hours from now.
We’re partly to mostly cloudy right now, but I’m hopeful.
For the eclipse last month, I tuned into SLOOH. It starts at 5:30 EDT, 2:30 PDT. They’re supposed to have something like 14 different video feeds going (you get to switch between them yourself). I’ll check out that CosmoQuest site as well.
Yes, it is still dangerous to watch as the sun sets. Whether the transit is still going on then depends on where you are. In the continental US, it will be.
so I will once again be watching the