Figures. The best partial eclipse around here in years, it’s been sunny all week, and today it clouds over. I was grumpy this morning when the forecast came true, but the optimist in me said that it might clear enough to see. So I spent some time today working on a projection frame for my telescope for solar observing:
The idea is that the (blindingly) bright image from the eyepiece is focused on the translucent sheet of paper, creating an image that you can view. The woodwork won’t win any awards, but it should do the trick. I haven’t had a chance to try it out, due to the overcast today, but I’ll try it on the first sunny day we have.
The frame mounts on the eyepiece mount of the telescope. I kept the frame as thin and light as I could, to try to keep stress down on the mount point.
I can’t wait to see how it works. I would give money to have a break in the clouds now. We’re about 1/2 hour from the eclipse maximum. Watching it in Stellarium just isn’t the same.
The maximum is past, and it’s getting brighter outside again. It got about as dark as a really cloudy day, even though it’s only a thin cloud layer in the sky.
Grumble. :-@
Looks really good Simon. Should work just fine for Venus observation.
Finally the Sun came out. I quickly moved the telescope to the driveway and pointed it at the sun. It worked, but needs improvement.
1) The image of the sun is somewhat small. The paper is too close to the eyepiece. Will be difficult to fix. Must put my thinking cap on.
2) The paper needs to be anchored more firmly to the frame. There was a gusty breeze and the paper was moving with it, in and out of the focal plane. Some glue, tape or staples would fix that.
3) The image was clearer on the underside than on the topside. The newsprint might be too thick. Tracing paper would work better.
This evening, I replaced the newsprint sheet with tracing paper bounded by stiff pastel paper. I managed to try it out before the sun went down, and it was fantastic! 🙂 The image projected onto the paper was bright and sharp, and it didn’t move around nearly as much. The 25 mm eyepiece projected a three-inch image of the sun, while the 10 mm made about a seven-inch image. The big active region on the sun was on the far side today, but I spotted six other sunspots in two groups. I am thrilled at how this is turning out. I am all ready for the transit on the fifth! Just hope the weather co-operates.