August 29, 2014: Some spectacular fireworks late in the afternoon

[michael.h.f.wilkinson]

I was out tuning my Frankenscope (LS35 + ST80) around 17:30 local time, when I spotted something bright emerging from western limb. I removed the ST80 because I was not satisfied with the alignment, and just used the LS35. As I watched, the little pair of proms developed into a spectacular eruption. A huge plume of twisting filaments of plasma rocketing away from the surface developed, which later curled round and started raining back. At 18:20 it looked like a tight knot of arcs. After dinner, just before the sun disappeared behind nearby house, only a small, tree-like prom could be seen. Amazing stuff.

Some other features had to take second place to this spectacle. A huge filament was visible to the northeast, close to a large set of arcing proms. Just west of centre a big sunspot surrounded by plage and thinner filaments could be seen.

I still have not got the Frankenscope aligned (although I did get a bit closer), but hope to have another go tomorrow

[Luke]

Amazing! That's two I have missed recently. Third time lucky, I hope!!!

[Stu]

Great stuff Michael.

Have you posted about the Frankenscope anywhere yet?

[Peter Drew]

Michael has a post about it on Solarchat. 

[michael.h.f.wilkinson]

I also put some stuff up here on SGL:

http://stargazerslounge.com/topic/223055-ls35st80-frankenscope-taking-shape/

I have now got the negative lens, and put everything together ( the plywood tube rings shown in that post have been painted by now). I am getting an image, but there seems to be a lot of aberration that is probably not spherical, because that should reduce rapidly with the scope stopped down. I rather think there is some astigmatism (not strongly affected by stopping down) due to misalignment, which would cause lenses to work as cylindrical lenses. I will set the scope up on the GP mount, because tracking means the front scope can first be aimed at the sun, and when the LS35 is mounted behind, it can be centred properly, with the ST80 kept aligned on the sun by the tracking system. If that does not give me good enough alignment, I will go talk to some guys at the astronomy department to see if I can use an optical bench to align the scopes. The glare I seem to pick up might also be caused by internal reflection. Removing one of the two ERFs in the system might reduce that. At the end of the day, the fast optics of the ST80 might cause too much spherical aberration for this to work. In that case I may replace the negative lens by a longer-focus version and go for a slower scope

[michael.h.f.wilkinson]

Just had another go at tuning the alignment, but no real luck yet.

[jonathan]

Grrr, why do I have to be at work when these things happen??  Oh yes, so that I can afford to buy more telescopes that I don't have time to use because I'm at work.