Saturday, March 31, 2012

More solar observing experiments

I am continuing to experiment with my solar projector, which uses a hard disc platter as a heliostat mirror, and two Surplus Shed lenses, one positive with 2600mm focal length, and one negative with -800mm.  While I can see sunspots, I can't see almost any structure in them, and there is a lot of chromatic aberration.  A bit of experimenting suggests that most of the chromatic aberration is due to the negative lens, so I've ordered a -1000mm achromatic lens.  We'll see if that improves things.

While ordering from Surplus Shed, I also ordered a 15mm focal-length Hastings triplet.  If it does not make a good planetary eyepiece--I will certainly will try--I will have a nice 15X loupe, replacing my 15X plastic-lens loupe (which is usable, but only in the center of field).

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