Date: 2003-11-19 08:06:00
Tags: astrophotography
good morning sun!
I ordered a solar filter for my telescope last week and it arrived on monday. Today I had a chance to try it out. It's neat to be able to see sunspots! The filter transmits only 1/100000th (that's a thousandth of one percent) of the sun's light, so it is safe to point a telescope at the sun. Without a filter, the sunlight would melt internal parts of the telescope (like a magnifying glass can start a fire, but on a larger scale). Click on the picture to see a bigger one with visible sunspots.

Early morning is quite possibly the worst time to try to do this, because the sun is low on the horizon and is subject to severe atmospheric distortion. This causes the picture to be blurry even if it's properly focused. When looking through the telescope with your eye, the edges of the sun appear wavy like a reflection in choppy water.

Another kind of filter, a hydrogen-alpha filter, allows only a narrow bandwidth of light through. With an H-alpha filter you can see solar flares and prominences and much more detail. Those filters are a lot more expensive though.
So you're going to be buying the H-a filter, week? :)

Very jealous, b.t.w. :)
Bonege kaj interese! Ironie, ĵus pasintan nokton, mi parolis per telefono kun mia patro, kaj menciis mian veterulan kolegon kiu verkas interesajn ĉielofotojn per lia farvidilo.

Nu, vi vere devas gastigi farvidilofeston. :)
damne, s/far/for/ :)
Greg Hewgill <>