Tuning the etalon


And I’m still quite excited that I have my very own etalon to tune.

I risked heatstroke today for an observation with the solar scope.

The red image is beautiful and I could see the active region which is about to rotate off the disc, some prominences including one which was showing the classic loop shape, and filaments looking darker on the bright background.  I am still training my eye and learning what can be teased out from the image with different eyepieces and by twiddling the ring which supposedly adjusts the etalon – handicapped by having the scope mounted on a flimsy camera tripod which wobbles like a b****r if you even breathe on it, and which of course has to be manually adjusted every couple of minutes as the sun moves out of the eyepiece.

Photography is an even more annoying animal, though I did get my little Canon out for an experiment.  Quite apart from the wobbling thing and the lining up with the eyepiece thing and the focusing thing there is the exposure thing:  based on today’s photos, if the exposure is long enough to reveal the prominences, the disc is so over-exposed that the filaments and even the sun spots disappear, and vice versa.  And the camera can’t render the gorgeous vermilion of the image at all.

Sun 22nd Jul 2016

For what it’s worth, here is a fuzzy and almost featureless image of the sun but NB it does actually show some prominences.  The eye of faith might even discern some indication of the active region (at about half past two on the disc).  So this is progress.  Let’s worry about focusing another time.

And did I get sunstroke?  No; in true astronomer fashion (who cares what people think?) I fended it off by putting a small ice pack inside my hat.  Dribbly!

Warning to non-astronomers:  never look directly at the sun, especially not through any optical equipment such as binoculars or telescope, as permanent blindness is the likely result. The solar telescope I use is  specialist astronomy equipment, which excludes almost all the light of the sun and is therefore safe to use.


8 responses »

  1. What a beautiful red! Aside from that, is the active region shaped like a squared-off “o”, or am I imagining I see something?

    And I agree with Dave Quayle – I was picturing an exotic musical instrument, maybe something resembling a theremin…wrong, wrong, wrong!

    • You probably are seeing it – there’s just a faint trace in the photo of the image I could see. Maddening not to be able to show others, which is why astro imagers get so obsessive. If you see an astro day at an observatory near you (or some sidewalk astronomy) it really is worth having a look with your very own eyes.

  2. How fascinating, and the red is amazing. I had no idea that non-Nasa folk could photograph the sun’s activity like this – or, are you secretly on the space station using Hubble!! 😉

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