21st April 2019 H-alpha experiments.

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I had a nasty moment when the binoviewers suddenly swung downwards along with the Lacerta prism. Fortunately they remained attached. Or they could easily both have fallen down through the ladder hatch! It was not the prism's fault [at all] but the cheap 2" x 80mm [Taiwanese] extension into which the big prism fits into.

There was a normal, brass compression band in the extension but only one, small thumbscrew. So I used the 3-jaw chuck in the lathe to mark the extension 120° apart. Then drilled and tapped two new 3.5mm holes, M4, for two more thumbscrews to compress the band. I borrowed large-headed thumbscrews from other compression fittings in my growing collection. It won't dare move now! Never [ever] trust a single thumbscrew!

The images show experiments with star diagonals to shorten the ridiculously long H-alpha, filter chain. A 2" and a 1.25" elbow were tried. Both set-ups achieved focus with the camera fitted as shown. Though various Barlows/GPCs were required.

Sharpness was lost compared with "straight through." Though the sky was showing thin cloud at the time so I should really reserve judgment. Increasing the magnification via Barlows also contributed to increased softness of the image. This also exaggerated any wind movement of course.

I am playing with ImPGG to see how it works. This is my first attempt at capturing and processing prominences. Overdone, so noisy and grainy.

The image on the right is using Registax and overdoing Wavelets to overemphasize surface features.

Click on any image for an enlargement.

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