24.03.19 Solar, sunshield and binoviewer success.

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Sunday, grey start becoming sunny with highly variable cloud. 

11.00 50/46F, WL Small area of plage and disturbance right on the limb.

H-a Only slightly more of the limb structure visible. A bright, pyramidal spicule came and went quickly. Hint of a prom in the same area. I managed to just reach focus with the binoviewers with the 2x WO Barlow nosepiece and 1.25" TS star diagonal. More comfortable, but lots of muck visible in the optical train and noticeably dimmer.

The PST etalon group acts as a weak Barlow lens. So moving it slightly towards the objective throws the focal plane longer. Providing more room for GPL [Glass Path Length] compensation without running out of inward focus. Which is the usual problem with binoviewers. The glass prisms eat up the focal length. Leading some owners to shorten their main tubes. Not an ideal situation where originality maintains its resale value.

In practice, my star diagonal must be rotated to point sideways towards the camera. Which means the binoviewer and eyepieces must be manually supported. Not ideal, because it can easily cause image vibration. I would have to use a stepladder to reach the eyepieces in this posed image to show the mechanical layout.

The bright, and wavy upright material almost against the backplate is a matt black, foam, sun shield. The sun is obviously reflected in a wavelength which is highly visible to the camera. The foam is from a camping mattress. Ideal to protect the cosmetics of the telescope fixings and easy to fit and remove in seconds without tools. A slightly undersized hole must be cut in the foam so that it can be gently stretched over an extension or even the focuser. Then rotated, as needed, to protect my face from direct sunlight.

The grip provided by the foam on the fitting allows it to remain precisely where it is left. Sun shields can greatly improve contrast when the user is not being blinded by direct sunlight. With the worry about long term exposure to UV, it saves the user having to regularly apply sun block. Which would not very practical in an observatory situation. I tried a baseball type cap but found the peak an absolute nuisance at the telescope. Nor did it provide much protection from the sunlight.

The gusty wind picked up mid morning. Making it feel rather cold inside the dome. Worse, it shook the telescope enough to move the image around on the screen of  IC Capture 2.4. Registax 6 is still making a mess of my videos so I'd better watch the YT tutorial again. "Limit" is my Achilles heel because I can see no user input controls.  I also get no previews during "Wavelet" adjustments.

13.45 56/48F Back indoors for lunch and to warm up.

Click on any image for an enlargement.

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