S194: Astronomy practicals

Put me firmly in the class of fair weather astronomers...

I have borrowed a fairly basic reflecting telescope to do some observing. Last Friday was an excellent night to try it out. Although I live in a rather light polluted area, the night sky was crisp and clear. Bright pin pricks of light could clearly be seen through the upstairs window. I went downstairs and stepped outside for a better look, and after a sharp intake of breath, I dashed back in - COLD COLD COLD!!
Observation was terminated before it had really begun.

However, last night, there were only a couple of minor squibs of cloud about, but on the whole things looked pretty good, and the temperature outside was much better. This was much more the way to do it, OK so it would require a coat, but not necessarily Arctic survival gear.

So I went back inside, and lugged out the telescope, set up the tripod, picked the least powerful of the lenses and found Mars with the spotter scope. After a while, I managed to get it well fairly centred, but realised that the cross-hairs which seem like such a good idea, when viewed at night, are black on a black background, with little light, are not in the slightest bit visible in the dark! Even with the least powerful eyepiece, the image has to be pretty much in the centre of the spotter scope to find it.

I went back in to get a more powerful eyepiece, there is only so much you can juggle in one trip...
I installed the eyepiece, and after a bit more hunting managed to re-find Mars, and it agreeably became a small disc, jumping around all over the place as I tried not to touch the telescope and induce any more wild oscillations. Have you ever seen Lissajous Figures on an oscilloscope (do they still use those?) - well that's pretty much what Mars looked like most of the time.


OK - time to try something a bit more tricky, how about that comet 17P/Holmes. I could be like a real astronomer, and casually drop into the conversation my cutting edge observations on the night sky. "Have you seen 17P/Homes perchance? No - oh what a shame..."

I'd already loaded the data into Stellarium and so fired up the laptop on the kitchen table. OK - so its approximately overhead at the moment. If I starts a Mars, and a line up, past Cassiopeia and a bit to the right, yeah that should work.

Went back outside with a couple of the constellations roughly memorised... and WHAT THE...??????

The night sky was now completely overcast, not a single celestial object visible! In the 3-4 minutes I'd been inside a cloud layer had just appeared, as if from nowhere, covering from horizon to horizon. I swear, it was like being on a prank TV program! How did that happen? I went inside and out again to see if I'd been mistaken, but no - complete overcast.

I left the telescope out, and checked occasionally, and about an hour later I could see Mars again in a clear patch of sky. Maybe the overcast was a transient feature. I refocused and re-centred, and then ran inside to get the highest mag. eyepiece. A quick squint to see if it was still centred, and as I watched it there, it slowly and majestically faded completely from view! The overcast was back! This time for good - I wondered if there was anything on TV...