From: TerryMoselaol.com
Message-ID: 
Date: Sat, 11 Dec 2004 20:25:01 EST
Subject: TV, Geminids, Lecture, Skylux

Hi all,

 TV Programmes:

1. Sunday, 12 Dec.:      
8.00pm on Channel 4: What we still don't know (2/3):
    Sir Martin Rees on the emergence of life and its place in the Universe.   
   See 
http://www.channel4.com/science/microsites/W/what_we_still_dont_know/index.html

2. Monday, 13 Dec.:   
7.00pm, BBC4 TV, The Planets: the fate of our solar system.
   
3. Wednesday, 15 Dec.:    
7.00pm, BBC4 TV, Bill Bryson: A Short History of Nearly Everything.
9.00pm, BBC4 TV, Light Fantastic: From light bulb to atomic bomb (3/4). 
Repeated 12.20am.    See: 
http://www.bbc.co.uk/bbcfour/documentaries/features/light.shtml
10 20pm BBC2 TV, The Planets: Brief Encounters - a 10-min account of the 
10-billion-year life of the solar system.
10.50pm BBC4 TV, Mark Steel on Einstein.  Repeated 2.20am.

4. Thursday, 16 Dec.:
7.00pm, BBC4 TV, Light Fantastic. Repeated 1.40am

GEMINIDS: Don't forget the Geminid meteors, maximum on Monday night/Tuesday 
morning. See previous emails.

IAA LECTURE, Wed, 7.30 p.m. Dr John Butler will give a talk entitled "The 
2003 Restoration of Armagh Observatory" (If you haven't visited the Observatory 
recently, you should do so - quite a few changes, including one completely new 
dome, a unique 'Human Orrery', and major refurbishments! But first, come & 
hear this lecture, to get the full story.) It will be at 7.30 p.m., Lecture Room 
5, Main Building, Stranmillis College, Belfast, with plenty of free parking. 
Free admission as usual and there will be some free seasonal refreshments as 
well!


LIDL SKYLUX REFRACTOR: The Skylux refractor is still available in various 
Lidl stores throughout Ireland - thanks to all who have emailed me giving 
details. If you can't find one locally, just ring around.
   This further information from IAA treasurer John Hall may be of interest:
   "Hello Terry,   I might as well add my tuppenceworth re the 70mm Skylux, I 
know I should not have bought it since I have enough telescopes already, 2 
Dobs and 2 Refractors. However I managed to convince my better half that the 
Skylux would be a nice high tech "ornament" to reside in the corner of the 
sitting room.???( joke )
Just how good is this instrument ?    The general finish is very good, but I 
noticed a lot of "plastic,"  for instance, the rack teeth seem to be made of 
this material then given a metallic finish, but essential parts subject to wear 
are all metal. 
   As regular skywatchers will know, during the last  few weeks we seem to 
have wall to wall cloud cover , so the opportunity to do a star test did not 
exist. Last night, however, the sky was clear for about two hours, so out came 
the Skylux. I inserted a Ronchi grating ( 200 lines per inch ) at prime focus 
with the telescope pointed at Sirius. The result showed an apparently turned 
down edge objective, as the Ronchi lines were sharply bent at the edge, and as 
you know this fault is an image destroyer.
  Remembering my days when I was trying to assemble a 100mm refractor, I 
recalled just this fault when I had tightened the objective lens down too tight ( 
you must have some play), so I removed the dewcap from the Skylux and tried to 
unscrew the objective retaining ring, and noticed that it was quite tight. I 
unscrewed it about half a turn, replaced the dewcap and repeated the Ronchi 
test, and believe it or not, the Ronchi lines were nice and straight right to 
the edge.
  Saturn was high up so I got my best Nagler (7mm) and zeroed in. I have to 
say I was a little disappointed. This eyepiece gave a power of 100, and I 
expected to see at least the Cassini division, but there was no sign of it and  the 
image of Saturn was soft and featureless, with some false colour. As a 
comparison my home made 100mm F13 refractor displayed a nice crisp image, with 
Cassini sharply visible.
Turning to the stars, Polaris was "star tested" with the Nagler and showed a 
reasonably good result. Possibly the lack of detail on Saturn can be explained 
by some surface roughness on the objective. 
   Finally, I noticed  a nearby streetlamp seemed to be causing reflections 
into the field, this was eliminated by painting the inside of the shiny plastic 
drawtube with blackboard paint, this will help contrast as well."

Thanks, John. I suppose for ё50 it's still good value, and maybe you didn't 
get a particularly good one. And I promise that's the last mention of the 
Skylux until next year!

Clear Skies (esp for Monday night!!)

Terry Moseley

Last Revised: 2004 December 12th WWW contact:webmaster@arm.ac.uk

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