Telescope Reviews: Full Moon test of edge sharpness.

< Kenny, does it count if I did this 20 years ago? >

ONLY if you got the idea from ME in the first place :-)

< What I think you and me (and whomever feels like joining) could already contribute, is checking the repeatability of the Full Moon Test for the same optic. How does it depend on seeing, residual twilight, altitude of the Moon above the horizon, transparency, etc.? >

Well Mark , I realise it's no longer a FULL moon , but following a very disappointing half hour out with the Zeiss diascope from around 9pm local time ( with the easterly moon blocked from view by my house ) looking at stars before clouds rolled in with more speed and purpose than Brett Lee , inspired by the snippet above , knowing our friend luna would be visible over the rooftop by now , I just went out to see what I thought tonight , through the Zeiss 7 x 42 .

The moon is quite high now , with lots of fast moving cloud providing an effect one described by our colleague Sir Isaac Stephen Napier as being THE catalyst for his lifelong interest in astronomy .

There were a lot of colour differences within the small area of sky surrounding the moon , with hues of brown , orange , yellow , grey , blue and white combining to create a moving picture so noteworthy that it almost took my mind off the purpose of having gone outside again .

Struggling to put aside the visual and emotional appeal of the moon appearing to rush through this riot of colour like a giant fireball , I tried to assess image degradation when moving it very slowly from centre to edge across the vast acreage of the 8.6 degree TFOV .

My concentration , already being tested , was ruined , particularly when scanning left , so that the moon was moved into the right side of the field , by a pronounced ghosting .

A " second ghost moon " , almost edge to edge with the real one , was becoming increasingly prominent as I slowly shifted the moon to the right hand edge of view .

I quickly diagnosed this rather cheeky intrusion to be the fault of my glasses !

As soon as I removed them , it completely disappeared , but upon doing so , another factor immediately came into the equation .

Astigmatism .

Without my glasses , my astigmatism is so severe these nights , that the moon becomes about as accurate a representation of it's true shape as " Flowery Tw-ts " was to Fawlty Towers .

In addition to which it's apparant overall size increases by a factor of about 30% .

Calculating the area of a gibbous moon would come about as easily to me as would calculating the area of the side elevation of one of my beloved sheep .

So even to suggest a figure of 30% is more a result of trying to " sound scientific " as much as anything else .

But there is no doubt that without my glasses , it looks a lot bigger .

But the field of view in my binoculars does NOT look any bigger .

This , in itself , makes a mockery of the whole exercise , and I am fast becoming aware ( because I always think fast and am often unaware ) that to be presenting myself as some kind of pioneering binocular experimentor with eyesight as bad as mine has become since spending so much time on this PC ( on cloudy nights ) makes about as much sense as a deaf person applying for a job as Pink Floyd's sound engineer for the forthcoming £100 million DARK SIDE of the moon tour.

Does anyone know of any contact lenses going cheap ?

Regards , Kenny

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If everyone is thinking the same thing , no-one is thinking - General George S.Patton

Zeiss 7 x 42 BGAT
Captain's Helmsman 7 x 50
Nikon 10 x 42 Superior E
Swift Audubon Kestrel 10 x 50
Helios 15 x 70 Observation
Strathspey 20 x 90
Televue 76 APO
Zeiss 85 Diascope
Helios 102 f5 refractor
Various eyepieces barlows tripods mounts etc.
Panasonic Lumix DMC - TZ5 digital camera