On Mon, 25 Sep 2006 19:59:43 GMT, "The3rd Earl Of Derby" <[email protected]> wrote:
>> Check it out!
>>
>> Regards
>> Neil.
>
>I presume this was intended for another group? too much gazing into a long
>tube is not good for the sight.
Spammers don't care what group they pollute
Mac
https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm
Dave Balderstone wrote:
> In article <[email protected]>,
> <[email protected]> wrote:
>
> > Just wanted to let you know about a great site that shows you how to
> > build and use a telescope for visual observing:
>
> To be accurate, the site offers to sell me the instructions rather than
> show me how.
And it does not appear to offer any infomation that is not available
for free from multiple sources.
DAGS "Dobsonian", "Newtonian", and "Amatuer Telescopre Making".
--
FF
The3rd Earl Of Derby wrote:
> [email protected] wrote:
> > Hi all,
> >
> > Just wanted to let you know about a great site that shows you how to
> > build and use a telescope for visual observing:
> >
> > http://www.buildatelescope.co.uk
> >
> > Check it out!
> >
> > Regards
> > Neil.
>
> I presume this was intended for another group? too much gazing into a long
> tube is not good for the sight.
>
I almost didn't get it.
Like most jokes about the sky, that was was over my head.
On a more serious note, I have casual observed that myopia is less
common among amatuer astronomers than in the population at large.
They do spend more time focussed at infinity and with a fully expanded
pupil than do most. Maybe that has something to do with it.
--
FF
Andrew Barss wrote:
> [email protected] wrote:
>
> : On a more serious note, I have casual observed that myopia is less
> : common among amatuer astronomers than in the population at large.
> : They do spend more time focussed at infinity and with a fully expanded
> : pupil than do most. Maybe that has something to do with it.
>
>
>
> More likely that they didn't have myopia to begin with. And people
> that have myopia not getting into astronomy because they can't
> see all that well in a scope.
>
People don''t have myopia to begin with, they develop it.
I should have clarified this by saying that my sample consists
mostly of those who got hooked on astronomy in their pre-teen
(and therfor typically pre-myopia) years.
I expect you will find the same is true for most people
who spent a lot of time outdoors in their preteen and
teenage years.
Focussing a telescope completely corrects for myopia or
presbyopia, unfortunately, not for astigmatism, as do
eyeglasses for the 'naked' eye observing, so neither is
much of a factor in the enjoyment of the hobby.
Even with astigmatism, I prefer to not use my glasses at the
eyepiece but that may be because the glasses do little to
correct my astigmatism.
Amatuer astronomers tend to have a favorite eye. One might
suppose that which ever eye is the best corrected would
be favored. Maybe that is so, but a majority seem to prefer
using their left eye. It may also be a left-brain, right-brain sort
of thing. I know one who claims he prefers to use one eye for
planetary detail and the other eye for nebulae. I'm a lefty for
both.
--
FF
Doug Miller wrote:
> In article <[email protected]>, [email protected] wrote:
> >
> >People don''t have myopia to begin with, they develop it.
> >
> >I should have clarified this by saying that my sample consists
> >mostly of those who got hooked on astronomy in their pre-teen
> >(and therfor typically pre-myopia) years.
>
> Not correct -- myopia normally develops in childhood.
>
My childhood was pre-teen.
--
FF
Doug Miller wrote:
> In article <[email protected]>, [email protected] wrote:
> >
> >People don''t have myopia to begin with, they develop it.
> >
> >I should have clarified this by saying that my sample consists
> >mostly of those who got hooked on astronomy in their pre-teen
> >(and therfor typically pre-myopia) years.
>
> Not correct -- myopia normally develops in childhood.
>
http://www.agingeye.net/myopia/1.8.php
Upwards to 2% of the US population has congenital myopia.
About 20% of the population develops it between the ages of 5 and 20.
About 8% between 20 and 40.
And some develop it later.
--
FF
In article <[email protected]>,
<[email protected]> wrote:
> Just wanted to let you know about a great site that shows you how to
> build and use a telescope for visual observing:
To be accurate, the site offers to sell me the instructions rather than
show me how.
[email protected] wrote:
> Hi all,
>
> Just wanted to let you know about a great site that shows you how to
> build and use a telescope for visual observing:
>
> http://www.buildatelescope.co.uk
>
> Check it out!
>
> Regards
> Neil.
I presume this was intended for another group? too much gazing into a long
tube is not good for the sight.
--
Sir Benjamin Middlethwaite
In article <[email protected]>, [email protected] wrote:
>
>About 20% of the population develops it between the ages of 5 and 20.
Doubtful. A more accurate statement would probably be that about 20% of the
population is *diagnosed* between those ages. That figure undoubtedly includes
some children who are congenitally myopic, or who developed myopia during
their first five years, but were never diagnosed until their first routine
vision screenings conducted by their respective public schools. I don't
pretend to know how many children fall into that category, but I'm quite
certain the number is greater than zero.
--
Regards,
Doug Miller (alphageek at milmac dot com)
It's time to throw all their damned tea in the harbor again.
In article <[email protected]>, [email protected] wrote:
>
>Doug Miller wrote:
>> In article <[email protected]>,
> [email protected] wrote:
>> >
>> >People don''t have myopia to begin with, they develop it.
>> >
>> >I should have clarified this by saying that my sample consists
>> >mostly of those who got hooked on astronomy in their pre-teen
>> >(and therfor typically pre-myopia) years.
>>
>> Not correct -- myopia normally develops in childhood.
>>
>
>http://www.agingeye.net/myopia/1.8.php
>
>Upwards to 2% of the US population has congenital myopia.
>
>About 20% of the population develops it between the ages of 5 and 20.
And how does that break down into the 5-12 and 13-20 age ranges?
>
>About 8% between 20 and 40.
>
>And some develop it later.
>
--
Regards,
Doug Miller (alphageek at milmac dot com)
It's time to throw all their damned tea in the harbor again.
[email protected] wrote:
: On a more serious note, I have casual observed that myopia is less
: common among amatuer astronomers than in the population at large.
: They do spend more time focussed at infinity and with a fully expanded
: pupil than do most. Maybe that has something to do with it.
More likely that they didn't have myopia to begin with. And people
that have myopia not getting into astronomy because they can't
see all that well in a scope.
-- Andy Barss
On Tue, 26 Sep 2006 16:27:04 GMT, "David Merrill"
<[email protected]> wrote:
>Typically, the construction of an amateur astronomy telescope is largely a
>precision woodworking project; sometimes metalworking, sometimes
>ultra-precision glass grinding/polishing as well. Rather appropriate to
>your part of the planet I should suspect (having previously spent 11 years
>in Arizona). DAGS on ATM.
>
>David Merrill
If you take a class from John Dobson or just follow his instructions,
or just build any Dobsonian mount, the woodworking and other
construction involved is hardly precision nor does it need to be.
Nowadays I am given to understand using a Dobsonian mount is by far
the norm for a amateur telescope; I know I have seen a bunch of
homemade Dobsonians but very few other kinds. Of course, that may be
because Dobson stops by in my little town (pop 8000) to teach
telescope making. He actually stays a couple houses down from me.
His whole focus is to teach how to construct a decent reflector with
commonly available materials. The only items that were purchased
specifically for the purpose in his class was the secondary reflector.
Everything else is from materials adapted to making the telescope. The
eyepiece for example was taken from a decent pair of old binoculars
purchased at a pawn shop.
And, grinding and polishing and testing and adjusting the primary
mirror, is done completely by hand and Dobson claims to get better
results that way than by using equipment to grind it. He corrected my
mirror after inspection of the diffraction pattern it produces off a
reflection from a power line insulator, by pushing around the
polishing rouge with his thumb in a circles for a few minutes.
In article <[email protected]>, [email protected] wrote:
>
>Doug Miller wrote:
>> In article <[email protected]>,
> [email protected] wrote:
>> >
>> >People don''t have myopia to begin with, they develop it.
>> >
>> >I should have clarified this by saying that my sample consists
>> >mostly of those who got hooked on astronomy in their pre-teen
>> >(and therfor typically pre-myopia) years.
>>
>> Not correct -- myopia normally develops in childhood.
>>
>
>My childhood was pre-teen.
Exactly.
To equate, as you did, "pre-teen" with "pre-myopia" implies that myopia
typically develops during the teen years or _later_.
That's just not true.
>
--
Regards,
Doug Miller (alphageek at milmac dot com)
It's time to throw all their damned tea in the harbor again.
On Tue, 26 Sep 2006 16:27:04 GMT, "David Merrill"
<[email protected]> wrote:
>Typically, the construction of an amateur astronomy telescope is largely a
>precision woodworking project; sometimes metalworking, sometimes
>ultra-precision glass grinding/polishing as well. Rather appropriate to
>your part of the planet I should suspect (having previously spent 11 years
>in Arizona). DAGS on ATM.
You aren't kidding about precision woodworking, though I don't think
this one is typical:
http://krtwood.com/IMG_2578.jpg
Not my work, something someone thought I'd enjoy seeing recently.
-Leuf
In article <[email protected]>, [email protected] wrote:
>
>People don''t have myopia to begin with, they develop it.
>
>I should have clarified this by saying that my sample consists
>mostly of those who got hooked on astronomy in their pre-teen
>(and therfor typically pre-myopia) years.
Not correct -- myopia normally develops in childhood.
--
Regards,
Doug Miller (alphageek at milmac dot com)
It's time to throw all their damned tea in the harbor again.
Typically, the construction of an amateur astronomy telescope is largely a
precision woodworking project; sometimes metalworking, sometimes
ultra-precision glass grinding/polishing as well. Rather appropriate to
your part of the planet I should suspect (having previously spent 11 years
in Arizona). DAGS on ATM.
David Merrill
"mac davis" <[email protected]> wrote in message
news:[email protected]...
> On Mon, 25 Sep 2006 19:59:43 GMT, "The3rd Earl Of Derby" <[email protected]>
wrote:
>
>
> >> Check it out!
> >>
> >> Regards
> >> Neil.
> >
> >I presume this was intended for another group? too much gazing into a
long
> >tube is not good for the sight.
>
> Spammers don't care what group they pollute
> Mac
>
> https://home.comcast.net/~mac.davis
> https://home.comcast.net/~mac.davis/wood_stuff.htm