World's simplest telescope

[ed_turco]

I know this isn't a fancy article but it is a lot of fun!  I show  US sources for the supplies, (not much!), but I am sure that there are many similar ones across "The Pond".

See the attached

ed

GALILEO.TXT

[ronin]

Optically the "simplest" is a positive front objective and a positive or negative rear eyepiece, simplest being a singlet.

Which is what Galileo used, his eyepiece was a negative lens.

The comment in the artical saying: "It leads me to wonder why more wasn’t discovered with Galileo’s telescope."

is pretty easy, they could not produce glass as flawless as we can now and they could not grind the surfaces anywhere near as good. The other bit is we know what we are doing and why, Galileo didn't have the basic optics equations we take somewhat for granted. The bits from Surplus Shed are many times more advanced then Galileo made. He made the lens by hand grinding glass, he couldn't order them from Surplus Shed via the internet.

So perhaps 400 years of development in materials and mathematics is the reason.

Over here it is the anniversary of Sir Malcolm Cambells speed record, it is 90 years since he held the world record of 150mph. You can buy a BMW and several ofthers that are capable of that from the garage down the road now.

[ed_turco]

Optically the "simplest" is a positive front objective and a positive or negative rear eyepiece, simplest being a singlet.

Which is what Galileo used, his eyepiece was a negative lens.

The comment in the artical saying: "It leads me to wonder why more wasn’t discovered with Galileo’s telescope."

is pretty easy, they could not produce glass as flawless as we can now and they could not grind the surfaces anywhere near as good. The other bit is we know what we are doing and why, Galileo didn't have the basic optics equations we take somewhat for granted. The bits from Surplus Shed are many times more advanced then Galileo made. He made the lens by hand grinding glass, he couldn't order them from Surplus Shed via the internet.

So perhaps 400 years of development in materials and mathematics is the reason.

Over here it is the anniversary of Sir Malcolm Cambells speed record, it is 90 years since he held the world record of 150mph. You can buy a BMW and several ofthers that are capable of that from the garage down the road now.

Thank you for reworking my work for me without attribution.  "Artical" is spelled "article".   I did refer to my probable resolution of Albeireo as an area that Galileo didn't pursue, seeing that he had other far more important things to do such as supporting Copernicus.

I smell pedantry here.  Is this what you do to accumulate so many postings to your credit, or do you do something more useful?

At least I tried to point out an interesting and exciting project for the DIY astronomer.

Do likewise; in fact, do better.

ed

[Stu]

I know this isn't a fancy article but it is a lot of fun! I show US sources for the supplies, (not much!), but I am sure that there are many similar ones across "The Pond".

See the attached

ed

Nice write up Ed, and a fun little project to do. I think you neatly covered all the factors of improved performance now vs Gallileo's hand ground lenses.

I've been known to make little scopes out of whatever I have lying around, but the idea of seeing what a very long focal ratio, small objective can do sounds fun.

Cheers,

Stu

[Mr Spock]

When I was young I used to try and make scopes out of old camera lenses. It never worked of course!

Thank you for taking the time to write such an interesting article. I'm sure people in that position now will read it and embark on this fun and educational project.

Imagine the excitement Galileo must have felt. We have such a depth of knowledge now but to him everything was new and being seen for the first time. Lucky chappie!

[Paul73]

I'll give it a go with my kids. They will love it.... OK. it's not just for them!

I'm pretty sure that my ham fisted diy skills will negate the effects of several hundred years of progress and give a realistic Galalean experience.

Paul

[Peter Drew]

In my mid teens I came across a 35mm disc of glass that at first sight appeared flat but closer inspection revealed it to be planoconvex with a focus of about 1 metre. I fitted it to a cardboard tube and the eyepiece assembly from a Galilean binocular for context. It gave a remarkably good view of Saturn which greatly impressed a visiting American serviceman friend of my father.    

[JamesF]

I seem to recall something about Galileo using a cannon ball to grind his lenses.  Not exactly high tech

James

[ed_turco]

I'll have to remember that cannonball trick the next time I have to grind a lens to that specific focal length!   Actually, a lens thus ground would turn out to be excellent.