2009 it was 400 years ago, Galileo Galilei (1564-1642) for the first time turned his home-built telescope to the sky, and for this reason is celebrated this year the International Year of Astronomy.

Question

anonymous · Answer

a group of astronomers, optical engineers and teachers developed a Galilean telescope kits that could be purchased via www.galileoscope.org for only $ 20. Here is a picture of the finished telescope and below is a table with specifications of the binocular optical characteristics:


Objective diameter: 50 mm (2 inches)
Objective focal length: 500 mm (f/10)
Eyepiece focal length: 20 mm
Magnification: 25x (50x with Barlow)
Field of view: 11/2◦
(3/4◦ with Barlow)
Eyepiece eye relief: 16 mm (22 mm with Barlow)
Eyepiece barrel diameter: 11/4 inches (313/4 mm)
(eyepiece = okular)



(a) As seen in the table, the telescope in its original form (ie without the so-called Barlow lens)
actually a Kepler binoculars, ie both the lens and eyepiece are positive lenses. What
becomes the normal pledged binocular length, ie, the distance between the lens and eyepiece,
in this case?


(b) The so-called Barlow lens that comes with the kit is nothing more than a negative lens with a focal length of -30 mm. By mounting this between the lens
and the eyepiece can peep the angular magnification is doubled to 50 times. This occurs
by image focal plane of the lens is enlarged to double size
(M = +2) and the eyepiece positioned so that the image of the lens image focal plane
ports in the object focus of the eyepiece. Draw a schematic view showing
in which the distance lens, Barlow lens and the eyepiece is placed in relation to each other. What will the binocular length, ie, the distance between the lens and eyepiece, in this case?


(c) A third way to mount the binoculars is to use Barlow-lens eyepiece instead standardokularet. Binoculars becomes a "real" Galileikikare, where the image is right side up. What will be the normal pledged binocular length, ie, the distance between the lens and eyepiece, in this case?

shamim · Answer

Going outside

anonymous · Answer

okey, a) must just be

$$L=f _{obj}+f _{oku}=500mm+20mm=520mm$$?

anonymous · Answer

b)

We know the ratio between s and s' because the magnification is M=+2

$$M = \frac{ -y' }{ y }=\frac{ s' }{ s }$$

$$2=\frac{ -s' }{ s }$$

anonymous · Answer

@Michele_Laino

anonymous · Answer

and we know that the barlow lens f=-30mm

michele_laino · Answer

It is a very long question, can you please wait, since I have to help another student?

anonymous · Answer

yes ofcourse, but will you comeback? I have a deadline in 4 hours :)

michele_laino · Answer

ok! I try!

anonymous · Answer

just write when your back :)

michele_laino · Answer

I'm sorry I'm not good with that subject! When I was at my university, I didn't attend the course of experimental optics, I have attended to an experimental nuclear physics course instead

anonymous · Answer

ah okey :) :/

anonymous · Answer

@amistre64 here is my question

michele_laino · Answer

@rational  can you help here, please?

michele_laino · Answer

@ParthKohli  can you help here, please?

michele_laino · Answer

@confluxepic can you help here, please?

michele_laino · Answer

@aaronq  can you help here, please?

michele_laino · Answer

@zepdrix  can you help here, please?

anonymous · Answer

for b)

M=+2
G=50
f_barlow=-30mm

$$M=\frac{ -s' }{ s } ->2=\frac{ -s' }{ s }$$

$$G= \frac{ f_{obj} }{ f _{ocu} }$$

$$50= \frac{ f_{obj} }{ f _{ocu} }$$

I dont understand how I should combine that, Cause I dont know anymore


@zepdrix
@confluxepic
@parthkoli
@rational

anonymous · Answer

@ParthKohli

michele_laino · Answer

@Data_LG2  please can you help here?

xapproachesinfinity · Answer

i do have allergy to lengthy question anyway lol

anonymous · Answer

Haha yeah me to...

xapproachesinfinity · Answer

@amistre64  optics :)

anonymous · Answer

I think I'll have to give this one up..

anonymous · Answer

im gonna try irishboy one more time! he havent answeared today

anonymous · Answer

@IrishBoy123 you are my last hope, can you pleeeeeease help me!

michele_laino · Answer

@IrishBoy123  can you help here, please?

michele_laino · Answer

@dan815  please can you help here?

anonymous · Answer

Hey michele I think im giving up now!

anonymous · Answer

I have tried but cant find anything!

irishboy123 · Answer

@pate16 
hi pate

i am really sorry but optics is not my bag.   happy to read what you have done and can circle back on that, but i truly don't have any answers.  this is a really interesting project but i suspect that you already know more than most about traditional optics.

had a troubled day today, should have got back earlier.  mea culpa.

anonymous · Answer

Its allright irishboy123, you are being so helpful when you can:)

michele_laino · Answer

@Nnesha  please can you help here?

anonymous · Answer

@iPwnBunnies 
@perl 
@Pompeii00 
@TuringTest