I am making a telescope at home whose front lens is off 500mm focal length and eye lens is of 1mm focal length so please help me to make it what should be the diameter etc....

[alankrit rajan]

Yes mm

[Mandy D]

Just now, alankrit rajan said:

Yes mm

OK, so get yourself a cheap eyepiece of around 25 mm focal length and set the two up about 500 mm apart. Look at something far away (NOT the Sun!!!) and see if you can get it into focus by moving them closer together or further apart. Then get a tube to mount the large lens in and make something to go in the other end that the eyepiece can slide back and forth in = instant telescope. Pat yourself on the back and grab a cup of tea.

[alankrit rajan]

Okay 😄

[alankrit rajan]

What is the aperture of eyepiece lens 

[Mandy D]

1 minute ago, alankrit rajan said:

What is the aperture of eyepiece lens 

It's irrelevant if you are buying a ready made eyepiece. Just get a 25 mm one in a 1.25 inch fitting. A really cheap one will do.

Edited September 1, 2023 by Mandy D

[alankrit rajan]

So @Mandy D where are you from 

[Mandy D]

1 minute ago, alankrit rajan said:

So @Mandy D where are you from 

I'm in  England. Where are you?

 

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Edited September 1, 2023 by Mandy D

[alankrit rajan]

India.

What do you do are you a scientist or what

[Mandy D]

Just now, alankrit rajan said:

India.

What do you do are you a scientist or what

I'm an engineer, but educated in physics and astronomy.

[alankrit rajan]

Ohh do you use whatsapp or Instagram 

[Mandy D]

3 minutes ago, alankrit rajan said:

Ohh do you use whatsapp or Instagram 

No, but you can contact me via personal messaging on this forum.

[AstroMuni]

On 01/09/2023 at 17:32, alankrit rajan said:

India.

What do you do are you a scientist or what

Do you live in a city or have access to relatively less light polluted skies?

It would also be good to know your background so we know how technical an answer is acceptable. 🙂

EDIT: Meanwhile read this https://www.skyatnightmagazine.com/advice/make-a-small-refractor-telescope

And

 

Edited September 4, 2023 by AstroMuni

[alankrit rajan]

See I have made a small one 

[AstroMuni]

40 minutes ago, alankrit rajan said:

See I have made a small one 

Good work. Point it at Jupiter which is not too far from the moon at the moment and check what you can see. Use a planetarium software like Stellarium to tell you where to look OR use a skymap app on your phone such as Skychart/Skeye

Edited September 4, 2023 by AstroMuni

[Mandy D]

49 minutes ago, alankrit rajan said:

See I have made a small one

The results from it are good. You should certainly be able to see the Moons of Jupiter with it, but will need higher ISO and longer exposure for your phone to image them. Jupiter will image easily with that telescope. Try this link which shows the moons of Jupiter in real time and see if you pick them out with your telescope.

https://skyandtelescope.org/wp-content/plugins/observing-tools/jupiter_moons/jupiter.html