All Questions
Tagged with newtonian-telescope observational-astronomy
8 questions
0
votes
0
answers
34
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Is it possible to estimate where the coma-free zone is based on the secondary mirror reflection seen through a collimation eyepiece?
If I understand correctly, the whole point of collimation is to make the coma-free zone at the center of the image at the image plane. I would like to understand how accurate the collimation needs to ...
- 147
1
vote
1
answer
69
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Is there any specific way to record observations on any celestial object while looking through a telescope? [closed]
Which aspects or factors do I take into consideration while I record observations on any celestial object?
- 3,455
6
votes
3
answers
4k
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Could someone explain what is wrong with my telescope, and what should I be able to see with it?
In January of 2016, I received my first telescope, through Astronomers Without Borders. It was and is my first telescope: an AWB 130 Newtonian tabletop telescope with a 650mm focal length and a 130mm ...
- 3,611
2
votes
0
answers
262
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What is the difference between a Cassegrain telescope and a Gregorian one? Which one is better?
Of the three giant (or 'Extremely Large') new telescopes being built, the Thirty-Meter (TMT), the the Giant Magellan (GMT) and the Extremely Large Telescope (ELT), only the Magellan, from what I ...
- 5,585
0
votes
1
answer
586
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How does diffraction occur in a reflecting telescope?
It's understandable how diffraction occurs in refracting telescopes, because the lens itself is a small aperture for light to pass through.
But what about reflecting telescopes? Since light is ...
- 17.7k
3
votes
2
answers
713
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Why are Cassegrain telescopes shorter than Newtonian reflecting telescopes?
Many websites say this is because the effective focal length of the objective is increased by making the secondary mirror convex. This allows a Cassegrain telescope to be shorter than a similarly ...
- 17.7k
3
votes
3
answers
2k
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Advice on first Telescope (refractor vs reflector), Barlow lens
I am planning on buying my first telescope. I am getting an 80mm refractor and a 114mm reflector for the same price range. Which would be a better option? Further, would a Barlow lens solve the ...
- 1,454
14
votes
1
answer
715
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How do I build a stargazing aficionado's Sun funnel to observe our nearest star safely?
How do I observe the Sun safely, with tools I could build myself and without breaking the bank? If I wanted to build a Sun funnel on my own and use it on my enthusiast grade telescope, how would I do ...
- 1,029