Questions tagged [refractor-telescope]

Questions about telescopes with lenses as their main optical component.

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Can I use an achromatic focal reducer to reduce chromatic aberration?

I am using 75/1000 Plano convex lens to build telescope. Can I use an achromatic focal reducer to reduce chromatic aberration?
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1 vote
1 answer
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Can I use 75mm Plano convex lens to build telescope [closed]

I want to see Jupiter with moon. So am planning to build telescope. Can I use 75mm Plano convex lens with 1000mm focal length?
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2 votes
1 answer
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Magnification with a refractor

Using a refractor telescope at 200x, how close will an object appear at four miles away? Is there a table out there enabling you to calculate apparent seeing by filling in known variables?
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3 votes
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Can the "haze" of a mirror telescope be quantified?

When reading Why was StDr56 discovered only now? and its answers and comments, I realized that refractor telescopes, and in particular the Dragonfly Telephoto Array are a great tool to find nebula and ...
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5 votes
2 answers
499 views

Upgrade tripod on a cheap telescope

I got a cheap refractor as a present - my intro to astronomy. I think it’s not great, but I’m having plenty of fun looking at the moon and planets, and who knows, maybe some other objects soon. The ...
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  • 151
2 votes
1 answer
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What Crayford focuser to buy for a B&L Criterion 8000?

I'd like to get a dual-speed Crayford focuser for my newly acquired a B&L criterion 8000 (8") as the mirror shift is pretty bad. I'm really not sure which one to buy because I'm quite ...
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0 votes
1 answer
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What would I see with a telescope of 70mm aperture , 300mm focal length and maximum magnification of 150x

What would I be able to see with 70mm aperture telescope with 300mm focal length with maximum magnification of 150 x?
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3 votes
1 answer
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What could I resolve with my Telescope

I recently won a Common 50mm refracting telescope with Solar Filter too.. I'm trying to Understand things I can skygaze with it. It's pretty basic and I should have known. Unfortunately, I don't ...
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1 vote
1 answer
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Verifying refractor lens about scratches

I found an used Skywatcher 70mm telescope for buying, but its lenses are a little suspect about harming. In one photo, it looks clearly a scratch, but in the another, it is not visible. Could it be an ...
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  • 143
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Methods for testing a refracting telescope lens

I have an old (nearly 50 years old)alt-azimuth three-inch (7.6cm) refracting telescope that someone else made. They ground the lens, created the cylindrical body and added a rack and pinion style ...
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  • 175
0 votes
1 answer
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How can I determine if a typical low-end telescope is a refractor or reflector?

Is there a way to distinguish (with no manual, product info etc)?
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4 votes
1 answer
169 views

What are the benefits of a large refracting telescope?

Currently, refractor telescopes are limited in aperture because gravity will deform the main lens over time. According to Wikipedia the largest practical refracting telescope is 1m. If we were to ...
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6 votes
3 answers
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Chromatic aberration in lens

Is there a way to prevent chromatic aberration without using an achromatic lens in refracting telescopes or in any other instruments...?
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4 votes
2 answers
3k views

Second Telescope: Maksutov Cassegrain vs Refractor

I bought my first telescope, a 3-inch refractor a few weeks ago. It has been a wonderful experience seeing the Moon, Jupiter, Saturn magnified and Andromeda, M33, M81 and much more for the first time. ...
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2 votes
1 answer
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Seeing a line rather than a dot when looking through refracting telescope

I bought an amateur(and rather cheap) refracting telescope and while I can see moon quite clear and crispy I am having difficulties in observing some larger stars. All stars appear as lines rather ...
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3 votes
3 answers
1k views

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 ...
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  • 173
3 votes
1 answer
191 views

It is possible to combine a reflector and a refractor telescope together?

I know it sounds crazy, but is it possible to connect a reflector telescope and a refractor telescopes (like monocular for bird watching) together to build a better telescope?
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1 answer
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Replacing Meade ETX with computerized mount

I've been using a Meade ETX 90 for a few years now. Since it doesn't have the new computerized mount (with goto), I am looking into buying one to swap out. Where might I find this and is there a more ...
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2 votes
0 answers
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Equipment question

I'm looking to get some optical equipment that will be used for both terrestrial and astronomical viewing (ratio 70/30). It will also have to be portable to a degree although I realise that with a ...
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2 answers
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Stabilizers/dampers for refractor telescope

I have a basic refractor telescope. It's pretty light and so it catches vibrations and they never really settle down. Can I attach some dampers on it to cushion these?
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5 votes
3 answers
1k views

Question about Telescopes , observations and explanations of the observations

Though I am active on Physics, I am new to Astronomy. I am an amateur astronomer, actually even worse than amateur. I have just started it. I have a 60 mm objective 700mm focal length refractor which ...
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3 votes
2 answers
93 views

Capability of observing transits with terrestrial telescopes of various sizes?

I have access to my university's telescope, Dearborn Observatory, an 18.5 inch refractor on the shore of Lake Michigan, just north of Chicago (yes, it's an atrocious location, but the telescope still ...
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4 votes
2 answers
23k views

How to make a telescope for viewing planets, moon and DSOs using a convex lens of aperture 100 mm and focal length 200 mm and other lenses at home?

I wanted to make a telescope with DIY things lying around in home. I read up that the aperture was a very important aspect and thus bought a convex lens with 100mm aperture and 200mm focal length, to ...
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6 votes
3 answers
2k views

Astronomical telescope making

I am thinking about making a telescope. I have a 100cm focal length lens which I can use as objective lens in my telescope. So which is the best focal length I can use as eyepiece in my astronomical ...
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6 votes
1 answer
6k views

Are Barlow lenses stackable for bright objects?

I'm back to the refractor that I own, and I want to maximize the zoom capacity. I realized today that I own more than one barlow lens, and I was wondering if I could stack them together for looking at ...
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11 votes
1 answer
180 views

Does the Reflection Method for Looking at the Sun Work For Refractors?

I own a newtonian reflector and occasionally use it (using the reflection method with paper) for looking at the sun. I happen to also own a refractor, but I'm not exactly sure if the reflection method ...
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14 votes
1 answer
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How Does a Refractor Telescope Work?

As I understand it, the difference between a reflector and a refractor is that a reflector uses mirrors on the back to reflect the light to the secondary mirror then the secondary mirror reflects the ...
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