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Questions tagged [newtonian-telescope]

Questions about reflecting telescopes using a concave primary mirror and a flat diagonal secondary mirror.

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4answers
154 views

Mars looks like a blur

I took my telescope out tonight (I am new, just got the telescope a few days ago, it's my first one) and I was observing Mars, however all I see is just an bright orange circle, with no surface detail,...
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3answers
370 views

What's the difference between a Newtonian telescope and a regular telescope

So, recently I was shopping for telescopes and I decided on the following telescope: https://www.amazon.com/Celestron-21049-127EQ-PowerSeeker-Telescope/dp/B0007UQNKY/ I had exactly $180 to spend, ...
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1answer
103 views

About bigger resolution of telescopes [closed]

Any idea about the design of new better telescope having small length of diameter and having more resolving power.
3
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1answer
74 views

Newtonian reflector collimation question

After an initial collimation, I took my scope (150mm/750mm) out for a star test. While I could see concentric circles when the bright star is at the centre of the video, when the star is on the side ...
1
vote
1answer
74 views

Using setting circle for Right Ascension

I'm a little bit confused about the setting circle of my EQ5 mount. Basically, I'm trying to find M42 nebula using Sirius star as reference. So, considere that I did the following steps: ...
2
votes
1answer
258 views

Collimating with a home-made collimation cap

I've made a home-made collimation cap and am trying to use the procedure linked to in another answer. However, I've run into two issues right off the bat. In this picture from the linked page, it ...
0
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1answer
350 views

Retrofitting a DSLR camera to a super-cheap Tasco reflector telescope

I was given a 1995 vintage Tasco "302003" Newtonian telescope recently and have had some exciting success with it. I have managed to view the Moon in beautiful detail and also had my first glimpse of ...
1
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0answers
64 views

My homemade telescope

My telescope is blurry and I am not sure why I used a 254mm primary mirror f/5 with a secondary mirror at 62.5 and I also used a 32mm eye piece I know if I stand back 20cm from eyepiece I see a clear ...
0
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1answer
285 views

Cannot calibrate “upgraded starpointer finderscope” for Celestron AstroMaster 114EQ

My wife just bought me an AstroMaster 114EQ which came with an "upgraded starpointer finderscope" -- it looks different than the one depicted in that link. I have tried following the instructions in ...
0
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1answer
59 views

Laser Collimator For Dobsonian vs Newtonian

Will a laser collimator like the Gosky 1.25 Metal Laser Collimator, https://www.amazon.com/gp/product/B01M4IVUYG/ref=crt_ewc_title_dp_1?ie=UTF8&psc=1&smid=AHQ6VCR020F8X, work for a dobsonian ...
2
votes
1answer
768 views

Why does any planet look like a (not so) big white ball through my telescope?

I have a 130mm (5") diameter Newtonian reflector with a 650mm focal length (f/5). I have collimated my telescope already but when I'm looking at Mars or Jupiter (not a star I'm sure), all I see is a ...
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3answers
1k views

Dish antenna as parabolic mirror for OPTICAL telescope?

Can I use a chrome painted dish TV antenna as a parabolic reflector for my optical telescope? Given that glass mirrors are quite expensive, I am thinking of using a Dish TV antenna and coating its ...
10
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1answer
1k views

How much of a difference do good lenses make?

I recently purchased a Celestron PowerSeeker 114EQ and with it I got three lenses (which I assume are low quality), a 4mm, a 20mm and a 3 x Barlow. I can get pretty decent views of the moon but a ...
5
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1answer
458 views

Telescope collimation issue

Recently I purchase Chinese 8 inch reflector telescope from local store. When I observing starts and planets I've been having trouble getting really sharp image from this telescope. I observe Venus ...
3
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1answer
2k views

How do I remove fungus from a telescope mirror?

I use a Celestron NexStar 130SLT Azimuthal Newtonian Reflector. I noticed that recently, due to the wet season, some tiny spots of what appears to be fungus have appeared. Having taking appropriate ...
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vote
2answers
8k views

Why does the focal length of a telescope have an effect on the magnification?

I previously asked that Is the angular resolution of a telescope irrespective of used eye-piece? I learned that the resolution is fixed when the light enters the telescope, and that the eye-piece ...
3
votes
2answers
718 views

Is the angular resolution of a telescope irrespective of used eye-piece?

Suppose a telescope has aperture $D = 20$ cm. The angular resolution of such telescope, according to the Rayleigh criterion (if I have understood it correctly), is given by $$\theta = 1.22\cdot\frac{...
1
vote
1answer
345 views

How to view Jupiter with 4.5" Newtonian Reflector

I have a 4.5" Newtonian Reflector and I took a look at Jupiter the other night. I was able to get a reasonably sharp view of it and see a number of it's moons, but I was unable to see any surface ...
2
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1answer
124 views

Difficulties in finding Jupiter

I am new to astronomy. Jupiter is now visible to the naked eye but I have difficulties in locating it with my (new Newtonian reflector) telescope. The lowest magnification I have is 36X, which I guess ...
1
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1answer
92 views

Working with high-magnification eye-pieces

My telescope (Newtonian reflector) has a focal length of 900 mm. So, using a 25 mm eye-piece, I get 900 mm / 25 mm = 36X magnification. Using a 10 mm eye-piece, the magnification would be 90X. My ...
3
votes
1answer
844 views

How to use a telescope to find a specific celestial body?

I am a beginner interested in astronomy. I bought a Celestron AstroMaster 130EQ telescope. It's a Newtonian Reflector and it's not computerised. I did manage to see the Moon in some magnifications but ...
13
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2answers
15k views

A good telescope for the viewing of Nebulae, Stars and Planets

So, I am a 15 year old interested in astronomy. My father used to have a reflector telescope, but was never so serious about it that he could recommend me a good telescope. I am looking to buy a ...
10
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1answer
1k views

What can be seen with a 4.5" telescope

I just got a 4.5" Newtonian reflector. The skies haven't been clear where I live lately so I've only been able to use it to see the moon and Jupiter (I was also able to see the Galilean moons). A ...
10
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2answers
4k views

Are Barlow Lenses Good For Deep Sky Observing?

I'm using a 750mm (focal length) by 150mm (aperture) newtonian reflector and I've been curious about using Barlow lenses on deep sky objects. Some of the astronomers at my local observatory say that ...
9
votes
1answer
332 views

Why does squinting make hard-to-see objects clearer?

So I, like most other astronomy enthusiasts, have, at some point, not been able to see something clearly, such as a star, and have had to squint to be able to see it better. When this happens, the ...
29
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1answer
774 views

How could a hobbyist astronomer determine apparent magnitude of a star?

Apparent magnitude is a rather complex way to determine the brightness of a star. Quoting the introduction text from the linked to Wikipedia page: The apparent magnitude (m) of a celestial body is ...
13
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1answer
530 views

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 ...