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2
votes
5answers
868 views

Recommended first accessories for starblast 4.5

My son got an orion starblast 4.5 for Christmas. It comes with orion explorer II 17mm and 6mm eyepieces. We are looking at some additional accessories and wondering what you would recommend as "first ...
4
votes
2answers
375 views

Novice interested in buying a used telescope. What questions should I ask? [closed]

I've noticed quite a few decent telescopes for great prices on craigslist, but I am a complete novice and don't know the first thing about them. I thought I would be able to pick up what I needed from ...
3
votes
2answers
160 views

The Bahtinov focusing mask

I'm looking for a webpage or a book or reference that might give me a better (and hopefully more scientific) understanding of how the Bahtinov mask works (which I understand to be the same as ...
11
votes
3answers
492 views

Why is this radio telescope's reflector spherical and not parabolic?

This is the Arecibo Observatory in Arecibo, Puerto Rico. Its reflector is spherical, measuring 1,001 ft. in diameter. It is considered the most sensitive radio telescope on Earth, but the fact that ...
-2
votes
2answers
70 views

Telescope “blue book” [closed]

I have a telescope that I may be in the market to sell in the near future and am wondering if there is a good source to find its value in the used market. Although it's never been out of the box, it ...
8
votes
1answer
106 views

Where can I find information for how to create amateur radio telescope?

Where can I find good source of information for how to create amateur radio telescope. Particularly interested in creating Fresnel Zone Plate Antennas (aka flat dish). design, diagrams, ...
4
votes
3answers
304 views

Pleiades through a 15x 76 mm telescope

How clearly can the stars of the Pleiades cluster be seen through a 15x telescope (for example, FunScope)?
6
votes
1answer
1k views

What are the minimum telescope requirements to view a nice spiral galaxy?

I would like to view some spiral galaxy. However, I would prefer not to spend lots of $$$. What are the minimum specs a telescope must have to resolve detail in a spiral galaxy?
13
votes
5answers
2k views

Telescope for 6 year old and dad new to astronomy

What's a good telescope for my 6 year old? We're both brand new to telescopes in general, but love space, stars, planets, cosmology, etc. Happy to spend up to $200 to start. Maybe more for a good ...
4
votes
1answer
23 views

What demonstrations for a five-hour optical and radio astronomy workshop? [closed]

I volunteer at a group that has restored the oldest German radio telescope. We are now at a point where we want to invite interested amateur astronomers and school children to workshops. I'm currently ...
4
votes
3answers
292 views

What is the minimum magnification needed for an instrument to see all the Messier objects?

I know someone that wants to buy a 60cm (1.5 inch) refractor and I thought about recommending what to look at the Messier objects. And I was wondering, can he see all these objects with that refractor ...
4
votes
3answers
150 views

Fall/Winter Viewing

I live in Seattle and am thinking of purchasing a telescope. Is fall/winter a decent time of year for viewing (aside from summer)? Are there any major viewings/events during that this of year? I know ...
-1
votes
2answers
3k views

Celestron NexStar 6 SE vs. Orion XT8 [closed]

I'm interested in purchasing a new telescope and have narrowed it down to the NexStar 6 SE vs. the Orion XT8. I'd like to be able to get into astrophotography and read that having the Go-To ...
5
votes
3answers
53 views

How to get started in Astronomy (UK based) [closed]

I have always been interested in space and astronomy (in my youth - I wanted to be an astronaut). However for various reasons, I never quite got started. I now want to get started - small but ...
10
votes
4answers
3k views

Is building your own reflector telescope worth it?

I have always fancied building my own reflector telescope. I am wondering - For a certain budget, can you get better results with a home made rig? Or is this a folly, and really it would be better to ...
3
votes
2answers
61 views

Particular targets of high angular resolution infrared telescopes

I work in the field of infrared interferometry, specifically instrumentation. As such, I need to be aware of the science goals of such an instrument. Is there a quick list of important and ...
1
vote
0answers
35 views

What equipment is needed for equatorial drift scanning/TDI with a Dobsonian?

It should be possible to do a "parked scan" along the celestial equator ("stripe 82" and "stripe 10") with a Dobsonian telescope, as no tracking is required. I can foresee two issues, though: first, ...
4
votes
3answers
54 views

Are our telescopes capable of taking actual images of brown dwarfs?

One nice result from NASA's WISE infrared survey of the sky is the discovery of particularly cool (as in 'not very warm') stars, now called 'Y dwarfs'. This was reported, for example, in NASA's ...
4
votes
4answers
783 views

Are telescopes with a concave lens useful for astronomy?

Are telescopes with a concave lens (instead of convex ones) ever useful for astronomy? And if so, where are they used? Do they ever affect resolving power?
6
votes
2answers
179 views

If you focus in on one image, is combining two telescopes really equivalent to a larger mirror?

Have a look at this example: In addition, the Keck I and Keck II telescopes can work together as the Keck Interferometer. The 85-metre (279 ft) separation between the two telescopes gives them the ...
2
votes
1answer
20 views

What was the most distant supernova spotted by a amateur astronomer until today?

What type of commercial amateur telescope and what method (difference imaging,...) did he use for identifying the supernova?
5
votes
2answers
68 views

Could many widely separated space telescopes be combined for VLBI on IR/visible wavelengths?

I have read about ground-based Very Long Baseline Interferometry telescope arrays able to achieve huge resolution at IR/visible wavelengths. There are also space-ground VLBI configurations in ...
5
votes
5answers
52 views

Which current big Earth-based telescopes are equipped with adaptive optics?

I know only that the VLT is equipped with adaptive optics (AO) to bypass atmospheric distortion. Is it the only one, or have other telescopes been build with AO in the optical and infrared spectrum?
6
votes
4answers
65 views

Does the current light pollution set a fundamental limit for the range of Earth-based telescopes?

As far as I know, all deep-sky pictures are captured with the Hubble Space Telescope. If there would be no atmospheric distortion, could we make deeper pictures in the optical spectrum with ...
4
votes
4answers
415 views

Can the Hubble telescope bring any star into focus?

Lets say I am talking about a view like this supernova - 13 billions light year away. In short can Hubble bring any star into focus in the entire universe? And if so, to what definition? I also ...
8
votes
5answers
97 views

Exoplanet detection via space-based parasol

I remember from watching Cosmos years ago, Carl Sagan suggested an interesting hypothetical method for directly seeing exoplanets. He proposed that in the 'future' we could launch a satellite designed ...
3
votes
8answers
2k views

Seeking Recommendation for Celestron Firstscope Eyepiece Upgrade

I have a Celestron Firstscope telescope and like it overall for my location and the amount of observing I do. I am disappointed in my view of the planets with the scope. What would be a good eye piece ...
6
votes
3answers
399 views

Is it possible to make a hydrogen-alpha solar scope?

Is the construction of an etalon / Fabry-Pérot interferometer within the reach of amateur telescope makers? Are there any resources pointing to such projects?
17
votes
5answers
292 views

Why don't we have a better telescope than the Hubble Space Telescope?

The Hubble Space Telescope (HST) was launched in 1990, more than 20 years ago, but I know that it was supposed to be launched in 1986, 24 years ago. Since it only took 66 years from the fist plane to ...
2
votes
3answers
831 views

How could I translate a field of view value into a magnification value?

When I zoom in with Stellarium, it indicates a field of view (FOV) value in degrees, but most binoculars and telescopes are advertised with value like "nX magnification power." How could I translate ...
4
votes
3answers
87 views

How long would it take to scan the visible universe for unique signals?

The article Amazing rays as star succumbs to dark side talks about a very large black hole swallowing up a star. The report goes on to say that the only reason it was discovered was because it shot ...
9
votes
1answer
44 views

How do I use this 'Horizon Observatory'?

Just around the corner, we have one of these: It's at the Halde Hoheward (article in the German wikipedia), and it's called a 'Horizon Observatory' by the people who built it. How does it work ...
6
votes
4answers
141 views

Mixing and matching across eyepiece designs / manufacturers?

Right now, I am considering moving from 1.25" eyepieces to 2". While I'm convinced of the quality of the premium eyepieces, it would take me years to afford a complete set and, if I go that route, I ...
8
votes
2answers
842 views

How do you clean a dusty lens?

The lenses of my telescope and binoculars are dusty. What is the best way to clean them without damaging the optic coating?
8
votes
2answers
462 views

Smaller free remote control telescopes?

There are several online services that let you control a large telescope (eg, lightbuckets.com and slooh.com), even some that are free (eg, telescope.org). Unfortunately, the pay services are ...
9
votes
1answer
519 views

Why is the Ritchey–Chrétien telescope preferred in professional astronomy?

Hubble, as well as numerous other professional telescopes, use the Ritchey–Chrétien design. What optical and instrumental advantages does this kind of telescope have for professional astronomy?
10
votes
2answers
147 views

How do air Cherenkov telescopes work?

The very highest energy photons, gamma-rays, are too energetic to be detected by standard optical methods. In fact they rarely actually make it to the surface of the Earth at all but interact with ...
10
votes
2answers
1k views

Observing Jupiter's non-Galilean moons

What strength of telescope is required to observe some of the non-Galilean moons of Jupiter? My current telescope at 50 magnification resolves the Galilean moons well, but I'm guessing it's far ...
6
votes
2answers
275 views

What makes a good set of binoculars? [closed]

After trying a bunch of binoculars at Star Parties and the like, I have a pretty good feel for about what aperture and magnification I'd like in a new set binoculars. I'm an eyeglass wearer so a long ...
7
votes
1answer
56 views

What size aperature would I need to find and see the supernova in M51?

On June 2, 2011, a new supernova was identified by an amateur French astronomer in M51. What size telescope aperture would one need to have any chance of seeing this? Given the right sized scope, ...
7
votes
6answers
838 views

Can any telescope be used for solar observing?

Can any telescope, such as a 8" reflector, that is normally used at night to look at planets be used or adapted for solar observing? What kind of adapters or filters are required or is it better to ...
21
votes
3answers
875 views

How to determine what size telescope to buy

A couple of years ago my son showed an interest in astronomy and we bought a 6" reflector telescope. We use it pretty regularly and have enjoyed it immensely. Lately we've both been wishing we had ...
6
votes
2answers
561 views

Optimal Angular Field of View (AFOV)

Given the rather huge price differences between eye pieces at the same focal length. How exactly does the AFOV affect the view seen through the eyepiece? Are higher / lower AFOV better for certain ...
27
votes
4answers
357 views

Telescopes to avoid as a beginner? [closed]

I've heard people talk about "department store scopes" or "trash scopes". How do I know what to avoid in a beginner scope? How can I know that I'm not getting something we will be more frustrated with ...
4
votes
1answer
577 views

What are the pros and cons of a german equatorial mount vs. a fork mount?

Not much more to add. Why pick one over another?
8
votes
2answers
487 views

What is exactly a Dobsonian, and what are the differences when compared with Schmidt-Cassegrain or Newtonian?

What is exactly a Dobsonian telescope, and what are the differences between this technical choice over a Schmidt-Cassegrain or a Newtonian configurations?
15
votes
6answers
2k views

Lenses (refractor) or mirrors (reflector) telescope?

What differentiates, in terms of practical quality, not technical implementation, a refractor from a reflector telescope? Why would one prefer a refractor over a reflector, when reflectors come with ...
11
votes
4answers
4k views

What does f/4.6 mean in a telescope and how important is this value? [closed]

In some specifications for telescopes, I saw a value marked as f/4.6. What does it mean exactly, and how important is when it comes to choosing a telescope?