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3
votes
2answers
835 views

Hartmann mask based collimation

Is there a detailed description for a Hartmann mask based collimation process? I've been told by a friend that is possible to collimate an SCT by placing a three round holes Hartmann mask at the ...
3
votes
3answers
109 views

Quality loss when adding more components to a telescope?

I would think this would be inherently true, but I'm curious: (Assuming the highest quality amateur instruments are used.) Is quality lost when, say, adding a T-mount adapter, diagonal or any other ...
4
votes
1answer
69 views

Should I be concerned about spot corrosion on a telescope's primary mirror?

I am considering buying a telescope with a large primary mirror that is about seven years old - it has a small spot of corrosion on the mirror, that the owner says is stable. Should I be concerned ...
0
votes
2answers
625 views

Do I need to focus the telescope?

I purchased a 90x refractor telescope with below configuration. Objective: 50mm diameter with 360mm focal length 2 Eye pieces: 6mm, 20mm (10-1/ 8" scope) 1.5x erecting eye piece It measures 13- ...
3
votes
2answers
208 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 ...
5
votes
5answers
61 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?
8
votes
5answers
105 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 ...
4
votes
3answers
104 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
45 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 ...
10
votes
2answers
172 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 ...
9
votes
1answer
775 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
2k 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 ...
8
votes
1answer
75 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
1k 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 ...
22
votes
3answers
1k 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 ...
29
votes
4answers
474 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 ...
8
votes
1answer
114 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, ...
-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
82 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 ...
3
votes
2answers
65 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
38 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, ...
6
votes
2answers
251 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 ...
3
votes
1answer
234 views

Error analysis of flux from telescope-CCD setup (photometric calibration)

I am doing photometric calibration of a telescope and am trying to work out the errors on the flux that I measure. I have attempted to work out the errors due to the process of removing bias, dark ...
6
votes
1answer
165 views

What sort of equipment would I need to take a photo like this?

I'm interested in doing some astrophotography and I'm looking into the equipment needed to get a photo like this: http://www.flickr.com/photos/cscunha1984/6619321531/in/faves-heyvian/ I'm not looking ...
3
votes
2answers
1k views

How to correct flares and sharply focus on my telescope when viewing planets.

A month or two ago I purchased a “Skywatcher Explorer 130P Newtonian Reflector” telescope - which so far is brilliant when looking at the Moon, esp. using a neutral density filter. However, when ...
6
votes
1answer
193 views

Why is the Hubble Space telescope able to see farthest in the universe?

What determines how far a telescope can see in the universe? How does recording data for a very long time (~10 years) help? If we could build a telescope which work at microwave region, will it be a ...
4
votes
2answers
402 views

How to adjust feather touch focuser for collimation?

I have a Starlight Instruments feather touch focuser for my Dobsonian telescope. While trying to collimate the secondary mirror with the focus all the way in, I noticed that my Howie Glatter laser ...
11
votes
3answers
655 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 ...
6
votes
4answers
79 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
3answers
710 views

Sky-Watcher Skyhawk 1145P SynScan AZ GOTO

What is the experience using the Sky-Watcher Skyhawk 1145P SynScan AZ GOTO telescope and can it be recommended for a new astronomer? Is it any good?
6
votes
1answer
712 views

What telescope would I need to observe Mars's polar caps?

What telescope refractor aperture size would I need to observe Mars's polar caps? I have a Levenuhk Strike NG 80mm, and I can see red disk of planet but cannot see any details on the surface.
6
votes
3answers
631 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?
4
votes
1answer
24 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
4answers
518 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 ...
5
votes
1answer
97 views

How to care for a Dobsonian around the ocean?

I live near the ocean where all the metal fasteners on a house quickly rust and am considering getting a large Dobsonian telescope but am concerned about the mirrors. Would keeping the dob inside a ...
5
votes
2answers
73 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 ...
3
votes
2answers
2k views

Issues with Celestron 130 SLT and shaking

I have a Celestron 130 SLT reflector. I am having some issues with it and I hoped you all could help me. I'm looking for some low tech and inexpensive solutions. My telescope shakes like crazy. I ...
3
votes
8answers
3k 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 ...
-2
votes
2answers
101 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 ...
4
votes
2answers
636 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 ...
4
votes
2answers
237 views

Why do we stop using optics for photons above a certain energy?

I'm reading about how the soon-to-be-launched NuSTAR is on the cutting edge of focusing x-rays, which captures 5 to 80 keV radiation by focusing them with optics that have a 10.15 meter focal length ...
4
votes
3answers
176 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 ...
8
votes
2answers
1k 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?
6
votes
4answers
183 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 ...
6
votes
4answers
137 views

Automated telescope system

I am living up north in Norway, 300 km above the Arctic Circle, which gives me six months per year of darkness and cold. I used to have a starter telescope when I was living in Spain, but I gave it ...
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?
6
votes
2answers
226 views

What's the best way to start out with astrophotography on a tight budget?

I'm new to astronomy and I don't have a great deal of cash to spend. I currently have a 3" reflector telescope which I've had great fun with. I also have a Pentax DSLR which I've been using to take ...
3
votes
1answer
426 views

Sky-Watcher Skymax-127 (AZ) 127mm (5") f/1500 SynScan GO-TO Maksutov-Cassegrain Telescope

I have not purchased the above item yet but was wondering whether or not I should? Can I hook this scope up to a monitor or laptop so I can see what my scope is seeing? Is this scope is any good at ...
5
votes
3answers
399 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 ...
7
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?