Wikipedia:Reference desk/Archives/Miscellaneous/2011 May 18

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May 18

telescope

which is the best telescope to buy for a starter with best picture quality and which can help view all the planets.. please advise —Preceding unsigned comment added by 117.199.66.118 (talk) 07:13, 18 May 2011 (UTC)

There are several variables, such as price and portability. There are web pages that give you advice and have reviews of various telescopes. Google for e.g. telescope beginner and start with the first two hits: scopereviews and rocketroberts. 88.112.59.31 (talk) 07:52, 18 May 2011 (UTC)

i think orion skyquest xt8 is a good deal..anybody else?? —Preceding unsigned comment added by 117.199.71.250 (talk) 09:25, 18 May 2011 (UTC)

Here's a link for that telescope on Amazon [1]. It gets excellent reviews for an inexpensive, moderately sized telescope. The five visible planets (Mercury, Venus, Mars, Jupiter, and Saturn) will all look very good in an 8 inch telescope. If it is well collimated, you may be able to resolve Uranus into a disk, and will perhaps be able to see some of its moons, on a good night in a dark location. You won't be able to resolve Neptune into a disk, but you'll probably be able to find it, if you are in a dark area and know where to point the telescope. Most of the Messier objects should be pretty good, if you are observing from a dark area.

You can also build a moderate sized reflecting telescope for about the same price, and it makes a good project. See Amateur telescope making. There are many plans, both online and in books, to help you. If you don't grind your own optics, it's essentially just a carpentry project. Buddy431 (talk) 02:09, 19 May 2011 (UTC)

The answer to this question is going to depend an awful lot on what you intend to look at, how often you intend to go stargazing, how good the 'seeing' is at your viewing site, how much light pollution you're dealing with, how much time you want to spend setting up and taking down equipment, how much you can lift (or whether or not you'll have a friend/spouse with you to help every time you go out), how far you're going to have to carry equipment, how much space you have in your vehicle (if you have a vehicle), how much storage space you have in your home (and how many stairs you have to carry the telescope up or down when you get there), and how much money you want to spend. For the XT8, bear in mind that the base and the optical tube weigh about 10 kg (a shade over 20 lbs) each, and the optical tube is a bit more than a meter long (a bit less than four feet). It can be a bit cumbersome to transport and set up, and this may dim your enthusiasm for the hobby. This isn't to say I have anything against the XT8 (and Dobsonian-mounted reflectors scopes like it); there's no way to get more aperture (more light and fainter objects) for less money. But sometimes a bit less telescope are a better buy. A little Maksutov-Cassegrain (90 mm, say) might be just 30 cm long, weigh three kilograms (including tabletop stand), and you'll be able to see Saturn's rings. Many Messier objects should be satisfying.

Seriously, if you're just getting into the hobby and you don't have a pair of binoculars yet, I would strongly urge you to start there. They're by far the easiest instruments to use in terms of setup and portability, which means you're more likely to have them with you or take them outside. They're also the smallest initial investment, and they're the easiest to share with friends and family. They're almost certainly the most durable option. Get to know your way around the sky – and think about your interests, and the type of viewing you'd like to do – then start shopping for telescopes. This article contains excellent advice. TenOfAllTrades(talk) 03:33, 19 May 2011 (UTC)

Take a look at the types of telescopes. Refractors (achromatic, department store-style false colour, or hyper-expensive apochromatic) are generally good for observing planets, while reflectors (Newtonian, Dobsonian or the massive and unaffordable Ritchey-Chretiens) are generally better for deep-sky objects, and compound telescopes (Schmidt-Cassegrains and Maksutov telescopes) can either be bulky or compact. Try the telescope shopping wizard to get an idea of what kind of telescope you probably want and the cheapest price you can get it at. ~AH1 ^(discuss!) 02:07, 20 May 2011 (UTC)

Note that you almost certainly don't want to purchase a cheap refractor from a department store. Generally they have very poor optics, an unsteady stand or tripod, and near-useless accessories. These instruments are almost guaranteed to provide nothing but disappointment. Avoid particularly any instrument that mentions magnification ("200x") before aperture ("50 mm"). TenOfAllTrades(talk) 13:08, 20 May 2011 (UTC)

Starter digital telescope ?

What about a starter telescope to make digital recordings of an object and play them on a windows XP SP3 computer ? (Instead of mechanically tracking the object, I picture a cheap version would just allow the object to pass thru the field of view, and then a program would provide the proper offsets to place the object on top of itself in each subsequent frame. Obviously, a wide field of view would be important.) Ideally this would increase light gathering power, just as a timed film exposure does. Is there such a starter system ? StuRat (talk) 09:09, 18 May 2011 (UTC)

I would recommend the Space Telescope Science Institute - great images for $0. The only problem is you can't pick your particular target.

A friend of mine gets get excellent images. He says he uses an inexpensive refractor telescope, an Atik 16ic cooled CCD camera and an EQ6 computerized goto mount. He typically takes a dozen or so 5 minute exposures and uses image stacking software to reduce the effects of random noise. Astronaut (talk) 13:53, 18 May 2011 (UTC)

Thanks. How much does that stuff cost ? Is that a monochrome or color camera ? StuRat (talk) 15:39, 18 May 2011 (UTC)

You are interested in basic astrophotography using a GoTo mount system that will automatically track the object, preferably through an equatorial mount. Webcam cameras (with the lens removed?) are often used for this purpose, or alternatively an astrograph could potentially suit your purpose, and you could also try for instructions from WikiHow. You can connect a USB to your GOTO system, and often the guided mount runs on battery or 6-12V DC converter power, and the telescope usually comes in the range of $300 - $600. ~AH1 ^(discuss!) 01:42, 20 May 2011 (UTC)

Hot rolling

how does the rolled stock behave during the hot rolling lof steel? Ahmed Eid

Can you be more specific with your question ? Obviously hot steel is more malleable than cold steel. Is that what you're asking about ? StuRat (talk) 08:40, 18 May 2011 (UTC)

Does the Rolling (metalworking) article help you any? Dismas|^(talk) 10:03, 18 May 2011 (UTC)

Ahmed, Remember To Sign Your Questions.184.163.238.18 (talk) 15:41, 18 May 2011 (UTC)

He did. StuRat (talk) 16:58, 18 May 2011 (UTC)

Haha. 184, how do you know his name if not from his signature? APL (talk) 17:37, 18 May 2011 (UTC)

Meteor identification

believed to be a meteorite or outer planetary stone by my granddad and is under my custudy since he's gone,which he found in myanmar about 60 years ago, is there a way to determine if it is real? can i take a picture of it and send it to some lab , i am in India..please advise —Preceding unsigned comment added by 117.199.65.93 (talk) 09:29, 18 May 2011 (UTC)

I doubt if a picture would be enough, they would likely need to analyze a sample. With a picture they could only give you a guess. StuRat (talk) 09:43, 18 May 2011 (UTC)

Take it to a university or science museum that has an earth sciences department. Roger (talk) 10:32, 18 May 2011 (UTC)

From watching the "Meteorite Hunter" TV show, a strongly magnetic rock or one with a visible fusion crust are good candidates. But there are many different types of meteorite. Knowing exactly where it was found can be helpful to, as related meteorites are often found in a "scatter field" after the meteor explodes in mid-air. 75.41.110.200 (talk) 15:50, 18 May 2011 (UTC)

Economic Activites In China ..

Hi. What Are The Economic Activities In China Now ?184.163.238.18 (talk) 15:43, 18 May 2011 (UTC)

Hi. China is the world's largest country. And with few exception, you will find virtually any sector of economy being active there. Please make more specific questions, and you will get more specific answers. --Soman (talk) 15:50, 18 May 2011 (UTC)

How Much More Specific Can I Get? What I Am Asking Is What Are The Economic Activities In China Now?. And Now Means IN 2011 .184.163.238.18 (talk) 15:57, 18 May 2011 (UTC)

Do You Want Me To Go More Specific?184.163.238.18 (talk) 15:58, 18 May 2011 (UTC)

China isn't the world largest country (Russia is bigger, and economically isn't the USA still ahead by every major measure?). That said our article Economy of the People's Republic of China will give you some information. Also note that China is referred to as 'the workshop of the world' these days what with it being a major manufacturing base for pretty much everything. In terms of what is 'hot' right now you'd probably be well judged to read some business newspapers 'Asia' sections to get a feel for what investors are seeing as growth industries/sectors. ny156uk (talk) 16:36, 18 May 2011 (UTC)

I think Soman was referring to population. --PalaceGuard008 (Talk) 01:50, 19 May 2011 (UTC)

Yes, you need to get much more specific. I don't think you want a literal list of every economic activity that takes place in China. Buying? Selling? Animal husbandry? Manufacturing? Wholesaling? Retailing? Importing? Exporting? Inventing? The list would be the same as anywhere else. Comet Tuttle (talk) 17:15, 18 May 2011 (UTC)

Surely there are international economic stats for the volume of industrial sectors in major countries? There are for the OECD. ILO would have employment by sector, perhaps. All sectors are present in China, but it is possible to work out the relative importance of textiles, engineering, transport etc. Itsmejudith (talk) 20:41, 18 May 2011 (UTC)

Deng Xiaoping Theory is a good read and may fill in some gaps for the OP. Schyler (one language) 20:44, 18 May 2011 (UTC)

Sounds like a homework question to me. I was surprised not to see the usual disclaimer. Kingsfold (Quack quack!) 12:03, 19 May 2011 (UTC)

Well, in brief: GDP - composition by sector: agriculture: 9.6%; industry: 46.8%; services: 43.6% (2010 est.). You may also find the Economy of China page helpful. Grandiose (me, talk, contribs) 14:51, 19 May 2011 (UTC)

From the production side, agriculture, fisheries, animal husbandry, forestry, mining, construction, utilities, manufacturing, transportation, storage, communications, wholesale and retail trade, finance, insurance, real estate, professional services, education, healthcare, social services, personal services and governmental services. From the demand side, private consumption, government consumption, capital investment, inventory adjustments, exports and imports. From the income accounts, wages, salaries and other income from labor, corporate profits, interest and other investment income. And, of course, government taxes and subsidies. DOR (HK) (talk) 08:14, 20 May 2011 (UTC)