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Choosing Your Telescope

Celestron hve put together this great guide to Telescope basics, and choosing the correct telescope that suits your needs -

 

http://www.celestron.com/media/444702/howtobuyyourfirsttel.pdf

 

 

 

Christmas Presents

Here is some help in choosing a telescope as a present for someone.

It will of course totally depend on the person you are buying for, whether its a passing phase, or long term hobby etc

This is just a quick guide, we do recommend reading on down below, to gather a little more information for yourself.

 

If its for someone under 5 or 6, we reckon a 60mm tripod mounted scope like this -

http://www.ktectelescopes.ie/Skywatcher-Mercury-607-Refractor-Telescope.html

Or a tabletop scope like these -

http://www.ktectelescopes.ie/Skywatcher-Heritage-76-Mini-Dobsonian-Telescope.html

http://www.ktectelescopes.ie/Skywatcher-Heritage-100P-Dobsonian-Telescope.html

 

If its for someone over 5 or so and under 14 or so, we recommend the following as a minimum - a bigger scope would be better as they will be unlikely to want to upgrade too soon.

 

http://www.ktectelescopes.ie/christmas-bundle-celestron-astromaster-70az-plus-accessory-kit.html

 

http://www.ktectelescopes.ie/christmas-bundle-skywatcher-70mm-telescope-book-torch.html

 

 

 

If its for someone over the age of 14/15 up to an adult (partner/husband/wife/sibling) then we think the minimum should be a 90mm refractor, like this -

http://www.ktectelescopes.ie/christmas-bundle-skywatcher-90mm-telescope-book-torch.html

 

http://www.ktectelescopes.ie/christmas-bundle-celestron-astromaster-90az-plus-accessory-kit.html

 

 

However, with adults, especially one that will remain in the hobby, it is best to get the biggest you can afford. Our most popular larger scope is this one, an 8" (200mm) Dobsonian -

http://www.ktectelescopes.ie/Skywatcher-Skyliner-200P-Parabolic-Dobsonian-Telescope.html

 

 

Hopefully this quick guide will help you choose, and if you need any further advice, drop us an email or a call -

http://www.ktectelescopes.ie/Contact-Us-5.html

 

 

How to choose your telescope

Please take the time to read this page if you are unsure what type of instrument best suits your requirements and budget.

 

An important consideration is the size and weight of the particular telescope you want. You always want to be safely able to manage it on your own. Also, its no use having a scope parked in the corner because its a chore to lift it and assemble it out in the garden!

 

***The best scope is the scope you use the most***

 

So first thing to figure out is exactly what you want from your scope.

 

Advice

Please remember you are welcome to call us seven days a week or email us with any questions. If you are thinking of buying a telescope, either for yourself or a budding astronomer in the household,  then read on!

Whether you have a large or a small budget, its important  that you choose a telescope that meets your needs and initial abilities successfully.

 

 

 

Aperture

Aperture is the first thing to think about. This is the size of the primary lens or mirror, typically 60mm up to 400mm. Larger apertures can pick up fainter objects, so always buy the biggest aperture that suits your needs, and your pocket!

 

On a typical clear night, away from city lights, the unaided or naked-eye can see stars down to magnitude 5 to 6. The table below details roughly what the limiting magnitude a given telescope will pick up. This does however depend on the observers eye, the type of telescope and the steadiness of the atmosphere, but it is a good general indication.

 

            Aperture Magnitude Limit
2.3"     (60mm)        10.7
2.7"         (70mm)        10.9
3.5"     (90mm)        11.7
4"     (100mm)      12.1
6"     (150mm)      12.9
8"     (200mm)       13.3
10"     (250mm)       13.8
12.5"       (320mm) 14.2 

 

 

 

Budget

Budget is the next thing to consider. Everybody's budget is different. Many beginners or younger astronomers do just fine with a small 60mm to 90mm refractor on manually controlled equatorial or alt-az mount, or on a goto mount, and indeed these instruments make a fine introduction to astronomy. Other, more experienced astronomers wont settle for anything less than a 12-16" telescope on a wifi enabled tracking mount!

 

 

Our most popular scopes for younger astronomers are the Skywatcher Heritage 76, the Celestron Astromaster LT70AZ and the Skywatcher Heritage Flextube 130P Dobsonians.

 

http://www.ktectelescopes.ie/Skywatcher-Heritage-76-Mini-Dobsonian-Telescope.html

http://www.ktectelescopes.ie/Celestron-AstroMaster-LT-70AZ.html

http://www.ktectelescopes.ie/Skywatcher-Heritage-130P-FlexTube-Dobsonian-Telescope.html

 

 

Our most popular scopes for older beginners are the Celestron Nexstar 8SE, the Skywatcher Skyliner 200P Dobsonian, the Celestron Nexstar Evolution 6, Skywatcher Explorer 130P

http://www.ktectelescopes.ie/Celestron-NexStar-8SE.html

http://www.ktectelescopes.ie/Skywatcher-Skyliner-200P-Parabolic-Dobsonian-Telescope.html

http://www.ktectelescopes.ie/Celestron-NexStar-Evolution-6.html

http://www.ktectelescopes.ie/Skywatcher-Explorer-130P.html

 

 

2 popular ranges are the Celestron Nexstar SLT Goto range, and the Skywatcher Synscan AZ Goto Range of scopes.

 

http://www.ktectelescopes.ie/Telescopes/Celestron/NexStar-SLT-LCM-Series/

http://www.ktectelescopes.ie/Telescopes/Skywatcher-Telescopes/Skywatcher-SynScan-AZ-Goto-Telescopes/

 

 

Do bear in mind that typically the more you pay the better the optics or accessories are with each telescope. Here at Ktec Telescopes we only supply products that we would use ourselves, that are good value and that give good results.

Remember that it is often better to test the waters with an inexpensive telescope, but sometimes if the interest has been there a while, and its not just a passing phase, it can be better to stretch the budget initially.

 

Focus tubes

Focus tubes are where you put your eyepiece or other accessory. Almost all telescopes come with either a 1.25" (31.7mm) or a 2" (50.8mm) focus tube. The 2" ones can use an adapter so the 1.25" accessories will fit it. All telescopes and accessories sold at Ktec Telescopes Ltd are supplied in either of these 2 sizes. This ensures that your purchases from us are not rendered obsolete as your ambitions in astronomy grow.

 

 

Eyepieces

Eyepieces come in 1.25" or 2" barrels for focus tubes.

They come in sizes from 2mm up to 50mm and beyond. The smaller the focal length, the higher the magnification, so a 5mm eyepiece magnifies twice as much as a 10mm.

The higher the magnification you use, the smaller the field of view in the eyepiece.

The magnification of an eyepiece can be worked out by dividing the focal length of the telescope by the focal length of the eyepiece.

So, longer focal length telescopes will magnify an object more than a short focal length telescope when used with the same eyepiece.

Typically, higher magnifications work better for planetary and lunar work, and the lower magnifications are better suited to star clusters, galaxies, nebulae etc.

 

Eyepieces can be found here - http://www.ktectelescopes.ie/Eyepieces/

 

 

Refractor Telescopes are the ones most people are familiar with, these are usually available in apertures from 60mm to 152mm. High cost is usually why they are rarely seen larger than this. Achromatic refractors are the entry level here, but they can suffer slightly from chromatic aberration (false colour, and purple fringing), particularly on brighter objects.

Apochromatic designs have, to a large degree minimized this but prices are usually a good bit higher for these as they have 2, 3 or more lenses built into them.

Refractors are relatively maintenance free. Both design of refractor can come on either an equatorial mount (manual or with tracking motors)or on a goto mount, as detailed in 'mounts' below. Skywatcher have a good range of refractors -

 

http://www.ktectelescopes.ie/Telescopes/Skywatcher-Telescopes/Skywatcher-Refractor-Telescopes/

 

 

 

Reflector Telescopes are where the real value comes in for those who want to see fainter objects. They range in size from 75mm to more than 400mm!. They use mirrors, which are cheaper to produce in larger sizes than lenses. Some maintenance of the optics is required in that the mirrors often need to be aligned or 'collimated'. A Cheshire Collimator or a Laser Collimator is best for this. Reflectors are mounted either on manual Dobsonian mounts, equatorial mounts (manually, tracking or goto), or on Alt-Az goto mounts, as detailed in 'mounts' below. Again, Skywatcher reflectors are very  popular -

 

http://www.ktectelescopes.ie/Telescopes/Skywatcher-Telescopes/Skywatcher-Reflector-Telescopes/

 

http://www.ktectelescopes.ie/Skywatcher-Dobsonian-Telescopes/

 

http://www.ktectelescopes.ie/Explore-Scientific-Ultra-Light-Dobsonian/

 

 

Catadioptric Telescopes feature the best of both worlds, combining big apertures with short tube sizes usually with goto capability. They are usually 90mm to 350mm. Very little maintenance is required for these scopes.

Catadioptric scopes commonly seen are Schmidt Cassegrains, Maksutov Cassegrains and Ritchey Chretiens all of which have very good optics and are better corrected than a standard reflector. Relatively high cost compared to a dobsonian mounted reflector is the only downside to these scopes.

Typically thay have longer focal lengths than equivalent  size reflectors and are slightly more suited to planetary and lunar observing. They will also usually have a narrower field of view in any given eyepiece compared to a similar sized reflector. Celestron have a few hugely popular ranges of Schmidt-Cassegrains

 

http://www.ktectelescopes.ie/Telescopes/Celestron/NexStar-SE/

 

http://www.ktectelescopes.ie/Telescopes/Celestron/NexStar-Evolution-Series/

 

http://www.ktectelescopes.ie/Telescopes/Celestron/CPC-Series/

 

 

Skywatcher also have a good range of Catadioptrics -

 

http://www.ktectelescopes.ie/Telescopes/Skywatcher-Telescopes/Skywatcher-Maksutov-Cassegrain-Telescopes/

 

http://www.ktectelescopes.ie/Telescopes/Skywatcher-PRO-Series/Skywatcher-PRO-Series-Maksutov-Cassegrain-Telescopes/

 

 



Mounts & Tripods
Telescopes come on a few different types of mounts. First is the simple alt-azimuth mount, which allows movement up/down and left/right, and the scope can be locked on target. They come
either manually controlled or goto.

 

Dobsonian telescopes are mounted in a wooden rocker box which also allows up/down and left/right movement, and are a simple, light and manageable way to point large reflectors at the sky. Manual dobsonians are some of the largest and cheapest telescopes available. Goto control is available also. Our range of dobsonians are linked below -

 

http://www.ktectelescopes.ie/Telescopes/Skywatcher-Telescopes/Skywatcher-Dobsonian-Telescopes/

 

http://www.ktectelescopes.ie/Explore-Scientific-Ultra-Light-Dobsonian/

 

 

 

 

Equatorial mounts, often used for astrophotography, are more complex than an alt-azimuth mount, and require a little bit of setting up as it needs to be aligned with the North Star, Polaris. These can be manual or driven with drives, and may or may not have a goto capability. Our most popular Equatorial mount is the Skywatcher HEQ5 PRO Synscan, which will last you along long time. These mounts can be viewed in the link below -

 

http://www.ktectelescopes.ie/Mounts/

 



Goto mounts are available in all 3 formats- Alt-Az, Equatorial and Dobsonian.

 

They have huge databases of objects to goto, and are ideal for beginners or those with less time on their hands for finding objects.

 

 

 

If you need any additional advice, send us an email, to sales@ktectelescopes.ie , detailing your requirements, budget, age, where you plan on using the scope and any other details and we will do our best to advise you.