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Small computerised Telescopes Are They Worth The Money?

July 14th 2002

Telescopes come in all shapes and sizes and for the beginner or lapsed astronomer such as myself one of the most talked about scopes of recent years is the computerised scope. Why have these things taken off? Simple! The promise of instant gratification. Simply punch in a few numbers into the control panel of these things and Ba-da-bing! The galaxy or planet of your choice appears!

Well there is a wee bit more to it than that, but that's the basic idea anyway. One of the most common scopes of this type is the Meade ETX shown below, the one that if you will, captured the public imagination. One of the draws of this sort of scope as well as the computerised malarkey is the optical design - Maksutov or Mak for short. Until recently this type of scope was the preserve of those with money to burn (and some to spend as well). One the best known and prized scopes of the Mak variety is still made by Questar USA, but with not much change from 3 or 4 grand for a 3.5" scope and no computerisation I decided to give that a miss.

Pictured below beside the ETX is one of the other popular beginners scopes a Dobsonian or "dob" reflector so called because of the type of mount. Highly regarded as simple and cheap to buy  for the size of the aperture, but also has the drawback that it isn't driven i.e. when you look at objects in the night sky at higher magnifications they will drift out of the field of view.

Also, as it is not driven it will patently not find any thing automatically for you. So what you say, but here is the point of the computerised scope, even if you don't know where an object is. the scope once set-up will find it for you! Further down I set out my choice for choosing a computerised scope over non computerised - a manual effort like the dob or usual mounting like alt/az or equatorial.

 

EAAS member examines 6" Dob scope to the right of that Meade 90 ETX with 35mm camera piggybacked on top.

 

Computerised Scope (MAK) v Manual Scope (i.e. refractor/ reflector) inc. thoughts on scope types

Feature

Computerised

 

Manual

 

 

Pros

Cons

Pros

Cons

Costs/ Features

 

Good value if you decide to use all the features, if you are the sort of person who likes the idea of features but can’t be bothered to set them up( like your home video) stick to conventional scope

Generally high 500+ 

Meade ETX around 600

Celestron Nexstar4 -599

 Vixen around 550 

Celestron 60mm refractor with computer 299 but too small to be much use

Generally much cheaper for a 4” scope capable of same resolution – good  refractor from about 275+

Feature set limited, cannot auto find objects.

Ease of Use

 

Simple if you follow the instructions

Can be frustrating if you get  a glitch or the instructions are not clear

What you see is what you get with alt/az, dob mount, but no tracking capability

Eq mount can work great but is tricky to set-up and setting circles are useless for finding objects unless really well made(expensive)

Variety of uses

 

Terrestrial & Astro use as image is right way up

 

Same for refractors

Mainly astro use for reflectors

Also non Mak scopes more cumbersome due to extra size

Portability

 

Small Mak very portable

Needs careful handling

Small refractors also portable but often need mount which is bulky

Dob scopes tend to be large and unwieldy in comparison

Expansion

 

 

Some scopes allow computer upgrades i.e. to track new comets

Some don’t! But rarely needed after all the stars don’t change too much

n/a

In some instances computer control can be added on but this tends to more expensive than picking a computer controlled scope from the start

Logging observing sessions

 

Can be logged to external computer with extension cable (and computer of course)

Use pen and paper unless you have all the bits indicated to the left.

Simple to do – use pen and paper

Laborious to do- use pen and paper!

Ease of tracking objects

 

Auto tracking once set-up choice of tracking types i.e. solar, lunar, sidereal etc. 5 minute job.

None that I have encountered

Eq mount tracking good once set-up but not easy to get set-up for beginners

If you move the scope, slow to get set-up again

Imaging capability

 

About the same

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About the same

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So it's not hard to guess which sort I decided to go for - computerised, my personal choice, but one many interested in Astronomy are also making today.

Why is this? Well the key attraction is being able to see more things and having a scope which is good quality at the same time. My particular choice was the Celestron Nexstar 4,  the more usual choice in this sector is the Meade 90mm ETX In particular these aspects appealed:

 

Having made my choice how do I find this scope. Well apart from not having used it for about 2 months due to the appalling weather in Ireland, it has been all I hoped for and more. Apart from early teething troubles which were to do with not putting the date into the scope in US format it has worked very well.

The set-up procedure is pretty simple and common to any computer scope, it allows the scope to find and keep it's bearings, basically you:

Also a feature I like about the N4 is it's compact dimensions, although I now have a tripod, I often take the scope out the back yard for a quick look at the moon or planets without bothering to set-up as below:

n4.jpg (40268 bytes)

The best part of owning this scope is finding stuff which you were never able to see before. Ah, all the real astronomers out there say but there is no substitute for finding things by knowing you way about. True to an extent but suppose it's a half cloudy night and all the guide stars you need to find the faint objects aren't about - well the real astronomers are stuck. As long as I can find 2 bright guide stars and my scope is aligned it will find anything in its catalogue of 4000 objects built-in. As as a result I have went out and seen great sights on what otherwise could be described as a mediocre night for star gazing.

Also, the optical quality of the 4" Mak is pretty good. Things are sharp and well defined. Of course unless you have a substantial size aperture you are not going to get really detailed views of things like Galaxies but there is still a really long list of things to see which draw a wow from you now and again. I have even seen faint stuff in moments of good seeing which I have never been able to see

But the stock in trade for the N4 and similar computerised scopes is finding and seeing really nice but not always easy to locate gems, the obvious stuff Moon, Saturn Jupiter, Venus Mars all look well but really outstanding are things like the Orion Nebula, Owl nebula, nice double stars and clusters M13 and some more obscure ones.  See below a sample shot of the Moon I took with a Canon s20 digital camera held to the eyepiece:

 

In short a strong recommendation for small computerised scopes in general and the Celestron N4 in particular. They may cost more but you will see more, and with the weather as it is in July 2002, you need to make the best of your time out under the stars

 

David Mullan

Webmaster

EAAS

 

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