Buying a budget telescope

Buying a telescope for under £100, what to look out for

Children often ask me about astronomy from their back garden. There is plenty to see even with a starter telescope, although the amount of light pollution can dramatically effect deep sky targets such as galaxies and nebula.

As a keen astronomer for many years I always like to try out the latest offerings. When I started out in the 1970’s the choice was either make your own or spend a large sum of money buying a telescope. Thankfully the new era of modern telescopes allows access to some great entry level instruments for a very small outlay. Three such telescopes are Celestrons Firstscope (£49.99), Travelscope 70 (£59.99) and AstroMaster 70 AZ (£89.00). Below I will give a brief overview of what you can expect for your money.

Before getting down to specifics, there are a few things worth knowing when buying your first telescope. Firstly, do not be attracted by entry level telescope advertising very high magnifications. This is a red herring and may lead to disappointment. To explain briefly, it is the eyepiece that magnifies the image, but the size and quality of the mirror or lens that limits the maximum ‘useable’ magnification. A rough guide is to multiply the size of the optics in mm by 2, to give you maximum useful magnification. For example a 60mm telescope will be good up to around x120 or so, after which the view will only become fainter and less clear.

On an average night in the UK magnifications of 200+ are not often used due the turbulence in the atmosphere. So, if you see a 60mm telescope advertised as having 400x magnification, don’t expect to use it a 400x and have satisfactory views. At this high magnification objects also move across the eyepiece very fast and would be very difficult for a beginner to track (without a motorised mount).

Also, when viewing the planets it is always best to view them when they are at their closest to the earth. A look through the current month of any astronomy magazine will tell you which planets are best placed, or of course an internet search will also provide this information. Finding your way around the sky is also of key importance, either a good star chart or free software such as ‘Stellarium’ are very useful.

One word of warning – Never look directly at the sun, especially through a telescope or binoculars as this can cause permanent damage or blindness. Also, avoid ‘sun filters’ that screw into the eyepiece – these can be very dangerous.

Below is a brief summary of 3 telescopes for under £100. I have kept this short to provide some basic information – please feel free to contact me if you would like more details. Other telescopes are available at this price range, and this is meant as a guide for what you can expect from different types of telescope. Binoculars are also an option when starting out. They are easier to use and great for star clusters, although don’t offer the same views of the moon and planets as a telescope.

Celestron Firstscope

This compact telescope packs a punch, is easy to use and very portable. The straight forward dobsonian design is easy for beginners, and enables you to set up on your garden table in seconds.
I have personally tried out all types of telescopes and spent a very enjoyable night testing this one out. There are 2 eyepieces provided, giving x15 and x75 magnification. The highest practical magnification is around x160, should you wish to purchase another eyepiece at a later date.
The Moon has enough detail with craters, rilles, mares etc to keep you occupied for hours. Jupiter’s bands and 4 main moons were visible using the higher magnification available (x75). Although I did not get the chance to view Saturn, it’s rings would be visible at the highest magnification, when the planet is well placed. The lower magnification is ideal for star clusters, such as the Pleiades, or finding the brighter galaxies such as the Andromeda galaxy (which is around 2 million light years away!). This a great way to dip your toe without a large outlay, and have many nights of fun. Also, be realistic in your expectations – no backyard telescope will give views of a Hubble space telescope photograph!

Celestron 70mm Travelscope

The Celestron 70mm Travel Scope is a good low cost unit intended for daytime viewing and casual astronomical observation. The package is light and compact, primarily designed for travel. All components can be stored in the backpack, which has enough room for accessories.
For those keen on the outdoors this telescope is easily carried around and quickly set up for wildlife spotting. With magnifications of x10 and x40 it also good for stargazing in the evening, particularly craters on the Moon and star clusters such as the Pleiades.
The telescope comes with a light weight tripod, so doesn’t need a table top and can be set up anywhere. I like to use this one to demonstrate to the public when we are at shows.

Celestron Astromaster 70AZ

With a sturdy tripod and longer focal length the Astromaster 70AZ offers the highest power of our 3 entry level telescopes, giving x45 and x90 magnification.
The 70mm aperture, long focal-ratio and coated optics provide pleasing views of Jupiter and some of it’s moons. Saturn with it’s rings is easily identifiable and the lunar surface will show a wealth of detail.

With all 3 of these telescopes, a number of the brighter deep-sky targets are also within reach including the Orion nebula, M13 Globular cluster in Hercules and the beautiful double-star Albireo

I hope that this brief introduction has helped. Keep an on our blog for similar tests on binoculars and an introduction to practical astronomy.

Below is an approximation as seen at x40 and x90 magnifications.

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The American Eclipse report

The American eclipse turned out to be all it was hyped to be. I first started planning my trip 2 years ago, being a little worried that local accommodation would sell out fairly quickly along the path of totality. The safest option was to book with a tour company, who opted for a location around 20 miles North of Idaho falls to view the eclipse. Whilst it would not be the longest eclipse duration (around 20 seconds shorter than the 2 min 40 sec maximum), it had one of the best probabilities of clear skies.

We set off from Idaho Falls just before 6am, expecting traffic jams, but the roads were clear so arrived well in advance at 6.30am. Along the journey we had a great view of the ‘Belt of Venus’.  This is where the pink scattered light of the sunrise (or sunset) sits above a dark belt caused from the shadow of the Earth.

Of course we all had our protective eclipse glasses so that we could look at the Sun during the early stages when the Sun is partially eclipsed. By 10:20am there was clearly a small ‘bite’ taken from the Sun’s disc by the Moon. There was a real party atmosphere for the event as totality slowly drew nearer. One of the presenter’s from ‘The Sky at Night’ programme had set up his imaging equipment nearby, while others used a tea strainer to project the partial phases onto white paper.

By 11:15 most of the Sun’s disc was covered and the light had taken on an unusual hue as the sky slowly darkened and the temperature began to drop. When we could see that only a tiny slither of Sun was visible through our protective glasses we knew that totality was about to occur and we would soon be able to look directly. The Moon’s shadow raced across the ground and darkened all around us, with the temperature falling at least 10 degrees. Venus was visible overhead and the few birds that were around started to sing.

Just as the Sun was about to disappear I look up to see the ‘diamond ring’, a bright flash of light on the limb of the Moon. The diamond ring soon vanished and we were in totality. There were gasps as the Moon appeared to be a dark disc surrounded by a silver ring. The Sun’s corona could be seen flailing out from behind the Moon, this is the outer atmosphere that is not normally visible. There were some prominences also visible, hot streams of gas larger than the Earth coming off the Sun’s surface. The pink from the Sun’s chromosphere (upper atmosphere) was not so evident as the 2015 eclipse, but still there. All too quickly the second diamond ring appeared with a flash marking the end of totality and our prompt to put protective glasses back on.

There was still the partial phases to see after totality, but this tends to be the least viewed part of the eclipse as people are still iawe struck by totality.  Once the Moon had moved away from the Sun the crowds dispersed, as did my companions and me, ending this show of astronomy’s most spectacular occurrence. Now it’s a wait until July 2019 and the next eclipse in Chile!

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The American Eclipse

We are lucky that by pure chance the Sun is both approximately 400 times larger and 400 times further away than the Moon. This means that whenever the Moon passes in front of the Sun from our view point we have one of the most incredible sights in nature known as a total solar eclipse. The Moon’s orbit is inclined by around 5 degrees to the Earth’s orbit around the Sun, resulting in a total eclipse once every 18 months or so. If the Moon’s orbit were on the exact plane as the Earth’s orbit around the Sun then the moon would cover the Sun every new moon and we would have an eclipse once a month.


You may have seen on the news recently that there is a total eclipse of the Sun this month that will sweep across the USA from the West coast to the East. It will actually begin over the Pacific Ocean before passing over the coast of Oregon and across the USA. The map below shows the path of the total eclipse and the amount of partial eclipse visible across the USA. You can see the band of the shadow moves across the country, where the eclipse will be visible at different times.  At locations North or South of the path of totality there will be a partial eclipse, where not all of the Sun is covered by the Moon. The further away from the path of totality the less of the Sun will be covered.

The American eclipse 2017


A slight partial eclipse, where the moon only cover a small section of the sun, will be visible in the UK. Please DO NOT LOOK DIRECTLY AT THE SUN AS IT WILL DAMAGE YOUR EYES. LOOKING DIRECTLY THROUGH BINOCULARS OR A TELESCOPE IS LIKELY TO CAUSE BLINDNESS.  If you don’t have specialist equipment you can project the sun  – the Society for Popular Astronomy has a solar observing guide

If you do happen to be in the USA on the 21st August, then you may be lucky enough to catch sight of this amazing spectacle. Should you decide to try and see the partial eclipse in the UK them make sure you read the guide to observing the sun, do not risk your eyesight with direct vision.

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Mobile planetarium films

We have added a page to our website listing all of our available mobile planetarium films.  Whilst we do currently incorporate some of them into existing school shows, such as ‘Earth and Beyond’ or ‘Journey into Outer Space, there are also a number available either as a stand alone film or a specially tailored show just for your school.

Please have a look at our full dome films and let us know if you would like to see any of the films not currently used in our standard shows or would like us to create a bespoke presentation around one of the films.

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Useful astronomical websites

As an active astronomer there are a few websites that I use often.  If you are interested in stargazing, then the following may be of use to you. There are many other websites available, so you may find others that you prefer. The ones below are a few to start with that off free information and,  are sites that I use regularly. I will continue to add useful links to this blog.


Stellarium –

The first is actually free software that you can download onto your PC/tablet or smart phone. Most amateur astronomers that I know use it as a tool for finding their way around the night sky and finding interesting solar system bodies or deep sky objects. If you want to know the exact position of the planets for a particular night, or hunt down a comet, asteroid or galaxy then this software is ideal.


Heavens above –

Heavens above is a very handy website for checking out all sorts of astronomical data. You can find predictions for satellites passing over your location (and the ISS) and their brightness. You can also look up asteroids and comets that are currently visible, and importantly how bright they are for that night (comets and asteroids vary in brightness so you will want to catch them at their brightest to stand the best chance of spotting them)


Aurora Service –

If you are lucky enough to live in an area with very little light pollution then this may be useful. It is possible to see the Northern lights in the UK, although generally the further North you live the more chance you have of seeing them. The website gives an estimated short term forecast and has map which indicates how far South the aurora is likely to be seen. I have seen the lights when camping in Kielder, Northumberland, but they have been spotted in the South of England to.


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Perseids meteor shower

The Perseids meteor shower is now underway. It will peak in mid August (evening  12th/morning 13th), so there is plenty of time to look out for them when the skies are clear. The shower will actually be active now until the 26th August.

The Perseids  shower is caused when the Earth passes through the path of Comet Swift Tuttle, which has left a dusty trail. The dust left by the comet burns up in the Earth’s atmosphere giving us a meteor shower.  Comet Swift Tuttle last passed by the Earth in 1992, and is due again in 2126.

The Perseids get their name from the constellation of Perseus, which is the part of the sky where the meteors appear to originate from. You can find online star charts, such as this one to identify where Perseus is in the sky.  The darker your sky, ie less light pollution, the more meteors you will see.  At it’s peak the Perseids shower can average over 100 meteors per hour. You will need to be wrapped up warm and  sitting comfortably (deck chairs are good so you don’t get a stiff neck!)  to observe meteors. There is no need for any optical aid such as binoculars – just your eyes will do! If you get a chance to observe them (especially at their peak), why not count how many you can see in an hour?

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Common astronomy misconceptions

School visits bring a lot of great questions from children. From the behaviour of fire in zero gravity to the theory of black holes (both have been asked). There are also a few common misconceptions that are brought up. With it being school holidays we are in our quiet period now, but it seems a good idea to give some of the regular misconceptions a mention on here as they arise. Here are a few from recent visits that have been quoted.

‘The Moon has a dark side’.  You may well here the phrase ‘dark side of the moon’ (or Pink Floyd album!), but there is no permanent dark side – only a side that we can never see from the Earth. Every part of the Moon receives 2 weeks of daylight and 2 weeks of night, but we can only ever see the Earth facing side. During a new moon the side we cannot see is in full sunlight and during a full moon the side we cannot see is in darkness.

‘There is no gravity on the ISS’. This is a half truth. The Earth’s gravity is actually around 89% the strength on the ISS as it is on the ground. The reason that astronauts float is because the ISS is in constant free full, but moving so fast that it never crashes to Earth. The exact same effect can be had on a parabolic flight where an aircraft descends at an angle of 42 degrees, causing weightlessness for the period of the dive. Professor Stephen Hawking took one in 2007.



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Stargazing Live 2017


Don’t forget Stargazing Live is back on tonight 8pm BBC – broadcast from Siding Spring Observatory, Australia this time.  It continues Wednesday and Thursday this week. There are also a number of related events going on around the UK.  More details on the BBC Stargazing Live website;



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8 shows in one day at Minet School!

We visited Minet School near Heathrow yesterday, as the children are learning all about the planets.  What better way to see the planets up close than in a 360 degree mobile planetarium?

As there were so many pupils eager to experience the immersive dome we scheduled 8 viewings of the ‘Great Planet Adventures’, having  30 minutes available per slot.  This allowed around 200 children (not to mention quite a few teachers!) to see our show in one day.



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Space Tourism

ujyzKIxfXWU                  space-tourism

You may have heard the exciting news that Spacex is set to take 2 people to the Moon next year on a privately funded trip.  Others have expressed an interest and there may well be more announced in the near future. Of course you will need tens of millions of pounds if you were thinking of going, and still have to undergo strict physical health checks and training.

The plan is to use the same launch pad as the Apollo missions, the last one being some 45 years ago. The individuals will then be on a course to circumnavigate the Moon. Their ultimate goal is to take space tourism to Mars – perhaps some of the children in your school will be the first to go Mars, or be the engineers, computer programmers or communications specialists needed to work on space exploration.

Private individuals have already paid to visit the International Space Station, and a number of spaceport  sites have already been proposed for development in the UK. It seems that space tourism is really moving forward.

Of  course we can’t all afford to take a trip to the moon, but you can take a virtual tour through the Solar System with one of our Alpha Dome shows. Who knows, perhaps a visit from us will help to inspire some future careers in the space tourism industry?


You can read more on the Spacex website here

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