Astronomy on a budget

Refracting telescope at home

Refracting telescope at home

Home astronomy on a budget

You were always interested in watching the Moon and the stars. You used mobile apps and those crazy compact camera zooms to come closer to the Moon. Then you check the recommended telescopes, and discover that this is a pricey hobby. Or, is it?

Assumptions

This article is directed to people that never used a telescope before, and are simply interested in the subject. I am assuming that the reader used phone cameras or compact cameras before. I also will assume that you do not own a DSLR camera or ultrazoom cameras, those are expensive.

I will attempt to address multiple groups of readers here. Overall in this blog, I plan to divide the readers by their currencies into four groups: the Americans with US dollars ($ or USD), the Eurozone Europeans with the euro (€ or EUR), the Brittons with pound sterling (£ with GBP), and finally, the Poles with złoty (zł or PLN).

Please note that all data is valid as of today, and any exchange rates (if applicable) are based just on Google search.

Budget range

Let’s go straight to the point and talk about money. Within the groups that I mentioned, I would prepare a budget as follows:

Your locationStarting budget
United States$100
Eurozone€90
United Kingdom£60
Poland300 zł

Those come from searches for a sample telescope Celestron Travelscope 70mm that I will be writing about in all those individual regions, mostly from Amazon (.com, .de, .co.uk). You will notice that at the time of writing, there seem to be very affordable offers on Amazon.co.uk! You might need to count in shipping, and in case of the U.S., which does not have VAT, tax.

Expectations

Here is what all of us end consumers love – there is great value for money to be received in terms of telescopes. Obviously, expensive ones give lots of extras, otherwise no one would want them, and so they wouldn’t be expensive! But chance is that you’re a city dweller and just want some space magnificence in your sight, and with lower range telescopes you will discover that you receive extra features that expensive telescopes rapidly lose with increase of their light-gathering abilities.

First of all, the difference between even a cheap telescope and mobile photo or compact camera photo is… astronomical.

Notice the immediate difference. The second setup costs more (312 EUR/370 USD), but most of you have phones already – and, likely, much better ones than I had back in 2018 when I took those two pictures.

You will notice several differences right away. First of all, you’re not looking at a digital picture when you use a telescope. You use your own eyes and a set of magnifying lenses. This vastly increases the satisfaction. Instead of looking at a picture like many others online, taken by the Hubble space telescope, or land observatories, or other astronomers, and of course fake pictures, here you see things as they are, using no sensor but your own human eyes.

Second of all, the quality is just better, as you can see above!

Third of all, you receive several extras. Telescope image quality is depending on many factors, of which the top ones are blunt old size, lens setup and quality, and electronic support. If you go deep with all three, and have a DSLR camera, you can take stunning pictures, but at the same time, you are bleeding important features, which is why many advanced astronomers decide to keep budget telescopes.

Telescope quality is just a trade of features

Let me walk you through the individual features, why they matter, and what do you gain with their decrease as you keep to strict budget, an aspect not many talk about.

  1. Size. Telescopes are buckets for light. The larger the aperture (which is defined differently than in photography, here it’s the diameter of main lens), the higher the light-gathering abilities, and therefore you see more stars and beyond a point, you can start taking pictures of nebulae and galaxies.
    1. Pro: if you go big with this, you start seeing nebulae and galaxies.
    2. Con: rapidly increased weight and bulk. I heard an opinion that semi-professional astronomers use their professional telescopes 1 time out of 10, and smaller ones more often due to bulk. Remember, to see nebulae and galaxies, you need a real dark sky. This means you need to traverse with your device a lot. And you need to store it. Finally, with naked eye you will not see anything fun in deep sky, the play is to combine with DSLR and tracking mounts, the three devices combined will cost you the value of a car, depend on where you are!
  2. Lens setup and quality. First of all, not all telescopes have lenses. You have three groups: refractors (lenses), reflectors (mirrors), catadioptrics (lenses and mirrors). Refractors use lenses and are low maintenance and good quality, but size matters to quality, and grinding a large lens results in astronomical price of the device, so beyond a point, you only see reflectors. Catadioptrics use too complex a system which darkens the picture, and tend to have absurd high focal lengths, which makes them perfect for watching planets and maybe the Moon, and pretty much nothing else.
    1. Pro: triplets (apochromatic telescopes) and more complex reflector/catadioptric designs (like Ritchey-Chrétien design) provide supreme image qualities, free of aberrations. They are perfect to use in tandem with a DSLR for astrophotography.
    2. Con: you really don’t need to sell your car and home for very good astro pictures and watching, and this is often how much high quality telescopes cost!
  3. Electronic support. Those mean usually two things: a tracking mount, and star finder. Tracking mount follows the movement of the sky when you take long exposure pictures, or otherwise the sheer rotation of the earth will blur everything on the picture. And the star finder automatically points at selected star or planet.
    1. Pro: as described above, prevents star trailing, and saves time and frustration finding objects.
    2. Con: very expensive, and usually very bulky.

A telescope is a delicate balance of features. At low end, you lose the light gathering capability and see more aberrations, but you gain mobility and a powerful daytime spotting scope at just the right magnification.

The conclusion is, go for a lower-end refractor telescope (lens one). Those give additional features:

  1. Low-end refractors tend to be very powerful daytime spotting scopes. You lose that ability with professional telescopes! Most reflectors give you an upside down picture, catadioptrics have extreme zoom which goes beyond the point of usefulness, and apochromatics are simply way too costly for what you get. A lower end refractor weighs about 1.5 kg (3 lbs) with a tripod to it, so you can carry it wherever you want.
  2. Ease of use and low maintenance.
  3. Ability to expand with widely-available lenses and accessories, which aren’t expensive.

Important point: don’t buy “toy” telescopes, from toy shops.

Astronomy vs photography

I will be writing more on that in another article. Here one might just ask: high quality camera lenses with 400 mm focal length are mighty expensive – they can well exceed $700 or €600 – how can a device fraction of the cost have any good optics?

The question is valid, because virtually all camera lenses are refractors – with a tiny exception of those strange ‘mirror lenses’ which are in essence miniaturised catadioptric telescopes. But the answer is still no, it is possible, because a telescope is a much simpler construction, and that is necessitated by their purpose: in a camera lens, you will find an entire array of lenses and moving parts that help steer the shutter blades. A telescope will always lack them, because each lens absorbs a portion of light, and decreases the light gathering ability. That is also why telescopes are much lighter.

This is, of course, an oversimplification, but one which is true in entirety when comparing camera lenses to low-end achromatic refractors.

What if you already have a DSLR and basic lenses?

Depends what you have. Goods news is that even old and lowest-end DSLR cameras in general should be able to take very satisfying images, and also using low-end and old camera lenses, as long as they are not damaged.

The picture below I took with a Canon 77D – a pricey DSLR – but with the lowest budget camera lens, Sigma 70-300 mm f/4-5.6 DG Macro. This will not allow you to go into deep astrophotography, as you need a large aperture and a tracking mount for it. But solar system objects imaging is kinda possible, especially with the Moon.

Moon photography
The Moon shot with a Sigma 70-300 mm f/4-5.6 DG Macro and Canon 77D.

Remember that for proper planetary imaging you need a very powerful magnification. At 300 mm and equipment above I was unable to distinguish Saturn’s rings. Using just the telescope and my eyes, I was unable to see them at 400 mm. That 400 mm telescope with 20 mm eye piece gave me a 20x magnification factor. Using 40x I still did not see Saturn’s rings. At 80x I was finally able to see them, barely, almost pressing my eye into the device.

Conclusion

It’s all in the ‘wow’ effect. If you never used a telescope and wonder if that ‘wow’ effect is achievable at high cost, the answer, good news, is yes – a low budget telescope might not show you the Andromeda galaxy in the middle of the city, but it will present the Moon and closest planets to you in a spectacular way. Weight and size are vastly increased, which increases mobility and motivates to actually go out and use the telescope. Finally, you receive a big bonus, a powerful daytime spotting scope with the right image orientation and very easy maintenance.

When to upgrade? If you want to really observe the details of the Moon and planets, you should invest more, into a high magnification catadioptric telescope, such as Maksutov-Cassegrain 127 or 150, and if you plan to really go into astrophotography, then you need a heavy tripod, a high quality tracking mount, and a decent DSLR.

Final conclusion: you do not need to sell your kidneys to come noticeably closer to the skies!

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