David’s Astronomy Pages


Web site created & designed by David Mottershead.

Copyright © David Mottershead


Home Stars Scopes & Families Gallery Reviews Links

The Helios Explorer 200mm Reflecting Telescope

What can you really expect from a budget telescope? The write up provided by the UK distributor of the Helios scopes promised ‘breathtaking views of night sky objects’ and ‘the Explorer 200 truly is an awesome package for the discerning enthusiast’. It certainly had an impressive specification, including a 200mm diffraction limited parabolic primary mirror, built in polar alignment scope, multi coated 10 & 20mm Plossl lenses, 2x Barlow lens and a 9x50 finderscope. The whole package was mounted on an EQ3-2 Deluxe equatorial mount and aluminium tripod, (please note that I bought my Helios scope about four years ago and the EQ3-2 was then the top of the range mount. All Helios Explorer 200s now ship with the EQ5 mount. For around £500(UK) what more could a keen astronomer want? However, tempting though the glossy adverts and the price were, I searched the internet for reviews of the scope and spoke to a couple of reputable astronomical telescope retailers for their views before making my final decision. The reviews, or those very few that I could find, and the feedback from the retailers was all positive. Apparently Helios enjoyed a good reputation for the quality of its products. So, in cheerful anticipation, I placed my order and sat back to await my new telescopes arrival.


The Explorer 200 arrived three days later in two large, heavy duty boxes. One box contained the optical tube assembly, the other the tripod, equatorial head and other accessories. After being used to the 60mm Tasco and the 114mm Knous scopes, the sheer size and weight of these two packages made me gasp. On opening both boxes I was pleasantly surprised at the care that had gone into the transport packaging.


Before removing the contents of the boxes I located the check list and assembly instructions. As with the Tasco scope both were clear and concise. Also included was a book on how to use the scope, including information on polar alignment. Everything that should be there was, and all items were undamaged thanks to the way the scope had been packaged and shipped.


Using the supplied tool kit, (all scopes appear to come with a basic tool kit to facilitate assembly), I set up the tripod and equatorial head unit. The head unit is more or less fully assembled out of the box. Only the polar scope, the counter weights and the slow motion control handles needed attaching. This took me about 20 minutes or so. Once assembled the tube cradle rings were attached to the head unit and the optical tube was located into these and secured. Finally the finderscope was attached to the tube and the accessory tray attached to the tripod. Total initial set up time, including checking everything was present and undamaged was about 50 minutes. So far so good. Then I realised I had a problem. Oh, nothing to do with the scope but the weather. Clouds had moved in leaving me staring frustratedly at the night sky. This state of affairs – not uncommon in England – continued for the next four nights until finally the weather broke and I was able to take the scope outside for a full test and observing session.


The first thing that was apparent was that although I could physically lift the entire telescope and tripod it would be a struggle to carry it out as a complete unit. However, all I needed to do was remove the tube, carry out the tripod and head unit as one, reattach the tube, and rebalance it. As this only took a few minutes it would prove no problem on future observing sessions. I left the scope to cool down for about an hour—if you do not allow a telescope to cool down, or equalise, to the outside temperature then air currents can affect the performance and views through the scope. At last all was ready. Choosing a bright star I carried out a star test, (see the Tasco Refractor Review for details on star testing). The collimation was excellent and the image displayed no signs of pinching or other optical defects. Satisfied with the star test I turned my attention to the thin crescent moon. The moon is a bright object that shows up well in any size of instrument but with the light gathering capabilities of the Helios, the level of detail was, in comparison to my other telescopes, phenomenal. What has to be remembered is that the 200mm scope has approximately 177% more light gathering power than the 120mm Skywatcher and a mind blowing 1000% more than the 60mm Tasco! The more light a lens or mirror gathers, the more detail can be resolved. This is not the same as magnification as an object magnified 25x will appear similar in all of the scopes—simply the detail revealed will be better in the larger scope. The detail and overall ‘sharpness’ of the view was superb. Craters showed more and finer detail than I had previuosly seen through either the Tasco or the Konus’scopes. In fact, so bright and sharp were the views that I had to use a moon filter to reduce the glare! I spent the next hour happily scanning the moons surface.Finally I turned my attention to Jupiter.  Starting on low power magnifications I observed Jupiters main cloud belts and some of it’s moons as they orbited the gas giant. To see just how good the optics on the Helios were I gradually increased magnification. One point that I need to make is that the atmospheric conditions—commonly refered to as ’seeing’ - will afect the quality of the view, and  restrict the amount of magnification that can usefully be used on a given night. That said, at a magnification of 200x the Helios rewarded me with a stunning vista of the main cloud belts and some of the smaller, less disernable cloud systems. Although on the first night out I did not see the great red spot, on other evenings I was able to clearly see it. Again, on lower magnifications, around 100x, the detail revealed was excellent. Saturn was the next target and this time my mouth really did drop open! The divisions in the rings were easily visible and structure was clearly seen in the cloud system on the planet — although not as sharply or in such detail as Jupiters. But the thing that really stood out was that Saturn was revealed as having faint yellowish colour. In my other ’scopes I had not been aware of any colour; Saturn appearing as a white disc, with shades of grey in the ring system. Because of the light grasp of the Helios, I could now make out the subtle shading of the planet. Most of the pictures currently in the gallery were taken through the Helios Explorer, which gives an indication of what you see at the eyepiece—the only proviso there being that I have some way to go in getting really decent pictures!  All in all my first expeirence with the Helios confirmed everything the brochures had promised.


On subsequent nights I turned my attention to nebula, clusters and the brighter galaxies. Again, the Explorer 200 lived up to its reputation. With a 40mm LER lens the Pleiades were pin sharp, and due to the low power and good field of view  a large proportion of this cluster was visible through the lens. The usual suspects were lined up—the Orion nebula, Andromeda galaxy, the Whirpool galaxy and so forth. The results were excellent, in particular M51, the Whirlpool galaxy. Although the 114mm Konus had been able, on nights of good seeing, to show a fuzzy patch with a brightish central nucleus, the Explorer was able to show some of the spiral structure. The Orion nebula, again a good sight through virtually any instrument, was far better defined and revealed more detail than I had previously seen. What I had thought to be difficult doubles were easily split.  In short, the telescope proved itself to be the equal of its advertising—no small task!


The construction of the unit was just as good. The optical tube is a single piece of metal, rolled and welded along the join. The matt black interior surface absorbs any reflections or stray light and so contributes to overall quality of the image at the lens. The main 200mm mirror is securely mounted in a substantial cradle; which in turn is very firmly fastened to the optical tube body. The secondary mirror is contained in a robust unit, attached to tube by a four vane spider. As an aside, the current crop of Explorer 200s have much thinner 0.5mm vanes on the spider, helping to reduce the diffraction spike effect which is common to all Newtonian telescopes. Both the main and secondary mirrors are fully adjustable to allow correct columation to be achieved. The focuser accepts standard 1.25 inch lens and accessories  and is threaded to take a camera T ring for direct SLR use—in other words you can attach your camera to the focuser, (using the appropriate T ring), and take pictures directly through the telescope; this is known as prime focus photography. In operation the focusers rack and pinion was smooth and reasonably precise. Occasionally, when using higher magnifications, it could be tricky achieving good focus, but with practise it became easier. The supplied 10 and 20mm Plossl lenses were of reasonable quality and performed well with the ’scope. One especially useful and welcome item was the 9x50 finderscope. The extra capabilities of this finderscope over, say, a more standard 6x30 were immediately apparent when hunting for particular objects in the night sky. Every manufacturer should include a 9x50 with an a ’scope of this size! The tripod and head unit were well made and gave a stable, solid platform for a nights observing. If you inadvertently knocked the tripod it would damp down; that is, stop shaking within 2 or 3 seconds. If I have any criticism of this telescope, (and I am really nit picking here!),I would have to say that the polar scope is awkward to use and not easy to set up. The supplied lenses are standard plossls; adequate, giving reasonable images, but much better ’after market’ lenses are available, and  would enhance the views obtained. Beyond that I really cannot fault this ’scope. Ok, I’m just an amateur astronomer—and one that is still learning—but having used the Explorer for over three years my honest opinion is that it represents exceptional value for money; has a well deserved reputation for quality, and lives up to the advertisers hype. In my view, if you want a large aperture telescope which is a good all round performer, comes with a good level of equipment and won’t break the bank, then this is the one to buy! Purchase the optional motor drive as well—essential for long exposure photography—and you will have a package that will see you through a lifetime of serious observing.

Please note, that the Helios range of telescopes are no longer available, having been replaced by the Skywatcher range - which are essentially exactly the same scopes.