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Review: Explore Scientific 16”, Europe edition, late 2016

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Explore Scientific 16”, Europe edition, late 2016


I have been considering buying or making a 16 incher for a while now. Mirrors only (if you wanted to make your own scope) cost at least 1200€ to 1400€ (Hubble optics or GSO, not counting import duties and shipping cost).

Likewise, I could find 16” starting in the upper 1800€ (imports from Poland in this case), but even that was hard to find. Most low cost scopes at 16” are in the 2200€.

So, when I learned that Explore Scientific had a European sales on their Ultra Light series, placing the 16” at 1698€, I jumped on it!

First, let me say that I love this scope. Having looked at a number of online reviews of the UL series, I can also say that Explore Scientific has improved things in the last couple of years (thanks).

The scope is relatively minimalist (which is what we want), it works, it is easy and fast to assemble and disassemble. The 2 boxes (rocker and mirror) can be carried by a normal adult without breaking his back. Convenient handles are located in/on the boxes to help you do so. I have no issues with the material quality.

I honestly, and surprisingly for a review,  do not have a lot to say about the scope itself, it works, and it works well, the optics seems OK (I am not an experienced enough astronomer to be a good judge). It is a great buy and I wholeheartedly recommend it.

This review will focus on 4 points: the main differences between this scope and other similar scopes, issues that seems to have existed in the past but were fixed (as seen in previous reviews), issues that are still there and, finally, things that I think Explore Scientific can do to improve the next generation.

Main differences between this scope and similar scopes


The first two differences that one will notice between this scope and other similar scopes are the eyepiece position and the collimation techniques.

The eyepiece is located, by default, horizontally, on the side, not at 30 or 45 like on most Dobson like scopes. Let me note that this positioning is the default positioning, but that the cage does have holes pre-drilled to change to a regular 45 degree position if that is what you prefer (Great thinking from Explore Scientific here)! So you are not forced to use the horizontal position. However, since the company did decide to propose that position, I decided to give it a try before switching. And I think that I will leave it as is. With the size of that scope, I find that the horizontal position is better as soon as you reach 45 degree or so (better position for me and my back at least), and allows me to go higher toward the zenith without having to get on my tippy toes (I am 1m70). Then there is an awkward position from 45 to 35 degree where you do not know if it is better to lean or to kneel (if you have the eyepiece in the “normal position”, you will have a similar weird spot, but a little bit lower). Lower than that, you have to get on your knees. Since the scope is so large, even aiming horizontally, the eyepiece is still high enough.

The collimation is of course performed on both primary and secondary. The secondary holder is of the so called “New style” with no center screw. The primary is collimated from the front which is something new to me. After a couple of collimation session, I am not super impressed by the collimation systems. The basic issue is jerkiness. You start turning a screw, things seems to go smoothly, but suddenly it moves by a much bigger step (probably something having to do with the springs catching and releasing on something). This is not a big issue as you just need to back off a little to reverse it, but I do have a beef against jerkiness (yes, the pun was intended).

The scope did come with a battery pack for the fans (a massive 8 D cell pack!) with a nice storing pouch! Thanks Explore Scientific! I assume that with so much power capacity, this pack will last a LONG time without having to change the batteries! Here again, I do have some improvement suggestions.

Despite the weird looking material that they chose for the bearings (altitude and azimuth), I find the movements very smooth and with a static friction equivalent to the dynamic friction. By this I mean that the force necessary to put the scope in motion is equivalent to the force necessary to continue the movement. This means that there is no “sudden start” or “jerk” that makes your overshoot your target when you do small movements. So it looks like they got it right. I do find that the movements are a little bit hard; by this I mean that, although the force that needs to be applied is constant and leads to smooth movements, quite a lot of force needs to be applied. This is, of course, particularly problematic at zenith (like for all Dobs). Now, this is a heavy scope (30kg or so for the OTA), and this might be a perfectly normal thing (my previous experience tops with 8” dobs). I can see at least one advantage here, there will not be any fiddling necessary when changing eyepiece!

The focuser is nice, smooth and precise. It is of course a 2/1.25” variety. In 2” mode, the eyepiece is held by 3 screws which provide a precise centering. However, I find the insertion of 2” and 1.25” eyepiece a little bit rough. You do not get that nice, smooth drop in of the eyepieces. My best guess is that this is due to a tight fit of the barrel associated with a lack of smooth beveling on the inside of the barrel that would guide eyepiece smoothly in place. In most scopes, this would be a problem as changing eyepiece would lead to a movement of the telescope and a lost of target. However, as stated elsewhere in this review, the telescope is hard enough to move that it does not happen. So, this is not a big issue…

The scope comes double packed in 2 large boxes inside of each other. This is great news as it provides enough play material to occupy the kids for a couple of hours while you unpack the scope and go for first sight!

Things that appear to have been fixed since previous reviews:


The mirror did come with a centered mark.

Various other reviews have noted rust points. I have seen any on my unit (I looked for them). There is still no desiccant in the package however.

The mirror box alignment system in the rocker box as been improved. No more metal on metal friction or anything like that. The centering is performed through the clever placement of the slightly oversized, and overhanging Teflon pads. No more felt, or break knob (as seen in older reviews). I do not know if the difference is due to the fact that they are not necessary on the 16 or because they have changed the system. Regardless, it works!

Things which are still a problem (in my opinion/experience at least):


There are still a large number of metal shavings running wild in the package, the boxes, in the tubes of the secondary cage. The mirror protection cover, when I opened the package, had a number of large aluminum flakes lying right there (see picture)! This really does not look professional and Explore Scientific should really add a vacuum stage in their manufacturing process! All parts should be shaken to make sure that there is no small shaving lying in them (and the shaving removed). When you first unpack your scope, use a rubber hose on your vacuum cleaner and vacuum everything, including the mirror box lid foam. Shake everything and clean everything. It takes 5 minutes top and is worth the time!

The screws on the Teflon pad of the altitude bearing were not fully screwed in, 3 out of 8 were protruding (very slightly) and hitting (or at least grazing) the bearing material. This is another easy and costless thing to fix in the manufacturing process (honestly, it is not hard to fix for the user, but it does not look good).

The 2 spring latches that close the mirror box were bent. This looks like a latch quality issue (spring too hard, metal to soft) or a latch placement issue. This is something that Explore Scientific can fix easily and at no cost… Please do it! Once again, it is not a big issue, just something that does not speak well for the build quality of the scope.


The red dot finder is just crap. Sorry to be so blunt, but mine at least, has so much play that t is useless (it rattles when you move it, not keeping its collimation). The 12€ unit that I have placed on my 8 inches dob is better. Now it might be that my unit is defective and that the normal ones are ok. Do not judge on a sample of one. However on the good side of things, (and this is yet another good mark for ES, something that shows that they do think about all cases), if you remove said viewfinder base, you will notice that they have placed 2 sets of screw holes, for the 2 types (horizontal and longitudinal) types of viewfinder base fixation! Great thinking there.

My battery cell had a bad connection which made it not work! Nothing that 5 minutes with a soldering iron did not fix, but one more example of lack of quality testing/verification from ES L

Personally, I am not a fan of the yellow altitude wheels. They do not convey (in my opinion) the feeling of an expensive, high quality item. This is purely looks.

Suggested Improvement


Here is a list of suggested improvement for Explore Scientific (some could be created after the fact by customers) that would add practically nothing to the cost of the scope, be of great value add for the user, and make the scope and the company look more professional. Please understand that these are not flaws in the scope, but improvement suggestions.

The most important improvement in my opinion is a good mirror protection system for when the scope is being setup and when it is setup but not yet in use. Please do think about an easy mechanism that will allow one to protect said mirror in these conditions. The important point is that this lid must be useable when the scope is assembled, easy and fast to place/remove, preferably a system that stays attached to the scope. At minimum provide a hard plastic or light metal cover that rests on a couple of ledges on the side of the mirror box. The cost would be next to nothing and be a great improvement. You could also think about a 3 fold system hinged on the side of the box and held with a magnet. The advantage of such a system would be that it could stay in the box and never have to be removed…

The collimation tool is great, but what does one do with it after use (besides loose it in the grass, in the dark)? Since collimation is not held perfectly over a long series of moves (which is normal in a truss scope), it is expected that one will be using it a couple of times during the night. Therefore, it would be great to be able to store it with/around the scope. Possibilities include a snap system to attach it to one of the trusses, or (my favorite alternative) make the collimation tool collapsible (similar to tent poles, but rotation locked) so that it could be placed in the rocker box.

The altitude bearings are held by 3 screws… and “One of them is not like the others, one of them does not belong”… yep, you got it, 3 screws, 2 types. Same length, different diameter! Three screws to find and place in the dark. Could you please at least use the same screw types? Or replace the screw that goes on the lid (the different one) by a pin, latch or other mechanism? This would solve the screw problem and the altitude bearing wheel direction issue (the wheel are not symmetrical and you need to place them the right way, as described in the manual).

Talking about screws, 2 of mine had difficulties being screwed in the first time. The inserts’ threads were not very clean. This is nothing that 20 seconds with a tap could not fix (or a couple of screw/unscrew cycles), but once again, it does not look professional.

The focuser comes with a dust protection cap (one could question this choice in an open truss design???). Why not transform it in an old style collimation cap? Add a small centered hole and a contrasting sticker on the inside.

Provide a way to attach the battery pack to the mirror box. This could be anything from a large sticky Velcro pad glued next to the fans on which we could Velcro the battery pack, or a little S hook on the battery pouch with a matching hole in the mirror box to hang said battery pack to the box. Add an on/off witch to the battery pack. Once again, cost: minimal, gain in professionalism: huge,

The lead of the mirror box is held with a piano hinge, BUT when you open the lid 180 degree and leave it there (which you have to do to remove the content of the mirror box), you can see that the metal of the box bends due to the weight of the lid. This, once again does not convey a high quality image. Adding a simple metal retainer (rod or wire) to stop the lid from opening more that 110 degree or so would be another great and cheap improvement.

The 4 Teflon pads on which the altitude wheels move are wear parts, especially the parts guiding the mirror box. It would be nice to provide a spare set.

To attach the secondary cage to the top of the trusses, one has to hold the cage, the trusses and the screw (with your 3 hands), and insert the later through the two trusses and in the right hole in the cage; not always an easy feat. Although ample warnings are given in the manual about the trickiness of this process, it seems that it could be improved if ES switched thread inserts around and increased the diameter of the holes in the trusses so that they fit over the insert outside diameter. Doing so would leave the trusses and cage at least partially fixed thanks to the mechanical hold before having to insert the screw (which would only have to be aligned with one hole). This would make the assembly process easier, faster and less dangerous. Once again at extra manufacturing cost. Too bad that this is not something that the user can easily fix.

While talking about the cage, some of the parts (in this case the 4 truss holders) are not well aligned with the cage ring. This again is not a problem (and can be fixed easily by slightly untightening one of the 2 screws holding each offensive part), but once again show a lack of attention to detail.

The user manual makes numerous comments about luminous stickers and paint, and how great they are. We believe you! How about adding a sheet of such stickers (with 1-4 numbers for the trusses, arrows for the altitude wheels and dots for wandering parts (as in parts that have a tendency to go wander around) for example). Once again, minimal cost, great professionalism shown.

ES notes in the manual that the plastic foam “thing” that is in the mirror box should be kept for mirror protection and item storing. I agree, this is a great idea. Why not make it much better, more professional by making this hunk of plastic into a multi layer user tunable storage box that rides on top of the mirror protection. I am thinking about 2 or 3 layers of foam, Velcro attached, with removable separators so that the user can make layers of the height that he wants, and with holes of the size he needs. This would look great! Here is a good place to take lessons from IKEA! (To give you an idea of the size of the thing, the black pouch visible in the photo here holds 8 D cell batteries!)

The upper cage does not fit in the rocker box unless it is propped up. This is problematic as it makes storage of the scope when not in use harder. Can you please work on a system that would allow easy and secure storage for the cage? It could be latches on the rocker boxes, fold down ledges… anything that would allow storing of the cage when not in use and for transport. Do not forget to add a section in the user manual on storage (Of course, an alternative would be to keep all the packing material that the scope came with, but this means extra stuff to keep, and not loose).

A system for protecting the secondary during storage would be great.

A bag/pouch for storing the trusses and altitude bearings, a skirt for the scope would be great accessories. But this is nothing that my wife can't do in an hour with the sewing machineJ but it would be nice if the scope came with them. Once again, this is not expensive, fabric is cheap by the meter, especially in manufacturing quantity.

They are 2 M6 threaded holes on the rocker box. I used them to make a wheelbarrow system for my scope (I sourced the wheels from my daughter’s old bike, fancy, isn’t it?). It would be nice if a small plan was included in the user manual, or even better if you provided it directly with the scope. The parts would definitely fit in the huge shipping box. However, I do understand that this is much more expensive to implement that the other proposed improvement. It could be offered as an option. To make this work better, it would be good to provide a lock mechanism between the rocker and mirror box. If possible one at 90° and one at 45°.


Let us talk about the user manual that comes with the scope (in English and German in my case, despite buying from a French site, which is against the law, a manual in French should have been provided). Now, you do know that if a review start nit picking the user manual, it means that the reviewer is scrapping the bottom of the barrel to try to find things wrong with an item! In this case, I do find that the manual has some flaws. To get started, the whole assembly procedure could do with more and clearer pictures (keep some text, this is not an IKEA table). The scope is black, the manual is printed in black and white, please make sure that the pictures are clear and readable (or use drawings)! The general writing style of the manual is not very professional. It is clearly written by someone who likes astronomy and scopes, but is not a technical writer. Parts of the manual are impersonal and reflect a traditional writing style; others are very personal, written at the first person. I find it somewhat “amusing”, and would not mind if the whole manual was like that, but let us try to be consistent.
I would advise that someone sat down with a second time scope owner and watched him go through the process of “discovering” his scope using the manual to see all the small spots where the manual and user experience could be improved. The manual does contain some gems (such as the section in optics cleaning and how opticians give you crap lenses cleaning cloths as they have to gain from you scratching your glasses!) All in all, this manual would greatly benefits from someone spending a day or so of work on it. Another thing not talked about in the user manual is how to store the scope when not in use. A couple of paragraphs on this subject would be good.



If you want a 16”, and are not looking for high end, jump on this offer, it is way worth the money. I definitely do not regret purchasing mine!

Yes, the scope does have some room for improvement, but, apart maybe from the latches, there is pretty much no modification that are not doable by someone with two working hands (while waiting for the clouds to clear up). And even then none of these changes are must.


  • Jaimo!, okiestarman56, Procyon and 20 others like this


Thanks for the post.  I was wondering how the improvements worked out.  I know Explore USA was working on their own improvements, it sonds like some or all of them were incorporated into the European version. 

    • Augustus likes this

Thanks for the review.

That is a very nice review!  Cool looking telescope.  I like your modification to move it around.  I think I am going to steal that idea and use it for my Dob.  I do like the look of that Explore Scientific Dobsonian much better, looks like a Porsche compared to my Toyota.



    • Gene@CN likes this



"I like your modification to move it around"

I took 2 20*20mm, 1.5m long square metal tubes. I bent them using 2 trees side by side. 2 holes were made in both 'handles', one for the wheel, one for the axis (M6 screw on which I welded a wing for hand tightening).


I attached the strap on the back side using 2 self drilling screws on each side.


Next improvements are paint (blue with white spackles for the wheel, black for the handles) and rubber handles for holding. I am also planning to switch to hand screws for the wheels so that they can be separated from the handles.



    • Gene@CN likes this



i wanted to give an update here as I have received a number of messages regarding my experience looking through the eyepiece.


unfortunately, I have only been able to spend around 30 minutes actually looking through the scope due to awful weather over the last 3 weeks ( new scope curse). We have literally had rain, snow and hail here! The one clear night was after the snow fall, with 10cm of snow on the ground, so I did not take the scope out that day.


The only time I took it outside, the mirror probably did not have enough time to cool of before I gave up (freezing wind :( ).


i was able to look at the moon, it was 3/4 lit, and the craters in the terminator with my 4mm EP were quite crisp, follow at that high power (*450) was easy and not jerky.


When the clouds covered the moon, I turned to the Mizar Alcor pair and the 3 stars (with zeta) came in crisp and nice in my 20mm.


My aim that day was the cluster in Hercule, but I was not able to see it due to clouds.


I then gave up and waited for a clear night with temps above 5° but have not had one since :(


The visuals did look much better than my 200/1200, but that is normal! And since I do not have any other comparisons points, I can not really say anything on the optics quality, apart form stating that they look satisfactory (i.e., I am satisfied).




    • Gene@CN and Osiris like this

Excellent review. Thanks! I have just bought the 12" version of this scope and have found the same problems. The most annoying is the metal shards everywhere inside, even in the paper wrap of the secondary! My scope even came with a tiny scrath in the mirror. Obviously I am to complain to ES. This is definitely a good scope, but carelessly leaving metal shards in the packaging is unacceptable. ES: you can do better than this!

    • Gene@CN likes this



I used the scope yesterday to look at Neptune, Uranus, Andromeda and Orion's nebula...


They were all nice sights. I am able to easily go to *450, at which point right/left follow is still very correct.


However, vertical following is not nice as springiness in the base make it 'spring' back when you attempt to make a very small move. so, you have to overshoot and hope that it will spring back where needed.


Another issue that I found on the scope is the collimating system. The mirror is stabilized between 3 points on the edge. 2 bearings at the "bottom" and one felt pad at the top. However, this felt pad is static (does not move up/down when colimating). This leads to some frustrating 'stickiness'. The main solution is to only collimate using the 2 other points, but this is still frustrating.

Another issue (in my opinion) is that the mirror is not secured against falling forward. Ie, the mirror cell does not block the mirror from going 'up'.

Although it is unlikely to ever be a problem, the day where it becomes a problem, it will be a BIG problem (mirror going awol!).

Note that there is a strap at the back of the mirror, but it is way to loose to really stop the mirror from going away.



    • Gene@CN likes this



I was able to contact Explore scientific customer support and they immediately sent me a replacement viewfinder to replace the bad one that I had. Very good experience working with the French team.



    • Gene@CN and audioaficionado like this

Thoughtful, informative and very helpful in my decision making. Thank you!



    • Gene@CN likes this

I purchase the es16 dobsonian Truss It is a great scope there is two things I need to improve sometimes there's not enough in focus which I will deal with by purchasing and mounting a shorty focuser. And I need to be able to mount weights to compensate for the heavy eyepieces that I have I'll get that figured out in due course



i saw a brand new ul12 yesterday.


the good news is that they have made improvements such as better latches.


however, they are still a lot of things that need fixing!


hopefully within a couple of iterations, it will be perfect!



Thank you, your review has pretty much sold me on my aperture upgrade.


Glad to see they have made some improvements since your review posting.

Great review. One problem with many telescope vendors is that they do not take care of the piddling, small things that although small, are a major nuisance to the user. 

    • Waldemar likes this

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