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11/29/2015

A Review of a YouTube Review of Explore Scientific 12" Truss Tube Dob


    I watched this online review of the new Explore Scientific Truss Dob, 12"  So after watching that, I wanted to do a post here about it.  Okay, this is not going to be a review of Dakota Starry Nights review of his new 12" Explore Scientific Truss Tube dobs (see below). I am going to state upfront that I think that Dakota Starry Nights did an excellent job in his video review of his new scope.  What I am going to do is to review the scope itself based on what he discovers.  I will have to refer you to the video for some aspects of this scope since I do not own it, I will not be owning it so my review is limited.

     One thing I need to start doing upfront in my reviews and probably in my posts, is to state my objective for the review, or state up front my objectives for my observing etc.  So in keeping with that my objective today is to 1. offer insight into the build of the Explore Scientific 12" Truss Tube Dob; 2. Review the capability of this scope in lieu of price point, materials, quality of build and modifications required to make it work efficiently; 3. Begin a discussion of cost vs quality and what a manufacturer of a dobsonian telescope should provide for what they offer.  In other words should a scope be perfect for what price?

     So without any adieu, I want to post from YouTube Dakota Starry Night wonderful review of his 12" Explore Scientific Truss Tube Dob.



     I could spend the remainder of this entry going over the quality of the review that is put together here. I'm not because the objective of this review is not to review Dakota Starry Night review, but to use his review to answer some questions about this scope.

     So, one of the first things I saw in this is that the telescope arrives in one package that weighs 75lbs. More importantly, the box will tell you this is a 12" or 305mm f5 dobsonian telescope. Being f5 is significant. It is below f5 that I would say that a coma corrector is required to enhance the view and reduce coma from the mirror in the eyepiece.  So do you need a coma corrector with this scope? At f5 I would assume you could probably go either way with one, using one or not using one based on one's preference.  That is one thing I picked up right away. Edit: Actually for myself, I want to add that at f5 I would use my TeleVue Paracorr Type II in observing to eliminate coma from the mirror.

     The next thing pointed out is the truss poles.  They seem to follow a basic construction method used by mass produce dobs and that is a two pole to on bracket on the top design. The XX14i and XX14g from Orion have a similar design to their truss poles. It is nice that they are blackened to reduce any glare from ambient light. These brackets are efficient and work though when I owned a XX14i I found them fun to get attached at first. With time that wasn't a problem.

     Bearings I do  want to touch on.  The bearings look to be made of aluminum and to have a "fiberglass" strip that is glued down and then riveted on the end. I have to say that my two dobs from Dennis at Dobstuff have also had a tack at each end of the alt bearing holding the formica down.  I found absolutely no use for them so on the 14" I removed them and used contact cement to glue down the bearing and it has held find now for over 3 years.  I did the same on the 17.5", though on the 17.5" the material on the bearing was already glued down nicely, something I had provided to Dennis as a suggestion from the build on the 14".

     My first issue with the build of this scope has to do with the roughness of sanding or grinding on parts of the mirror box in the rocker.  I don't care if a dob is $700, $2000, $5000 or $10000 or more.  It should be delivered in a working and in excellent condition. Anything else is laziness on the part of the builder in my opinion.   The rough parts that occur and are shown at around 5:05 into the video are simply inexcusable in my opinion. Now, having said that, I am going to offer a counter argument to that. For less than a $1000 for a 12" dob you get a pretty functional dob here that yes, as we'll review, needs some mods, but nothing so bad that you can't do them and have a really nice functioning dob for less than a $1000.  If you want a scope or dob that is perfect, needing no modifications, then I would steer you to a Teeter or StarStructure or JP Ashcroft dob but your going to pay a very premium price for that. So not an objective so to speak, but at some point cost versus quality has to be a point that is raised here. Edit: I believe the counter argument is not valid but will leave it here.

     The next point that I did not like in the review is the notion that the back plate is made of aluminum, while the sides are made out of steel. Furthermore, there is rust that is showing either underneath the paint through the paint.  Rust is not something that a purchaser of this dob needs to be worrying about.  This is seen around the 5:25 mark in the video review.  Explore Scientific needs to replace the steel with aluminum asap and keep them that way.  They need to make Dakota Starry Nights dob right by replacing the rusted parts.  It's one thing to make a mistake, but the notion of personal responsibility is something that individuals, small companies and large companies need to remember in this reviewers opinion. The latches on the upper lid are also of poor quality and would require replacement by a part that would be more lasting in my opinion. Either a bolt of some sort or latch mechanism that would be more secure.

     The lack of a center spot on the primary mirror is something I am actually glad to see. It is something that I believe an amateur in the hobby needs to learn how to do.  Having said that, a template should be offered by Explore Scientific to help those not so mechanically inclined amateurs to spot this.  However, as I stated, this is something beneficial for a newbie to learn how to do, and if they are uncomfortable to get someone locally in the amateur community or from their club to help them do this.  I LOVED Dakota Starry Night use of a dry erase marker to make his spot, and then his easy removal of that mark after the spot was applied. I would highly recommend replacing the donut here with a Catseye Collimation triangle or hot spot.  You'll find later with collimation that it will work better if you do that.

     The shavings in the rocker box are something to be aware of, and to clean out as you don't want them getting on your mirror.  The apple board or bead board used on the bottom for azimuth motions seem to be very similar to what many ATMers and other manufacturers of dobs use for controlling their azimuth motions. Since the azimuth motions are not an issue in this review, I can only assume that Explore Scientific got this part right.

     The upper cage and spider seem to work well.  The focuser is a base two speed focuser, one that I had on my XX14i and it worked nicely.  The secondary cell is interesting and I'll be interested to see how it holds collimaiton over the long term. I don't anticipate an issue with it, it is different than the traditional secondary's I have used including a Bob's Knobs or something similar to them. One thing, it will easy to reach around and collimate the secondary.  In terms of collimation, I am not sure I like the long pole to collimate the primary mirror. Actually, I don't like that method. There is the advantage of never having to move to the back of the scope and turning the primary mirror dobs, It is probably a good thing for someone new to the hobby, and who will be content with this scope being their primary scope for sometime. Those who may want to move up in aperture in time, needs to know that is not how other dobs are collimated and you'll have to learn a new method moving forward. A Howie Glatter Laser and TuBlug eliminates the need for a long handle like this though.

      I find it very interesting that in this mass produced dob, it is the altitude that has issues and not azimuth motions. Typically in a mass produced dob, and for that matter in most dobs, if there is an issue with motions it is in the azimuth motions.  Not with this dob. Dakota Starry Night has to make some decent modifications to get his altitude motions working smoothly and to square the bearings on the rockers of the base. I also think that I would have cut some of the teflon away from the bearing as too much teflon can increase friction as well, causing some stickiness.  On my two dobstuff dobs, I cut back the altitude teflon pads on the 14" and a little less on the altitude pads on the 17.5 to get the smoothness in altitude that I like on my scope.  This is something I would do on this Explore Scientific Truss Dob.   I do like Dakota Starry Night's additional felt pad to help his altitude motion as it goes low or up to zenith.  It is evident that Dakota Starry Night is comfortable modifying his telescope for himself and what he feels it should be.

     One of the things pointed out in the review is the ability to move the placement of the focuser and the red dot finder and the ability to move their location. In a traditional dob. you can set up the focuser and finder on either the left or right side of the dob. In this dob you can place the focuser to where it is centered straight up. If you watch the video this gives you a better neck position in using the eyepiece.  Focuser placement is a preference that each observer has to determine for themselves. I observe with my focuser on the right side as I am left eye dominant. That means I pull the scope to me, and not push it away from me. It means for me that I am sometimes taking a step backwards as I move the scope. Sketching, is where I find pulling toward me sometimes an issue as I have to dismount my chair, move it, remount it, and make sure I still have the object in the finder. Then again, I am usually sitting five to five and a half feet above the ground when I am sketching. My point, focuser placement is a personal decision.  Dakota Starry Night shows where he likes his, and how to make adjustments. If you purchase this scope it will be up to you to do the same.

     So what is my view of this scope based on Dakota Starry Night's video review? I am really into the saying in the hobby that "everything, and I mean EVERYTHING, is a compromise."  The Explore Scientific Truss Dob 12" is a great example of this. The aperture is a good size at 12".  12 inches on a primary mirror in a dob will give a lifetime of viewing.  In the review we do not know the quality of the primary mirror as no star test was offered by Dakota Starry Night nor was their the opportunity to test the mirror using a variety of traditional methods.  A star test would have helped to confirm how good the quality the primary mirror is, at least providing a guide until a more traditional method could be done. My guess on the primary is that it is a good mirror, not excellent or suburb, but good.  It will provide good views and for most of the time, unless your use it, you would never tell the difference between this mirror and a premium mirror's performance on most observing nights.

     The materials of Explore Scientific Truss Dob 12" is mixed.  The aluminium parts seem okay, with the bearings working.  Adjusting the materials to make the altitude motions acceptable is perhaps the biggest challenge I took away from the video review. If you purchase this scope, be prepared to deal with that as I find that in most mass dobs, companies don't listen to their customers and the same issues continue to exist. I would assume this will be true since Explore Scientific did not respond to Dakota Starry Night's input to them.

      The use of steel on the sides of the rocker is discouraging. Rust is evident and that means it will have to be dwelt with if one is going to use this dob for a long period of time. There are answers out there, perhaps using a drill and a metal sander to take out the rust and then reinforcing the metal with other newer parts welded in.  It could simply be sanding out the rust and applying a cure that stops the rust and painting over it. I do like the baffling and the dark color means ambient light will not be an issue.

      In terms of thermal management, this scope has two behind the mirror fans. This should help to to cool the mirror, but I would like to see a fan on the side blowing across the top of the mirror sideways to break up any heat currents radiating there.  This should be an easy modification to make with this scope, but it will take some planning and design to execute it effectively.  That would go a long way to helping to eliminate any thermal management issues. This may not be needed and probably won't be pursued by most owners of this scope, but a boundary layer fan would improve viewing.

   I haven't used the scope but this is what I would rate it for what was shared in the video:

Ease of Use:  5/5
Collimation: 3/5 (the long lever I am not sure of but that could change)
Materials: 3/5 (You are going to have to make modifications to make this scope work; watch for the rust)
Cost: 5/5
Baffling: 4/5
Primary Mirror: ?/5
Secondary Astingmatism: ?/5
Azimuth Motions: 5/5
Altitude Motions: 2/5
Build Quality: 3/5
Overall:  Around  3.5/5  (rust issue has to be resolved, quality of primary would help, fix the altitude motions are needed to get to a 4.5/5).  It would equal I imagine about what I felt my XX14i was, a solid 4/5.

Remember, I DO NOT own this scope nor have I used it.  I am basing this on what I saw from the video.  Gary Seronik on his website LINK states the following that I think pertains to this scope (and most scopes).

No telescope is perfect — every instrument has its shortcomings, some of which are simply part of the design, while others arise from how the design is implemented. But there’s a difference between “perfect” and “useful.” Although we should do what we can to make sure our scopes are running well, don’t get so obsessed with absolute perfection that you never take the time to enjoy the wonders that even an imperfect scope can show you.

 I have to reiterate what Gary Seronik says here, NO TELESCOPE IS PERFECT.  Like I said, they are a compromise.  Some issues are a result of the design. Some are from how the design is implemented. I know in my two Dobstuff dobs, I love the simplicity and easy of cooling that the telescopes offer. I have had to make my own adjustments, make my own improvements to get motions, and function where I want them.  Those are things I made a conscious decision when I purchased the scopes, knowing I would have to make improvements and changes to make the scope my own.  This Explore Scientific 12" scope is no different. It is not perfect (I have never seen a perfect scope, EVER) but it is useful.  Primary mirror quality would help to satisfy if this is a good mirror, a poor mirror or a suburb mirror.  I do believe for the cost, this telescope will deliver quality views of the universe, enough so that it will keep most people busy for their entire amateur career.  Again, if you USE this scope on a regular basis, it will show you more, teach you more about observing than a JP Ashcroft that sits in your garage except for six to eight times a year.

I would like to thank Dakota Starry Night for his tremendous and wonderful review. Perhaps one day I will be given the opportunity to use an Explore Scientific Truss Dob 12" or 16" and can give a more in depth review. I enjoy Explore Scientific as a company, and I enjoy their products.  I hope this scope becomes the winner that their other equipment has been for many looking for useful astronomical products of high quality.


     So finally, the quote by Gary Seronik raises a question. Do you need a premium telescope to observe? What are the differences or trade offs?  There are always compromises.  The 18" Teeter may seem perfect, until you have to lift it, keep the finish up because your in the field all the time with it, and you have to make some adjustments to make it fit your own observing style.  That 32" Webster may seem perfect too until the same things come into pass, including having to get a new vehicle to carry it to a dark site.  Or you find that you don't have the time in the backyard to wheel it out or load it up to the dark site. The mere thought of transporting the scope makes you cringe about even going and you make other plans for that night.  I could go on and on about this.  I did in one post where I basically said what matters is not your telescope, but how often you use it.  Again, no scope, NO scope is perfect.  Perhaps I should say no scope is perfect for anyone. I believe a scope is a work in progress, that grows with you as you grow as an observer. As a tool, you will make changes and adaptations to it.  That is natural.  The question comes down to what scope are you going to use.

     Since I believe that no scope is perfect, and I believe that every scope has compromises, the question comes down to what do I want? Most amateurs probably have a 2 to 5 year lifespan in the hobby. Is it worth spending $3000, $4000, $5000, $6000, $7000 or more for a top tier telescope?  Are those in the best interest of every amateur. Of course not. Each of us in the hobby when we buy a telescope have to determine what we want out of that tool, what compromises we are wiling to make, what we are not willing to compromise on.  As no scope is perfect, the key comes down to is this scope useful for what I want to use it for for the cost I can afford?  If it is, and it is a useful scope, the most important thing is to get looking upward and enjoy the night sky and what your scope can and will show you.  We need less competition among equipment and more about using what we have to really enjoy those wonders above us.

     So my final conclusion is this. This scope has the promise to be a good scope, capable of really showing the wonders of the night sky above.  There are some materials (steel) that need to be replaced by Explore Scientific to stop rust from coming in.  The altitude motions need to be resolved.  If you fix those two items, add some baffling and perhaps a fan for thermal management on the side, this would be a scope that will deliver.  The price is right, there are modifications needed and I would like to see the steel replaced as a material.  Other than that, this scope, which is not perfect, but useful and can be made very useful as Dakota Starry Nights shows, can be a very useful scope. The question comes down to whether you as the user want to make the adjustments and modifications needed to make this a good to very good scope? Do you have the skills and materials you'll need? Those are some of the hard questions you need to ask yourself.


   

     

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