By: Vlad Fedosov
Over the years I have had the privilege of owning many, many scopes(over 100 in my 20+ years in the hobby)! Even though I have owned a lot of different scopes of every design out there, somehow refractors have always had a special place in my heart. I have owned some very nice APO’s over the years including models from William Optics(80FL, FLT-110 TEC), TeleVue(TV-85, NP-101), Stellarvue(SV80S LOMO, SV4 LOMO, SV130EDT), Takahashi(FS-60, FS-128) but somehow I have always had a desire to try out a truly ultra-premium APO. I guess I just wanted to see what all the fuss is all about when you read on the internet astro forums regarding optics that are made to be about as perfect as possible. Would it be worth the ultra-high price? Well to scratch this itch I decided that I would buy an Astrophysics of TEC APO. These two brands of American made refractors are widely regarded as the best that money can buy. After some searching I pulled the trigger on a used TEC 140!
The TEC 140 is a 140mm(5.5”) APO that is made 100% in the state of Colorado by a team of gents that came from the former Soviet Union. The scope has a focal length of 980mm and weighs in at a very manageable 19lb. So what’s the verdict on the best optics that money can buy? Well, let’s dive in and find out!
Perhaps a good place to start is talking about the basic physical characteristics and features of the scope. Starting from the back, the scope is fitted with a top-of-the-line no compromise 3.5” Feathertouch(FT) focuser. This is about as nice of a focuser as money can buy for both photographic and visual use. I can’t say enough good things about FT focusers. They are very smooth and machined to an incredible prevision. The 3.5” model that TEC chose to use is nice as it allows you to use even monster accessories such as Explore Scientifics(ES) 3″ 30mm 100° field of view(FOV) eyepiece/diagonal(see review). The focuser is mated to the OTA with a collar that can be loosened so you are able to rotate it. This is very useful for astrophotography in regards to framing. It’s also nice for visual use as you can change the orientation of your diagonal though I often find that just loosening the thumbscrews and rotating the diagonal in the focuser is easier. The focuser does also includes a nice aluminum TEC 2” dust cap.
The tube itself is powder coated and not painted. Its also not a flat finish but has a bit of a texture to it. The color is an off white. I absolutely love the finish on the scope! If you are not familiar with the significance of powder coating let me fill you in. Powder coat is sprayed on like paint but then is effectively baked on to the surface for a much, much more durable finish. On a premium scope, I think it’s awesome that they do this as it will help to keep scuffs and scratches to a minimum. Also, the slight texture to the finish helps to hide any small scuffs you might put into the finish. Comparatively speaking something like a Takahashi(Tak) has some of the worst paint I have ever seen on a premium product. It’s a very thin coat of finish and is easily chipped/scratched. For all the fans out there I’m not nocking Taks, but the finish that they use is just not very good at all… Overall the tube of the TEC 140 is just very solid feeling.
Next up the tube is the retractable dew shield. I find that it is a perfect length and sliding it up and down the tube is fairly smooth. It does not have a set screw to help hold it. So far in my use of the scope, I have not had it slide down even when pointed at zenith. Lastly, we get to the dust cover. This thing is amazing! It is made out of aluminum with a pinch latch system to hold it in place. This, unfortunately, brings me to my least favorite thing about the TEC 140. This latch system is designed to snap into the lens cell with the dew shield 100% retracted. That works well for storage, but when you have the scope set up and want to simply have the lens cap on with the dew shield fully out it does stay on with the latch but very, very loosely and rattles around… I really think that this is not a very good design for real-world use.
Moving on to the mounting of the scope. You can, of course, use any appropriately sized mounting rings with the TEC 140. TEC does make their own rings and that is what came with my scope. These rings have a nice clasp lock system to secure the rings around the scope. From what I gather a lot of people really do like these rings because they are very easy and fast to remove and put on. I have mixed feelings about the clasp idea. I do like how easy it is to use but do find the typical thumb screw rings from other brands somewhat easied to use in regards to fine balancing the scope. I can set just the right amount of tension with the thumb rings to where I can move the scope up and down the rings but still have it securely heald. This is not really possible with TEC’s clasp system as its basically either all the way lose or fully tight. But the TEC rings are very high quality and do work will. My scope came outfitted with 2 TEC dovetails and while they are fairly short I have not had an issue with balancing the scope using them in my application. Mount wise any Atlas class mount or higher will work. I have even used the scope visually on an AVX and that works ok but not ideal. The G11 is a very good setup for this scope but not required visually(kind of overkill). Once setup cooldown time with the TEC 140 is fairly short since it does use an oil spaced triplet. I feel that on most nights 15-20 minutes is about all the cooldown that is required. It’s certainly longer than an 80-100mm APO.
Next up I want to talk about the finderscope that the TEC 140 comes with. It does not come with one! Not surprisingly as many high-end scopes do not include one. What is surprising to me is that TEC does not make one! What they offer are Baaders finders. They are nice finders from what I understand but they do not match the finish of the TEC! For such a premium product I find this a huge letdown. In my opinion, TEC needs to make a finder available that is the same powder coat finish as their scopes. I don’t even care if it uses Chinese optics. I just want it to ascetically match the scope. Now a few ways around this. You can, of course, use a black finder and I think that’s a nice look. I’m a red-dot kind of guy so that’s what I use and it works great for me.
Ok, so let’s move onto the meat of the review and talk about the optical performance! I have owned this scope for quite a bit at this point have used it on many nights both from my light-polluted back yard and from several dark sky sites. I’ll start off by talking about the low power performance of the scope and move on higher in power. My widest power setup eyepiece setup for the scope is about the widest money can buy: the ES 30mm 100° FOV 3” eyepiece. This setup produces a 3.06° true FOV at 33x. On the higher power range, I have used up to a 6mm Ortho with a 2.25x Barlow. This produces 367x. Naturally, I have also tried many other eyepieces from TeleVue, ES, and Baader in between these two extremes.
Optically what do I think about the scope overall before going into the details? Well, the optics are nice. They are quite nice! The image that the scope produces is high in contrast and is very sharp. Color correction is well executed. That is my brief description, now let’s get into the details and some examples. I will start by talking about the low power/wide FOV performance with my monster ES 100° 30mm. How does it perform with this setup? To sum it up, pretty much any object that I looked at from a dark sky site was one of the best and most memorable views that I have ever had of it!!! Even though it was only produced 33x I saw detail in objects that I would not figure possible! Maybe the skies made it so special, maybe the TEC 140 made it special, but the view was out of this world!
On the higher end of the power range when looking at the planets with seeing allowed I was easily able to use my higher power at 367x. Truth be told my local seeing is rarely that good and a more typical power for me is closer to 200x. I got the TEC 140 later in the planetary 2019 season so my observations of Jupiter and Saturn where kind of limited but the TEC did not disappoint. The views where secondary color free and high in contrast. In all honesty, the best views I had of Jupiter and Saturn did not come from the TEC 140 during 2019 as I did not own it at the time. It was with my(at the time) Stellarvue SV130EDT. I had one night where I was able to take the power up above 300x with that scope and the views were just jaw-dropping with detail. This does not mean that the TEC 140 is a lesser scope, but rather a good example that in a lot of cases the seeing has more to do with what can be seen then the quality of the optics.
The other type of object that I like to observe is double stars. This class of objects can also benefit from high power for closer pairs. The TEC 140 is a surgical instrument in splitting double stars. It is able to easily split close doubles right down to what seeing allows. In my neck of the woods seeing rarely gets good enough to see sub-arcsecond pairs. Color rendition of stars is very good! In fact, the TEC a40 and FS-128 have sowed me some of the most breathtaking color tones in stars.
To sum it up form my experience the TEC 140 has very good optics. Are they really that much better than a good sample Stellarvue or similar mid-range APO? In all honesty its not an earth-shattering difference. The contrast is very good with the TEC but my former Tak FS-128 had even better contrast. Sharpness is probably a hair higher with the TEC compared to my former APO’s. The secondary color is controlled quite well and I’m sure that most people would consider it to be non-existent. My eyes are very sensitive to blue light in general and I could tell that my SV4 LOMO did have a bit more of a secondary color-free image on really bright blue stars like Vega at high power(250x). I’m not much of an astrophotographer but below is an example of the only picture I have takes so far with the TEC 140. Nothing glamorous but it will give you an idea of the photographic color correction of the scope. It’s very good, but for someone that’s very picky you can pick out a little purple around the brightest stars when fully zoomed in on the original raw image. Indeed this is one reason that TEC went to the fluorite version of the scope.
In conclusion, is the TEC 140 really worth the relatively high price? Well, it depends. If you are after a largish APO and want to know that you have some of the best optics in the world, then YES! There is just something about using a scope and knowing that you are getting the maximum performance possible with that aperture. If on the other hand you are more budget-minded and do not need to have the shiniest car on the block, in all honesty, you are not giving up too much if you get a mid-range APO with a good sample of optics and a Feathertouch focuser. You can easily spend half the money(buying both used) and get like 95% of the performance if you get something like my former Stellarvue SV130EDT.
Having said that again there is something very special about the TEC 140 and that’s why it’s so popular. It just checks a lot of boxes. It is a relatively large aperture. It is small enough to ride on a mid-weight mount. It looks amazing. It provides amazing views. Its go the best focuser money can buy. Its simply one of the best overall telescope packages that a person can buy! If I had to live for the rest of my life with only one scope I would not hesitate for a second to choose the TEC 140. You can go from a 3° FOV one second on the Andromeda galaxy to viewing Jupiter at 400x the next second. It really does it all! The concluding thought that I will leave you with regarding premium APO’s is that you do need to remember that you are buying about as good of a 5.5”(in the case of the TEC 140) scope as possible. At the end of the day, there is no defying physics and it is just a 5.5” scope no matter how good that 5.5” is.