Some thoughts refractors versus reflectors By daniel mounsey

https://www.astromart.com/articles/article.asp?article_id=790

INTRODUCTION

I decided to put these two high-end telescopes head to head to share some insight that most observers and amateur telescope makers themselves are not even aware of. I seldom sell telescopes and keep most of the ones I acquire, so I have several different types of high-end models to choose from. Most of us know that no telescope is perfect, so having choices obviously makes things easier. So, why would anybody compare a 6" refractor to a 14.5" reflector? The main reason is because each design does something the other one can't do as well. Most observers are quick to adopt the idea that aperture rules, a very foolish statement. This cliché has been passed around forums quite carelessly with little or no regard to the issues that come with aperture. Aperture may rule in some cases, but it doesn't apply to everything in astronomy, and not every top quality telescope is flawless either.

NOTE: Most of the photos I've provided will follow at the end of the article and should be pretty self-explanatory.

REFRACTOR VS. REFLECTOR

These opinions are based on my own hands-on experiences of using both of these telescopes in the field. In my opinion, there are still too many observers who continue to compare these telescopes on the wrong targets. For resolving fine details in globular clusters, galaxies, planetary nebula, selected nebula and smaller open clusters, the 14.5" Starmaster wins hands down. Its greater resolving power simply allows it to excel in these areas of deep sky observation. It can also out-perform any refractor on multiple stars as well as the Moon and planets BUT not without some inherent issues that plague its contrast and sharpness in a major way and I'm not just talking about a boundary layer at the primary or heat currents from the ground. Here, the larger reflector will not appear to perform as consistently as the refractor no matter how good the optics. Some objects will appear to take on a more processed or noisier appearance, while the refractor, although dimmer makes every target appear completely unaltered and pinpoint with stunning contrast.
The refractor will more often than not, surpass the larger reflector on large, extended nebula, extended star clusters, star clouds, multiple stars, and produce wide field vistas of the Milky Way that a larger reflector would be completely unable to compete with. More often than not, larger refractors like the FS152 can also outperform a larger reflector on the Moon & planets more consistently in just about every manner for specific reasons we will discuss. A refractor, simply by its nature has unparalleled contrast that few reflectors could possibly match if their gremlins are not under control and getting them under control is a huge challenge in ways observers never imagined. The learning curve for a reflector is monumental compared to a refractor.

There's also something else that's extremely appealing about a large refractor like the FS152. I'm sure some of you will understand that you get the feeling like you're actually looking through a conventional looking telescope with a tripod, like something you saw in a textbook or classic sci-fi movie when you were a kid. That feeling is something that no dobsonian design can rival. When you are sitting down in a chair, relaxed, using a precision mount, you can really focus and concentrate on what you're viewing. I'm sure many of you could share countless experiences and opinions regarding the attributes of each design but these are just a few to consider.

SO HOW DO YOU KNOW WHAT TELESCOPE YOU SHOULD HAVE?

The simple answer is not to look for absolution in any one telescope, as you will most likely never find it. Just collect as many different telescopes as you can afford, so you can make the choice that best suits your desires at the time. If you don't have enough money, then you will have to learn what questions to ask yourself in order to make the best choice to suit you.

STARMASTER 14.5" HYBRID

Starmaster telescopes are arguably some of the finest dobsonians in the industry. Rick Singmaster is a stickler for optical quality in fact he is quite adamant about making sure his scopes are good before letting them out the door. Part of what has made this easier is Carl Zambuto, who is arguably one of the finest and most consistent mirror makers in the industry in my opinion. This combination of dedication is a wonderful mix. The Starmaster Hybrid is a really fast F-4.3 reflector. Telescopes of this nature will usually benefit from a coma corrector to increase contrast around the outer visual periphery. This will allow stars to appear as points, nearly all the way across the field of view, with minor side effects on axis except for the most demanding purists.
This particular model has goto and uses the latest XP4 Sky Commander DSC for its deep sky navigating and can be updated at any time. The goto drive is practically silent and exclusive to Starmaster. In order to move the telescope manually with your hands for star hopping, you must first make sure both the altitude and azimuth clutches are disengaged. As long as the telescope has been aligned to two stars, the computer will not lose memory on where it's pointing in the sky during this procedure. The clutches can later be reengaged at any time without the need for realignment. The hand paddle has several features which are nice for fast slewing or fine centering of objects. It's pretty nice to have a dobsonian of this aperture with features like this when you realize it tracks as well. You also do most of your observations without any ladders, a big plus.

There are some pros and cons with regard to the Sky Commander XP4. I've been viewing deep sky objects for many years and enjoy observing elusive targets. To me, the database is still very limited when compared to the Argo Navis. For example, let's say you are using a popular book like the Night Sky Observers Guide and you decide to view all the objects in one particular constellation, also known as constellation mopping. Some constellations cannot be completely mopped and you are left to move on to another constellation prematurely.

The Night Sky Observing Guide has an almost inexhaustible object list and yet, there are several catalogues it has that the Sky Commander does not. I wouldn’t mind this so much were it not for the next issue. Even if you enter the RA and DEC coordinates provided by these references, the Sky Commander does not allow you to enter an accurate enough decimal for its declination axis in particular without some careful thought. This proved to be quite debilitating with regard to the accuracy and confidence I had that I found my target. Although you can store and even download a limited number of objects of your choice, I still find the XP4 somewhat limiting for a telescope of this caliber. I suppose the next step will be to use something portable like the Pocket Sky or if you wish to use a computer, you can install the wireless SkiFi that Carina Software now offers.

Once you have found an object of interest with the Sky Commander, you simply press the enter key and press the goto key on the hand control and away it goes. Regardless of some of the cons, this telescope is super user friendly and the drive system is amazingly smooth. The focuser on the Starmaster is beautiful too. It uses the Feather Touch focuser by Starlight Instruments, which have become a favorite among purists these days.

MIRROR CELL

This is something I always check with dobsonians. The mirror cell in the Starmaster is very nice. Metal cable slings have received excellent ratings with regard to edge support but there are a few key features consumers are rarely aware of regarding mirror cells in general. The biggest one is how the edge supports behave, relative to the flotation points that support and move the primary mirror forward and backward while collimating the telescope. An issue I've seen in some competing designs is the use of a sling that does not move in unison with the flotation points. This can cause binding, shifting or pinching of the mirror and even cause the mirror to get hung against the side support pins in some cases, depending on their position. I've even seen where some telescopes have to be pointed vertical to get the primary mirror to drop back down. The Starmaster uses a flotation, edge support but more importantly, the edge support and rear flotation points all move in unison, the way a proper cell should move.

Collimation is held in place quite firmly without the issues of flexure. I placed a laser collimator in the focuser and watched the red dot on the primary to see if it shifted out of the bull’s-eye as I moved the altitude up and down and it stayed centered. This is a common problem not often mentioned in reviews because it either gets overlooked or ignored. This is something I always check in a dob to help verify if it's coming from a lack of strength from the secondary support, the mirror cell or the truss design, etc. Overall, the Hybrid is a solid, little system.
The secondary is adjusted with four thumbscrews that are quite smooth when turning and they hold collimation extremely well. Wood structures in general sometimes have a tendency to expand and contract in various temperatures, so it isn't a bad idea to check collimation a couple of hours into the observing session. For the most part, I'm impressed with the Starmaster in that regard.

OPTICAL PERFORMANCE

The optical performance on deep sky targets with the Starmaster are wonderful and in some cases, quite stunning, especially when you consider that this has a 14.5" mirror. Newbie’s should understand that no matter how well figured mirror is, the coma is inherent in a system this fast. With the coma corrector in place, stars appear like small points on nights of good seeing and their colors shine vividly. We also commonly forget that a good secondary mirror is also a crucial element of the optical train. Don’t under estimate the secondary. During several star tests I conducted, the patterns appeared concentric, clean and practically identical on both sides of focus without any bothersome issues of astigmatism, spherical aberration or common turned edge. To me, it’s just another typical Zambuto. Star clusters like NGC7789 and M11 appear like salt sprinkles with dark backgrounds. Galaxies, planetary nebula and various types of objects shine beautifully through this telescope.

PLANETARY PERFORMANCE AND “YOU” OF ALL THINGS

There's no doubt that Starmaster’s are good planetary telescopes, even with their fast optics. There have been a number of reports of this from the most reputable and well-known observers. But how consistent are these planetary images, really? The Starmaster is not without its issues and it has a major one I'm about to discuss.

One of the biggest oversights regarding not just one, but literally every single ATM who specializes in large dobsonians, is focuser placement. It can destroy everything you’ve paid the extra money to defeat, mainly the quality of the image you get with planets. Just go to the galleries of all the big ATM's and see for yourself what side their focusers are placed on. None of them are on the left hand side of the upper cage assembly. It's as if they all copy each other without any regard to the dire thermal consequences, a HUGE mistake for some planetary enthusiasts!

In order to picture a focuser on the right hand side, imagine standing in front of the telescope looking down the tube. In this case, the focuser would appear on your left. If you were standing behind the telescope looking up the tube, the focuser would then appear to be on the right. An ATM can put the focuser on the left side or right side of the upper cage assembly, but putting one on the right side all the time as every ATM does is like asking a right handed golfer to play with their left hand all the time. This focuser placement has serious side effects with your body currents when using higher magnifications on stars and planets depending on your viewing location.

It stuns me to see how much observers obsess over optics, yet give little or literally no regard to this very serious problem. Imagine all the time and effort put into a finely figured set of mirrors in a wonderfully crafted telescope, only to have the images degraded because of a faulty focuser placement. Just to give you a perspective of the seriousness of the issue, professional observatories that allow public tours, require that all occupants leave by a certain time. Why is this? Because humans are a major source of heat plumes, and domes have to be acclimated so their sensitive cameras can do their work properly. Viewing planets and tight, multiple stars at high magnifications in an amateur telescope are also sensitive in the same way.
Now imagine an open truss tube and you’re savoring every second of the precious seeing to resolve the most spectacular planetary detail and you're standing right next to a completely open optical path and BTW, a typical light shroud will not stop it. This will have profound consequences on the image quality and this can easily be proven. ATM's should always offer focuser placement as an option to the consumer, especially if they are planetary and double star enthusiasts paying thousands of dollars. Unfortunately Starmaster does not offer this option despite several suggestions I've made. I've even discussed the issue for years in forums and have even given talks on the topic at public events.

HERE'S HOW TO PROVE THIS FOR YOURSELF

You can conduct this experiment with an out of focus star using an eyepiece but nothing makes it more obvious than a barlow lens and a binoviewer. This method produces one of the most remarkable and clear pictures of the schlieren or streak test in vivid detail. For this test, do not use any eyepieces with your binoviewer. First, point your telescope on a planet or a really bright star. The Moon itself is too bright in case you're wondering. Center the object carefully, so you can get a clear picture of the secondary spider vane with the illuminated light in the background. Just as an experiment, hold your hand in front of the optical path and you can see your body currents pouring off like fire plumes!

Even if you are using a thick, down glove or jacket, it will not stop these heat plumes from occurring and possibly crossing the open optical path as well. The boundary layer will appear to move slowly, like ripples on a pond in various directions while bad seeing will display itself as a fast, flowing stream in one direction. It's up to you to teach yourself what each movement of air represents. Body currents will usually pour across the field depending on the direction the telescope is pointed “relative to you”. Humans are all a major source of heat, like a furnace. When that heat is exposed to the cold, the difference in temperature is what causes the plumes. Remember those helicopter cameras that the military and police use to catch the bad guys in the dark? They appear as a heat source on their monitor. That's how much heat we give off.

COMPARING THE TAK AND STARMASTER ON JUPITER

During this shootout, my observing buddy John Curry and I put the Takahashi FS152 next to the Starmaster for a shootout. While John observed through the 6" Tak, I observed with the Starmaster on a night of excellent seeing. No matter what magnification we used, more often than not, I was continually getting blurred or softened images in the Starmaster at precisely the same time John was not in the FS152! This occurred over the course of the entire evening. Most observers would probably dismiss this as bad optics, thermal behavior of the primary mirror or various fluctuations in seeing if they didn't know any better.

What’s the problem here? The problem is that YOU are also a major source of the thermal activity. Bigger aperture isn't going to compete with a world-class refractor on double stars and planets if the focuser isn't on the correct side for your viewing location, not to mention the other serious thermal issues reflectors are plagued with already. So, just remember that aperture does not always rule in every case.

John and I both watched while the FS152 continually pulverized the Starmaster on Jupiter, producing consistently tack sharp images with vivid surface detail, a truly beautiful sight! Jupiter's moons were nothing short of sensational, appearing like perfect, tiny, little pin-balls. You could also make out their relative sizes in the FS152 while the Starmaster's were harder to define. Sure, there were a couple of moments where the Starmaster was amazingly tack sharp on Jupiter with vivid colors and surface detail, but they were no where nearly as consistent as the Tak and it's hard to concentrate with distractions like that. Concentration and relaxation are the keys to seeing more detail.

There was one time where we switched scopes and John yelled out that the Starmaster was amazing on Jupiter, then I quickly ran over to get a peek and by the time I saw it, the sharpness was gone. Rarely ever did this happen with the refractor. When I removed the eyepieces from the binoviewer in the refractor to see the thermal behavior, the picture was perfectly clean, no thermals at all! When we compare the mountain of challenges a reflector must face in the field to what a refractor faces, it's literally like comparing an elephant to a flea. Once again, so many things can go wrong with a reflector while practically nothing can go wrong with a refractor. The Starmaster is a very nice dobsonian but the focuser placement is a major blunder for observers on the west coast and a truly frustrating one to say the least.

UNDERSTANDING THE DIRECTION OF YOUR SEEING CONDITIONS AND YOUR FOCUSER POSITION

The focuser placement for my circumstance may not be the same for yours. In order to determine what side the focuser should be on depends on what direction the air moves when your seeing conditions are actually good, and you need to learn that first. Here on the west coast, the on-shore breeze only occurs when the airflow moves from the south-west to the north-east or west to east. Since the planets in North America rise in the east and usually transit towards the south, think about what's happening with a focuser that's positioned on the common, right hand side of the upper cage assembly. The results are a disaster!
Your body is now tragically positioned upwind, relative to the position of the planets you are viewing. This consistent breeze is carrying your body currents directly across the optical path. Now, let's imagine the focuser on the left side of the upper cage. Now your body is positioned downwind and the air will carry your body currents away from the telescope instead of across. Have you ever seen a golfer throw grass in the air so they have a better idea which way the air is moving? The same thing applies to telescopes, it’s no different. The amount of air we are talking about is very subtle in fact sometimes you may even need to dampen or wet your finger and hold it up just to tell which side of your finger the breeze is on. Another way to tell is to light a match and see which way the smoke trails. Remember that it only takes a small amount of air movement to cause a problem

SOLUTIONS

So you ask, why not just rotate the upper cage? Because the focuser board on this Starmaster is angled slightly upward on the right hand side. If you rotate the upper cage so the focuser is on the left side, the focus board is now angled downward along with the finder, not to mention the Sky Commander and clutch system are also on the right hand side of the telescope. Why not rebuild the upper cage? Why not use a special shroud material or an extended light baffle? Why not use a large fan to suck or blow body currents away from the telescope? Well you know what? I have a better solution. Just put the focuser on the correct side of the upper cage and it's done! No more fussing. The rest is counterintuitive and it's a lot of unnecessary work anyway. Telescopes of this caliber should always be made to order, not the other way around. Another issue is fans. Starmaster does not provide you with any primary mirror fans, which speed up the acclimating process in colder temperatures, so be prepared to install your own. This Hybrid has Floyd Blue fans installed with variable speed control and they work excellent. Note that there are no current shrouds included with any telescope on the market that stop body currents.

TAKAHASHI FS152 / EM200 TEMMA II

Oh do I ever love Takahashi. The Japanese are a truly dedicated culture when it comes to their telescopes. There's practically nothing to be desired after owning one of these. It's like owning the finest pocket watch money can buy. Whether it’s an astrograph for shooting the night sky or visual intimacy, it all ends here for me. Takahashi produces my favorite telescopes in the world.
To me, the FS152 is still the finest 6" refractor in the world for visual use. It's also one of the most incredible telescopes I've ever owned, not just because the images have so much contrast, but because they are consistently beautiful. Just set it up and it works every time. No fussing with collimation, thermals, fans, body currents, focuser placements, etc. To this day, given the choice of any 6" refractor currently available, I would still pick this particular model over any other, even if I had to pay more money for it. It has several advantages going for it that most consumers are not aware of. One of those advantages is the fact that the lenses can be taken completely apart, cleaned, put back together again and collimated right at home without any sophisticated equipment. Takahashi has a simple collimator that will help you do the job on your own.

I'm not suggesting you do this but should anything happen to the lenses in a triplet, be ready to pack it up and ship it back for tuning. You will not be working on it yourself if the glass elements shift out of alignment, especially during shipment. Another issue is consistency. I've tested countless triplets and finding an especially good one for planets is like shopping for a straight 2x4 in a stack of lumber. These simple doublets were easier to produce and more forgiving to work with than triplets but don’t get me wrong. A nice triplet can be seriously excellent too.
I've also had this refractor right next to two different world-class 8" triplets from TEC and TMB and about the only differences detected visually, were that the images in the 8's were slightly brighter or larger. Even the 8" owners were stunned. Being that the FS152’s focal length is only 1216mm's means that it's also an F-8. But, what's even better is that it's still a relatively wide field instrument. The stars are crisp and pure across the whole field while viewing with high quality, wide field eyepieces at this focal ratio. It’s also just a fluorite crystal doublet, making it extremely lightweight compared to most triplets and therefore, much easier to mount solidly. You don't have to lug a massive mount around if you want to travel with it. It also acclimates quickly, being a simple doublet with thinner, shallow optical curves. An 8” triplet can take as long as three hours to hit its optimal performance. This particular doublet was star tested after being exposed to a temperature difference of 30 degree F. The immediate star test revealed savere under correction and reached perfect spherical correction in just 65 minutes. That’s fantastic when you consider how much temperature variance it was exposed to.

Another issue I have with triplets is their weird looking appearance when you balance them on the DEC axis. You pay $15,000 to $20,000 dollars for a nice 6” setup and the optical tube assembly looks like it slid backwards in the tube rings. You later realize that this is how they look when they are properly balanced. Some companies offer counter weight tube rings, but once again this adds, more unwanted mass. These are just several advantages the FS152 doublet has over triplets for visual observers. It would be nice if companies came up with a way to offer really simple, high quality doublets like the Takahashi FS and FC series at F-8 for observers who are really into visual observing and even then, some incredibly good astrophotography can still be done.

COLOR CORRECTION HYPE AND CONFUSION

Many observers prematurely obsess over color correction without realizing its place or even worse, without having any actual experience behind an eyepiece with various refractive designs. They read about different glass and all the sudden, they make premature choices. Remember that a camera picks up light differently than the human eye. Cameras saturate light, while the human eye is not as sensitive to colors as a camera.

If you leave a camera exposed long enough using a state of the art apo refractor, it’s still possible to eventually see false color at some point on brighter stars. Sure, you may see a tinge of very minor false color on Vega with the FS152, but just about everything including planets are color free to the human eye most of the time. Another common mistake I read is observers using the edges of the Moon as a guide to revealing false colors. You can do that but you have to be careful. False color can occur even while using a Newtonian with an eyepiece in place. I've seen this many times with my own reflector.

The issue occurs in the air with a color dispersion associated with Earth's atmosphere. Sometimes when objects are being viewed slightly closer to the horizon, you will often see a reddish fringe on the lower side of a planet and a greenish, or bluish fringe on the upper side. An observer could easily mistake this as an issue regarding the telescope’s color correction without even realizing the actual cause. This is the same phenomenon that causes the Sun to still appear on the horizon at sunset, when in actuality, it's already below the horizon. If you are a big double star fan and you're seeing all kinds of atmospheric turbulence and false colors for example, take a #25 red filter and watch what happens.

The FS152 puts planets and stars on a very serious diet and will easily compete with any 6" triplet sold today regardless of price. Sadly, the FS and FC series are no longer in production. This model utilizes a 4" focuser and has some truly fantastic options. In order for it to come to focus, it needs a 3" extension tube. Instead of using this extension tube, the space is occupied by a Moonlite focuser with a fine focus that simply screws on the back of the tube with the aid of a Takahashi adapter. I had no intension of removing the stock focuser because I wanted to preserve its originality and value. Telescopes like these are investments. Another plus is that the FS152 has enough in-travel to allow a completely sealed 2" filter wheel in conjunction with a 2" star diagonal. I can quickly flip through each filter from Broadband, Narrowband and OIII to determine which one provides the best view in seconds!
The EM200 Temma II is another high quality product from Takahashi. I love this mount as much as I love the telescope. It moves with high precision and the polar scope is second to none! As a test one evening, I did a polar alignment. After completing the polar alignment, I took a cross hair reticle eyepiece and pointed the telescope on a star at 215x towards the south and went into the house for 15 minutes to make some coffee and came back outside and it was still dead center, over the cross hair. Sure, there are software programs for polar aligning but it’s still a time consuming process and it’s mainly for photography. I'd just rather polar align and be done.

EM200 TEMMA MYTHS

Some myths have floated on the internet about the EM200 Temma I'd like to clarify. One is that it only runs on 24 volts, which is not true. The fact that you can run the mount on 24 volts simply allows it to slew faster. You can run it on 12 volts, but it will move at half the slew rate, that's all. The only reason I usually run the EM200 at 12 volts is because it draws less current from my battery. I have an AC outlet on my particular battery but have no reason to use it with the converter. Takahashi has now introduced an even newer version of the Temma II which allows it to slew at the faster 700x rate with just 12 volts instead of 24 volts. It also has a few additional improved features.

Another myth is that the EM200 does not have a goto hand control. The EM200 does have a goto hand control but the only difference is that it's optional. There are two hand held DSC computers you can purchase for the EM200 and I use both. The first one is the original Temma II DSC produced by Takahashi. Although it's discontinued, you can still find them floating around on the used market for a few hundred dollars. Sadly, this DSC received a lot of criticism from consumers because of its extremely limited database. It also used yellow LED's instead of red. Maybe the technicians at Tak had a fondness for colors at the time, I don't know.

Even though this computer and the Sky Commander have limited databases, there's one advantage this controller has that most observers overlook. If you’re using the Night Sky Observers Guide for example, you can enter RA and DEC coordinates very accurately for all the obscure catalogs, unlike the Sky Commander which does not allow you to enter in the dec coordinates more accurately. Takahashi also offered a newer, optional, hand held IPAQ with Pocket Sky by Software Bisque but now both hand controls have recently been surpassed by LLC. This company is now offering a controller that has many features and a huge database and will be available November 15th 2010. All you have to do is plug it in, no different than plugging in any other handset on a modern computerized telescope that's already been programmed.

The Pocket Sky by Software Bisque has an optional T point targeting algorithm but I never use it because it's more for permanent installations and it needs a good number of points. The EM200 moves like silk and makes a beautiful sound when slewing. Some observers describe it as a dentist drill, but it's a very pure, high pitch sound. I usually avoid meridian flips and view objects in one constellation over the course of each night. If you like jumping all over the sky, a German EQ mount is not for you.

HOW ARE THE VIEWS IN THE FS152?

Spectacular! Star clouds and Milky Way vistas are a sight to behold! Star clusters look like powdered sugar. For example, NGC7789 under a dark sky with this telescope is the finest image I've seen in any telescope, regardless of aperture. I recall one evening at a large star party using the rare 30mm Leitz widefield eyepiece on the Double Cluster with the FS152. It was the best I’d ever seen it and that eyepiece is a fantastic combination with the telescope. I couldn't take my eyes off this view, in fact there was a 24" dob parked right next to it and most of the observers were still gawking at the views in the 6" Tak even more. You have to remember that everything is relative. If you decide to use a huge telescope, that just means you're going to be viewing smaller, fainter objects on a louder level. The 6" Tak produces tailored quality with darker backgrounds.

I agree that there are many cases where aperture is awesome and you really need it, however, you have to choose your targets wisely and learn to appreciate the advantages and disadvantages of each instrument. I have a pretty good picture of the night sky and I love just about everything I see, even if it's just a single faint star. It’s more about knowing and appreciating what you are looking at. Another vivid image at a different star party was the North American nebula using the original 50mm Axiom from Japan (now discontinued) and the 30mm Leitz with a UHC filter. If you've never seen this, you have no idea what you're missing. It practically looks like a picture. You can literally see the Central American region and all the hard outlines around North America. This is one of nature’s greatest spectacles! There is so much to be said for wide field views of targets like the M24 star cloud, M35, M44, M45 etc. Double stars consistently look textbook perfect with tiny airy discs that resemble miniature pin-balls at high magnification under good seeing.

CONCLUSIONS

Every dob owner should have a refractor and every refractor owner should have a dob. To disregard either design is a closed minded approach to the hobby as far as I’m concerned. The Starmaster is a beautiful telescope in almost every regard, but the focuser position is absolutely frustrating to no end and huge blunder for any ATM. Most planetary observers know that a Starmaster will kill any refractor when the thermals are not an issue, but the fact that the design is not a consistent performer at higher magnification because of it will remain an issue for me and probably for many others who are unaware of the actual problem. Of course this will depend on your observing location.

The Takahashi leaves me with little or nothing to be desired regarding the targets it's intended for and it's practically immune to thermals. That in itself makes it an extremely efficient optical system, even if it is just 6". It's a pleasure having both telescopes together. They each have their attributes. The EM200 mount is amazing too and in my opinion, still, the finest mount in its class. If I had to live with one though, I'd pick the 6" Takahashi system. It combines the accuracy I need for double stars and the comfort of sitting down compared to the bigger dob and the image quality is absolutely smashing! Reflectors are still king for planets and still my favorite choice, but there's a lot more to a reflector than just size. Execution of the design is paramount and the Starmaster Hybrid would still need to carry some of the same modifications as Ed Grissom's spectacular planetary Newtonians. I’ve never seen anything that could rival Grissom’s designs and it's not as simple as most observers think.

Steady skies,
Daniel Mounsey
aka Dr. D