BARLOWS AND MISCELLANEOUS COMPARISONS -- PART I

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December 19, 1997 : 17:00 to 18:00 Mountain Standard Time

I just got in from an hour's worth of viewing with the Quantum 6.

I could see the smoke of the fires, but I could not smell it. A favorable calm breeze. Clear skies with low level clouds or fog puddling up around the mountains to the east and west. Warning: the scope never had any chance at all to reach thermal equalibrium -- so use your judgment regarding the accuracy of this report.

My report. I got out after sunset, just as the sunlight was touching the tips of the peaks of the 10,000 foot Wasatch Range of the Rockies off to my east. Venus was visible with the naked eye.

Through the 6 inch f/15 Quantum Maksutov (Q6, as it's sometimes called), Venus had a nice sliver of a crescent shape. My purpose was to test some of the new eyepieces and equipment that I have recently acquired. The turbulence was way too extreme to get any sharp edges to the view at any magnification. However, a few things could be gleaned anyway.

First, the 8mm Brandon eyepiece. It had a piece of gunk or dust on the lense. It is one of those eyepieces in which junk on the glass is visible in the image. The junk seems to come to a focus at about the same time that a planet does. Some vigorous work with a bulb blower solved the problem. Really quite a nice field of view, more than the short eye relief allows access to. No ghosting noticable.

Second, the 9mm Intes monocentric planetary eyepiece. More than enough eye relief to allow full access to the very narrow field of view. Ghosts, ghosts, ghosts. Ghosting of Venus and Jupiter even on axis -- the crescent Venus seemed to show the ghost on axis or the center of the planet. Always a ghost. The ghost would only bury itself within the disk of Jupiter on axis. For a 'planetary eyepiece' the level of ghosting is very unacceptable. Could even sense the dark blockage of the secondary in the ghosts at times.

The 10.5 Pentax XL with its generous field of view makes a very useful high power finder after the scope's 8X50 finder has done its job.

Back to the scope, the eyepieces, and Jupiter. After half an hour, kind of interesting. The views through the 8mm Brandon and the 9mm Intes were sharper than the 7XL or the 10.5XL. The moons of Jupiter would pinpoint more and the banding were more noticable through the 8mm and 9mm. The 7 and 10.5 were fuzzier around the edge of the planet. Due to obvious tube currents or turbulence, I am not ready to concede that the 8mm and 9mm have better contrast, but I do feel ready to say that the 8mm and 9mm were less susceptible to poor seeing -- whatever that means. The edge sharpness and pinpoint of the moons of Jupiter were comparable among the 9mm Intes, the 8mm Brandon, and the 14mm Pentax XL.

It would be very interesting if I were to have 3 hours of cool down on the scope to see what the images produce, and if the results are the same. A task for another night. Again, take it all with a grain of salt.

In the past, the 7mm Pentax XL has always proved to be too much magnification for the Quantum 6. I don't know what the situation would be like if I were to have a night of perfect seeing. The slow motion controls are more than adequate for fine and consistent tracking of objects at 7mm. I don't know of any other non-powered control system that can boast ease of use at 326X. The slow motion hand controls is even doable at around 550X using the built in 1.75 barlow. The Quantum 6 is the only scope I have come across that can honestly say that it is not capable of living up to its very capable mount. 550X is really beyond the capabilities of 6 inches in almost any circumstance -- especially 6 inches with a central obstruction. My humble opinion.

The 8mm Brandon and 9mm Intes were not usable in my 6 inch f/10 Intes Maksutov on top of a Bogen Tripod. I kept losing the objects. The Intes scope and the Bogen tripod required the 65 degree field of the 10.5 Pentax XL to keep much of anything in the field of view somewhat easily.

Hope that helps for those who have asked. I'll try to report back again when I get a scope or two that have reached equalibrium.

Darwin Bagley

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March 7, 1998

Daytime comparison of my 2.8X University Optics Klee barlow with my friend's 2.4X Vernonscope Dakin Barlow.

The scope I used was my 80mm f/6.25 UO refractor. I chose the refractor for a multitude of reasons. I have proven to my satsifaction that my 80mm UO refractor is a better daytime scope than any of my others.

The 6 inch f/15 Quantum Maksutov would achieve unacceptably high levels of magnification for across-the-valley viewing of the mountains. The barlows tend to enhance shadows and blackout, and I figured the central obstruction of the Quantum 6 (Q6) would only enhance the problem.

I used the 80mm refractor straight through to eliminate any diagonal aberrations from being introduced.

The Klee is half the size of the Dakin, though the Klee weighs as much if not more. The lenses in the Klee are much easier to get to when it comes time to clean them. I thought the Dakin had a scratch on its lense, but the scratch washed off when I cleaned the barlow; instead of being an indentation into the surface, the 'scratch' was something on the surface. The Dakin is threaded to take filters, and my Klee is not.

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I started out with a generic 1.25 inch approximately 45mm eyepiece that is probably a plossl type design. By itself, I like this eyepiece because it has the least amount of blackout of any 1.25 inch eyepiece in the 45mm range that I have ever used. There is actually a usable range.

The barlowed results of the 45mm with the Dakin is that the shadows and dimming were very slight. The Dakin produced a good, clean, wide, and brighter image with this eyepiece than the Klee, when the sweet spot was found. While looking at TV antennaes across the street, the 2.4X Dakin also seemed to produce more magnification than the 2.8X Klee with this eyepiece for some reason, contrary to what one would expect.

The Klee with the 45mm eyepiece produced wholesale shadows, dimming, blackout, and the sweet spot was basically not there. The Klee also introduced lateral color into the eyepiece. The Dakin was clearly and obviously superior.

So, I figured from my first experience that the Dakin was vastly superior to the Klee; but, such was not to prove true. Read on.

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I then tried the barlows with my 1.25 inch 32mm UO Konig. The initial gut feeling was that the Klee gave an ever so slightly better image or performance than the Dakin. But, the overall impression is that there was not much difference between the Dakin and the Klee with the 32mm Konig. The image was basically the same on the mountains during the day.

The Dakin had a tad more shadow to it, and it was easier to blackout with the 32 Konig.

The Klee had a narrower field of view, and panning produced a slight woozy feeling.

Despite the shadows, the Dakin redeemed itself by having a wider usable field and no woozy distortion feeling while panning.

Though neither was completely immune from blackout, the blackout situation was minor enough to be ignorable.

A very close call on this comparison, and I can't declare a winner.

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It gets even more interesting. I tried both barlows with my 26mm Celestron Plossl on the mountains during the day.

The Dakin had a noticably wider field of view.

The Klee was easier to focus, had a larger sweet spot or range of focus, and more contrast. The telephone poles on the mountain were much more easily seen and more contrasty with the Klee.

Blackout was not a real factor with the 26 Plossl in either barlow.

The differences between the barlows might could be attributed to the magnification factor, but my gut feeling says that should have given the edge to the Dakin. In this case, it did not.

This time the Klee was the winner.

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Time to try out my UO 24mm 1.25 inch Konig on the mountains.

The Klee accentuated the 24mm Konig's blackout problems. Even though the Klee produced an ever so slightly more contrasty image with this eyepiece than the Dakin, the Klee's benefits were all lost to a continuous fight against blackout.

I could sense the heat waves more easily in the Klee, for whatever that's worth.

The Dakin had less blackout and a noticably wider field of view. The Dakin with a whole lot less blackout had the benefit of at least being usable with the 24mm UO Konig.

The Dakin was the winner with the UO 24mm Konig.

In all eyepieces, the Dakin produced a wider field of view than the Klee.

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The 32mm Konig and the 2.4X Dakin produces a 13.33mm focal length. The 32mm Konig and the 2.8X Klee is supposed to produce an 11.43mm focal length.

For comparison with the barlowed views I had been seeing, I stuck my 10.5mm Pentax XL into the 80mm refractor. 10.5mm is somewhat close to the 11.43mm and the 13.33mm mentioned above.

The XL quickly commands attention with a much much wider field of view. There is something nice about mountains and a wide field of view. While looking at the mountains during the daytime, the 10.5XL will get a huge kidneybean shaped blackout spot if you get too close to the eyepiece. If you stay away, then all you have is occasional dimming or shadows like that found with the 32 Konig on top of the barlows. A good comparison.

One second I think the XL is sharper than the barlowed views, and the next I am giving the edge to the barlows. After much confusion, I came to the conclusion or belief that the XL is much more affected by air currents, heat waves, and turbulence than the barlowed images of the 32 Konig. During one period of time with the 10.5XL the image sharpness actually would come and go; I could actually see it doing so.

When the 10.5XL images sharpen, it is on par with the barlowed views, and the wider field does give a more pleasing view. On the other hand, the consistently sharper image of the barlowed views had its advantages as well.

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Basically impossible to declare any winners. It was literally like comparing apples and oranges. And, I thought one of the three, Dakin, Klee, or XL would stand out superior. But, I could not see any consistent superiority during my daytime viewing. It all depends upon what you like.

Darwin Bagley

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The following is a small essay. It may or may not be helpful to some, but it is here so as to give a small background concerning me and some of the scopes I have owned and used. There is also a moral to the story, for those who think that short stories need morals. Written in the Spring of 1998.

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I noticed one person commenting on the fact that he had been to hundreds of star parties and had never once seen a Questar nor a Quantum Maksutov. The maksutov owners never brought their scopes to star parties, and he was wondering why.

I cannot speak for others, but I can say that I will never take my Quantum 6 to a star party. Why? Long story, but here goes.

Years ago I had a 4.25" f/26 Schiefspiegler. I took it to a star party at the request of one of the club members. Someone had brought dogs to the star party, and the dogs were rough housing around as young dogs like to do. In the middle of the fur ball was my Schiefspiegler and I. The dogs did a full length tackle of my scope. The only thing that saved the scope was the fact that I was there to catch it as it was falling.

Telescopes and eyepieces are my primary addiction. Despite the fact that I concentrate all of my resources into acquiring scopes and goodies, I am on average relatively poor compared to others. It took me nearly 10 years to acquire enough to be able to afford my 6 inch Quantum Maksutov. I am not going to take it someplace where the dogs can tackle it; I cannot afford to buy another one.

The Questar owners paid more for their scopes than I paid for my Quantum, so I can fully understand their desires not to take their scopes to a star party.

Also, the Quantum 6 is actually a work of art. I tend to prefer to keep it in the 'museum' of my backyard. I sold my Schiefspiegler, its equitorial mount, my Brass Televue Ranger, a bunch of equipment, and a couple of homemade telescopes in order to raise the needed money for my Quantum 6.

I take my 70 pound all metal dobsonian mounted 10 inch f/4.5 newtonian to star parties. If the dogs try to tackle that one, they are going to come away with lumps on their heads. They could hit that one full on and it probably would not budge. I also didn't pay an arm and a leg for the scope.

I sometimes take my C90 or my 80mm UO refractor to a star party because I don't have as much invested in them, and I probably wouldn't feel the need to sue if someone accidently broke one of them.

For those wanting to see a maksutov at a star party, this last fall I purchased a beat up 6 inch f/10 Intes maksutov. It is very ugly looking and had chips on the edge of the corrector. It had the old helical focuser, and the diagonal actually has a hole in it. The scope cost me $450. I bought it so I could have a maksutov take to star parties.

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Miscellaneous notes regarding barlows:

Past observations. Around the fall of 1996, I got the whole collection of Easy View eyepieces. I was told they were really great for planetary viewing. I used them with my 80mm UO f/6.25 refractor and my Brass Televue Ranger. I noticed two things.

First, the Easyviews didn't on the whole have enough magnification for planetary viewing through the two rich field refractors. Second, the Easy Views all had ghosting problems on the moon, and some of them had a touch of lateral color as well while viewing the moon.

To get some magnification, I acquired 2X Televue and 3X Televue barlows because folks were saying that they were the best. I also had my Klee at the time. Using the Televues and the Klee, I learned a couple of things. The Televues were larger and more awkward to use and store in the small eyepiece case. Also, on the moon the Televues introduced a lot of ghosting into the image. The ghosting was bad enough with the Easy Views by themselves, but when they were on top of the Televue barlows additional ghosting was introduced, enough to make the image totally unusable in my opinion.

I later figured out that the barlows were not introducing ghosts per se, but that the bright light of the moon was reflecting off the walls of the very long barrels of the barlows and into the field of view; the effect was essentially the same as the worst ghosting possible. I also figured that the long barrels of the Easy Views were also to blame at least partially for the stray reflections and/or ghosting seen in the Easy View eyepieces.

The Klee did not introduce any additional ghosting or reflections into the Easy Views; but, it didn't eliminate their inherent ghosting problems either. The Klee does not seem to eliminate any problems that an eyepiece has, but the Klee also does not introduce ghosting or reflections like the Televues seemed to do.

So many of the reviews of barlows don't mention this little fact, or they make the claim that barlows don't ghost. Some have belabored the fact that the reviewers are beholden to Televue and others for advertising dollars, so the information never gets mentioned. I tend to think that many of the reviewers just don't do any lunar observation -- they work during the lunar phases and view only during new moon with their barlows.

I am a little different. It seems like the only time I ever use a barlow is to get a little higher power on the moon. I do sometimes barlow for planets, but they never seem to be around when I have a collection of barlows to try out. For lunar observation, the Klee is better than the Dakin or the Televues. I sold the Televues because they were not helping me with lunar observation. I also sold the Easy Views for the same reason.

The Dakin that I just mentioned belongs to my friend. He did give me the option of purchasing it; but, I opted to keep my Klee instead, as the Klee was better suited to lunar observation in my opinion.

I personally like the Pentax XL's on the moon. I also keep a 7mm Nagler on hand because it is perfect for putting the whole moon into the field of view with my C90. I have long eye lashes, and I was constantly cleaning my Nagler eyepieces. The Naglers just don't have enough eye relief in my opinion; otherwise, they are perfectly fine. The higher power Naglers and XLs have built in barlows so to speak, to acquire their higher magnifications.

The only other barlow that routinely does well in the reviews, that I have not tried, is the 2X Celestron Ultima. Many have tried and really liked this barlow; but, I have not seen it in action.

Darwin Bagley

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BARLOW REVIEW -- END OF PART I.