Categories See All →
- CN Reports
- User Reviews
- How to . . .
- Observing Skills
- Astronomical History
- Optical Theory
- Vision and Related Experiments
- How to Gain the Support of your Family for your Astronomical Pursuits
- Evaluation Tips
- Special Events
- The Elements
- New Articles in [!monthname!]
- Telescope Articles
- Submit a Review / Article
- Monthly Guides
- Behind the Scenes
- About Us
- Copyright ©
- Terms & Conditions
- Tiny Eyes on the Skies
- From the Editor's Desk
- What's Up . . .
- The Light Cup Journals
- Who is this Super Light Cup?
- Cloudy Nights T-Shirts
- Imaging Contest
- Small Wonders
- Previous Imaging Contest Winners
- This Month's Skies
- Mike's Corner
- The Cloudy Nights Friends and Family Discount
- Uncle Rod's Astro Blog
- Fishing for Photons
- Binocular Universe
Borg 77ED SWII Ultra Light Refractor
Voice your opinion about this subject in our forums
In 2007 I moved to urban South Florida. With the bright city skies I completely gave-up on astronomy, and put my telescopes into long-term storage. Whenever I'd walk outside of my apartment at night and would see the ghastly orange and pink sky glowing above, I'd recoil in disgust. This past year, however, a gift subscription to Sky and Telescope whetted my interest in backyard astronomy once again. By the middle of the year, I was eager to observe, and figured that I could at least get good views of the moon and planets, despite my city skies. The only problem was that I lacked a telescope suitable to my living situation. Living in a small apartment meant that I required a scope that would not take up much storage space. More importantly, since I do not have a private yard, I would need a telescope setup that I could easily transport in a single trip. Finally, I wanted uncompromising optical performance. After considering multiple options, I settled on Borg's 77mm ED refractor on the Borg single-arm fork mount. I ordered the Borg 77ED SWII package from a major United States dealer that was unaware I would be reviewing the scope at a later date. Within a week of placing my order, the telescope arrived (along with cloudy skies).
The Borg 77ED SWII set was packaged in a single box that, while somewhat large, was deceptively light weight. Within this main shipping box was a series of three other boxes, a set of instructions (in English), and the alt-azimuth mount head, which was secured in dense layers of bubble-wrap. Opening these boxes, I was confronted with a range of additional smaller boxes.
(Above) Like a Russian matryoshka doll, Borg telescopes arrive as a series of components within boxes contained within more boxes.
Those unfamiliar to the Borg design philosophy will likely be surprised with how the company's telescopes arrive. Nowhere will one find a complete optical tube assembly. Instead, the different telescope components are all separate. This modular design makes the Borg telescopes easier for individual users to customize to suit their own unique needs and also allow the Borg scopes to be disassembled for storage in surprisingly small spaces (more on this later).
After setting out the individual telescope and mount components, I was able to easily follow the clear instructions which included helpful, if not small, black and white photographs. Working at a leisurely pace and enjoying the parts' smooth fit, I assembled the Borg 77ED optical tube and the alt-azimuth mount in under an hour. The initial impression from the fully assembled telescope is that it is an instrument with excellent fit and finish and is exceedingly portable. This impression is readily supported by the fact that the optical tube, mount, tripod, and accessories together weigh under 10-pounds (4.5 kg), while the optical tube alone weighs a mere 3.7-pounds (1.7 kg). Comparatively, the Borg 77ED optical tube weighs less than a pound more than a Tele Vue 60 and is a feather-weight compared to other 70mm to 80mm apochromats.
(Above) On the single-arm Borg alt-azimuth fork mount, the Borg 77ED refractor is easily one of the most compact and light weight complete telescope systems available in its aperture class.
Optical Tube Assembly & Focuser
The Borg 77ED optics are housed in a 16.25-inch (41.3cm) long glossy white optical tube with a flat black focuser assembly. This length includes the Borg 2-inch #7508 adapter, but removing this adapter will shorten the optical tube by about an inch. The optical tube features a sliding dew shield that is just over 4-inches long (appx. 11cm) and a helical focuser. The sliding dew shield is slightly looser than the sliding dew shields I've encountered on Tele Vue telescopes (for comparison). While this does not pose much of a problem, occasionally when aiming the Borg 77ED nearly straight up, the dew shield retracts itself.
The helical focuser included in the Borg 77ED SWII set is common to the Borg line. Like the focusers used for high-quality camera lenses, the Borg focuser rotates without spinning the eyepiece and allows 20mm of travel for fine focus. This focusing action is augmented by a simple drawtube assembly. For those unfamiliar with this type of focus system, it works by the observer first coarsely focusing the eyepiece using the drawtube. After locking the drawtube in place with the two metal bolts, the observer then achieves fine focus with the helical focuser. While this may seem complicated compared to more typical rack and pinion or Crayford focusers, I took no objection to the Borg focuser and quickly became accustomed to it. Users who strongly prefer a Crayford style focuser can purchase a Starlight Instrument's Feather Touch focuser from Astro Hutech that will fit the Borg 80-series optical tube assembly used with the 77mm ED objective.
In operation, the focuser movements are smooth provided that heavy diagonals and eyepieces are avoided. With my orthoscopics or plossls combined with a 1.25-inch diagonal, I found the helical focuser provided the buttery smooth movements attributed to high quality focusers. With heavier gear plugged into the focuser, however, the movements feel coarse. How much a user objects to this will depend on the individual. For visual use, I can still achieve excellent focus without much trouble even when using large eyepieces such as the classic Meade Series 4000 ultra wides and I prefer the helical focuser for it being so compact. Astro-imagers, however, would likely prefer smoother focus if using heavy imaging equipment, and such users would do well to upgrade to the Feather Touch focuser.
Looking down the tube, one finds a matte grey-black (similar to the matte on the interior of Takahashi refractors) finish free of glossy areas and a single knife-edge baffle. The focuser drawtube interior, though, shows slight gloss that theoretically could reduce contrast, but this was never noticed in field use. The interior of the helical focuser sports a series of small threaded ridges, all of which are a uniform flat black. This baffling system works well, and attempting to peer down the optical tube under even bright light is like looking into a tunnel.
(Above) The Borg 77ED's lenses are fully multicoated while the optical tube has various features to control for stray light. For comparison under identical light, a typical Short Tube 80 achromatic refractor tosses up a multitude of bright reflections.
The final detail worth noting about the optical tube is the mounting block situated just above the focuser. This metal block offers a variety of different diameter threaded holes useful for mounting accessories to the Borg telescope, such as a finderscope (using optional accessories).
(Above) Remember - it's a bad idea to look at the sun, unless of course you're using a properly fitted full aperture filter. Just above the warning label is the mounting block, useful for attaching accessories to the optical tube.
The Alt-Az Mount
The 77mm aperture Borg refractor is small and light enough that it would work well paired with most quality photo tripods. For those who desire dedicated slow motion controls and would like a mount capable of allowing near-zenith viewing, the Borg single-arm fork mount provides a welcome visual platform.
At about 6-inches (15cm) length from tripod connection point to the top of the fork arm, the Borg mount is surprisingly tiny and is also very light weight (note the pattern here - small, light weight). The mount is well constructed of metal with plastic reserved only for the various knobs, all of which feature metal bolts - in many cases, these are brass. While the alt-az mount can be affixed to a standard photo tripod, I especially like using the mount with Borg's custom Slik tripod. The mount attaches to the Slik tripod in a way that lets it be tilted similar to an equatorial mount. In theory this can allow one to mimic equatorial mount motions, but I find it simply handy to allow the optical tube to clear the mount and tripod for near-zenith viewing. If using the alt-az mount on a different tripod, one could tilt the mount by attaching the mount to a tripod's fluid pan head. With the Slik tripod, an eyepiece will sit about 31-inches (79cm) above the ground with the tripod's elevator shaft retracted or about 40-inches (102cm) up with the elevator shaft fully extended. I'm a fairly tall fellow, but this range is comfortable when seated.
In practice, the alt-az mount and Slik tripod combination work well, though do allow for vibration at moderate and high powers (above 50x). I've found these vibrations dampen out quickly enough to not cause much of an issue at powers under about 150x, but individual tolerance for wobbles may vary. Since I spent my first several years in amateur astronomy using sorely under-mounted telescopes, these vibrations do not particularly bother me. Those who prefer a steadier image and can compromise some of the portability afforded by the tiny Slik tripod could use a heavier tripod.
The optical tube assembly attaches to the alt-az mount by means of a plastic tube holder. Although plastic, the Borg tube holder is sturdy enough to withstand the occasional bump. Should a metal tube holder be desired, the Astro-Hutech website indicates that a Takahashi tube holder can be used as an alternative. When I first attached the tube holder to the mount, I felt it to be difficult to snap into the mount's quick release. I've since learned that this was because I was attaching the tube holder without the optical tube in place. With the additional weight of the optical tube, the quick-release dovetail system used to connect the optical tube and tube holder to the alt-az mount works flawlessly.
(Above) The Borg alt-az mount features dual manual slow motion controls useful for tracking objects. When combined with the Borg custom Slik tripod, the mount can also be tilted to let the optical tube clear the mount base and tripod for zenith-viewing.
Quality fit and finish means little if a telescope's optics do not perform. Fortunately, as expected, the Borg's 77mm two element ED objective perform as would be expected of this type of lens system. Focused images are essentially completely free of spurious color. With moderately high power (147x), the lunar limb is crisp with only the faintest touch of false color, noticeable mainly if one looks for it. Optical testing using actual and artificial stars revealed typical ED refractor performance, with clean, uniform, airy discs readily apparent, and blue false color on the in-focus image and a yellow-tinge in the out-focus. On Jupiter, the little Borg does quite well, presenting the Jovian planet's disc and four brightest moons against a dark black background. Considering other refractors I've owned and used, the Borg 77ED's color correction fares better than a Tele Vue Pronto, and only slightly worse than a Meade 102ED or Tele Vue 102. It should be noted that both of these 4-inch apochromats operate at longer focal lengths than the Borg. For a 77mm ED scope to yield such little false color at f6.5 is a testament to its high quality optics. On most nights of observing with the 77ED I use powers in the 125x to 150x range. Yet typical of apochromat refractors, the Borg 77ED is capable of pushing beyond the 50x power per inch of aperture guideline. Thus far I've pushed the Borg 77ED up to 238x with good results in the field. With an artificial star test, I've been able to achieve a sharply focused image at 357x - though I doubt such a magnification would be routinely useful in actual practice given atmospheric effects.
Portability is the main reason I purchased the Borg 77ED. Thanks to the Borg 77ED and alt-az mount compact design, I can fit the entire optical tube assembly along with a selection of eyepieces, star-diagonal, barlow or powermate, filters, sketch pad and pencils, star charts, and a red flashlight all in a messenger bag intended for carrying a laptop. Strapping the bag on one shoulder and carrying my stool and the alt-az mount, I can hike wherever I'd like to observe on a given night. The freedom to easily transport all of my equipment is very helpful for observing in an urban environment. I frequently need to move to different observing locations in a park I frequent to avoid soccer field lights or sudden lawn sprinkler invasions.
Of course, the Borg 77ED's portable design makes it ideal for airline travel and excursions to exotic locations. While there are other optical tube assemblies that will retract to a size comparable to the Borg's collapsed optical tube, I know of no other refractors that can be readily disassembled without tools. Simply detaching the focuser and drawtube assembly from the rest of the optical tube allows the entire optical tube system to be housed in a diminutive case. I can fit all of these components in a typical 12-inch long cooler with enough room left over to house eyepieces, a camera with interchangeable lenses, or even the Borg alt-az mount head. Because of the Borg's modularity, the telescope can readily be made to fit into just about any space available to it. This modularity would be especially helpful to astro-imagers who travel, as the Borg objective could be simply detached from the rest of the optical tube and the lenses then could be safely carried with sensitive imaging gear as an airline carry-on.
(Above) How compact is a Borg scope? There's enough room in this 12-inch long cooler to fit two Borg 77ED optical tubes (note the metal ruler straddling the cooler near the base of the cooler's top).
SWII Set Accessories
Briefly noted, there are several included accessories if purchasing the Borg 77ED as part of the SWII set. These include an assortment of eyepieces, a 2x barlow, a turret eyepiece holder, and several different adapters. I confess that I do not fully know what the adapters are used for, but they do accept 1.25-inch diameter eyepieces. They seem to be mini extension tubes, perhaps used to guarantee eyepieces reach focus when used with the turret. This is only a guess, though, as I've never had to use these adapters with any of my gear.
The included eyepieces are noteworthy for several reasons. Foremost, on first pass they seem dangerously close to being "junk" eyepieces usually included with department store telescopes. Why is this? Well, the eyepiece designs include a 13.5mm orthoscopic, a 22mm kellner, and a 50mm huygens. Furthermore, all of the eyepieces feature plastic barrels. Before dismissing these oculars completely, I decided to test them out. Surprisingly, they all perform very well - even the 50mm huygens design. On all of the eyepieces, focus was sharp and I detected no serious problems. Despite the eyepieces' competent performance, I still find my high quality orthoscopics, plossls, and modern wide-field designs to be better performers.
The 2x barlow is an adequate performer, comparable to today's mass-market "shorty" barlows. Uniquely, the Borg 2x barlow's lens system unscrews from the barlow barrel, allowing the lenses to be threaded into a 1.25-inch eyepiece like a filter.
Finally, the most interesting accessory is the Borg turret eyepiece holder. Although made of plastic and rubber, the turret has smooth movements and works quite well. It securely holds either five 1.25-inch oculars or four 1.25-inch eyepieces and one of 2-inch diameter. Except for the eyepiece that is placed at the end of the turret, all of the eyepieces on the rotating component are held in place strictly by friction. At first I was dreading the thought of one of my eyepieces slipping out of the turret and meeting a dire fate. In field use, though, I've found no issues with this friction gripping method. My orthoscopic, plossl, and smaller wide-field eyepieces all remain secure in the turret. I do not dare use my large, heavy wide field eyepieces in this setup, however.
In terms of optical performance, a standard star diagonal will perform better than the turret. In viewing Jupiter with the turret and with a Lumicon star diagonal, for example, the image with the diagonal provides a considerably sharper, more detailed image of the planet's cloud belts. I suspect that the culprit here might be the mirror used in the turret. The mirror does not appear to be coated and seems to be under-sized. To me, the turret is still a nice accessory to have. It's helpful when observing with children, for example, who tend to have less patience for changing out eyepieces or for adjusting a telescope's position. With the turret in place, it's a simple manner to swap from higher to lower power to adjust the scope's field.
Based on the late 2009 pricing for individual components indicated on the Astro Hutech website (U.S. version), purchasing only the components needed to form the Borg 77ED optical tube assembly as reviewed here along with the Borg alt-az mount would cost the same, if not slightly more, than purchasing the system as the SWII set. Thus, these included accessories are effectively free extras.
Thanks to its small stature and solid performance, the Borg 77ED is not a telescope prone to becoming a dust-collector. While most would likely consider a 77mm aperture refractor an ideal second scope, suited for a quick peek role, I've found the Borg 77ED capable enough to be my primary urban telescope.
While I'm primarily a deep sky observer, the Borg 77ED performs well as a lunar and planetary scope. The lunar disc reveals its mass of craters, mountains, and riles with gorgeous detail and superb contrast through the ED doublet. At 149x, Jupiter easily reveals four bands with subtle color differences between each of these and the hemisphere regions. The Great Red Spot (more salmon in color) is quite visible as are the four brightest Galilean moons, which appear as spectacular tiny pin points of light.
As unconventional it seems, the portable Borg refractor is a solid deep sky performer, despite its diminutive 3-inches of aperture and my using the scope under badly light polluted skies. From my regular observing location, I can barely glimpse stars to between magnitude 4.0 and 4.5 near the zenith and across my eastern sky. With the Borg 77ED's optics providing excellent contrast, I've been able to enjoy spectacular views of many deep sky favorites such as the Ring Nebula (M57) and the Dumbbell Nebula (M27), especially when using light pollution reduction filters.
(Above) The Ring Nebula withstands light pollution quite well and is a terrific object with the Borg 77ED. Careful observation showed the planetary to be slightly elongated and having differences in the "ring" brightness.
With the 3-inch refractor, I've also been able to observe numerous more obscure deep sky objects. Recently, I've studied the NGC7788 and NGC7790 family of open star clusters in Cassiopeia and easily found planetary nebula NGC40. This latter object was a particular prize, as when I located it, it was setting in my northwest sky where light pollution is more pronounced. The Borg 77ED is even does well with galaxies, at least the brighter ones. I've enjoyed a fantastic view of M77, in Cetus. Using the Borg 77ED at 139x, I was able to observe this galaxy's bight core and even parts of its dimmer outer halo when the object was sinking into the bright grey-white dome of light pollution that erupts across my southwestern skies. At the time, even Mira was hard to see through the bright city sky glow, but with the Borg 77ED, the galaxy was visible and presented fine detail.
Finding deep sky objects is relatively easy with the Borg 77ED, as its 500mm focal length allows the telescope to provide terrific wide field views. The 18mm wide field eyepiece I routinely use delivers an actual 2-degree field of view with the Borg 77ED. With this eyepiece in place, I can readily sight along the optical tube to locate a given star or target. Then, I can use the 2-degree field of view to star-hop to the object I wish to view.
From my observing experiences with the Borg 77ED, it is an uncompromising super portable 3-inch apochromat. Nothing in the optical tube's design will limit its performance; it is a refractor that will reward anyone desiring such a grab and go telescope for a lifetime.
(Above) With its high surface brightness, M77 in Cetus is a good galaxy for amateur astronomers who dwell in cities. The Borg 77ED presented this galaxy as a ghostly orb with a very bright center surrounded by an ever dimmer halo.
Will You Join the Borg?
Whether the Borg 77ED is the right scope depends on the individual. The current astronomy marketplace is saturated with 3-inch apochromat refractors of all price ranges. Purchased new, the Borg 77ED SWII set will run just under $1,500 (as of December, 2009). The optical tube assembly with Borg helical focuser and 2-inch eyepiece adapter retails for approximately $1,200 (per pricing the OTA components included in the 77ED SWII set using Astro Hutech's website). This price point is considerably higher than the Chinese manufactured 80mm apochromats available under numerous names and is on-par with other premium 3-inch aperture apochromats.
The Borg 77ED's main strength over competing refractors is its modular design. Through this modularity, the Borg refractor can be made to fit in nearly any case for transport. No other refractor that I'm aware of can be broken down into small individual components, safely traveled with, and quickly reassembled without tools. This modularity has another benefit - it allows each user to customize his or her Borg refractor at any time. This feature is especially worthwhile for astro-imagers to consider, as it allows all sorts of unique imaging configurations to be set-up. The modularity is not lost on visual observers, either. For instance, should aperture fever strike, a Borg 77ED owner can purchase the Borg 101mm ED lens cell assembly and swap out the smaller lens. The Borg refractor also comes with a transferable 3-year warranty, which provides peace of mind for owners buying new or purchasing a recently new used Borg telescope.
Whether for eclipse chasing or backyard observing, the Borg 77ED is about as "grab and go" as telescopes come. With its light weight, quality build, and excellent optics, the Borg 77ED is a great apochromat refractor and should be seriously considered by observers or imagers who desire superb performance in an ultra portable package.
Bio sketch: Having owned 14 different telescopes to date, Jay Michaels averages one new scope per year he's been active in backyard astronomy. He enjoys turning the usual deep sky observing wisdom on its side by chasing faint fuzzies with small apertures under severe light pollution.