Celestron 102mm Wide View Spotting Scope
[ARTICLEIMGR="1"]The stalwart and dedicated amateur astronomers who brave the sub-freezing temperatures, cold winds, and routinely overcast skies of winter in the northern U.S. to catch a brief glimpse of the Orion Nebula, Jupiter, or the first-quarter moon need all the help they can get. With constantly changing weather conditions, a “grab and go” telescope that can be pressed into service at a moment’s notice may be the best solution short of hibernation. While larger scopes have superior performance, their sheer bulk, long cool-down times, and susceptibility to poor seeing conditions limits their use. On the other hand, a small, highly portable refractor is likely to see more frequent operation.
The popularity of the Orion 80mm Short Tube refractor attests to its utility, and its reasonable price puts it within the reach of most observers. More expensive 3-inchers from Stellarvue, William Optics, and Orion have also garnered a strong following. But for those who feel that a 4-inch telescope and its increased light grasp is the minimum needed for satisfactory views, there is an alternative.
Enter the Celestron 102mm, f/5 Wide View spotting scope. Although designed primarily for terrestrial observation, this short-tube, light, and inexpensive achromatic doublet functions admirably as an astronomical instrument. Weighing just 5 pounds with a length of 21 inches, this nicely built, black tube OTA retails for only $250. The package includes a 2-inch rack-and-pinion focuser with 1.25” adapter, an 8x20mm finderscope, a 45 degree (erect-image) star diagonal, 25mm and 10mm eyepieces, removable dewcap, dustcaps, and a ¼-20 mounting block attached to the tube. For about $100 more, the scope is available with an altazimuth mount, aluminum tripod, and 6x30 finder – clearly a good deal IF the telescope is a solid performer.
There was a mix of joy and trepidation when the UPS truck pulled up with the anticipated package: I was apprehensive about the optical quality of this Chinese import and certainly expected gobs of bright purple chromatic aberration to limit the telescope’s span to low-power, rich-field observation. What a pleasant surprise! Despite its short f/ratio and simple Fraunhofer doublet objective lens, this scope turned out to be an excellent performer even when pushed to relatively high magnifications. After the customary and expected period of overcast skies, I was finally able to put the short-tube achromat to the test on the celestial sights of mid-autumn. The scope’s capability on terrestrial objects had already proven to be quite good; the crisp low to medium-power images of birds, other wildlife and flora were very pleasing and almost devoid of false color. The standard 45 degree erect-image star diagonal, however, had to be replaced by a quality 90 degree mirror unit for higher power celestial viewing. The straight-through 8 x20mm finder was also replaced ( by a 6x30mm) as it proved to be too small and devilishly hard to collimate. The eyepieces provided, of light-weight, aluminum barrel Plossl design, are of decent quality, the 25mm having an apparent field-of-view of almost 60 degrees, the inner 65 percent being very usable. The 10mm has acceptable image quality, but it suffers from limited eye relief. Overall, not bad for an inexpensive telescope.
As I wanted to affix the 102 to a variety of mounts, I removed the ¼-20 mounting plate and slipped the scope into a pair of inexpensive 100mm Orion tube rings; they fit perfectly and were mated to a standard CG-5/GP dovetail plate. With a Universal Astronomics Unistar light and Celestron adjustable aluminum tripod, the combination proved to be very light and reasonably stable – a perfect grab-and-go setup. The larger Unistar mount also worked well as it was extremely stable but weighed about 5 pounds more. On a Celestron CG-5 equatorial, the configuration was virtually hurricane proof.
With the moon just past first quarter in a dark blue twilight sky, the Celestron served up a sharp view of our planet’s natural satellite. With the sun just setting, the sky background absorbed most of the purple fringe associated with short f/ratio achromats. Plato stood out in bold relief at 75x in a 6.7mm Meade UWA eyepiece, and the subtle banding inside Archimedes was not difficult to see. At the same magnification, the Alpine Valley and lunar Alps exhibited stark contrast and satisfying sharpness. At 100x, (using a 5mm Nagler T6, an eyepiece costing more than the telescope itself!) the delicate chain of coalesced craterlets near Copernicus was quite apparent, but a purple “wash” began to overrun the black shadows. This expected chromatic aberration became far more obvious as the sky became dark, and a bright purple band hugged the lunar rim at powers of 50x and above. Nevertheless, detail remained very sharp.
While many observers are unperturbed by false color, those who are would find that a Sirius Optics MV-1 minus-violet filter removes about 90 percent of the excess purple. Though the moon takes on a yellowish cast, visibility of minute detail and overall image sharpness is drastically improved. The views in this configuration are similar to those obtained in a long-focus achromat, perhaps a 4-incher of f/10 or so. A Sirius MV-20 filter also enhances image quality, cutting the purple excess in half, but giving the lunar surface a nearly neutral shade.
The bright planets were not well positioned for observation when the Wide View arrived, but I did manage to get an early-morning glimpse of Saturn in November. At 100x, the ringed planet stood out with crisp definition and just a touch of red and blue false color adjacent to the disc of the planet and the rings. The Cassini division was visible despite mediocre seeing conditions, and the South Equatorial Belt was prominent. Four of the planet’s moons could also be seen. This was an image far superior to that obtainable in my Orion Short Tube 80, but it did fall well short of what a quality APO refractor could deliver, as one might expect.
Stellar diffraction patterns and double stars are often a revealing test for the quality of an optical system, and the 102 Wide View acquitted itself quite well even when pushed to moderately high magnifications. On brilliant Vega, the classic intra- extrafocal examination displayed nearly identical out-of-focus patterns: good correction of spherical aberration but VERY colorful patterns typical of fast achromats. The “Double-double,” Epsilon Lyrae, normally an easy split in fairly small scopes, did not disappoint as it resolved into four well-defined and sharp discs at only 67x. At 200x, using a 2x Orion 3-element Barlow and a 5mm Type 6 Nagler, the stars’ central airy discs were hard and sharp with a fairly clean first diffraction rings when the seeing was steady. The stars were not pure white, however, as a yellow-green cast predominated, and flashes of red and violet spiked from them in moments of degraded seeing. The much-more-difficult Delta Cygni did show glimpses of its faint companion at 155 and 200x, though the colorful flares from the second- magnitude primary made for a challenging split. Finally, the close and tricky Zeta Aquarii was resolved at just 100x, with 200x providing an easily visible dark space between the two bright components.
Because of its short f/ratio and excellent light throughput, the little Celestron seemed like a natural for deep-sky observation. The multi-coated objective lens and tube baffling made for a dark field-of-view with minimal background glare. Though the scope is advertised as a “102,” I measured its clear aperture at exactly 100mm. With its 500mm focal length, this translates into an f/5 system. Because an achromat squanders some of its light in the unfocused red and violet ends of the spectrum, light grasp, although quite good, is not equivalent to that of an apochromat of the same aperture. Side-by-side comparison revealed magnitude penetration and image brightness roughly equal to that of an excellent Takahashi Sky 90 APO.
Bright globular clusters such as M 13 and M 22 were partially resolved at powers of 67 and above, the just-visible stars being sharp pinpoints set against a dark background. This is a telescope that can effectively use enough power to penetrate to at least 13th magnitude under a dark sky. But the real beauty of the lightweight f/5 is best found at low power where its 2-inch focuser and wide field-of-view come into play. At 20x, using the standard 25mm Plossl supplied with the scope, the Andromeda Galaxy filled most of the field with delicate nebulosity, its two companion galaxies, a hint of dark lanes, and myriad foreground stars. In similar fashion, the Pleiades were neatly framed and quite striking with the faint stain the nebulosity around Merope being easily visible.
With the magnification increased to 56x by a 9mm Type 6 Nagler, the numerous open star clusters of autumn became attractive targets. The Double Cluster in Perseus was beautifully framed at this power, the “diamonds on black velvet” effect not too far from what one would expect from a good APO. The trio of Auriga clusters, M 37, 38, and 36 also revealed pinpoint stars, the scope’s inherent chromatic aberration being a non-factor on stellar objects fainter than magnitude 5 or so.
With nearly 4 inches of aperture, the Wide View is large enough to allow the use of a nebula filter. With a 20mm Erfle and Lumicon Oxygen III filter in the drawtube, I was able to spot both major segments of the Veil Nebula and discern a fair amount of detail. With the same configuration, the Helix( NGC 7293) appeared as a faint “Cherrio” embedded in a sea of dark chocolate milk – a neat sight!
Overall, I’m very impressed with the value that the 102mm Wide View represents. It does have a few shortcomings, but in light of its reasonable price, many observers would be very happy to have one. Clearly, this is not a telescope for purists who demand optical and mechanical perfection. The hefty doses of chromatic aberration alone might deter some. The standard finderscope is inadequate, the star diagonal really for terrestrial viewing, and the focuser (although smooth) overrun with Chinese grease making it too stiff. But these problems are not difficult to rectify. The novice observer might find this to be the perfect starter scope, especially if it’s purchased with the alt-az mount with tripod and the upgraded 6x30 finder. Then too, those who enjoy the virtues of the Orion Short Tube 80 or similar grab-and-go scopes could achieve a huge upgrade in performance and capability at minimal cost. Personally, I believe the 102 would be a perfect telescope for travel: it’s airline carry-on portable, fairly rugged, and inexpensive enough to remove the potential trauma of loss, theft, or damage. No, it won’t prompt anyone to put a Takahashi or AP up for sale on ASTROMART, but it will be a real pleaser for those who put a premium on value and love to “sneak a peek” at celestial sights through a semi-hopeless overcast.
Clear skies or a reasonable facsimile thereof!
Larry Carlino
Click here for more about this scope. -Ed.
The popularity of the Orion 80mm Short Tube refractor attests to its utility, and its reasonable price puts it within the reach of most observers. More expensive 3-inchers from Stellarvue, William Optics, and Orion have also garnered a strong following. But for those who feel that a 4-inch telescope and its increased light grasp is the minimum needed for satisfactory views, there is an alternative.
Enter the Celestron 102mm, f/5 Wide View spotting scope. Although designed primarily for terrestrial observation, this short-tube, light, and inexpensive achromatic doublet functions admirably as an astronomical instrument. Weighing just 5 pounds with a length of 21 inches, this nicely built, black tube OTA retails for only $250. The package includes a 2-inch rack-and-pinion focuser with 1.25” adapter, an 8x20mm finderscope, a 45 degree (erect-image) star diagonal, 25mm and 10mm eyepieces, removable dewcap, dustcaps, and a ¼-20 mounting block attached to the tube. For about $100 more, the scope is available with an altazimuth mount, aluminum tripod, and 6x30 finder – clearly a good deal IF the telescope is a solid performer.
There was a mix of joy and trepidation when the UPS truck pulled up with the anticipated package: I was apprehensive about the optical quality of this Chinese import and certainly expected gobs of bright purple chromatic aberration to limit the telescope’s span to low-power, rich-field observation. What a pleasant surprise! Despite its short f/ratio and simple Fraunhofer doublet objective lens, this scope turned out to be an excellent performer even when pushed to relatively high magnifications. After the customary and expected period of overcast skies, I was finally able to put the short-tube achromat to the test on the celestial sights of mid-autumn. The scope’s capability on terrestrial objects had already proven to be quite good; the crisp low to medium-power images of birds, other wildlife and flora were very pleasing and almost devoid of false color. The standard 45 degree erect-image star diagonal, however, had to be replaced by a quality 90 degree mirror unit for higher power celestial viewing. The straight-through 8 x20mm finder was also replaced ( by a 6x30mm) as it proved to be too small and devilishly hard to collimate. The eyepieces provided, of light-weight, aluminum barrel Plossl design, are of decent quality, the 25mm having an apparent field-of-view of almost 60 degrees, the inner 65 percent being very usable. The 10mm has acceptable image quality, but it suffers from limited eye relief. Overall, not bad for an inexpensive telescope.
As I wanted to affix the 102 to a variety of mounts, I removed the ¼-20 mounting plate and slipped the scope into a pair of inexpensive 100mm Orion tube rings; they fit perfectly and were mated to a standard CG-5/GP dovetail plate. With a Universal Astronomics Unistar light and Celestron adjustable aluminum tripod, the combination proved to be very light and reasonably stable – a perfect grab-and-go setup. The larger Unistar mount also worked well as it was extremely stable but weighed about 5 pounds more. On a Celestron CG-5 equatorial, the configuration was virtually hurricane proof.
With the moon just past first quarter in a dark blue twilight sky, the Celestron served up a sharp view of our planet’s natural satellite. With the sun just setting, the sky background absorbed most of the purple fringe associated with short f/ratio achromats. Plato stood out in bold relief at 75x in a 6.7mm Meade UWA eyepiece, and the subtle banding inside Archimedes was not difficult to see. At the same magnification, the Alpine Valley and lunar Alps exhibited stark contrast and satisfying sharpness. At 100x, (using a 5mm Nagler T6, an eyepiece costing more than the telescope itself!) the delicate chain of coalesced craterlets near Copernicus was quite apparent, but a purple “wash” began to overrun the black shadows. This expected chromatic aberration became far more obvious as the sky became dark, and a bright purple band hugged the lunar rim at powers of 50x and above. Nevertheless, detail remained very sharp.
While many observers are unperturbed by false color, those who are would find that a Sirius Optics MV-1 minus-violet filter removes about 90 percent of the excess purple. Though the moon takes on a yellowish cast, visibility of minute detail and overall image sharpness is drastically improved. The views in this configuration are similar to those obtained in a long-focus achromat, perhaps a 4-incher of f/10 or so. A Sirius MV-20 filter also enhances image quality, cutting the purple excess in half, but giving the lunar surface a nearly neutral shade.
The bright planets were not well positioned for observation when the Wide View arrived, but I did manage to get an early-morning glimpse of Saturn in November. At 100x, the ringed planet stood out with crisp definition and just a touch of red and blue false color adjacent to the disc of the planet and the rings. The Cassini division was visible despite mediocre seeing conditions, and the South Equatorial Belt was prominent. Four of the planet’s moons could also be seen. This was an image far superior to that obtainable in my Orion Short Tube 80, but it did fall well short of what a quality APO refractor could deliver, as one might expect.
Stellar diffraction patterns and double stars are often a revealing test for the quality of an optical system, and the 102 Wide View acquitted itself quite well even when pushed to moderately high magnifications. On brilliant Vega, the classic intra- extrafocal examination displayed nearly identical out-of-focus patterns: good correction of spherical aberration but VERY colorful patterns typical of fast achromats. The “Double-double,” Epsilon Lyrae, normally an easy split in fairly small scopes, did not disappoint as it resolved into four well-defined and sharp discs at only 67x. At 200x, using a 2x Orion 3-element Barlow and a 5mm Type 6 Nagler, the stars’ central airy discs were hard and sharp with a fairly clean first diffraction rings when the seeing was steady. The stars were not pure white, however, as a yellow-green cast predominated, and flashes of red and violet spiked from them in moments of degraded seeing. The much-more-difficult Delta Cygni did show glimpses of its faint companion at 155 and 200x, though the colorful flares from the second- magnitude primary made for a challenging split. Finally, the close and tricky Zeta Aquarii was resolved at just 100x, with 200x providing an easily visible dark space between the two bright components.
Because of its short f/ratio and excellent light throughput, the little Celestron seemed like a natural for deep-sky observation. The multi-coated objective lens and tube baffling made for a dark field-of-view with minimal background glare. Though the scope is advertised as a “102,” I measured its clear aperture at exactly 100mm. With its 500mm focal length, this translates into an f/5 system. Because an achromat squanders some of its light in the unfocused red and violet ends of the spectrum, light grasp, although quite good, is not equivalent to that of an apochromat of the same aperture. Side-by-side comparison revealed magnitude penetration and image brightness roughly equal to that of an excellent Takahashi Sky 90 APO.
Bright globular clusters such as M 13 and M 22 were partially resolved at powers of 67 and above, the just-visible stars being sharp pinpoints set against a dark background. This is a telescope that can effectively use enough power to penetrate to at least 13th magnitude under a dark sky. But the real beauty of the lightweight f/5 is best found at low power where its 2-inch focuser and wide field-of-view come into play. At 20x, using the standard 25mm Plossl supplied with the scope, the Andromeda Galaxy filled most of the field with delicate nebulosity, its two companion galaxies, a hint of dark lanes, and myriad foreground stars. In similar fashion, the Pleiades were neatly framed and quite striking with the faint stain the nebulosity around Merope being easily visible.
With the magnification increased to 56x by a 9mm Type 6 Nagler, the numerous open star clusters of autumn became attractive targets. The Double Cluster in Perseus was beautifully framed at this power, the “diamonds on black velvet” effect not too far from what one would expect from a good APO. The trio of Auriga clusters, M 37, 38, and 36 also revealed pinpoint stars, the scope’s inherent chromatic aberration being a non-factor on stellar objects fainter than magnitude 5 or so.
With nearly 4 inches of aperture, the Wide View is large enough to allow the use of a nebula filter. With a 20mm Erfle and Lumicon Oxygen III filter in the drawtube, I was able to spot both major segments of the Veil Nebula and discern a fair amount of detail. With the same configuration, the Helix( NGC 7293) appeared as a faint “Cherrio” embedded in a sea of dark chocolate milk – a neat sight!
Overall, I’m very impressed with the value that the 102mm Wide View represents. It does have a few shortcomings, but in light of its reasonable price, many observers would be very happy to have one. Clearly, this is not a telescope for purists who demand optical and mechanical perfection. The hefty doses of chromatic aberration alone might deter some. The standard finderscope is inadequate, the star diagonal really for terrestrial viewing, and the focuser (although smooth) overrun with Chinese grease making it too stiff. But these problems are not difficult to rectify. The novice observer might find this to be the perfect starter scope, especially if it’s purchased with the alt-az mount with tripod and the upgraded 6x30 finder. Then too, those who enjoy the virtues of the Orion Short Tube 80 or similar grab-and-go scopes could achieve a huge upgrade in performance and capability at minimal cost. Personally, I believe the 102 would be a perfect telescope for travel: it’s airline carry-on portable, fairly rugged, and inexpensive enough to remove the potential trauma of loss, theft, or damage. No, it won’t prompt anyone to put a Takahashi or AP up for sale on ASTROMART, but it will be a real pleaser for those who put a premium on value and love to “sneak a peek” at celestial sights through a semi-hopeless overcast.
Clear skies or a reasonable facsimile thereof!
Larry Carlino
Click here for more about this scope. -Ed.
Funding Member
