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"A first-rate four inch aperture Apo that happens to be beautifully made in brass...as striking to look at as through"
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Above: TeleVue "102" telescope optical arrangement; 1. air spaced doublet objective, 2. 2" focuser, 3. 2" to 1.25" reducer (5,683 bytes) |
The objective lens of the 102 is of an SD air spaced doublet design where two lenses (crown and flint) are matched to work as one; the positive element is of a fluorocrown substitute with special dispersion glass. In fact this design allows excellent color correction without annoying purple fringes (secondary color) common to less sophisticated achromatic refractors. And it will perform better than a number of older triplet and modern doublet apochromat designs. There will be a barely perceptible false color in this design, and what there is may be visible only to the more discriminating observers when using the telescope at very high magnifications well in excess 300x on some of the very brightest starts. Spherical correction is very good also with the air gap objective contributing to this correction. Images of the stars and the planets are presented in their natural colors, daytime objects viewed at commonly used magnifications will appear quite three dimensional, sharp and high in contrast.
The objective's four air to glass surfaces multi-layer anti-reflection coatings improve overall light transmission across the visual wavelengths and from 400nm to well beyond 700nm. Overall the complete system provides about 202 times the light gathering power of the unaided human eye. On most nights, the settling down time for the lens is on the order of minutes: from room temperature to sub-freezing conditions it rarely requires more than 30 minutes to acclimate.
Company Seven's Q.C. testing of each telescope we receive has shown the lenses are well figured and the design so refined that the consistency between telescopes is quite good; each is capable of operating at very high magnification cleanly (even with optional "Barlow" or "Powermate" lenses). This telescope reaches the threshold necessary to routinely obtain meaningful views of the planets; showing several bands and their shades of color (beige, tan, browns) on Jupiter, observe the four largest moons of Jupiter and their shadows cast on the surface as distinct discs as they transit across the planet! Study the Cassini division and banding on Saturn, the polar cap and dark markings on a fiery red Mars. With an eyepiece that shows 1/2 degree field or so (such as an 8mm "Radian") take a walk on our apparently three dimensional Moon possibly resolving objects on the Moon as small as 4.4 km in diameter. Or follow its' terminator throughout the moon phases (optional neutral density filters suggested to attenuate the brightness). With an optional white light solar filter (such as our Baader AstroSolar film) one may view Faculae and Sunspots on the Sun! With optional Hydrogen Alpha filters (such as our DayStar ATM or University series) observe Faculae, Sunspots, the Peach-fuzz like photosphere on the Sun as well as the sheer curtain like Prominences as they erupt from the Sun out into the blackness of space!
Included with the telescope is the TeleVue 90 degree angled 2 inch diameter "Everbrite" Mirror (or "Zenith") Diagonal incorporating a high precision 1/10th wave P-V mirror. This accessory makes the observing of objects overhead more comfortable. The male 2 inch barrel is threaded to accept 48mm photo and visual filters. The interior is fully anti reflection ribbed and coated. A 2 inch to 1.25 inch reducer adapter is furnished to permit the use of 1.25 inch diameter accessories. This diagonal permits an observer to employ any of a broad selection of 2 or 1.25 inch diameter oculars. The lock screw with a knurled head that is at the proximal (to the operator) end of the female 2 inch barrel adjusts tension to retain accessories such as the 2 to 1.25 inch reducer or lenses; this set screw is captive and so it too will not easily come out. The "Everbrite" mirror was introduced in 1999, it features a very high-tech dielectric coating (developed originally for military optics used in hostile environments such as blowing desert sand) which provide optimum performance and years of use. This new TeleVue 2 inch diagonal has no aluminum or other reflective metal coating. Instead, the reflective surface consists of 52 layers of thin film oxides similar to those used in anti-reflection coatings. The coatings are deposited by an electron beam evaporator at a high temperature. The result is that reflectivity is above 99% over the entire 4000 to 7000 Å (Angstrom) photo-visual range. Thin film coatings have extremely low surface scatter compared to aluminum or enhanced aluminum coatings; examination with a laser source shows approximately a five fold improvement in surface scatter. The mirror diagonal provides a comfortable viewing position for the observer by diverting the image at the rear of the telescope off axis by 90 degrees to the side, with minimal degradation of image quality. The view when using the telescope as it is provided will appear to be right side up, and is reversed left to right; this is not usually a problem for astronomy or nature observing because the image quality provided by the high quality mirror and 2 inch diameters panoramic oculars is exceptional.
Above: TeleVue 102 Renaissance telescope 2" Focuser with TeleVue engraved Everbrite 2 inch Mirror Diagonal (54,505 bytes), and telescope with Company Seven's option of 2" Focuser with Astro-Physics Maxbright 2 inch Mirror Diagonal and brass fittings (54,505 bytes). Telescope is shown with the optional Televue Starbeam sight installed atop its mounting collar. |
With TeleVue's 2" focuser and a matched wide angle ocular the 102 reveals its very good wide field of view ability showing up to 3 degrees at 16X to reveal the entire Messier Catalog of deep sky wonders, or to be employed for panoramic viewing of a seashore or countryside. Imagine a telescope that at a dark sky site has the combination of resolving power and field of view to sweep the Milky Way, see the Double Cluster in Perseus (NGC-869), find the Andromeda galaxy (M-31) and see it's ellipsoid shape, and with no doubt see the distinct forms of large Nebulae such as the Veil and North American Nebulae! With a wide angle eyepiece the TeleVue 102 can reveal all three stars of Orion's belt, closer in it reveals the jewel like stars of the Trapezium - a birthplace of stars, with a sweeping wisps of greenish gas clouds surrounding it. With a higher magnification M13 (the Hercules star cluster) takes on a three dimensional "salt and pepper" appearance even from suburban skies on a clear night. By the time one finds a large enough aperture Catadioptric, reflecting, or achromatic refractor to see similar detail, then one can only see a fraction of their area due to the relatively high focal length of these competing telescopes; with other telescopes it would be something like trying to observe the night sky through a straw!
In fact, one of the finest advertisements ever published for a telescope concept is the book Deep-Sky Companions: The Messier Objects where the author Stephen O'Meara sought to keep the drawings relevant to the amateur. To produce the highly detailed drawings of these celestial objects Stephen chose to observe with the second generation TeleVue "Genesis" telescope (4" aperture, 500mm f5) which has since been replaced by the improved 101 and 102 apochromatic telescopes. This book has become one of our best advertisements for the versatile, readily transportable fast 4 inch (10cm) refracting telescopes. Similarly to keep things simple, and relate as much as possible to the average amateur observer Stephen chose to use the telescope on the simple but sturdy TeleVue "Gibraltar" alt-azimuth mount with Ash Wood tripod. He equipped the telescope with only a modest selection of accessories: TeleVue 22mm "Panoptic" eyepiece (providing 23X, 2.85 Degrees Actual Field of View), a 7mm Nagler eyepiece (71X, 1.08 AFOV), and a TeleVue Barlow lens to increase the magnification by 1.8X.
The 3 degrees provided by the 102 compares favorably against many telescopes in field of view:
In fairness, the cost the TeleVue 102 (equipped with either an optional Alt-Az or Equatorial mount) is positioned at a higher cost than most of the above telescopes. And as a practical matter for some applications in astronomy the nominal match of the "102" exit pupil to an average dark adapted human eye will be obtained at magnifications of between 20X and 16X. The best performance will be obtained at all magnifications if a wise choice of good quality oculars is made however, since the 102 telescope incorporates a focal ratio of 8.6 then it is compatible with most of the simpler eyepiece designs. Again consider that an optional good quality "Barlow" or "TeleVue Powermate" amplifying (negative) lens, or optional long eye relief TeleVue "Radian" ocular (introduced in 1999) will usually be put into use to attain the highest use able magnifications which are necessary for observing small bright objects including planets, and double stars.
The TeleVue 102 Renaissance can operate on any of a number of suitable optional German Equatorial or for extreme ease of use or portability consider our alt-azimuth mounts including:
Furthermore, this is a telescope one can grow with since most of the accessories that one would buy for this telescope are upwardly compatible with any larger telescope that one is likely to buy at Company Seven.
The 102 Renaissance has a fully machined aluminum front cell to house the objective lens and focuser housing with a captive retracting Dew Shield/Lens Shade, and a fully machined rear cell and 2 inch diameter rack and pinion style Focuser with brass drawtube. The interior of the optical tube assembly, including the focuser drawtube, are lined with an anti-reflective covering unique to TeleVue telescopes. This is then finished with anti reflective black paint. Also provided is a thread-on Lens Cover of machined aluminum resulting in a tube assembly that has an overall length of only about 33 inches even with it's 2 inch diagonal attached. The objective lens is permanently aligned to the barrel as is the focuser assembly. Unless subjected to gross abuse this telescope will provide many lifetimes of service with no need for any other than cleaning of the front surface of the objective lens using common camera lens cleaning techniques. Its construction is extremely rugged to allow it to withstand all the handling that is typical of airline travel. However, some caution should be practiced not to damage the focuser pinion of any telescope; our experience with this focuser is that with routine handling this will not happen and in its hard shell case is routinely transportable.
Above: TeleVue 102 Renaissance telescope at Company Seven showing open 2" Focuser Drawtube (53,288 bytes).
Click on image to see enlarged view (160,577 bytes).
The precision TeleVue 2 inch focuser is a rack and pinion design with a tension/lock screw which helps to lock focus for uses including photography; this is one of the smoothest focusers made. The 1-1/2 inch diameter machined aluminum hand knobs resemble model car brushed aluminum mag wheels. The knob hand grips are rubber covered to facilitate operation in all extremes; even when wearing gloves all the controls on the telescope are easy to manipulate. The set screw has an easy to grip knurled head, this permits one to adjust resistance of the focuser to its draw tube thereby compensating for heavy loads that might otherwise cause an unintended shift of focus. The lock screw that is in the draw tube ring at the proximal (to the operator) end of the draw tube adjusts tension to retain accessories such as the optional 1.25 or 2 inch diagonal, or a camera; this set screw is captive so it will not easily come out.
The objective (front) lens cell, focuser housing, mounting collar, and diagonal are anodized in a lustrous black finish. The barrel and focus drawtube are made of a seamless solid Brass that feels cool to the touch, and smooth with an almost slightly lubricated feel! Periodic cleaning with a Brass Polish (about once a year) will maintain the bright brass sheen, or if left over time it can develop a golden patina. The optical tube interior is lined with an anti-reflective covering unique to TeleVue telescopes, which is then finished with anti reflective black paint.
The TeleVue Mounting Collar is included with this telescope. This is a two piece machined aluminum bracket that permits the attachment of the telescope optical tube assembly onto an optional mount such as the TeleVue Gibraltar mount and tripod system or onto third party alt-azimuth or German equatorial mounts. On one side of the collar is an Allen head screw (wrench provided - but not necessary), while on the other side is a manually operated tension adjustment knob. This design permits one to adjust the grip on the barrel so that the telescope may be easily moved back and forth to compensate for changes of accessory loads that may affect the balance of the telescope on a mount. At the 10:30 and 1: 30 o'clock positions on the top of this collar there is a female dovetail platform to accommodate a variety of TeleVue options including the "Starbeam" sight, or a
Included with the telescope is a die cut, foam lined hard shell carrying case with latch closures. This case is 38-1/2 x 10-1/2 x 9-1/2 inches in dimension, and it has extra space to accommodate several 1.25 and 2 inch oculars, a camera adapter, etc. And in a nice touch the case has a cutout provision for the optional Starbeam or Rigel QuikFinder sights. The case will fit into the overhead storage area of most commercial aircraft (one exception being the L-1011). However, many airlines do not permit such "oversize" packages on board; even if they do you will not be too popular with other passengers so you might ask a Flight Attendant to store the telescope for you - possibly in the garment bag storage area.
The telescope, in it's case is well padded and then packaged for delivery within one box, and then this is placed into another box. We suggest that telescopes such as this be sent by a priority air service (FedEx, UPS, U.S. Mail, etc.) to reduce risks of loss or damage in shipment. If you intend to ship the telescope regularly, or check in the telescope on airplanes then you should consider buying a Company Seven Airline Transport Assoc. Appoved transport/shipping case.
Above Right: TeleVue 102 Renaissance telescope at Company Seven with optional Starbeam sight on Gibraltar Walnut finished stand (84,304 bytes).
* Specifications are subject to change without notice.
Right: TeleVue Ash Gibraltar Mount with optional telescope, Starbeam Sight, Eyepieces and SkyTour CPU on Accessory Tray.
The mount head is made of fully machined of aluminum which is black anodized, with brass elevation bearings and azimuth nylon bearing providing smooth vertical travel from 10 degrees below the horizon up to 85 degrees overhead, and smooth full 360 degree rotation. Clutches on the elevation axis permits the operate to compensate for changing accessory loads, or with the Azimuth control to lock the telescope in place. The tripod is made of American ash, in a two section extension design providing a range of 3 feet up to 5 feet, with accessory tray/leg brace. The "Gibraltar" mount solved a problem of ease of use for those who are frustrated by the weight and relative complexity of equatorial mounts, and it provides a mount far better suited to terrestrial applications than an equatorial mount or common camera tripod would be. These mounts remain available with either a beautiful ash tripod in natural finish (Yes, ash is the hard wood used to make baseball bats)with black trim, or a in solid walnut. Since it's introduction the "Gibraltar" head has been engineered to accept optional encoders to feed a "Digital Setting Circle" CPU such as that offered by TeleVue and third party units; this helps one to navigate the sky and find objects that might be hard to find particularly from suburban settings.
* The telescope is capable of operating at magnifications greater than listed in this briefing above.
Above: Company Seven ATA Case custom fitted for a TeleVue NP101 telescope and accessories (138,840 bytes).
Features include:
Please contact Company Seven for additional information and pricing.
TELEVUE 102mm f8.6 TELESCOPE SPECIFICATIONS
Specification
Clear aperture:
101.95mm (4")
Focal length:
880mm (34.6")
Resolution (visual):
1.15 arc seconds
Resolution (photo):
260 line pairs per mm
Coatings:
Multi-layer
Magnification range:
16x to 360x
Tube assembly:
Seamless brass tube; fully baffled,
permanently aligned cell construction
Focuser type:
2 inch rack and pinion
Focuser Travel:
2-3/8 inches
Telescope length with diagonal:
33-11/16 inches (85.56cm) dew cap retracted
OTA with 2 to 1-1/3 Reducer Weight:
12 lbs. 8 oz. (5.68 kg kg)
Weight with Collar, Diagonal, Reducer:
15 lbs. 2 ounces (6.88 kg)
Shipping Weight:
33 lbs. (13.2 kg)
Shipping Dimensions:
40 x 13 x 10 inches
35mm prime-focus field:
2.28 x 1.6 x 2.8 degrees @ f8.7
35mm field with Focal Reducer:
2.9 x 2 x 3.5 degrees @ f6.9
35mm field with 2x Barlow:
1.1 x 0.8 x 1.4 degrees @ f17.4
Click on image to see enlarged view (205,107 bytes).
SUGGESTIONS
Suggested options include either a 2X or 3X "Barlow" or 2.5X "Powermate" lens, and some of these oculars:
Mounting Rings: sold by the pair, each is a hexagonal split ring hinged bracket used to attach the telescope onto one of a number of available German Equatorial mounts. On one side of each ring is a knurled hand knob (wrench not necessary) so that one may loosen the grip of the rings and then adjust the the optical tube assembly back or forth (on the felt lining) to balance of the telescope on a mount. At the top and bottom of each ring there is a platform with threaded holes to accommodate a variety of TeleVue and third party options such as a photo-guide telescope. Most third party Mounting Rings are not compatible with the TeleVue Gibraltar mount and tripod system, nor will they readily fit into the provided telescope carrying case.
Eyepiece
Magnification
Actual field of view
Exit pupil
55mm Plossl
16x
3.0 degrees
6.38mm
35mm Panoptic
25x
2.52 degrees
4.06mm
31mm Nagler Type 5
28x
2.71 degrees
3.59mm
27mm Panoptic
33x
1.99 degrees
3.13mm
22mm Nagler Type 4
40x
2.03 degrees
2.55mm
22mm Panoptic
40x
1.62 degrees
2.55mm
20mm Plossl
44x
1.11 degrees
2.32mm
17mm Nagler Type 4
52x
1.58 degrees
1.97mm
12mm Nagler Type 4
73x
1.11 degrees
1.39mm
9mm Nagler
98x
0.80 degrees
1.04mm
8mm Radian
110X
0.54 degrees
0.93mm
6mm Radian
147x
0.41 degrees
0.70mm
5mm Radian
176x
0.35 degrees
0.58mm
Eyepiece
Mag. w/2X 2 Inch Barlow
Actual field of view
Exit pupil
35mm Panoptic
50x
1.26 degrees
2.03mm
31mm Nagler Type 5
57x
1.36 degrees
1.80mm
27mm Panoptic
65x
0.99 degrees
1.56mm
22mm Nagler Type 4
80x
1.01 degrees
1.28mm
22mm Panoptic
80x
0.81 degrees
1.28mm
20mm Plossl
88x
0.56 degrees
1.16mm
17mm Nagler Type 4
104x
0.79 degrees
0.99mm
12mm Nagler Type 4
147x
0.56 degrees
0.70mm
9mm Nagler
196x
0.40 degrees
0.52mm
8mm Radian
220X
0.27 degrees
0.46mm
6mm Radian
293x
0.21 degrees
0.35mm
5mm Radian
352x
0.17 degrees
0.29mm
Contact Company Seven for additional advice about outfitting the 102 for high magnification observing.
Click on image to see enlarged view (240,578 bytes).
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