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Details
TEC APO 140 f/7 Tripelt Apochromat
The TEC APO 140 has a number of features that in a given combination are rarely found in one scope:
- Precision apochromatic objective with modern coating that makes lenses almost invisible
- Oiled and fully sealed lens triplet, for fastest thermal adaptation and minimum of haze and reflections
- Retractable baffle
- Light tube assembly
- FeatherTouch 360° rotatable focuser with coarse and fine focusing
- Collet type eyepice holder
- Line of accessories, including: Precision tube rings with adjustable latches, Dovetail plate (same width and fit as Losmandy plates), Finder bracket with new principle of finder adjustment, Choice of two kind of cases.
- APO140 is an Aplanatic Oiled Triplet refractor with ED glass (FPL-53) as a middle element.
- The color correction is optimized for visual use with focus shift less than 0.02% from 436nm to 1000nm. Calculated Strehl for e-line (546nm) is 0.99.
- Intereferometry of the first run lenses showed that the average Strehl is close to calculated with a very smooth wave front and RMS less than 1/50. air-spaced objectives. The outside surfaces of front and rear lenses are coated with 7 layers of antireflective coating, that reduce light reflection to the average 0.25% in range of 400-700nm.
Specifactions
Clear aperture 5.5" / 140 mm Focal length 980 mm Focal ratio 7.0 Image scale 3.5 arc min/mm Resolution (theoretical) 0.8 arc sec Focuser Feather Touch 3545 Eyepiece holder 2" Collet type Focusing range 4.5" / 114 mm One turn focus travel Coarse 21.5 mm / Fine 2.3 mm Back focus distance 6.7" / 170 mm Focuser load capacity 10 lb Tube assembly diameter 5.9" / 150 mm Baffle dia. 7" / 178 mm TA length (shortest) 34" / 864 mm Balance point position 14" ± 1" (350 mm ± 25 mm) from the focuser flange OTA weight 19 lb / 8.6 kg / (for tube rings - add 2 lb) Lens coatings: Broad band 7 layers antireflection coating (BBAR) Includes : Optical tube assembly, front cover, plug. Pictures taken with TEC APO 140 ED
More pictures are available here: Homepage
Recommended 0.72x Telecompressor Corrector # 140 5371 of Astro Physics
This Reducer/Corrector reduces the focal length of the 140 ED from 980 mm to 700 mm and gives you a focal ratio of f/5. For a full frame camera (24 x 36 mm), this results in a field of view of 3 x 2 degree at an image circle of 50 mm, diffraction limited and free of vignetting.
Related Articles
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Apochromatic Triplet Objective: Why oil-spaced lenses?
Why an oil-spaced triplet-lens? The first successful experiments with oil-spaced triplet-lenses were probably done by Wolfgang Busch from Ahrensburg, who had several discussions about this with Carl Zeiss Jena, back in the days of the German Democratic Republic. Even then, this technique was far superior to the standard technics like air-spaced or cemented lenses. But it was hard to keep the joining medium inside of the lens, because of insufficient synthetic oils and many other reasons. Because of this, the lens could freeze or dry out. It took Zeiss more than ten years of research to solve these difficulties and present the first APQ-lens. Besides Zeiss, only Astro-Physics and TEC were able to produce long-lasting oil-spaced lenses. It takes some tricks and knowledge to keep the oil (if the fluid can still be called oil) inside of the lens – at least over a long period of time with always-changing temperatures. But with the necessary craftsmanship and patience, it can be done. Nevertheless, many people still think – wrongly – that an oil-spacing is especially prone to aging. This is surely true if you didn't master the technology, but we want to present a list of the pros and cons...
Additional Information
| General | |
|---|---|
| Manufacturer | TEC |
| SKU (#) | 1351000 |
| Manufacturer SKU (#) | 140 700 |
| Weight (kg) | 11.6 |
| Optics | |
| Optical Design | Apochromatic Refractor |
| Clear Aperture | 5.5" (140mm) |
| Focal Length | 980 mm |
| Focal Ratio | f/7 |
| Back Focus Distance | 6.7" (170mm) |
| Tube diameter (max) | 5.9" (150 mm) |
| Image Scale | 3.5 arcmin / mm |
| Optical Tube Weight Copy | 19lb (8,6 kg) |
| Mount | |
| Included Items | |
| Focuser | Feather Touch 3545 |
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