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My Ideal Telescope


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Introduction

A small, fast refractor is the ideal telescope. The short focal length makes it almost as compact as a similar reflector while costing several times more. A rather restricted aperture enables one to practice their averted-vision techniques while searching for deep-space objects such as M31. Planetary observation is a strength of these instruments and the necessary magnification is easily obtained by stacking two or three barlow lenses. Chromatic aberration is an important criterion and these scopes have plenty of it. Higher quality scopes use exotic and expensive lenses that can actually reduce chromatic aberration to that of a good f/15 Tasco. With these points in mind, I set out to find my ideal scope.

I began my search by reviewing the latest offerings from the major manufactures. However, I longed for something different. Several months of searching the used telescope market turned up a lead. After careful consideration I purchased the short-tube refractor that is the subject of this review: the Fisher Price short tube shown in Figure 1. This model was only produced from 1986 to 1990. To buy one, you will have to find someone willing to part with theirs. Keep in mind that these scopes hold their value very well in spite of often being well used.

Figure 1. My ideal telescope: the Fisher Price Short Tube #6605. Brilliant red with handsome appointments, this scope stands out in a crowd.

Optical Tube

The tube is made in the United States from a light-weight space-age material. Unlike many other so-called high-end scopes, the manufactureÕs name is embossed and painted with gold lettering. Inside, the tube has a finish similar to its outside. The lens shown in Figure 2 is a high-quality air-spaced doublet. In spite of being almost a twenty-year-old design, the lens is heavily stopped down. The tubeÕs delicate objective is protected by an integral rubber dew shield. One feature that isnÕt found on any other high-end refractor is an integral storage compartment (see Figure 3) that also forms part of the dove tale. Overall, the fit and finish of the OTA are well above average.

Figure 2. The objective is an air-spaced doublet and the optical tube is well baffled

Figure 3. An integral storage compartment holds the filters.

Focuser

The focuser shown in Figure 4 is an excellent rack-and-pinion design with a generous 40 mm of travel. Control is very precise: thereÕs no glue grease on this puppy. The large knobs make focus adjustment easy even for those with very small hands.

Figure 4. The rack-and-pinion focuser is silky-smooth and has tonnes of travel.

Mount

A nifty matching table-top tripod is included (an option on even the most expensive modern refractors). Although very light, the mount is solid - in contrast to modern extruded aluminum mounts. Illustrated in Figure 5 is the very cool way the tripod folds for storage. Tension in altitude is adjustable.

Figure 5. The tripod folds for storage.

Eyepiece

This scope was available with a range of magnifications: this example has the very-wide-field 7X eyepiece. An unusual aspect of this scope shown in Figure 6 is that the eyepiece is integral to the star diagonal. It is well-matched optically to the main objective and has a rubber eyecup. Eye relief is excellent.

Figure 6. The eyepiece is integral to the star diagonal and has a slot for the included filters .

Accessories

Included were a number of specially-designed filters (Figure 7), which slide under the eyepiece. With these, image resolution and contrast improved several orders of magnitude.

Figure 7. Included was a set of very good filters .

Performance

ItÕs the lightest scope IÕve used and is an excellent Ògrab-and-goÓ scope. Set up and cool down was fast...really fast. The focuser is a joy to use and is certainly better quality than many Chinese-made units. Optics are textbook - in more ways than one. The low power eyepiece yielded a very wide field-of-view. Views of the moon were truly amazing with purple haze no worse than that produced by other high-end short-tube refractors. Galaxies and diffuse nebula were easily viewed by using generous quantities of averted vision. For astrophotography the scope was mounted to a Losmandy GM8 (see Figure 8) which is about the minimum requirement for this type of work: an EQ-5 isnÕt up to the task. As expected, views of planets are small, however the included filters improved contrast as illustrated by the image of Jupiter shown in Figure 9.

Figure 8. For astrophotography this scope is an ideal match for the Losmandy GM8.

Figure 9. This image of Jupiter was obtained through the eyepiece [it really was!] with a Canon A70 digital camera and a Fisher Price #4 red filter.

Conclusions

In the end is it a good scope? For the price you will be fishing to do better.




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