Pentax Eyepieces & the PF 80mm ED–A Spotting Scope
Spotting scopes are both simple and complex instruments. The front end, the objective, is of fairly straight forward design. Two types of glass/ fluorite and anything between 4 – 6 shaped surfaces. The size of the objective lens will determine the light gathering capacity while the quality of the elements will determine the purity of the image - in terms of colour, contrast, sharpness and distortions. But all it will do is create a tiny image inside the barrel of the scope.
The XW series of eyepieces are heavier and bigger. They are much more complex in construction. They are among the most sought-after eyepieces by astronomers. The XW series can be segregated into those with an 850 apparent angle of view. These two eyepieces are specifically designed for astronomy. These are XW 23 and XW 16.5.
For decades, Pentax has been enjoying a reputation for being the manufacturer of some of the best eyepieces for astronomy in the 1.25-inch mount. They have the simpler XF range and the larger, complex XW range of eyepieces. Most users are unanimous about the performance of these eyepieces in terms of colour fidelity, aberration correction, contrast, field and eye relief. The lightweight Pentax XF eyepieces come in 8.5mm, 12mm and the 6.5-19.5mm zoom eyepiece. The magnification, field, eye relief exit pupil each of these eyepieces offer varies with the scope being used.
Just as birdwatching is a popular hobby and the industry has designed equipment to maximize the pleasure of birdwatchers, amateur astronomy too is a popular hobby all over the world. There are instruments designed specifically to watch the night sky and celestial objects. For an astronomer, the telescope he uses is as important as the eyepieces he uses. The 2 inch and 1.25-inch standard astronomy mount are by far the most popular and standardized eyepiece mount sizes and various manufacturers offer a wide variety of astronomical eyepieces in these mount sizes. These are serious optics – often large, heavy and expensive.
For decades, Pentax has been enjoying a reputation for being the manufacturer of some of the best eyepieces for astronomy in the 1.25-inch mount. They have the simpler XF range and the larger, complex XW range of eyepieces. Most users are unanimous about the performance of these eyepieces in terms of colour fidelity, aberration correction, contrast, field and eye relief. The lightweight Pentax XF eyepieces come in 8.5mm, 12mm and the 6.5-19.5mm zoom eyepiece. The magnification, field, eye relief exit pupil each of these eyepieces offer varies with the scope being used.
For the purpose of bird-watching I shall restrict the discussion to the XW8-24 zoom eyepiece and the XW14.
The 8-24 X zoom eyepiece is big and heavy at 550gms. Excellent fit and finish it offers a field of view of 40mts – 21mts on the 65mm scope and 31mts – 16.5mts on the 80mm angled scope (both figures are at 1000metres).
As you zoom in however, the field becomes narrower and darker.
Over all the view is excellent with very good colours, contrast and sharpness and very little aberrations.
The XW14 eyepiece, at 365 grams is lighter than the former. It has a 44 mts field on the 65mm scope and a 33 mts field on the 80mm scope (@ 1000 metres). The eyepiece glass is huge and the view through it is akin to seeing a wide screen TV in 4K. Absolutely sharp and bright with marvelous colours. I find the 37X magnification on the 80mm angled scope perfect, 99% of the time. The wide view is priceless. Reds, greens and blues are shown with fidelity and the resolution is superb
Now let us talk about the scopes themselves. What Pentax has done is that they have designed scopes to suit the superlative eyepieces. The objectives have ED glass and the prisms are phase corrected. The coatings are excellent, both on scope and on eyepieces.
As you might have guessed by now the scopes come in angled and straight forms. The 65mm scopes are around 1 kg in weight and the 80mm scopes are around 1500 gms. The 100 mm scope is 2 kgs. The minimum focus distance with the eyepieces mentioned is around 5 mts approx. The eyepieces slide into scope barrel and the base is tightened through the turning of a ring. The focusing knob is single and on the barrel and has very smooth operations. The scopes have black rubberized armour and a sliding objective hood. The 80mm scope is fairly large in size but not ungainly. It balances well when on a tripod. Do remember scopes need good tripods for stabilization.
These scopes and eyepieces provide excellent value for money, especially when compared to the much more expensive scopes from European manufacturers. The difference here is the eyepieces which offer some of the most pleasing views of them all.
