Kowa TSN-99A PROMINAR Review

Long Term Review - Kowa TSN-99A PROMINAR angled spotting scope, TE-11WZ II 30-70x wide zoom eyepiece and Kowa TE-80XW Extreme Wide Eyepiece

By Brian J Small


There is no doubt the Kowa TSN-99A is a very good telescope and must be considered by those wanting the best.However, even before you open the box, it is obvious that the TSN-99A, with its 99mm objective lens, is a size up from the TSN-883, with 88mm objective.

Brian J Small

Over the past five months I have been able to use the Kowa TSN-99A along with two eyepieces, TE-11WZ 30-70x and the 40x wide angle TE-80XW, also I have been able on many occasions to compare it directly with my own older model Kowa TSN-883 using both eyepieces, which on the smaller body give 25-60x and 35x respectively.

There is no doubt the Kowa TSN-99A is a very good telescope and must be considered by those wanting the best. However, even before you open the box, it is obvious that the TSN-99A, with its 99mm objective lens, is a size up from the TSN-883, with 88mm objective. Alongside the larger diameter of the glass on the TSN-99A there is an increase in length and weight – all of which will need to be born in mind by prospective buyers.


Out of the box the new styling on the body is eye-catching, with slightly brighter olive-green paint and plastic covering near the eyepiece mount. The tripod mount is also redesigned. The dual-focus system used by Kowa is very pleasing to use, with both quick and fine focus wheels operable by two fingers: smooth and accurate the telescope moves minimally during use. In comparison, the barrel/helical focusing on the large Swarovski (sited next to the zoom wheel) requires the whole hand to turn it and can cause more vibration when turned. A solid tripod must be used with this ‘scope; the extra 350g extra weight (almost 20%) necessitates it as there is more vibration movement than with the 883.

With the TE-11 zoom eyepiece attached the image is bright and, especially when seawatching on early autumn watches, lets a lot of light through. The fact that the zoom starts at 30x compared with 25x on the 883 negates much of the point of the larger objective as the 99 has a 3.3mm exit pupil compared with 3.52mm on the 88mm. Likewise, the angle of view is greater on the 88 due to the 25x lowest magnification. In direct comparison, I found little or no difference in the quality of the image on the 99A and 883; both were excellent and I still believe the image of the Kowa is unsurpassed. The larger glass of the 99A produced some slight artefacts around the edge of the image that were not apparent on my 883; I have seen the same fall in quality on the huge 115mm Swarovski module with an ATX eyepiece.

Switching to the TE-80XW wide-angle eyepiece, I found the image incredibly immersive, a result of both the relatively large magnification and superb wide angle of view – the same feeling can be had with the Swarovski BTX dual eyepiece. On the 99A the magnification is 40x and on the 883 it is 35x. This eyepiece is very enjoyable to use as it gives such a wide view, however I again found the image better and the view wider when on the 883 with its smaller magnification. It is perhaps a personal thing and I would certainly suggest that my experiences may not be matched by others.

Further, and this may also be a personal preference, I still question the need (obsession) for such high magnifications. Given the facts that the image is better and brighter at lower magnifications, also the angle of view wider, and that many people digiscope, which is much easier and again of better quality at a lower mag, I would much prefer a zoom eyepiece that starts at 20x and ends at 50x and a wide angle of 25x.


As I stated earlier, no doubt this is a fine telescope – one of the best – but as a bird guide I do a lot of traveling in the UK and abroad and have to balance weight with optical quality. The size and weight of the 99A is prohibitive for me and I believe that the quality of the image on the 883 is so good (maybe on the units I compared better) that my decision would be an easy one. Also, I would possibly need to upgrade my tripod, which adds further to the financial and physical burden. Then there is the financial burden…

I can thoroughly recommend the TE-80XW eyepiece especially if you have the TSN 883.

SMARTOSCOPE VARIO - Universal Smartphone Digiscoping Adaptor

Alongside my time with the 99A, I was also able to use the new metal universal smartphone adaptor, which can be set to be used with different sizes and shapes of phones.

It is a simple device that clamps to the phone sides by a knurled ring; the attachment for the telescope is then moved to align with the camera on the phone and the exit pupil of the eyepiece. This set up is easy and handy if you change your phone or use different-sized phones, but it is quite heavy. I found that it even when pushed on quite securely to the eyepiece it sometimes drooped and did not view straight through the exit pupil.

The system I use personally is the dedicated smartphone adaptor, made specifically for my phone. This unit is plastic and lighter and never drops and is much easier to carry/set up.