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Kowa 99A astro experience (1 Viewer)


Well-known member
United States
I use 99A for birdwatching and natural observations. My early review is posted here:

One interesting specs of 99A is it can use 1.25 inch astro eyepieces with adapter. After owning Kowa 1.25” grub adapter, I have tested astro eyepiece.
1. Explore Scientific 24mm 68 degree: it is a great eyepiece giving 25x with great resolution and contrast.
2. Baader Morpheus 17mm 76 degrees: it cannot reach infinite focus (maximum 250 m). It gives very sharp image with good contrast.
3. Svbony (APM clone) 9mm ultra flat eyepieces: it gives surprising good contrasty image and nice eye relief.
4. ES82 series eyepieces can’t reach focus at all.

New to astro and interested in learning astronomy. Have az-gti goto mount with 99A to learn astronomy.
Visual using te-11z zoom w/ or w/o 1.6x. Venus is bright crescent without CA. At ~110x Jupiter is observed its stripes in good viewing conditions. Stars in the field of view are pinpoint sharp and round.
Interestingly, observing Deep Sky Objects (DSO) is much better to use camera to take pictures for 60-300 seconds exposure. Photos with long exposure can show very good details and colors. Attached M42 and M31 taken from 99A with QHY178 astro camera with ax-gti at equatorial mode.
40CCC0EA-9E7D-43DB-BB58-7C6D69512F95.jpeg CE936338-E08C-4FCF-A08A-173D270E4E9F.jpeg 621BDAD4-5F4F-4342-8B68-6CC9AB2FA709.jpeg

In summary, it is very fun to use 99A in both birdwatching and astro.
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Well-known member
Hello. Thanks for your impression. I am using the Kowa TSN-99 with some high resolution eyepieces, s as Takahashi HI-LE 2.8mm and Vixen HR. I observe the bisected dome near Birt and some other features similar to some large 90 and 100mm refractor telescopes. Obviously for my lunar and planetary observations I use a Takahahsi FS 128 but I really appreciated the contrast and the better color correction compared to a common ED doublet like that of the Sky-Watcher ED series.
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Well-known member
Hi Piergiovanni,

But is any more seen than George Alcock saw with his Ross 100mm f/12 uncoated Ross triplet refractor?

Or Dawes with his 158mm uncoated refractor.

Jupiter is low nowadays, but is detail seen on Jupiter's four Galilean moons with the Kowa 99 or the Takahashi 128mm refractor?

Dawes drew quite good detail on these moons with the 158mm refractor and George Alcock's drawings of Mars with the Ross100mm triplet equalled then current 400mm reflectors used by his fellow astronomers.
George Alcock's observations were not believed and he switched to discovering comets and Novae with a Schneider 25x105 triplet objective binocular.

I truly doubt that the Takahashi 128mm refractor equals what I saw on Mars with Horace Dall's 204mm Maksutov at 400x through his loft hand finished plate glass window.

Best wishes,
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Well-known member
Hi Piergiovanni,

I looked up the Takahashi FS128, and it is a fine telescope with a properly long focal length.
It is also a surprisingly low price.
It is a telescope that I would like to use.
I don't know if it would survive 100 years as do old telescopes.

What I am pointing out in the previous post is that in 180 years there has not been a big advance in refractor telescopes.

Also that a good big telescope is better than a good smaller telescope, i.e. aperture matters.

Also, that the acuity and experience of the observer is all important.
And the choice of observing location, timing, and choosing very fine observing conditions.


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