34 replies to this topic

[beanerds]

Another +1 from me when looking at the southern milkyway from a dark site and using a TV 19mm Panoptic the views were PERFECT ! as stars should look , and all the way to 300x with a 3mm Radian and 2x Ultima barlow was easy when the seeing allowed .

Stupidely sold it !@! .Here it is between my M210 and FS60C .

Beanerds.

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[samovu]

I’m debating at the moment if the FS102NSV makes sense when having the Sky90. I love both scopes, but they do overlap in aperture a little. As of portability the sky90 is hands down the best option.

I was reminded of this thread when someone “liked” my post a couple of days ago and I wanted to see what that post was. 
 

What did you decide to do with the FS102NSV? 
 

Cheers,

John

[Mcloud]

You know, Phil Harrington gave this telescope high praise in Star Ware as did Dickinson & Dyer in The Backyard Astronomers Guide. I've also seen lots of positive independent reviews. I think we may have a possible men in black conspiracy theory going on with the bad rap this Tak tends to get!

[Traveler]

My late best friend had a Sky 90II.

If there was anything wrong with his Tak, it was repairable. And although 90mm is relatively small, that makes the Sky easy to transport. He has taken his Sky everywhere, even to very distant destinations...

The reducer/flattener is indispensable for astrophotography.

 

I have very good memories of his Sky...

 

After a friendship of 30+ years, I miss my best friend still every day...

[SandyHouTex]

Actually my Sky 90 has the best serial number.  00007  "Bond, James Bond."

[chemisted]

Actually my Sky 90 has the best serial number.  00007  "Bond, James Bond."

I have to give you that but my SN 00018 has been in my possession since November of 2000 so I have you on longevity of ownership.

Edited by chemisted, 31 July 2022 - 07:25 AM.

[GQuestar]

Does anyone know what year/serial number the design changed to the Sky90 II; collimatable lens cell. I have #02128, but my dew shield won’t unthread to confirm if the extra screws are present.

[Richard Lynch]

Does anyone know what year/serial number the design changed to the Sky90 II; collimatable lens cell. I have #02128, but my dew shield won’t unthread to confirm if the extra screws are present.

My 2007 Sky 90 had the collimatible cell, and I don’t think it was a new thing, from memory.

 

I’m on my sixth Sky 90 now, having bought the first around 25 years ago. I keep thinking that my FSQ does everything that the Sky 90 can and has a flat field to boot. So, when thinning the herd the Sky 90 goes. However, I love Tak fluorite doubles and if I see one at a good price I can’t resist it.

 

After selling my Mk II here on Cloudy Nights a few years back I found my old Extender-Q, forgotten about in a case containing all my rarely used or redundant kit. It reignited my love of Tak doublets and I started looking for a Mk II. Couldn’t find one so when a Mk I came up last year I bought it, only for a friend to decide to sell his Mk II earlier this year.

 

The Mk I was shipped from the US to the UK, and was out of collimation on arrival. The vendor was quite honest about this, warned me it likely would be out of kilter and included an artificial star in the deal, telling me that he collimated it with the three recessed screws under the dew shield.

 

Whatever is said about collimating Mk I Sky 90s, I find both Mk Is and Mk IIs easy to collimate with a little time and care. Using the three screws on the Mk I, I carefully ‘centre’ the OG cell in the OTA and that seems to do the trick. Star and Ronchi tests both look very good.

 

I’m unsure about how the cell is designed, but I’m assuming the screws in the Mk I are seated in an internal recess and when the cell is centred properly the tilt is corrected by the screws seating correctly in its base. It takes maybe half an hour of careful adjustment, but it hasn’t ever been difficult so far. I assume that the Mk II holds collimation better but I’m pleasantly surprised by the ease of adjusting the Mk I.

 

Since I now have two Sky 90s I’m considering building a binocular scope, something I’ve considered doing with a pair of FS60Cs for many years but haven’t ever actually got round to…

Edited by Richard Lynch, 24 March 2025 - 04:41 AM.

[lwbehney]

@Richard- If I may ask, what attribute of fluorite doublets makes you feel so positively about them?  Did you compare views against non-fluorite refractors, and if so, did they perform differently in some way?

[Richard Lynch]

@Richard- If I may ask, what attribute of fluorite doublets makes you feel so positively about them?  Did you compare views against non-fluorite refractors, and if so, did they perform differently in some way?

Part of it is simple sentiment, my first real apo was an FS102 about 25 years ago. I was new to astronomy at the time though, with anything more than binoculars at least, and with it being my first decent scope everything looked good through it.

 

Whenever I’ve compared my FS128 critically with triplets of similar aperture the view is ‘clearer’ and the colours more vivid. I’m not sure if this is apparent sharpness due to greater colour contrast, or what it is. A friend and I compared the 128 with his custom-made 6” f12 triplet earlier this year, on Jupiter and Mars. We used Baader/Zeiss binoviewers and Tak TPL eyepieces in the main.

 

The view was a little brighter through the 6” but not dramatically. The 6” should have had the edge in resolution, and seeing was good enough to support it. Nonetheless, without being prompted, the other chap, also an experienced observer, commented that the view of Jupiter through the FS128 was sharper and the colours clearer. One of the white zones beneath the northern equatorial band stood out particularly sharply in the 128, almost three-dimensional to my eyes, and whilst clear in the 6” was somewhat less pronounced.

 

I’ve several LZOS triplets, 105/650 through to 152/1200, an AP130EDF GT and TSA102, but I tend to default to the 128 now for planetary viewing. Part of this is because it cools quickly - the LZOS152 takes well over an hour to settle thermally, though the TSAs are faster - and partly because my alt-az handles it comfortably, but mainly because I prefer the views through the 128. I sold my TSA120 a couple of months ago in favour of the FS128, and will likely sell one of the LZOS triplets soon.

 

I haven’t had the AP130 long enough to make a proper comparison, and I bought it mainly for travel to more southerly skies, but that should be interesting. It cools rapidly for a fast triplet and it would be difficult to atribute any differences to slow cooling, as for the LZOS OGs. 

 

My FC100DC comfortably outperformed a Mewlon 210, A&M/LZOS 130/780 and FSQ106ED during the Martian opposition in 2022, but that was almost certainly because of the rapidly falling temperature (the Mewlon was superb when cooled, on a steady night):

 

http://www.scopeview.../TakFC100DC.htm.

 

I’ve been a professional scientist all of my adult life, so I’d prefer to be able to give a more objective reason, but this is the best I can manage. I am not consciously perpetuating what some have called the fluorite myth, in fact I’ve ‘almost’ tried to be biased against it, but I really do find the FS128 in particular out-performs triplets of a similar aperture on planets. It is my second in 25 years, but that’s still a small sample size, and I haven’t owned either for more than a year, so maybe I’ve just been lucky.

 

Having said all this, a friend has just acquired an APM/LZOS 130/1200, and I may need to re-consider. In the the comparative images of the Pleiades here, taken with the LZOS130 and an FC100DZ, the difference is quite striking, even given the mismatch in aperture: 

 

http://www.scopeview...uk/TMB130F9.htm