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TS 120mm 900MM FL ED Doublet

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#1 Charlie Hein

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Posted 03 August 2013 - 02:23 PM

TS 120mm 900MM FL ED Doublet Apochromatic Refractor

By Steven P. Sukel

#2 jrbarnett


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Posted 03 August 2013 - 03:50 PM

Well done, practical and comprehensive review of a really, really nice looking, tempting scope!

Thanks for the well-written, informative review.

- Jim

#3 wprince


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Posted 03 August 2013 - 09:56 PM

Thanks for the informative review. I really want a scope like that now!

#4 george tatsis

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Posted 03 August 2013 - 11:36 PM

Excellent review!

Certain changes need to be made in the Mag. Table because a 6mm eyepiece gives 150X, a 5mm is 180X, a 4mm is 225X, and a 3mm is 300X.


#5 spsesq


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Posted 04 August 2013 - 09:16 AM

Thanks for the input. I am not the author of the table. It's a plug in the value and it spits out based on aperture and focal length. The actual review has the correct magnifications for the eyepieces used in the observations. Thanks again for the input.

#6 spsesq


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Posted 04 August 2013 - 12:40 PM

Corrected below

#7 spsesq


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Posted 04 August 2013 - 12:44 PM

I went back to the table and I believe based on entering other scope specs they are rounded figures. For example the highest practical magnification for the 120 mm scope is 282x. The closest eyepiece to get you there is a 3mm. Hence, the tables format. The magnifications are not exact but rather what eyepiece to use to get to the theoretical limits. :idea:

#8 Gert K A

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Posted 09 August 2013 - 05:23 AM

Love it!.. Congratulations. It is a very tempting scope indeed.
Thanks for taking the time to share

#9 Traveler



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Posted 09 August 2013 - 05:35 AM

Hi Steven: you wrote a very nice review!

#10 dvb


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Posted 09 August 2013 - 03:58 PM

Thanks very much for the well-written review. I was looking very carefully at this scope, but jumped at a used Skywatcher Black Diamond 120ED f/7.5, which uses the same optics.

Like you, I am delighted by the optics and the aperture - for me, it will get a lot of use when I don't want to set up the 10" Newt.

Being used to the 10" and 8" apertures of Newts, I expected to be disappointed with the views from my light-polluted location (Red at best, probably White). I was not disappointed at all!

On a New Moon night, with great seeing, the Ring/ M57 was beautifully presented - obvious at 37x in with a Panoptic 24, and it just got better at 100x with a Nagler T6 9mm, a Delos 6mm, and a Nagler T6 5mm.

The Double/ Double (Epsilon Lyra) was beautifully split at 100x.

I'll look forward to your future reports - 120mm f/7.5 is a sweet spot for refractors - bigger is too much scope for me to handle (I had a 6" achro) less does give me the light grab I like (I had a 100ED).

#11 spsesq


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Posted 12 August 2013 - 07:41 PM

Thank you for all your comments. I am glad the review helped out.

#12 Maverick199


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Posted 21 August 2013 - 06:42 AM

Nice review and Jim's advice seemed to have clinched it.:grin:

#13 Teo79


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Posted 31 December 2013 - 12:04 PM

Hello Gents!
I'm Matteo, from Italy, and I need some help!
I'm desperately serching for a 120 ed refractor that could reach the focus with a baader maxbright binoview, without a focal multiplier!
I hope that this nice refractor can do that, but I need to know its exactly backfocus. Do someone of you have this instrument? How can I contact with Steven Sukel?

#14 SteveG



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Posted 04 January 2014 - 01:41 PM

Teo, I suggest you move this question to the refractor forum.

I have it's cousin, the WO Megrez 120. When I tried binoviewing, I had the cheaper Orion unit. I found that I could achieve focus without the correcter using a 1.25" diagonal. Hopefully some who has this scope can confirm.

#15 amicus sidera

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Posted 05 January 2014 - 12:08 PM

I'm in the market for a a 120mm-140mm apochromatic refractor, and at first glance this model looked inviting; however, while I'm sure that the views through this instrument are first-class, what I primarily took away from this review was that:

1. The interior of the focuser adapter was machined to tolerances that did not ensure compatability with one of the world's most popular 2" diagonals;

2. Dust particles that should never have been present within the tube at final assembly ended up on the objective during transit, necessitating partial disassembly of the instrument by the customer to rectify the situation;

3. No provision was made for affixing a finder scope and rings, apart from mounting them at a less-than-desirable position on the mounting rings, far from the eyepiece;

4. The objective is made in part from "secret" glass, if I'm reading the review correctly. This would seem to imply that no data or specifications are available for the material, especially as regards any potential hygroscopic tendencies or other physical aspects of the element.

I do not find the above issues acceptable in a plus-$2000.00 instrument.

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