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TSA102 Bench Test

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#1 gjanke

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Posted 17 February 2020 - 12:50 PM

So I got this TSA102 last year off of AM. I have done several upgrades to it to include the starlight FTF3035B A Feathertouch 3.0" dual speed focuser with 3.5" draw tube. It replaced the Tak draw tube and starlight micro focuser. The tak draw tube had been used by the previous owner for binovewing and had taken a toll on the functionality of the focuser. I was able to pick up the SL draw tube focuser and finder used from a nice gentlemen from Australia. In addition I was lucky to Paul Leuba locally and had him do a bench test on the scope. Here is the summary of the bench test.

 

There are no real zones to speak of and I saw no polishing artifacts. The lens is slightly under-corrected this could be caused by the lens being at a different temperature then the surrounding air.  Usually a lens will show marked undercorrection as it reaches thermal equilibrium.

 

Here is the breakdown by color:

White its slightly undercorrected.
Green very slightly undercorrected.
Red its slightly undercorrected
Blue is slightly overcorrected.

 

The red and the blue are almost always opposite with one being undercorrected and the other being overcorrected.  Its done this way to balance the ends of the spectrum.  Best correction is always in green.  And your scope is no different.

There is no turned edge and the optic is very smooth. 

 

Summary: The lens is overall quite good; really good; high contrast etc.

 

 

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#2 gjanke

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Posted 17 February 2020 - 12:51 PM

Heres the white 

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#3 Tyson M

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Posted 17 February 2020 - 12:57 PM

The TSA102S was one scope I regret to have let go.  Everything was clinical and high contrast.  Best view of the moon I ever had.

 

"The lens is slightly under-corrected this could be caused by the lens being at a different temperature then the surrounding air.  Usually a lens will show marked undercorrection as it reaches thermal equilibrium."

 

How long did you wait before doing the DPAC?   Edit: if cooldown wasnt the issue, is it possibly because it wasnt in the basement or otherwise a thermally stable room?


Edited by Tyson M, 17 February 2020 - 01:03 PM.

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#4 peleuba

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Posted 17 February 2020 - 02:52 PM

Gerald - the focuser looks awesome and the whole setup looks great on the Losmandy Alt-Az.

 

These TSA telescopes are really good, optically.  


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#5 peleuba

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Posted 17 February 2020 - 03:11 PM

How long did you wait before doing the DPAC?   Edit: if cooldown wasnt the issue, is it possibly because it wasnt in the basement or otherwise a thermally stable room?

 

Tyson - the scope was taken from the car and immediately put on the bench.  The room was thermally stable with no air currents.  The scope had not warmed up to room temp.  I usually have  scope on V-Blocks for 24 hours or more before testing.  Gerald and I got together for another reason and I selfishly asked if he could bring a telescope down to test.  This is the first TSA102 I have ever had on the bench and it was not planned test session.  

 

The DPAC images were taken quickly so as not to delay Gerald from the rest of the days activities.  I am VERY appreciative to have had the privilege of getting a closer look at the scope.  These TAK TSA's are really nice.   

 

I live in an astronomy/refractor desert, so I don't get to see many really high end telescopes without either buying them myself or borrowing from my friend John B. I was glad that Gerald was able ot bring it down.


Edited by peleuba, 17 February 2020 - 03:13 PM.

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#6 25585

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Posted 17 February 2020 - 05:09 PM

I would be interested in a comparison with a Vixen AX103S triplet. 



#7 peleuba

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Posted 18 February 2020 - 09:27 AM

I would be interested in a comparison with a Vixen AX103S triplet. 

 

Yes - I have never seen one in person.  Would be fun to see how it compared.  



#8 Paul G

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Posted 18 February 2020 - 11:05 AM

The TSA 102 is one of my all time favorite scopes.


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#9 Lola Bruce

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Posted 18 February 2020 - 01:37 PM

Mine too




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