TS optics imaging star

[Ken82]

I’m thinking to purchase this scope for imaging smaller galaxies etc etc. I currently use a tak fsq 85 and would get the 130fsq apart from the incredible price tag! What do people think of this scope ? Alternatives ?? 

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p8373_TS-Optics-Imaging-Star-130-mm-f-5---6-Element-Flatfield-Apo-Teleskop.html

[RayD]

The TS stuff is ok, my 80mm one works fine, but it isn't just the price that makes this different to the Tak of course they are different designs.  I like the Petzval design of my FSQ106 and, whilst my Esprit 100 is superb, it was a bit of a mission to get the spacing spot on to the FF when using it with the larger 16200 sensor.

 Have you considered the Esprit 120?  For the money the Esprit range is right up there, and you don't often hear those of us with them complaining about them.

A nice conundrum to have as they are all very nice.

Edited April 7, 2018 by RayD

[Ken82]

1 hour ago, RayD said:

The TS stuff is ok, my 80mm one works fine, but it isn't just the price that makes this different to the Tak of course they are different designs.  I like the Petzval design of my FSQ106 and, whilst my Esprit 100 is superb, it was a bit of a mission to get the spacing spot on to the FF when using it with the larger 16200 sensor.

 Have you considered the Esprit 120?  For the money the Esprit range is right up there, and you don't often hear those of us with them complaining about them.

A nice conundrum to have as they are all very nice.

I thought the TS imaging star was also a Petzval design so the spacing wasn’t necessary? 

I am also considering the espirit 120 but at f7 and lack of focal reducer I’m not sure yet. 

Im also using a 36mm sensor and get excellent results with the baby Q but would the TS imaging star be as good ?? 

[DaveS]

The 130 Imaging Star is a triplet apo with a matched 3-element reducer. The spacing is very critical, I have the 80mm f/4.4 and it's a real pig, not helped by the picture on TS not being the same as the actual scope. Trying to get a meaningful figure for BF out of TS was like blood from a stone.

When I was looking for something longer I went for the 130 f/7 with 2.5" flattener. At least I had a usable figure for BF. I also added an APM / Ricardi reducer.

[RayD]

6 hours ago, Ken82 said:

I thought the TS imaging star was also a Petzval design so the spacing wasn’t necessary? 

I am also considering the espirit 120 but at f7 and lack of focal reducer I’m not sure yet. 

Im also using a 36mm sensor and get excellent results with the baby Q but would the TS imaging star be as good ?? 

No as @DaveS notes, it's a standard triplet so you would have to sort out the spacing behind the FR.  I'm not sure about the image circle on these, but from experience I think TS are somewhat optimistic with their declared image circle, so I would be a little cautious.

They are decent OTA's, so if the focal ratio is key for you then I suspect this is going to go high on the options list.

Edited April 7, 2018 by RayD

[DaveS]

If you're lookjng for more FL for galaxies, then I think you'll find the 130 f/5 too short. Have a look at the various 130 f/7 apos, then add a suitable flattener.

[Ken82]

Thanks for all the feedback it appears this was the wrong option and I’ll have to look at f7 130 refractors as you’ve advised. I’ll start a new topic shortly. 

[UKAstroBill]

So I am looking around for an imaging refractor and the specs of this imaging star for the price caught my eye. The info I have seen suggests 73mm from the M68 adaptor to the sensor and a 42mm imaging circle, and there is a viewing option now with an adaptor. The first distance is easily created with some Baader bits and the second figure suggests most of a full frame sensor will be lit. So I am not sure what the problem is? Is the 73 wrong? Is there a lot of vignetting at 42mm?

[DaveS]

My experience with the TS 80 mm f/4.4 has made me very wary of the combined 6 - element TS designs, possibly unfairly, but once bitten as they say. In my view a 130 f/7 and APM 0.75 reducer gets you down to f.5.25 and 682.5 mm, while still leaving you the option of f/7 and 910 mm FL if you want something longer.

I will admit to having been tempted by the 130 mm Imaging Star, and also by the 102 mm version, but my experience has held me back. That and the parlous state of the UKP.