Back to forums

TS Photoline 125mm f7.8 FPL 53 / lanthanum for imaging

TS-Optics SD-APO 125mm f/7.8 Refractors Buying Advice
13 replies•355 views
Pariah avatar
Pariah avatar
Hi

I'm considering adding this scope to my existing equipment as a primary imaging scope, with the dedicated 0.8 x reducer.

I have both the 533MM and MC Pro, so pixel scale will be around 1"/px, which should give a better resolution than my TS CF 90mm f6 APO, assuming it is optically good at this pixel scale

I plan to use this for globular clusters, galaxies and smaller GSO DSO. I will likely be doing narrowband HSO and LRGB, so the CA/SA and spot size in RGB and bloat are all important considerations. 

I will also use it with a Baader Hyperion barlow for lunar & planetary.

Also possibly some solar using a herschel wedge. I will likely also use it occasionally for visual use.

I am interested to hear from current users of this scope. I have had feedback from a couple of Astrobin imagers (with excellent images here) who are very happy with this doublet. 

Your opinions are appreciated smile
framoro avatar
framoro avatar
Hi Pariah,
I had one and have been happy with it.
Very good both optically and mechanically. More than fair in terms of chromatic aberration.
Here a couple of images with an ASI2600MC:
https://app.astrobin.com/u/framoro?folder-type=gear&active=NT481&i=2iau8t
https://app.astrobin.com/u/framoro?folder-type=gear&active=NT481&i=tjtomr
Also nice in terms of visual use.
I enjoyed having it and I changed it only to move to a triplet.
CS
Francesco
Concise
StefanL avatar
StefanL avatar
Hello Pariah,

I have one of these and I'm really happy with it.

You can check my gallery here:
StefanL - AstroBin

Roughly half of these pictures were taken with that telescope and the reducer (the other half with a redcat). I use it for smaller deepsky objects, just as your intention is.

I use it also for visual, without any complaints.

Best regards, 
Stefan
Well Written Concise Supportive
Pariah avatar
Pariah avatar
Hi Pariah,
I had one and have been happy with it.
Very good both optically and mechanically. More than fair in terms of chromatic aberration.
Here a couple of images with an ASI2600MC:
https://app.astrobin.com/u/framoro?folder-type=gear&active=NT481&i=2iau8t
https://app.astrobin.com/u/framoro?folder-type=gear&active=NT481&i=tjtomr
Also nice in terms of visual use.
I enjoyed having it and I changed it only to move to a triplet.
CS
Francesco

Many thanks Francesco, and nice images. Would you say the triplet is a significant improvement? My other option is a 115 triplet but I would prefer the 125mm aperture and focal length if there isn't a noticable difference in star testing
Pariah avatar
Pariah avatar
Hello Pariah,

I have one of these and I'm really happy with it.

You can check my gallery here:
StefanL - AstroBin

Roughly half of these pictures were taken with that telescope and the reducer (the other half with a redcat). I use it for smaller deepsky objects, just as your intention is.

I use it also for visual, without any complaints.

Best regards, 
Stefan

Thanks @StefanL your feedback is much appreciuated. Nice images!  I notice some flares around brighter stars, do you image in cold temperatures or is this maybe internal reflections somehow? I image in Finland so cold weather here (-20c or more) can really push a scope optic and cell.

Best regards

Richard
Deepan Vishal avatar
Deepan Vishal avatar
I plan to use this for globular clusters, galaxies and smaller GSO DSO. I will likely be doing narrowband HSO and LRGB, so the CA/SA and spot size in RGB and bloat are all important considerations.

I once used the Stellarvue 125 Access, same specifications as what you are looking for. 

My stars showed more CA than triplets. Stars were bloated. Narrowband imaging was okay.
But the 125 F7.8 was really good for the visual use. 

I’d advise to start looking at triplets for imaging. But triplets do not magically solve all these problems. My Photoline 130, a triplet still showed some CA and bloated stars

If I am in your shoes today, I’d start looking at William optics FLT132, (has good spot sizes with one of their flatteners), Askar triplets (cheap, but better than doublet), 130 Photoline CF Apo.

If budget is not a limiting factor TOA 130/150 plus 645 flattener produces the best spot sizes. 

I don’t know how spot diagrams/star sizes / aberrations change with introduction of baader hyperion.

I hope it helps.

Thanks,
Deepan
Helpful
framoro avatar
framoro avatar
Hi Pariah,
I had one and have been happy with it.
Very good both optically and mechanically. More than fair in terms of chromatic aberration.
Here a couple of images with an ASI2600MC:
https://app.astrobin.com/u/framoro?folder-type=gear&active=NT481&i=2iau8t
https://app.astrobin.com/u/framoro?folder-type=gear&active=NT481&i=tjtomr
Also nice in terms of visual use.
I enjoyed having it and I changed it only to move to a triplet.
CS
Francesco

Many thanks Francesco, and nice images. Would you say the triplet is a significant improvement? My other option is a 115 triplet but I would prefer the 125mm aperture and focal length if there isn't a noticable difference in star testing

It depends on several factors. 
What 115 are you thinking of? With what glass? 
The 125 f/7.8 has FPL53/lanthanium glasses, that gives good CA correction. 
i went to the Photoline 130/910 triplet with FPL53 glass and it brought some improvements.
The other 2 aspects I would think of are the focal length (with the 125 you will have 975mm, what about the 115mm?) and the aperture that brings with it the ability to catch finer details.
Marco Luigi Tassi avatar
Marco Luigi Tassi avatar
I just bought the TS-Optics 126/882 Petzval quadruplet, I will receive it in June. I have had very positive feedback, the spot diagram is outstanding. It is made by KUO with two ED lenses similar to FCD100.

https://www.teleskop-express.de/en/ts-teleskope-143/high-end-apo-with-3-element-apo-objective-no-color-aberation-288/tsapo126phq-18411
Pariah avatar
Pariah avatar
Deepan Vishal:
I plan to use this for globular clusters, galaxies and smaller GSO DSO. I will likely be doing narrowband HSO and LRGB, so the CA/SA and spot size in RGB and bloat are all important considerations.

I once used the Stellarvue 125 Access, same specifications as what you are looking for. 

My stars showed more CA than triplets. Stars were bloated. Narrowband imaging was okay.
But the 125 F7.8 was really good for the visual use. 

I’d advise to start looking at triplets for imaging. But triplets do not magically solve all these problems. My Photoline 130, a triplet still showed some CA and bloated stars

If I am in your shoes today, I’d start looking at William optics FLT132, (has good spot sizes with one of their flatteners), Askar triplets (cheap, but better than doublet), 130 Photoline CF Apo.

If budget is not a limiting factor TOA 130/150 plus 645 flattener produces the best spot sizes. 

I don’t know how spot diagrams/star sizes / aberrations change with introduction of baader hyperion.

I hope it helps.

Thanks,
Deepan

Thanks Deepan. Thanks for the feedback.

There were some issues with the SV 125 QC  from what I have read, and they were discontinued. That seems to confirm your experience.

A better match would be the AT 125 EDL, which has good reviews and an excellent DPAC test on Cloudy Nights.

I'm keen on the 125 doublet for aperture, flexibility, pixel scale and weight. I've also had feedback that it performs better than the 130 triplet from another user.

It is also on sale at TS at the moment, so on a aperture/price basis it is tempting.

The WO, Askar and Tak options are out on cost or QA reasons. 

Decisions, decisions...
Helpful
Pariah avatar
Pariah avatar
Marco Luigi Tassi:
I just bought the TS-Optics 126/882 Petzval quadruplet, I will receive it in June. I have had very positive feedback, the spot diagram is outstanding. It is made by KUO with two ED lenses similar to FCD100.

https://www.teleskop-express.de/en/ts-teleskope-143/high-end-apo-with-3-element-apo-objective-no-color-aberation-288/tsapo126phq-18411

Thanks Marco. I'm not sure that is a true Petzval. Looks similar to the Askars with a triplet and rear corrector, so very sensitive to collimation. Also no name glass AKA Askar style.  I'll be interested in your real world first light feedback.
StefanL avatar
StefanL avatar
"do you image in cold temperatures?"


Not really that cold, at least compared to Finland :-)
Night temperatures are roughly  from -5°C to +15C, over here in Belgium.
Marco Luigi Tassi avatar
Marco Luigi Tassi avatar
The information I got from KUO is 4 lenses in three groups, front doublet and two other spaced lenses, this is a Petzval configuration. The information from TS and Tecnosky, on the 126/882, confirms. I have had several refractors and I still own three, waiting for the fourth. I have always obtained good products from TS Optics that do not differ much from my current Takahashi and the previous ones. Certainly the sky test will give confirmation quality or not.
Pariah avatar
Pariah avatar
Marco Luigi Tassi:
The information I got from KUO is 4 lenses in three groups, front doublet and two other spaced lenses, this is a Petzval configuration. The information from TS and Tecnosky, on the 126/882, confirms. I have had several refractors and I still own three, waiting for the fourth. I have always obtained good products from TS Optics that do not differ much from my current Takahashi and the previous ones. Certainly the sky test will give confirmation quality or not.

I took mine from the TS page for this scope you linked. It states air spaced 3 element objective. However, if there is no backfocus requirement, perhaps this is a mistake by TS in their data.

Anyway, good luck with the scope. It looks like an interesting design. I've never had any issues with TS scopes either 
Marco Luigi Tassi avatar
Marco Luigi Tassi avatar
I already own a TS Optics quad without the need for a specific backfocus, even the 126/882 is indicated in the same way, I think the description you highlighted is wrong. Anyway, below is the Tecnosky version: Technical specifications:

Optical scheme: 4-element Petzval, 126/882mm, F/7

Glass: double ED for advanced color correction

0.8X reducer: optional, reduces to 705mm F/5.6

Focuser: 3.2" rack and pinion with field rotator and micrometric knob

Visual/photographic compatibility: 2" adapters, 1.25" and M48, M54, M68 threads

Mounting and accessories: rings, Vixen bar, CNC handle for accessories

Weight: 7.85 kg

https://www.tecnosky.eu/index.php/rifrattore-apo-126-882mm-f-7-quad-series-tecnosky.html