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TS Optics Imaging Star 80 mm f/4.4 Flatfield APO review


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Well perhaps its me then, the last slow scope I got was a

 F9 Ritchey Chretien Astrograph, and that had loose mirror bolts

and the spacing was wrong, apart from that it was great

sarcasm has never been my strong point, that scope was easy to take apart

and sort out, I would not like to attempt this scopes optics.

6 hours ago, Davey-T said:

There was a post on CN a while ago from a guy with a WO132 that had problems and William Yang personally took him another one to try along side it to see if it worked any better.

Shame he couldn't pop over to the UK with a few Star 71s to distribute :)

Dave

Came out and took him one you say, Well that was sweet, was it his neighbour.

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2 hours ago, DaveS said:

There are bench tests for optical alignment, but they're a bit specialised, Zygo interferometers etc. The optical elements can be parallel to each other, but if they're not centered then the stars will not be round. And if the elements are not correctly spaced there certainly will be errors, quite severe ones.

May I ask a really stupid question?  Why change the habit of a lifetime, I hear you ask?  I have just looked on the website and these are advertised as being 6 element flatfield scopes.  I had understood this to mean that - like the Takahash FSQ scopes are supposed to do (and the WO Star 71) - these already produced a flatfield image.  If so I am not sure what the spacers are doing.  Yes you may need a spacer in there so that the limited travel on the focuser allows you to achieve focus, but altering the spacing by small amounts will simply mean that the focuser ends up at different physical places, not that the chip to rear element distance has changed.

Have I lost my marbles?  It is possible.

I have seen a number of images from different Petzvals (I have had 3 x WO71s, for example).  Some of these seem to show the corner effect that you get when you don't have the spacing correct between flattener and sensor in a triplet.  Others seem to show the corner effect that you get when you have too much spacing between the flattener and sensor in a triplet.  

I wonder if these corner issues (that I also got on my FSQ 85) could be down to spacing between the various lens elements. If so, I have no idea what can be done about that.

Caveat: I have no idea what I am talking about, and I am one of the first to scoff when some internet loon starts spouting nonsense about my area of expertise.

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Well the Taks are designed as a piece, a Petzval quadruplet. All these six element astrographs are built from existing apo triplets with a supposedly matched three element reducer / flattener built into the focuser. Therefore like any other 'scope with a reducer / flattener you have to get the spacing right.

It's just a pity that TS don't seem to know the correct value and release the thing with optics that aren't square or even possibly centered.

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Ah OK.   I hadn't aprreciated that it was a triplet with a 3 element flattener - I just read the 6 element thing on the rim of the objective.  Sorry for wasting your time.

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  • 1 year later...
On 31.05.2016 at 22:03, ultranova said:

Well perhaps its me then, the last slow scope I got was a

 F9 Ritchey Chretien Astrograph, and that had loose mirror bolts

and the spacing was wrong, apart from that it was great

sarcasm has never been my strong point, that scope was easy to take apart

and sort out, I would not like to attempt this scopes optics.

Came out and took him one you say, Well that was sweet, was it his neighbour.

I know I'm reviving an old topic, but what happened at the end? TS is still selling these scopes and yours is the best review I could find online. If possible I would like to know how the story ended :)

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On ‎05‎/‎04‎/‎2018 at 18:10, KemalOz said:

I know I'm reviving an old topic, but what happened at the end? TS is still selling these scopes and yours is the best review I could find online. If possible I would like to know how the story ended :)

Hi, In the End it was sent back. shame as it was what I was looking for,

I was lucky enough at the time to have quite a few clear nights to try and get it sorted

unfortunately I never was able to get it to a level where I could say the stars are ok in the corners,

using a adjustable  spacer I was going in and out of the purposed sweet spot, never did get right.

Not to say they are all like that, you might be lucky and get one that's good from the start.

I would like to see some astro photos take with one of these scope at 100% ,

at the time I could not find one.

Paul

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I've been persisting with mine, but agree with Paul that the corners are hard (Impossible?) to get right.

I've been sort-of bodging along with an ASI1600MM and now with a ASI183MM.

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This is nearly the last of my images from the 80 f/4.4 and ASI1600 MM-C

5aca5119006d0_AllDataStack.thumb.jpg.1fbe69edd0ccb910912ac3fbd85134b1.jpg

The Rosette in NHO, lost count of the number of hours I collected data, but is was several, some of it from last year. The corners don't bear too much inspection, and it's a crop as I had severe alignment issues in all data.

But you know what? I don't care anymore. It is what it is, OK for "pretty pictures" provided you don't look too closely.

I've now set it up with the ASI183MM-C for Markarian's chain. Whether I'll get any data is unknowable, given our rubbish weather lately.

 

Edit: Looking at the TS site, it should give reasonable stars out to 6.5mm, and usable to 10mm. Beyond that they start to get bloated. So imaging circles of 13 and 20mm respectively. The ASI183 runs just under 16mm, and the ASI1600 runs 21mm.

Edited by DaveS
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On 08.04.2018 at 17:28, ultranova said:

Hi, In the End it was sent back. shame as it was what I was looking for,

I was lucky enough at the time to have quite a few clear nights to try and get it sorted

unfortunately I never was able to get it to a level where I could say the stars are ok in the corners,

using a adjustable  spacer I was going in and out of the purposed sweet spot, never did get right.

Not to say they are all like that, you might be lucky and get one that's good from the start.

I would like to see some astro photos take with one of these scope at 100% ,

at the time I could not find one.

Paul

 

22 hours ago, DaveS said:

This is nearly the last of my images from the 80 f/4.4 and ASI1600 MM-C

5aca5119006d0_AllDataStack.thumb.jpg.1fbe69edd0ccb910912ac3fbd85134b1.jpg

The Rosette in NHO, lost count of the number of hours I collected data, but is was several, some of it from last year. The corners don't bear too much inspection, and it's a crop as I had severe alignment issues in all data.

But you know what? I don't care anymore. It is what it is, OK for "pretty pictures" provided you don't look too closely.

I've now set it up with the ASI183MM-C for Markarian's chain. Whether I'll get any data is unknowable, given our rubbish weather lately.

 

Edit: Looking at the TS site, it should give reasonable stars out to 6.5mm, and usable to 10mm. Beyond that they start to get bloated. So imaging circles of 13 and 20mm respectively. The ASI183 runs just under 16mm, and the ASI1600 runs 21mm.

thank you guys for the answers. Yes I also had trouble to find any other review or sample images. I guess it isn't a popular scope.

 

So Dave what I'm getting from your answer is that this scope won't work with an APS-C sensor. Even though in the specs it says; " Well corrected and illuminated image field with 42 mm diameter ".

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I would take what TS say with a pinch of salt and look at the spot diagrams. If the spots corrosponding to the corners of APS-C are OK for you then go with it, else crop.

Myself, I'd rather go with a normal triplet apo and either a plain flattener or a reducer, as I did with the 130 I bought.

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6 minutes ago, DaveS said:

I would take what TS say with a pinch of salt and look at the spot diagrams. If the spots corrosponding to the corners of APS-C are OK for you then go with it, else crop.

Myself, I'd rather go with a normal triplet apo and either a plain flattener or a reducer, as I did with the 130 I bought.

hmm I'll probably pass this scope. Thanks again for the info :thumbsup:

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  • 1 year later...

Thank you for the post. I am looking for a new small triplet apo after having horrible experience with Explore Scientific ED 80 Essentials FCD1 version (extreme field curvature that was never corrected whatever the FR/FF used or what ever the spacing used). I was almost about to buy this scope thinking that it is a real good deal but threw the idea away after reading this. What do you recommend for a price tag around 1000$ (or €)? What about WO GT 71, TS Photoline 80 f/6, TS Photoline 71 quadruplet? I already own Televue TRF 2008 FR/FF and Explore Scientific FF.
 

Thank you

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