William Optics Flat73A suitable for TS-Optics of similar size ?

[Newforestgimp]

Hi All,

A friend of mine has a TS-Optics ED Refractor in the size range of 70/73mm id like to say its a photoLine but im not sure, we are wondering if the William Optics Flat73A would be a suitable flattener for scopes of this type from other brands or does he need to buy the TS-Optics specific flattener ? Or sany other suggestions for flatteners to consider would be appreciated.

Regards

Andy H

[Newforestgimp]

He’s just sent me this link to his scope....

 

Edited March 16, 2021 by Newforestgimp

[Adam J]

15 hours ago, Newforestgimp said:

Hi All,

A friend of mine has a TS-Optics ED Refractor in the size range of 70/73mm id like to say its a photoLine but im not sure, we are wondering if the William Optics Flat73A would be a suitable flattener for scopes of this type from other brands or does he need to buy the TS-Optics specific flattener ? Or sany other suggestions for flatteners to consider would be appreciated.

Regards

Andy H

Honestly they all come off the same production line in China WO just tweek the retaining ring to increase the aperture by 1mm it will work perfectly with the TS. Optically it's the same flattener design 

 

[Newforestgimp]

7 hours ago, Adam J said:

Honestly they all come off the same production line in China WO just tweek the retaining ring to increase the aperture by 1mm it will work perfectly with the TS. Optically it's the same flattener design 

 

Thank you, as I suspected.

It would be nice to intercept a 100mm APO direct from China before it gets re-badged 🙂

Andy H

[alexbb]

TS have a dedicated reducer/flattener for 70-72 refractors, but check also the return policy. I only had an issue with a camera that I bought from FLO which they solved very quickly and sent me a gift too (a collar for the camera if I remember well), but dealing with issues with TS is going slower for me. My copy of 70-72 reducer/flattener is a bad one and I'm waiting for about a month now for a reply from TS to return it. In fact, out of 4 reducers I bought from TS, only an old 279 was good, a newer RED JM63s is only almost decent and the other 2 were/are complete rubbish. I returned the WO flat 6A III, and I'm still trying to return the 70-72 one. I also had the Photoline 72 scope you mention, but that also was a bad example which went back. The 102 Photoline doublet I have is an excellent one though.

The point is that all these being mass produced, getting a good item seems like a gamble. Unless you have an option to buy a tested corrector, there is a high change that you'll need to return it, whether is a QC passed WO or another brand.

On the good side, the larger summer targets are coming back only in a few months so you have time to sort it out.

[Adam J]

1 hour ago, Newforestgimp said:

Thank you, as I suspected.

It would be nice to intercept a 100mm APO direct from China before it gets re-badged 🙂

Andy H

I wouldn't the QC on most of these scopes is poor. Also they tend to ship the scopes as individual components to avoid some import to taxes. 

[Newforestgimp]

51 minutes ago, alexbb said:

TS have a dedicated reducer/flattener for 70-72 refractors, but check also the return policy. I only had an issue with a camera that I bought from FLO which they solved very quickly and sent me a gift too (a collar for the camera if I remember well), but dealing with issues with TS is going slower for me. My copy of 70-72 reducer/flattener is a bad one and I'm waiting for about a month now for a reply from TS to return it. In fact, out of 4 reducers I bought from TS, only an old 279 was good, a newer RED JM63s is only almost decent and the other 2 were/are complete rubbish. I returned the WO flat 6A III, and I'm still trying to return the 70-72 one. I also had the Photoline 72 scope you mention, but that also was a bad example which went back. The 102 Photoline doublet I have is an excellent one though.

The point is that all these being mass produced, getting a good item seems like a gamble. Unless you have an option to buy a tested corrector, there is a high change that you'll need to return it, whether is a QC passed WO or another brand.

On the good side, the larger summer targets are coming back only in a few months so you have time to sort it out.

That's rather worrying, sounds a lot like the carbon frame bike industry just as likely to get a poor example when buying a £3k branded frame as opposed to a £500 frame direct from the factory in china, in fact in the cycling world its becoming clearer that some of the chinese branded frames are actually better quality and more likely to be within tolerances. Depressing to think I'm in another area where its like pulling a ticket from the tombola. 😞 

[KP82]

On 16/03/2021 at 07:51, Newforestgimp said:

Hi All,

A friend of mine has a TS-Optics ED Refractor in the size range of 70/73mm id like to say its a photoLine but im not sure, we are wondering if the William Optics Flat73A would be a suitable flattener for scopes of this type from other brands or does he need to buy the TS-Optics specific flattener ? Or sany other suggestions for flatteners to consider would be appreciated.

Regards

Andy H

I actually emailed TS Optics directly about useable reducers/flatteners with the 72ED doublet. I've got the Altair model which is essentially the same scope as the TS and WO. But because I've got one of their 2" reducers (TSRED279 which had been used with my larger scopes until I got the Riccardi), they are happy to help.

They've confirmed that any reducers/flatteners which are designed specifically for 60 - 70mm scopes  will work with the 72ED. This includes the WO Flat73A. They've also said that correctors designed for larger scopes such as the Hotech SCA, APM Riccardi and many other universal 0.8x/1.0x 2" - 3" including my TSRED279 will most likely not work. They haven't tested every single one of them, but this is their experience so far. I'll give the TSRED279 a try anyway as it has a M54 thread that works with the focuser on the 72ED without any additional adapters. If it turns out what TS have said is true, I'll replace it with an Altair 60-70mm reducer.

[alexbb]

1 hour ago, KP82 said:

I actually emailed TS Optics directly about useable reducers/flatteners with the 72ED doublet. I've got the Altair model which is essentially the same scope as the TS and WO. But because I've got one of their 2" reducers (TSRED279 which had been used with my larger scopes until I got the Riccardi), they are happy to help.

They've confirmed that any reducers/flatteners which are designed specifically for 60 - 70mm scopes  will work with the 72ED. This includes the WO Flat73A. They've also said that correctors designed for larger scopes such as the Hotech SCA, APM Riccardi and many other universal 0.8x/1.0x 2" - 3" including my TSRED279 will most likely not work. They haven't tested every single one of them, but this is their experience so far. I'll give the TSRED279 a try anyway as it has a M54 thread that works with the focuser on the 72ED without any additional adapters. If it turns out what TS have said is true, I'll replace it with an Altair 60-70mm reducer.

I have a WO Star 71 II, a Lacerta 72ED and a SkyWatcher 72ED. The doublets seem similar regarding the correction and the focal length at ~430mm.

For me, the TS RED279 is actually the only one that works properly with the above scopes. The correct backfocus seems to be around 65mm.

The WO corrector gave me elongated stars asymmetrically over the frame with the WO triplet.
The TS RED JM63S doesn't seem very asymmetric, but does not correct a 22mm imaging circle and I tried to adjust the backfocus from 55mm to >65mm. On the wider field of the WO 71mm triplet it seems to be worse than on the 102mm F/7 doublet which it manages to correct decent, but still very obvious not perfect towards the corners.
The 70-72 dedicated reducer doesn't correct a 22mm imaging circle and it has an asymmetric elongation on both the WO triplet and the Lacerta doublet.

I am too looking for a good reducer/flattener for these small scopes, but it needs to end with an M48 thread so that I can easily move the OAG + EFW + camera easily between the scopes. The TS RED279, although good, ends with a T2.

[KP82]

32 minutes ago, alexbb said:

I have a WO Star 71 II, a Lacerta 72ED and a SkyWatcher 72ED. The doublets seem similar regarding the correction and the focal length at ~430mm.

For me, the TS RED279 is actually the only one that works properly with the above scopes. The correct backfocus seems to be around 65mm.

The WO corrector gave me elongated stars asymmetrically over the frame with the WO triplet.
The TS RED JM63S doesn't seem very asymmetric, but does not correct a 22mm imaging circle and I tried to adjust the backfocus from 55mm to >65mm. On the wider field of the WO 71mm triplet it seems to be worse than on the 102mm F/7 doublet which it manages to correct decent, but still very obvious not perfect towards the corners.
The 70-72 dedicated reducer doesn't correct a 22mm imaging circle and it has an asymmetric elongation on both the WO triplet and the Lacerta doublet.

I am too looking for a good reducer/flattener for these small scopes, but it needs to end with an M48 thread so that I can easily move the OAG + EFW + camera easily between the scopes. The TS RED279, although good, ends with a T2.

Thanks for sharing your findings.

I'm glad to hear the TSRED279 actually works with the 72ED doublet. That will save me from the hassles of replacing it. I don't mind its T2 connection as I've got both T2 and M48 T rings as well as a set of extension tubes.

BTW have you tried a T2 to M48 step up adapter with the TSRED279? I thought going from a smaller connection to a bigger one shouldn't cause any issues like vignetting unless you're using a full frame camera. You could always factor in the optical path of the adapter and adjust the M48 extension length in your existing imaging train.

Edited March 17, 2021 by KP82

[alexbb]

2 minutes ago, KP82 said:

Thanks for sharing your findings.

I'm glad to hear the TSRED279 actually works with the 72ED doublet. That will save me from the hassles of replacing it. I don't mind its T2 connection as I've got both T2 and M48 T rings as well as a set of extension tubes.

BTW have you tried a T2 to M48 step up adapter with the TSRED279? I thought going from a smaller connection to a bigger one shouldn't cause any issues like vignetting. You could always factor in the optical path of the adapter and adjust the M48 extension length in your existing imaging train.

It would definitely cause severe vignetting on the OAG prism as I have it set up now as the OAG is the closest to the corrector and I want the prism to stay out of the cone of light that falls onto the main sensor. I can insert the prism more in the OAG, but not too much.

As I use a dual setup, I need a second corrector besides the 279 and I wouldn't buy the small one. Perhaps I'll wait for the https://www.teleskop-express.de/shop/product_info.php/info/p12938_TS-Optics-REFRACTOR-0-8x-Corrector-for-TS-70-mm-f-6-CF-Apo.html