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Imaging Train for RC 12" Truss

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#1 AstroDarien

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Posted 03 April 2024 - 02:57 PM

Hello all,

 

I hope all is well with everyone.

 

Our university is in the works of upgrading the equipment at our research observatory and one of the telescopes we are looking at is a 12" RC truss OTA. But I would like know if it's ok  to share your imaging trains with a reducer (0.8x) to see how it works. We currently are using the EQ8-R pro mount.

 

 

 

Thanks again for your feedback,

 

Best,
Darien



#2 GaryShaw

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Posted 03 April 2024 - 05:12 PM

Could you please clarify your next to last sentence.
Thanks

#3 syxbach

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Posted 03 April 2024 - 06:26 PM

I can elaborate more on this. Darien and I try to set up our teaching observatory and we will have 6 scopes for classes and data collection.

 

We plan to use RC12 with 0.8 reducer (TSRCRED). We would like to know what type of focuser can accommodate this reducer so that we can achieve focal point.  Reducer usually will reduce the total backfocus. Therefore, this TSRCRED must be in inside the focuser.

 

We would like to see such an imaging train as an example

 

Yuexiao 


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#4 AstroDarien

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Posted 03 April 2024 - 06:55 PM

Could you please clarify your next to last sentence.
Thanks

Hi Gary,

 

 

Just as Yuexiao said above,

 

Sorry for the confusion its been a busy day today here at the university! Brain spinning!lol.gif

 

 

Thanks for your help,

Darien





 



#5 GaryShaw

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Posted 03 April 2024 - 10:04 PM

Hi

If you are purchasing the RC telescope and the TSRCRED Reducer from TS optics in Germany, then you should contact Simon at TS Support and he will be best able to specify and provide the appropriate focuser to you. I have purchased many items there and he has always been helpful. 

 

Based on the product info ( see link below) that I found at their website, the focuser needs to accommodate screwed 68mm connections but you really need to get Simon’s input on a specific focuser that works. Here’s the link to the Reducer you identified in case you haven’t seen it  :
 

https://www.teleskop...onnection-17588

Hope this helps…

Gary


Edited by GaryShaw, 03 April 2024 - 10:12 PM.

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#6 Mike7Mak

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Posted 04 April 2024 - 01:33 AM

I can elaborate more on this. Darien and I try to set up our teaching observatory and we will have 6 scopes for classes and data collection.

 

We plan to use RC12 with 0.8 reducer (TSRCRED). We would like to know what type of focuser can accommodate this reducer so that we can achieve focal point.  Reducer usually will reduce the total backfocus. Therefore, this TSRCRED must be in inside the focuser.

 

We would like to see such an imaging train as an example

 

Yuexiao 

Hi Darien and Yuexiao,

 

I have a 14" GSO RC with an Optec TCF-3 focuser...

 

https://optecinc.us/.../products/19705

 

The TSRCRED 0.8x reducer fits inside the 3 inch focuser tube but it required custom modification of an Optec adapter, which the folks at Optec were very quick to do.

 

This adapter...

 

https://optecinc.us/.../products/17847

 

...was machined with M68 female threads (telescope side) to accept the reducer and shortened to only use 11mm of the reducers 82mm backfocus. Camera side it's 54x0.75mm female.

 

If you're interested in this option I can provide further details, Optec contact info, and maybe some pics of the setup if the sleet and rain ever let up.


Edited by Mike7Mak, 04 April 2024 - 01:37 AM.

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#7 Rasfahan

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Posted 04 April 2024 - 09:45 AM

I use the TSRCRed3 0.8x reducer on a CFF RC (with GSO optics, so same BF). I use the FT 3245 focuser. I also use a M82/M68 adapter to thread the reducer into the focuser and the same adapter to thread the image train into (Baader M68 variable spacer, ZWO M68 tilt plate, ZWO OAG-L, ZWO EFW, ZWO ASI2600). The newer TSRCRed3 v2 already has fitting threads so no adapter will be needed. I would love to fit a rotator somewhere, but there just isn‘t enough space.

 

Concerning the TS reducer: Compared to the plain image train it introduces some bloating of stars (probably spherical aberrations), in my seeing raising FWHM from 2.3“ to 2.5“ on average. This might be significant for scientific use.

 

I‘ll be happy to provide images, but i‘m currently travelling.

 

I‘m currently thinking about moving to a PLL Esatto 3“ LP/Arco combination, but haven‘t figured out yet if that will work.


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#8 AstroDarien

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Posted 04 April 2024 - 10:39 AM

Hello All,

 

 

Thank you for your feedback  its much appreciated. I think Yuexiao and I have came to the conclusion that the C11 Edge HD(our plan B option) might be better to also suffice for visual observing as well. All though our observatory is only used for the short period of time for visual observing for one of the courses we offer, having and RC will much more complicated to suffice this.

 

We can used the V3 variant from moonlite along side a 0.7x reducer and also QHY 268m camera system set up. We can un-hinge the v3  cray ford to use for manual operation which will suffice our needs and obviously when using for time domain astronomy we will use the appropriate spacing needs if need.

 

 

 

Thanks again everyone.

 

Best,

 

Darien


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#9 syxbach

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Posted 04 April 2024 - 02:34 PM

Thank you Mike and Torben

 

Based on what I have found, we need an at least an 3-inch focuser that can accommodate the reducer plus a customized adapter. Consider uncertainty, the long leading time of feather touch focuser, potentially bloating of stars, especially no available RC12 image training example, we do not want to risk on university based equipment. Although personally I am an RC person:)

 

As Darien mentioned, C11HD with 0.7 reducer should be a more matured plan. So many people use it with Moonlite focuser. I also have good connection with Ron.

 

Best

 

Yuexiao 

 

Hi Darien and Yuexiao,

 

I have a 14" GSO RC with an Optec TCF-3 focuser...

 

https://optecinc.us/.../products/19705

 

The TSRCRED 0.8x reducer fits inside the 3 inch focuser tube but it required custom modification of an Optec adapter, which the folks at Optec were very quick to do.

 

This adapter...

 

https://optecinc.us/.../products/17847

 

...was machined with M68 female threads (telescope side) to accept the reducer and shortened to only use 11mm of the reducers 82mm backfocus. Camera side it's 54x0.75mm female.

 

If you're interested in this option I can provide further details, Optec contact info, and maybe some pics of the setup if the sleet and rain ever let up.

 

 

I use the TSRCRed3 0.8x reducer on a CFF RC (with GSO optics, so same BF). I use the FT 3245 focuser. I also use a M82/M68 adapter to thread the reducer into the focuser and the same adapter to thread the image train into (Baader M68 variable spacer, ZWO M68 tilt plate, ZWO OAG-L, ZWO EFW, ZWO ASI2600). The newer TSRCRed3 v2 already has fitting threads so no adapter will be needed. I would love to fit a rotator somewhere, but there just isn‘t enough space.

 

Concerning the TS reducer: Compared to the plain image train it introduces some bloating of stars (probably spherical aberrations), in my seeing raising FWHM from 2.3“ to 2.5“ on average. This might be significant for scientific use.

 

I‘ll be happy to provide images, but i‘m currently travelling.

 

I‘m currently thinking about moving to a PLL Esatto 3“ LP/Arco combination, but haven‘t figured out yet if that will work.


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#10 Rasfahan

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Posted 05 April 2024 - 10:43 PM

Thank you Mike and Torben

 

Based on what I have found, we need an at least an 3-inch focuser that can accommodate the reducer plus a customized adapter. Consider uncertainty, the long leading time of feather touch focuser, potentially bloating of stars, especially no available RC12 image training example, we do not want to risk on university based equipment. Although personally I am an RC person:)

 

As Darien mentioned, C11HD with 0.7 reducer should be a more matured plan. So many people use it with Moonlite focuser. I also have good connection with Ron.

 

Best

 

Yuexiao 

I know you‘ve decided, but if the aberrations introduced by the EdgeHD reducers are no deterrent, the performance of the 0.8x reduced RC will surpass any requirements you

have regarding optical quality by a large margin. For a 3“ focuser, may I recommend the PLL Esatto? They are truly excellent (I have both a 2“ and 3“ one). I just can‘t vouch personally yet for the Arco rotator but am in the process of replacing the FT with that combo.


Edited by Rasfahan, 05 April 2024 - 10:44 PM.

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#11 AstroDarien

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Posted 05 April 2024 - 11:33 PM

I know you‘ve decided, but if the aberrations introduced by the EdgeHD reducers are no deterrent, the performance of the 0.8x reduced RC will surpass any requirements you

have regarding optical quality by a large margin. For a 3“ focuser, may I recommend the PLL Esatto? They are truly excellent (I have both a 2“ and 3“ one). I just can‘t vouch personally yet for the Arco rotator but am in the process of replacing the FT with that combo.

Hi Rasfahan,

 

 

Thank you for your reply. We see some reports of problems with color channel alignments with C11 and reducer which is a concern. We need to do research on this. I think RC might be a better route.

 

Best,

Darien




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