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Holes in back of FT 3.5” - does anyone know what they’re for?

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#1 Bkmiller4463

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Posted 06 December 2021 - 10:05 PM

Does anyone know what the holes at 12, 3, 6 and 9 o’clock are for?

 

This is on a new SVX140 with a 3.5” FT focuser. They are threaded and were open to the OTA, so I filled them with 4mm set screws. 

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#2 Bkmiller4463

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Posted 06 December 2021 - 10:10 PM

Another angle….

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#3 Bkmiller4463

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Posted 06 December 2021 - 10:16 PM

View down the tube through the obj toward focuser prior to inserting the set screws.  

Normal??

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Edited by Bkmiller4463, 06 December 2021 - 10:17 PM.


#4 photoracer18

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Posted 06 December 2021 - 11:02 PM

Those look like the setscrews holes for the drawtube cap I think. I never took that cap off my old TEC140's FT3545B but I have taken the caps off my FT2535HD to put 63mm accessory caps like Click locks on it. I sent that one to Stellarvue to use on my SVX127D.

It looks like you don't have to correct end cap on yours. It should fit over those exterior threads and 3 screws should go in to lock the cap on.

 

The end cap on the FT3545 should look like this.

 

EC35-505CR-120x120.jpg

 

Yours looks more like the endcap for one of the 3" focusers.


Edited by photoracer18, 06 December 2021 - 11:04 PM.

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#5 Bkmiller4463

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Posted 06 December 2021 - 11:23 PM

Thanks Photo, I’m thinking the same thing re the cap. Truth is, i wouldn’t have noticed it if not for the fact I could see light entering the focuser end when looking down the tube.  
 

Those look like the setscrews holes for the drawtube cap I think. I never took that cap off my old TEC140's FT3545B but I have taken the caps off my FT2535HD to put 63mm accessory caps like Click locks on it. I sent that one to Stellarvue to use on my SVX127D.

It looks like you don't have to correct end cap on yours. It should fit over those exterior threads and 3 screws should go in to lock the cap on.

 

The end cap on the FT3545 should look like this.

 

attachicon.gifEC35-505CR-120x120.jpg

 

Yours looks more like the endcap for one of the 3" focusers.



#6 StarAlert

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Posted 07 December 2021 - 07:16 AM

Wait! What? This is how your new SVX140 arrived from Stellarvue?

 

Did they remember to put the lens cell in? lol.gif


Edited by StarAlert, 07 December 2021 - 10:04 AM.


#7 Bkmiller4463

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Posted 07 December 2021 - 02:03 PM

Sure did, and it’s outstanding. SV explained the small holes are for adjusting focuser tilt, though that wasn’t needed in my case. I’m more curious about the threaded area on the circumference of the focuser. 
 

Wait! What? This is how your new SVX140 arrived from Stellarvue?

 

Did they remember to put the lens cell in? lol.gif



#8 ris242

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Posted 07 December 2021 - 02:28 PM

Sure did, and it’s outstanding. SV explained the small holes are for adjusting focuser tilt, though that wasn’t needed in my case. I’m more curious about the threaded area on the circumference of the focuser. 
 

reducer thread?



#9 Bkmiller4463

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Posted 07 December 2021 - 02:39 PM

Bingo, that or a flattener. Mystery solved. Looks a bit funky, but no functional issues. 
 

reducer thread?



#10 StarAlert

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Posted 07 December 2021 - 03:25 PM

Sure did, and it’s outstanding. SV explained the small holes are for adjusting focuser tilt, though that wasn’t needed in my case. I’m more curious about the threaded area on the circumference of the focuser.

I’m confused. The pictures you posted of the exposed threads on the focuser. Is that how you got the scope? Or did you remove the collar and were just wondering what the holes were for?

Edited by StarAlert, 07 December 2021 - 03:25 PM.


#11 Bkmiller4463

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Posted 07 December 2021 - 04:29 PM

I didn’t remove anything; that’s how they’re built, exposed threads and all. The holes are for focuser adjustment, per Isaac at Stellarvue. 
 

I’m confused. The pictures you posted of the exposed threads on the focuser. Is that how you got the scope? Or did you remove the collar and were just wondering what the holes were for?



#12 StarAlert

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Posted 07 December 2021 - 04:51 PM

That’s weird. My 3.5” FT doesn’t have any exposed threads or open holes. 

 

Call me skeptical. I don’t buy the story that those open holes are supposed to be there. 
 

FE67A119 FF16 4B9C 8CD2 61F8CE55273D

 


Edited by StarAlert, 07 December 2021 - 05:06 PM.

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#13 alnitak22

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Posted 07 December 2021 - 05:46 PM

 

That’s weird. My 3.5” FT doesn’t have any exposed threads or open holes. 

 

Call me skeptical. I don’t buy the story that those open holes are supposed to be there. 
 

 

 

 

I agree. Those sort of look like the holes TeleVue uses to adjust focus tilt on the “is” scopes, except that here the holes are just through holes that go through the open tube, are not pushing against anything, so cannot be providing tilt. Further, there are four of them. If they were used for tilt, there would be 3 of them 120 degrees apart. Have never seen a scope with 4 collimation screws 90 degrees apart. Maybe the guy at SV wanted to say something besides “ I don’t know why those are there.” 


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#14 Bkmiller4463

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Posted 07 December 2021 - 05:56 PM

Interesting….yours is completely different. Yours looks like it has sort of a click-lock adapter whereas mine has three screws to hold the adapter. Apparently Starlight has different end caps for different scopes. 
 

 

That’s weird. My 3.5” FT doesn’t have any exposed threads or open holes. 

 

Call me skeptical. I don’t buy the story that those open holes are supposed to be there. 
 

 

 

 



#15 Bkmiller4463

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Posted 07 December 2021 - 05:57 PM

Excellent point re 3 vs 4. Something is odd here, methinks. 
 

I agree. Those sort of look like the holes TeleVue uses to adjust focus tilt on the “is” scopes, except that here the holes are just through holes that go through the open tube, are not pushing against anything, so cannot be providing tilt. Further, there are four of them. If they were used for tilt, there would be 3 of them 120 degrees apart. Have never seen a scope with 4 collimation screws 90 degrees apart. Maybe the guy at SV wanted to say something besides “ I don’t know why those are there.” 


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#16 Space_Race_T.J.

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Posted 07 December 2021 - 06:21 PM

I have the 3" FT focuser on my SVX102D. I checked right now and don't see any exposed threads or screw holes.

 

Is it possible that a 3" visual back could be installed incorrectly on your 3.5" focuser and that is why the threads and holes are exposed?

 

T.J.



#17 StarAlert

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Posted 07 December 2021 - 06:46 PM

Interesting….yours is completely different. Yours looks like it has sort of a click-lock adapter whereas mine has three screws to hold the adapter. Apparently Starlight has different end caps for different scopes. 
 

Yes, Starlight offers different options for the visual back. Every option I’ve seen, however, leaves no exposed threads or open holes. I just don’t buy that Starlight would send out a focuser like that. 
 

I would call Starlight directly and explain what you have. They’ll straighten it out. 
 

I can’t wait to hear what happened. lol.gif


Edited by StarAlert, 07 December 2021 - 06:49 PM.

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#18 Bkmiller4463

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Posted 07 December 2021 - 07:36 PM

That’s the plan. Will let everyone know. 
 

Yes, Starlight offers different options for the visual back. Every option I’ve seen, however, leaves no exposed threads or open holes. I just don’t buy that Starlight would send out a focuser like that. 
 

I would call Starlight directly and explain what you have. They’ll straighten it out. 
 

I can’t wait to hear what happened. lol.gif


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#19 scooke

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Posted 08 December 2021 - 10:36 AM

Sure did, and it’s outstanding. SV explained the small holes are for adjusting focuser tilt, though that wasn’t needed in my case. I’m more curious about the threaded area on the circumference of the focuser. 
 

Anyone seeing a photo of this can see that this couldn't work for focuser tilt.  The threaded holes are open to air, there is nothing for set screws to push against to enable tilt.  Maybe they ran out of the correct adapter?  It looks like you have a few pieces threaded together.  I've purchased a few telescopes from Stellarvue over the years and always had a great experience and excellent optics and mechanics.  I think someone in the assembly department was having a bad day.  I would ask for the correct focuser back.  You paid a lot for that scope and deserve it to be right.


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#20 alnitak22

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Posted 08 December 2021 - 12:46 PM

Anyone seeing a photo of this can see that this couldn't work for focuser tilt.  The threaded holes are open to air, there is nothing for set screws to push against to enable tilt.  Maybe they ran out of the correct adapter?  It looks like you have a few pieces threaded together.  I've purchased a few telescopes from Stellarvue over the years and always had a great experience and excellent optics and mechanics.  I think someone in the assembly department was having a bad day.  I would ask for the correct focuser back.  You paid a lot for that scope and deserve it to be right.

Agree...pretty much what I said in post #13



#21 scooke

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Posted 08 December 2021 - 12:49 PM

I wonder if the threaded section is the tilt plate from one of their reducers?  Sure looks like it.



#22 Bkmiller4463

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Posted 08 December 2021 - 02:15 PM

Might be. Isaac told me their flattener screws onto the threads. 
 

I wonder if the threaded section is the tilt plate from one of their reducers?  Sure looks like it.



#23 Rich V.

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Posted 08 December 2021 - 02:26 PM

Looks like a specialized SV adapter attached to that FT end cap somehow.  In the standard FT3545 end caps, the screws holes should have set screws inside to lock the threaded end cap onto the drawtube end by pressing against the tube's end surface.  That's how mine works but it's years old now.

 

Seems all the FT 3.5" end caps have those set screws:

https://starlightins...gory&path=43_59

 

Rich



#24 StarAlert

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Posted 08 December 2021 - 02:56 PM

I'm really surprised that Stellarvue would ship a premium scope with a focuser that looks like that. ohmy.gif

They must be having labor issues like virtually every other business in the U.S.



#25 Bkmiller4463

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Posted 08 December 2021 - 03:10 PM

Isaac at SV replied that’s what SVs adapters look like, so that’s probably correct.

 

As for the end caps holes, they do, but it looks like they have 3 holes, whereas mine has 4. I don’t want to make this a bigger deal than it probably is, I just want to figure out why it’s designed like that. Waiting on Starlight to call me back. Working with Kitrick there, seems like a great guy. 
 

Looks like a specialized SV adapter attached to that FT end cap somehow.  In the standard FT3545 end caps, the screws holes should have set screws inside to lock the threaded end cap onto the drawtube end by pressing against the tube's end surface.  That's how mine works but it's years old now.

 

Seems all the FT 3.5" end caps have those set screws:

https://starlightins...gory&path=43_59

 

Rich




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