1131 replies to this topic

[nateman_doo]

One of the biggest flaws of the inexpensive R/C scope, is that the focuser is attached to the primary which doesnt allow good collimation.  By making a new back, I can now move the primary independent of the focuser, a feature of the more expensive R/C scopes.

 

 

 

 

 

 

 

 

 

 

The jelly bean slots allow access to the factory collimation screws to move the primary:

 

Accessing the factory screws:

 

Thread milling:

https://imgur.com/yQCptmV

 

 

 

 

I apologize for the enormous pictures,  I was trying to use more normal sized images.   In terms of usage, I put a fine laser in the focuser, and centered it on the marking of the secondary mirror.  Then did the standard DSI method of collimating.  Sharpest images I have ever had with this scope.  

[PirateMike]

That looks amazing. Do you have any milling experience? 

 

I just bought this for my RC8 which does the same thing as your solution and I imagine that it weighs less. I had to get it from Europe as I couldn't find any here in the US.

 

 

 

Miguel   8-)

 

 

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[pfile]

unfortunately the TS optics flange does not do the same thing at all, in that if you adjust the primary then you need to go in and undo that change using the TS-optics flange. the camera is still attached to the primary mirror, via the tilting adapter. with nateman_doo's new back, the primary mirror moves independently so the optical axis of the camera stays put when you move the primary.

 

moonlite used to make something like what nateman_doo created here, but it does not span the whole of the back of the telescope. just like he did though you have to drill into the back of the telescope to mount the isolation flange, and the threads on the back of the mirror cell are no longer used to mount the camera. instead the camera attaches to the isolation flange. unfortunately moonlite does not make this part anymore.

 

rob

[PirateMike]

unfortunately the TS optics flange does not do the same thing at all, in that if you adjust the primary then you need to go in and undo that change using the TS-optics flange. the camera is still attached to the primary mirror, via the tilting adapter. with nateman_doo's new back, the primary mirror moves independently so the optical axis of the camera stays put when you move the primary.

 

moonlite used to make something like what nateman_doo created here, but it does not span the whole of the back of the telescope. just like he did though you have to drill into the back of the telescope to mount the isolation flange, and the threads on the back of the mirror cell are no longer used to mount the camera. instead the camera attaches to the isolation flange. unfortunately moonlite does not make this part anymore.

 

rob

Yes, I see your point. With the part I bought when the primary is adjusted that also moves the camera so the camera would have to be readjusted again. I didn't think of the above modification as working in a slightly different way.

 

But the tilt mechanism I purchased does save me the cost and bother of setting up a machine shop and learning how to use all the machines, so all considered even if I have to readjust my camera tilt once in a while I see it as a decent solution. 

 

But I still think that nateman_doo's work is magnificent.

 

 

Thanks for the clarification. 

 

 

Miguel   8-)

 

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Edited by PirateMike, 14 June 2022 - 12:09 AM.

[Mert]

Brilliant job, very nice machining
As I use the tiltplate adapter myself I can confirm the hazzle of collimation.
It works but the focusser is stil connected to the primary mirror.
Super job!

Edited by Mert, 14 June 2022 - 02:23 AM.

[nateman_doo]

Yes, I see your point. With the part I bought when the primary is adjusted that also moves the camera so the camera would have to be readjusted again. I didn't think of the above modification as working in a slightly different way.

 

But the tilt mechanism I purchased does save me the cost and bother of setting up a machine shop and learning how to use all the machines, so all considered even if I have to readjust my camera tilt once in a while I see it as a decent solution. 

 

But I still think that nateman_doo's work is magnificent.

 

 

Thanks for the clarification. 

 

 

Miguel   8-)

 

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I used to have that same part.  I used to try and get the focuser co-planer to the primary mirror.  Having the ability to now move everything independent is a game changer.  Glad you like it.  Its not a hard part to make now that all the design work was put into it.  

[nateman_doo]

Brilliant job, very nice machining
As I use the tiltplate adapter myself I can confirm the hazzle of collimation.
It works but the focusser is stil connected to the primary mirror.
Super job!

Thanks!  I was looking for our Magnum Opus on collimating this scope 3 years ago.  couldnt find that thread sadly.  would have loved to post it there, but with the forum changes I think it was lost.

[nateman_doo]

unfortunately the TS optics flange does not do the same thing at all, in that if you adjust the primary then you need to go in and undo that change using the TS-optics flange. the camera is still attached to the primary mirror, via the tilting adapter. with nateman_doo's new back, the primary mirror moves independently so the optical axis of the camera stays put when you move the primary.

 

moonlite used to make something like what nateman_doo created here, but it does not span the whole of the back of the telescope. just like he did though you have to drill into the back of the telescope to mount the isolation flange, and the threads on the back of the mirror cell are no longer used to mount the camera. instead the camera attaches to the isolation flange. unfortunately moonlite does not make this part anymore.

 

rob

Fortunately I do

I remember hearing about it a while back.  A friend of mine has this same scope and we were sitting in the catskills imaging together and we talked about it.  He came over and we did some pencil sketches of the concept and this is what I came up with to machine.  having a CNC helps when you think about all the little things that can improve your imaging experience.  I machine so many small things here and there that help.

[PirateMike]

In reference to the OP's first post... We like big pictures! 

[rainycityastro]

I love to see posts like this. Imaging has been pretty much reduced to someone sitting at a computer running NINA and PI. Would like to see at least a partial return to the ATM days of yore. Though you look like quite the CNC maven.

[nateman_doo]

Thanks!  Ironic part is that is exactly what I do, sit inside while the scope does its thing and monitor it on my home computer with TightVNC  (but I dont use NINA or PI).

 

I always like to make my own things when nothing exists for the function I want performed.  No one makes a polemaster adapter for my specific mount so I made my own.  Its a pride making my own things, also fun.  Not to mention much cheaper.  This project was a bit out of my comfort zone having to drill into the scope itself and thread milling has to be on point.  Once I figured out a way to indicate the back part of the scope, I just had to figure out how to move the parts as little as possible so the machine does most of the work.  It took an entire day from the time I woke up until the time I went to bed to machine that top plate. 

 

Truth be told, it could be scaled down, but I liked the idea of it having some wow factor, and more importantly... be super robust and overengineered.  I feel like every time I grab my RC and go portable with it, I am grabbing the back of the scope/focuser/image train and that throws off the collimation because of the tiny screws they use.  With this monster plate and thicker screws, you can hold the scope by it and it can support that weight without throwing off the primary at all.   

[nateman_doo]

 

Collimation seems good to me.  Final adjustment was adjusting the shape of the stars with the tilt plate.  

[Mert]

How did your adapter solution affect the available backfocus?

Edited by Mert, 16 June 2022 - 09:31 AM.

[nateman_doo]

Not in the least.  I just use the single smaller of the M90 extension tubes and its less than 10mm extended out for perfect focus.

[avarakin]

moonlite used to make something like what nateman_doo created here, but it does not span the whole of the back of the telescope. just like he did though you have to drill into the back of the telescope to mount the isolation flange, and the threads on the back of the mirror cell are no longer used to mount the camera. instead the camera attaches to the isolation flange. unfortunately moonlite does not make this part anymore.

 

I don't think they ever made it for RC8, only for RC10. The part for RC10 was pretty simple, but for RC8 it has to be much more complex. 

[pfile]

I don't think they ever made it for RC8, only for RC10. The part for RC10 was pretty simple, but for RC8 it has to be much more complex. 

you are right - i have an RC10 and ordered this thing but never mustered the courage to start drilling. eventually i'll do it, but for now i have been using my refractor and my RC6. would like to use mach2 i ordered 3 million years ago with the RC10, but so far it doesn't exist.

 

the RC6 has the primary collimation screws right near the focuser attachment and i can see from the images above that the RC8 is the same. of course on the RC10 the collimation screws are way out near the edge of the primary so that makes the isolator design a heck of a lot easier - it resembles the tip-tilt adapter posted upthread, just a bit larger and thicker.

[HockeyGuy]

Very well done! I've been wanting to purchase an 8 or 10" RC for long focal length work, but the mechanical coupling issue always steers me away. Kudos. Out of curiosity, have you tested slewing across the night sky with your decoupler after initial collimation, to confirm that collimation holds/the primary mirror is indeed stable?

[nateman_doo]

I don't think they ever made it for RC8, only for RC10. The part for RC10 was pretty simple, but for RC8 it has to be much more complex. 

Nothing complex about this part.  Just is M90x1.0 thread that is independent of everything.  Bolts right to the back of the part.  I was able to easily indicate the back part of the scope.  Could probably make one for the 6" as well if I had one.  

[nateman_doo]

you are right - i have an RC10 and ordered this thing but never mustered the courage to start drilling. eventually i'll do it, but for now i have been using my refractor and my RC6. would like to use mach2 i ordered 3 million years ago with the RC10, but so far it doesn't exist.

 

the RC6 has the primary collimation screws right near the focuser attachment and i can see from the images above that the RC8 is the same. of course on the RC10 the collimation screws are way out near the edge of the primary so that makes the isolator design a heck of a lot easier - it resembles the tip-tilt adapter posted upthread, just a bit larger and thicker.

The jellybean slots make it workable.  Not easy, but workable. I would imagine I could use much longer set screws, and much longer socket cap screws to make the screws protrude out more towards the slots.  

[nateman_doo]

Very well done! I've been wanting to purchase an 8 or 10" RC for long focal length work, but the mechanical coupling issue always steers me away. Kudos. Out of curiosity, have you tested slewing across the night sky with your decoupler after initial collimation, to confirm that collimation holds/the primary mirror is indeed stable?

Currently my guiding is garbage.  I have APT disregarding anything that moves over 1.5" and its throwing subs like crazy.  I have my mount doing some predictive PEC as well as PHD doing predictive PEC.  No idea why my guiding is bad (this predates this mod) but the only 2 targets I have hit with it, are the ring nebula, and the fireworks galaxy.  I have slewed all across cygnus and all the open star clusters look great.  Its M6 screws held into almost an inch thick slab of aluminum.  You can pick the scope up by this plate and I dont think it would move.  Not that I would do that, but its certainly going to hold collimation better then when we pick up the scope by the back (focuser) that is attached to the primary, and those tiny factory collimation screws they use.  Robust is the name of the game.  The primary no long has to bear the weight of your image train, so it will hold up no matter where I slew it.  The back of the scope is actually thicker than I thought.  So the aluminum feet are a very stable platform to mount this plate on. I was originally going to use Delrin, but I had scrap aluminum laying around for the feet.  

[nateman_doo]

A single sub of the fireworks galaxy.  

 

guiding is way better closer to the pole.  Need to get a better view of the eastern horizon and re-calibrate PHD2 since ditching focal reducer and using just the scope itself.

[Mert]

You made a very sturdy mounting on the backplate! Now is the time to take orders for us, poor RC8 owners
Wish I had the option doing the same!

[galacticinsomnia]

That is very nice.  I'm an amateur machinist wannabe  
This kind of work is always encouraging. 

Really nice work !  congrats !!

Clear Skies !!

[nateman_doo]

You made a very sturdy mounting on the backplate! Now is the time to take orders for us, poor RC8 owners
Wish I had the option doing the same!

I can make the plate, but the catch is, drilling into your backplate.  it has to be indicated on a machine with precise coordinates.   12 holes drilled exactly in their specific locations, concentric to the optical axis. 

 

But as I pause and think, a "kit" could be made where you can throw it on a drill press and get the holes drilled.  You may have to use larger holes to give some more wiggle room.  But it would also add to costs etc.  

[nateman_doo]

That is very nice.  I'm an amateur machinist wannabe  
This kind of work is always encouraging. 

Really nice work !  congrats !!

Clear Skies !!

Same here.  Made a CNC in my basement and its been a wild ride.  Its very helpful when there aren't people making the things you want to see in your hobby.