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Finally made an R/C Collimation adapter

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#901 DavesGalaxy

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Posted 07 December 2023 - 11:30 AM

Thanks!  It probably can be a bit better if I collimate further with a star after collimating with the cheshire eyepiece.  There were so many images I've thrown out before purchasing your collimation adapter. 

A bit off-topic, but for folks looking to double duty the RC for planetary and DSOs, now that collimation is painless, I have 2 quick-swappable imaging trains beyond the RC8 focuser:  DSO: CCDT67 reducer, OAG, filterwheel, ASI533MM.  Planetary: Bunch of spacers, helical focuser, GSO 2.5x barlow, ASI585MC. 

ASIAir can platesolve with the DSO train, but not Planetary train.  So I use Imaging Train 1 to platesolve and center Jupiter (with ASIAir), swap in Imaging Train 2, hook up a USB 3.0 cable between ASI585MC and a laptop.  The large sensor of ASI585MC helps recenter the planet after swapping the imaging train.  I still use the ASIAir to nudge the planet to the center and EAF to adjust focus (with a phone).  The laptop gets all the fps that the ASIAir can't get.  After a few 60s, 120s, or 180s videos, then I swap back the DSO train. Planetary itch scratched. Thanks nateman!

Yep as you seen in one of my posts previously, I managed to get a Baader ClickLock 2" to work on a Esatto2.  So now if I want long FL, the Apex-R, planetary setup, all can be changed with a flick of the wrist now!  I have the Player One Ares on my rig now but I also have the Uranus-C Pro that I use on my RASA which has a IMX585.  With NINA it has a plugin to slew to solar system objects now :-)


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#902 DavesGalaxy

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Posted 07 December 2023 - 11:56 AM

i actually did this but completely messed up the scope in the process. the mirrors were definitely too close together as the FL was too long by like 30mm IIRC. i think what happened is that somehow i didn't seat the primary properly when reinstalling it. but instead of investigating that, i figured i'd just move the secondary outwards a couple of mm. that turned out to be a big mistake as the secondary baffle was then letting light leak around it, and despite the mirror spacing being mostly correct, i have some kind of on-axis aberration. amazingly i do not have any images taken at the native FL, but only with a variety of reducers, so i'm not even really sure if the native FL was really that wrong to begin with.

Last night I decided to completely tear down my RC8 as the mirror was a bit too loose and I reset the primary and secondary by placing them far away from each other.  Then I calculated my back focus which is supposed to be 254 not 280!  So after using my improved OCAL collimation procedure I positioned my camera where the sensor was exactly at 254mm with my Esatto right in the middle of focus since it only has 15mm of travel.  Then after letting my scope cool down outside, I loosened the lock ring around my secondary and started twisting until my stars were perfect.  I did a test with focusing in and out and even though the stars were now out of collimation and they stayed the same shape this time regardless of focus!  My focal length went from 1629 down to 1603 and my back focus was now exactly 254.  But now I had an issue, my Apex-L could not get complete focus anymore.  So I had to add a few mm to my back focus and that fix that issue but didn't cause any spherical aberrations or other issues.  I hope to re-collimate and actually capture something tonight, just hope the wind doesn't come back!


Edited by DavesGalaxy, 07 December 2023 - 03:47 PM.

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#903 nateman_doo

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Posted 07 December 2023 - 03:41 PM

Something I havent done in quite a while.  a 6" version:

NzJnGO8l.jpg

 

 

up next is a 10" version.


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#904 boogiemk4

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Posted 07 December 2023 - 08:35 PM

Which Barlow did you use?  I have a William Optics one that isbt bad I have always wanted to try.  How many intentions did you need?  

For that image I use the GSO 1.25" 2.5x barlow 

This all started after seeing Jupiter images taken by Grégory Fabre on Astrobin using a relatively cheap 3x GSO barlow and the RC8.  I have both the 2.5x and 3x GSO barlows, but haven't had clear skies to try out the 3x yet. 


Edited by boogiemk4, 07 December 2023 - 08:35 PM.


#905 CTerry

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Posted 07 December 2023 - 10:24 PM

Forgive me, i saw this thread and have blasted around it a bit but im curious.  are these strictly ment for ritchey chretien scopes or will they also work on classical cassegrains as well?  and what exactly do they so. just separate the focuser assembly from the screws that adjust the primary mirror so they can be collimated separately?  Ive been having an issue getting my GSO CC6 to line up perfectly and wonder if this would help.

 

heres best i can get. used coll. caps and lasers and nothing seems to work.

 

 

 

Attached Thumbnails

  • cap coll. with overlayed centering circles.jpg


#906 nateman_doo

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Posted 08 December 2023 - 12:25 AM

I would imagine it would work as well.  M90x1.0 is the threading for this adapter.  

 

It de-couples the focuser so that you can adjust the focuser independent of the mirrors.  I generally put a laser in the focuser and point in the center of the secondary, then adjust the secondary to point the laser back on itself.  Now you have 2 of the 3 elements aligned.  Then cheshire the primary to the rest and its now collimated.  final adjustments with a star test.  

 

edit:  the backplate of the classical cass looks identical.  I would say yes it works, but I would have to see the inside.  If there is the same thickness in gaps then it should be fine.  to be honest I cant tell the difference between the CC and the RC aside from the slower optics. f/9 vs f/12


Edited by nateman_doo, 08 December 2023 - 12:30 AM.


#907 PFitzhorn

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Posted 08 December 2023 - 02:46 PM

As nateman_doo posted yesterday in post # 903, he has a GSO RC 10" up next. Mine! I'm pretty excited to finally decouple the mirror cell from the imaging train. When I first bought the scope ~ 8 years ago, I was entirely visual. A couple of years ago I started selling my eyepieces (old, tired eyes that take way too long to dark adjust, and too much astigmatism) and moved to EAA and now toward astrophotography. Each succeeding step added weight to the image train. Bought and used a TS-Optics focuser collimation ring (shown in the first picture below) but clearly it connects only to the M117x1 threads on the mirror cell. Does a nice job of collimating the focuser with the secondary, but doesn't remove the entire imaging train load from the primary mirror cell. I'm getting ready to put it up for sale on CN classifieds. The second pic shows the mirror cell threads and gap to the OTA backplate. Third photo is the entire RC10 on a pier in my backyard.

 

After reading through all >900 posts here, I've asked that he anodize it in red. I think it'll look pretty good with the other red on the scope, and, I won't forget that it's there!

Attached Thumbnails

  • rc10 2.jpg
  • rc10 3.jpg
  • rc10 1.jpg

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#908 nateman_doo

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Posted 09 December 2023 - 07:20 PM

I repurposed an old fixture plate for this project.  Flattened it out with my 45° face mill.  I love the took paths where they meet:

1NbfVw3l.jpg

 

Now the raw material is installed, holes are drilled and roughing done:

YjLSNAql.jpg

 

Same face mill looks wonderful on a piece that wont even be seen =/

bBpDlBBl.jpg

 

And a horrible picture of the completed lower ring.  

w0UIziyl.jpg

 

 

There are a bunch of holes in this thing.  

5 4-40 threaded holes bind the ring to the scope.

5 1/8" counterbored holes were used to hold the part to the fixture plate.  They are also going to be used for the transfer punch to mark the holes on the scope for drilling.

3 are threaded for M6 that the main adapter uses

3 are pockets for the M6 push screws.  They are much bigger than they need to be and I will adjust for the future should someone else want this.  

 

More to follow on the main adapter


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#909 nateman_doo

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Posted 09 December 2023 - 10:36 PM

Main body all set and cutting:

Lp31mom.jpg


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#910 PFitzhorn

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Posted 09 December 2023 - 10:40 PM

Main body all set and cutting:

What lovely work! I'm very excited to have this on the back of my 10".



#911 PFitzhorn

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Posted 09 December 2023 - 11:14 PM

Tomorrow, Sun Dec 10, I intend to pull the 10" RC scope off its mount and disassemble to prep the back plate and an extension to send to nateman_doo. I'm a bit worried about removing the primary mirror from its cell. I've heard that it might be stuck on with double sided sticky tape on its reverse side. If so, I intend to try some monofilament fishing line and "saw" back and forth behind the mirror to unstick it. However, I wonder if any of you might have some expertise removing a 10" mirror from its cell?



#912 nateman_doo

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Posted 10 December 2023 - 02:24 AM

HedggH3l.jpg


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#913 PFitzhorn

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Posted 10 December 2023 - 01:10 PM

GSO RC10 with carbon tube disassembly complete. I have the mirror cell (without mirror) and back plate ready to pack and ship to nateman_doo. It went much smoother than I thought it might. Removed the OTA from the mount and brought it inside and onto blanket to disassemble. Used a silver paint pen to paint an alignment mark on the bottom plate to carbon tube to ensure reassembly is easier. Removed the D-series dovetail plates and then their small black mounting plates on both ends of tube. Removed 4 silver phillips-head screws from around back plate ring. Removed back plate and mirror cell/mirror as a single unit. Removed black collimation locking screws. Screwed on M117x1 blanking plate onto mirror cell (a focuser would work as well) to prevent mirror/mirror cell from dropping out of back plate. Removed all three silver collimation screws counting turns to facilitate reassembly, but lost count when they were nearly off because of slop. Just means I'll have to do a major collimation when it's all together.

 

Then the removal of the mirror from the cell. Turned out to be pretty straightforward. There are three cork rests on three spider rails of the mirror cell, resting on the back of the mirror. They are not secured with adhesive to the mirror, so they were left alone. Then found three black rubber pads/inserts between the side wall of the cell and the mirror. When I pressed my thumbs to the back of the mirror it was clear they were holding it in. Took a very thin, flat x-acto blade and inserted it between mirror and rubber pads. Then carefully pressed the mirror out of the cell a bit at a time by hand. Once it was mostly out, I grabbed the mirror sides (with white cotton gloves) and finished sliding the mirror out. Only took a few minutes. During reassembly, I think the mirror will just be a press fit back onto the pads since its also held in by the baffle tube locking collar.

 

Now to put the cell back in the back plate, pack it up with an M117x1 extension to check threads, and send it off for modification.

Attached Thumbnails

  • IMG_5031.jpg
  • IMG_5036.jpg

Edited by PFitzhorn, 10 December 2023 - 01:19 PM.


#914 PFitzhorn

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Posted 10 December 2023 - 01:11 PM

and a few more pictures.

Attached Thumbnails

  • IMG_5040.jpg
  • IMG_5041.jpg


#915 PFitzhorn

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Posted 10 December 2023 - 01:17 PM

Two more pictures showing the cork pads on the spider arms of the mirror cell, and the mirror cell side insert recesses for the rubber pads. The second photo shows a closeup of one of the rubber pads. The only tools I used were a small phllips-head screwdriver, a set of metric allen wrenches, a silver paint pen, a flat-blade, thin x-acto blade and holder, and a flashlight. Took about 30 minutes to disassemble the whole thing and some of that time was of the form: "What the heck do I do next?" While the mirror cell and back plate are off to be upgraded, now's the time to give the primary mirror a thorough cleaning.

Attached Thumbnails

  • IMG_5042.jpg
  • IMG_5043.jpg

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#916 jamiecflinn2019

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Posted 11 December 2023 - 11:45 AM

Another Happy Customer!
 
iOptron Photron 8" RC (still using stock focuser  - new arrives this week)
 
The unit was a breeze to install and HIGHLY recommend using a drill press for your holes if you have one - rapid fire hole creation :-)...all the feet and parts were exact and was done in about 1 hour! - 
As for that gap between the decoupler and the original threaded neck, I re-purposed the supplied O-Ring: cut it to fit in the gap under it's own elastic pressure, and crazy glued the ends  together.  It fills the gap perfectly under it's own pressure - I have an image to take of this once the new focuser arrives.
 
Performed indoor collimation and MAN is it easy with this - also figured out the decoupler attachment to the feet also act as a tilt adapter for the focuser itself -> so placing my flat panel in front of the scope and with my camera/reducer in place, I was easily able to center the flat's hot spot and then go back and tweak the secondary/primary - not sure if this technique will work until I have stars but it SEEMS logical
 
More to come as I wrap it up
 
whole Rig
Album: RC8
2 images
0 comments

 

 


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#917 nateman_doo

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Posted 12 December 2023 - 06:08 PM

So I attempted cheshire collimation of the primary using the spider as a reference where it joins the main body.  Not gonna lie, I like it.  This is just with my normal laser in the focuser, to the secondary, then bounced back on itself... and using the farpoint 2" cheshire and bam:

 

vains.JPG


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#918 nateman_doo

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Posted 13 December 2023 - 07:57 AM

I think I have fooled ASTAP into thinking I know how to collimate.

 

ihSjxOz.jpg

 

Flaming Star nebula under there.  *mic drops*


Edited by nateman_doo, 13 December 2023 - 07:58 AM.

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#919 ekallgren

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Posted 13 December 2023 - 10:39 PM

Thats about as good as it gets.



#920 nateman_doo

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Posted 14 December 2023 - 04:48 PM

i really dont believe its that perfect.  it may be balanced and I know seeing has a lot to due with it. 



#921 DavesGalaxy

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Posted 14 December 2023 - 05:36 PM

I think I have fooled ASTAP into thinking I know how to collimate.

 

ihSjxOz.jpg

 

Flaming Star nebula under there.  *mic drops*

NICE!  I am glad that worked!  I have been working a lot lately and haven't had time to image anything good yet but I did receive my Ronchi eyepiece so did some testing in between clouds and I have to say adjusting the focal length actually worked out!  This image looks a little rough thanks to seeing but I used the eyepiece without the camera with an artificial star at my back focus and focal point and showed perfect straight lines inward and outward focus!  This was a back focus of 254mm and focal length of 1605mm for my TSO RC8.

Attached Thumbnails

  • 403412517_879626073855813_5636164970146187439_n.png

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#922 nateman_doo

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Posted 15 December 2023 - 12:31 AM

I have never even heard of a Ronchi eyepiece.  



#923 nateman_doo

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Posted 15 December 2023 - 01:39 AM

Actually the aberration inspection looks pretty decent.  

AI.JPG

 

Seeing is pretty decent tonight



#924 Che

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Posted 15 December 2023 - 01:56 AM

I have never even heard of a Ronchi eyepiece.  

https://www.telescop...ronchi_test.htm     

 

https://www.gerdneum...i-eyepiece.html


Edited by Che, 15 December 2023 - 01:58 AM.


#925 nateman_doo

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Posted 15 December 2023 - 02:42 AM

math? gross. No thank you. lol.gif

 

10" is almost finished:

VALAan5l.jpg

 

unaiqTDl.jpg

 

PU1FOAIl.jpg

 

0Zp2YIFl.jpg

 

t20MVj1l.jpg




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