1308 replies to this topic

[nateman_doo]

Finally had a clear night with no clouds, however the seeing was less than optimal.  First chance to work on collimation since installing the nateman collimation adapter. Got the collimation as close as I could with the seeing conditions.  Did a quick imaging session on C23.  Wanted to see some stars.  Stars are round to the corners but are soft.

 

So long as your image is balanced you are good to go.  We are our own harshest critics.  

 

I added some additional chamfering on the underside.  Why?  no idea.  just some additional de-burring.  for funzies.  

 

 

And this one is off to IL.

Edited by nateman_doo, 28 December 2023 - 04:42 PM.

[Dark_Knight18]

Question- When I installed my collimation adapter, I think I rotated the primary so it was not in the same position it was when it was first removed.  Does the position of the primary mirror matter?

 

 

Brian

[Mert]

No, I don't think it matters.( at last in my particular case )
I dismantled my RC8 a couple of times and never have observed problems with that.

[XELAO]

Looks great!  You really have some nice dark skies where you live :-)  I have to drive an hour away to get so many stars like that!  You should give GraXpert a try to clear up the gradients, it free :-)

Ive forgotten how nice it must be to get a clear night once in a while....

tonight is night 51 since my last clear night here in northeast Ohio.....

more clouds this week...possible weekend storm.....I'm betting maybe early Feb till my next clear night....

but it has given me time to process my nights from late Sept through early Nov....only problem is I keep tweaking everything....

[nateman_doo]

Question- When I installed my collimation adapter, I think I rotated the primary so it was not in the same position it was when it was first removed.  Does the position of the primary mirror matter?

 

 

Brian

Its round, it doesnt make a difference.  I am sure we all rotated the mirrors during installation.

[nateman_doo]

I have been pondering an idea for guiding with the RC's.

 

The biggest benefits to OAG is perfect guiding with no flexure, and its more lightweight as you dont need a guide scope.  The downsides are if you want to play around with your image train you have to completely reconfigure your OAG to accommodate. 

 

That being the basis, I was wondering if I could design the M90x1.0 extension ring to integrate an OAG prism into it.  It would be a fixed focal length and you can rapidly adjust between reducers, barlows or native focal length.  It would have to be a longer than usual prism of relatively the same size, and the camera would be up a ways from the extension needing its own backspacing 

 

It's just an idea I am tossing around.  I want to be able to do planetary with a Barlow, but still guide with stars.  And then go back to DSO imaging with my regular reducer/flattener.  Its a tall order I think, but not outside the impossible.   

[DevonRob]

I have been pondering an idea for guiding with the RC's.

 

The biggest benefits to OAG is perfect guiding with no flexure, and its more lightweight as you dont need a guide scope.  The downsides are if you want to play around with your image train you have to completely reconfigure your OAG to accommodate. 

 

That being the basis, I was wondering if I could design the M90x1.0 extension ring to integrate an OAG prism into it.  It would be a fixed focal length and you can rapidly adjust between reducers, barlows or native focal length.  It would have to be a longer than usual prism of relatively the same size, and the camera would be up a ways from the extension needing its own backspacing 

 

It's just an idea I am tossing around.  I want to be able to do planetary with a Barlow, but still guide with stars.  And then go back to DSO imaging with my regular reducer/flattener.  Its a tall order I think, but not outside the impossible.   

No idea on the practicality of building it - but love the concept. I can see backspacing being tricky - my last M90 is a long way from my image sensor when in focus. So we'd be talking a long tube to the OAG - which then seems like it could risk it's own flexure, mitigating one of the main benefits of an OAG. Don't let me put you off tho - my mechanical knowledge is pretty low so I could be talking rubbish!

[nateman_doo]

I am working under the assumption that using my adapter and a focal reducer imaging at 1066mm, this needs to fit in one of the 25mm spacers.  I only use a single 25mm spacer, focuser, and the reducer/filter drawer and camera.  

 

 

Now, it may not work with my original adapter due to the lip, but thats not a problem for the new smaller version.  I found a 15mm prism that might work.  the OD of the M90x1.0 adapters is 3.7" and the ID is roughly 3.06" (just ball park with calipers)  ID doesn't really matter other than to clear the ID and dip the prism into the light path, but the OD is critical, as I have to design it to mate with that surface. 

 

I think it would be a fun project to try.  You are correct that it would need a tube of decent length so while there may be some vignetting it may still be possible.  Im not worried about the rigidity of it yet, it will be designed for a 1.25" drop-in style camera, and some nylon tipped set screws.

Edited by nateman_doo, 10 January 2024 - 08:19 AM.

[nateman_doo]

OK, just took a quick VERY ARBITRARY run at this.  The only accurate thing on display here is the M90 25mm extension, the prism I think that can be used 15mm^3 and the outline of a full frame sensor with an APS-C inside that.  (the blue rectangles) 

 

 

 

There is the main OAG body, the prism assembly, and the tube that would hold the 1.25" camera.    

The prism assembly is an aluminum U channel with the prism glued in via CA glue, (back side painted black) and that U channel can slide up and down as needed and secured via set screws from the side (not shown in the CAD). 

 

I get it, its not pretty, but it has the potential to function and its plenty rigid to hold up a 1.25" camera.  Life would be much easier using the 50mm extension, but as it stands, I dont see any way I could easily manufacture this.  The stock adapter would have to be drilled, milled, and filed  by hand, for the prism cutout, and then bolt holes drilled and tapped.  

 

All in all it just looks like a fun project to try out.

[DevonRob]

OK, just took a quick VERY ARBITRARY run at this.  The only accurate thing on display here is the M90 25mm extension, the prism I think that can be used 15mm^3 and the outline of a full frame sensor with an APS-C inside that.  (the blue rectangles) 

 

RC OAG 01.JPG

 

RC OAG 02.JPG

 

There is the main OAG body, the prism assembly, and the tube that would hold the 1.25" camera.    

The prism assembly is an aluminum U channel with the prism glued in via CA glue, (back side painted black) and that U channel can slide up and down as needed and secured via set screws from the side (not shown in the CAD). 

 

I get it, its not pretty, but it has the potential to function and its plenty rigid to hold up a 1.25" camera.  Life would be much easier using the 50mm extension, but as it stands, I dont see any way I could easily manufacture this.  The stock adapter would have to be drilled, milled, and filed  by hand, for the prism cutout, and then bolt holes drilled and tapped.  

 

All in all it just looks like a fun project to try out.

Looks very cool - I could be super interested in this. As well as the other benefits I love it has a large prism. You mentioned you use a reducer - I run my RC8 at the full 1600mm, so I'd need to be able to get focus with the OAG at that longer FL - poss that just means a longer extension tube for the 1.25" camera. At present I'm running a 220 mini - I could be tempted for the pricier 174mini though at some stage. OAG was a toe in the water for me originally (I also run a 60mm guide scope on the RC8).
 

[nateman_doo]

The point of this, is that it is using the scopes native focal length to guide at all times.  whatever you do behind the OAG is irrelevant.  Throw on a bunch of extensions and use a barlow, or shorten it with a reducer, its always going to guide itself at the native scopes 1600mm focal length.  This is one stop shopping for all RC guiding.  

 

For example if I have this on right now, I am guiding at 1600 and imaging at 1066 with my reducer.  If you had it on, you would be guiding at 1600 and imaging at 1600.  If you wanted to do planetary, you could use multiple extensions after this extension and image at 3200mm with a 2X barlow and still guiding at 1600mm.  You would never have to touch your OAG again.  the guiding would always remain the same.  

 

Keep in mind, there are 1.25" focal reducers.  I have put one on a guide camera in an OAG before. So possibilities exist to keep the tube shorter.  Before I used a 174 as a guide camera I used a reducer and a smaller sensor and it actually worked.  

[DevonRob]

The point of this, is that it is using the scopes native focal length to guide at all times.  whatever you do behind the OAG is irrelevant.  Throw on a bunch of extensions and use a barlow, or shorten it with a reducer, its always going to guide itself at the native scopes 1600mm focal length.  This is one stop shopping for all RC guiding.  

 

For example if I have this on right now, I am guiding at 1600 and imaging at 1066 with my reducer.  If you had it on, you would be guiding at 1600 and imaging at 1600.  If you wanted to do planetary, you could use multiple extensions after this extension and image at 3200mm with a 2X barlow and still guiding at 1600mm.  You would never have to touch your OAG again.  the guiding would always remain the same.  

 

Keep in mind, there are 1.25" focal reducers.  I have put one on a guide camera in an OAG before. So possibilities exist to keep the tube shorter.  Before I used a 174 as a guide camera I used a reducer and a smaller sensor and it actually worked.  

Very nice. One thought to maybe keep in mind - I've found in very sparse parts of sky, at 1600mm I sometimes need to rotate my OAG to get enough stars for guiding. For info - my prism is i think 10mm or 12mm square (I can check). Could be the larger 15mm prism will mitigate that of course. Given this is part of the extension rings, I guess rotation options are limited!

Edited by DevonRob, 10 January 2024 - 11:10 AM.

[nateman_doo]

which OAG are you using?  Its rare that i have no stars in my OAG (the helix nebula comes to mind with just  1 star in my OAG) using the QHY medium.  I think with the 0.5X 1.25" focal reducer You can get twice as many stars.  They stars may look awful, but i dont care that much, so long as the guiding does its job.  the smaller the better obviously.  would also cut down the height requirement for the OAG.  Kinda wish I had a 3d printer to fool around with various distances.

[pfile]

i think the only problem with this is that you'd need a really long extension for the guide camera and so flexure might creep in again.

[nateman_doo]

i think the only problem with this is that you'd need a really long extension for the guide camera and so flexure might creep in again.

thats why I like the idea of the focal reducer on the OAG.  you can really play around with those things.  I was able to focus on the secondary mirror at one point when playing with the spacing.  wasnt the desired outcome, but I found it pretty neat regardless.  I was using the 6" RC and just getting my feet wet in OAG's and was using the cheapest 120 guide camera at 1600 (or whaever the FL is on the 6)  the reducer really helped.  

[lambermo]

Hi nateman_doo,
Can you make the adapter for a 12" GSO clone model as well ?

-- Hans

[nateman_doo]

I assume its the same M117x1.0 as the 10"?

[nateman_doo]

just looking at a picture on Agena on their steel tube versions, yea, the look exactly like the 10" versions.  

[nateman_doo]

added another panel to the previous flaming star attempt.  Just 2 nights on the bottom half:

 

[Mert]

Looking great James!

[nateman_doo]

The first Electric blue adapter.  

 

Had another blue laying around for comparison.  If you use a Touptek camera, this is the same color. 

[jamiecflinn2019]

Update for RC8 iOptron - after basically 3 months of solid cloud I FINALLY got a two hour window to finish collimation as per my earlier posts - using a TRI-Bhatinov mask and Capella I was able to determine that my indoor process WORKED...I was one small tweak of one collimation screw  out of perfect.  The super nice thing is that the decoupler held collimation despite a number of massive temperature swings between collimation checks.  Unfortunately I did not save any of the snapshot beyond this one attached but despite 60km wind (yikes) I was snap-on  - this was after removing the TB mask...great diffraction spikes - Thanks again James for a great product!

[nateman_doo]

dear god, THREE months?!  I think I would lose my mind without seeing the sky for 3 straight months.  

 

Glad to hear it turned out well for you  

[nateman_doo]

Finally mounted the 10"

[PFitzhorn]

Wow!  That photo and the piece are a work of art! Can't wait to get it back and fit it all out, pop it on the mount, put the imaging train on it, and try it out. In anticipation of great results I've already put my GSO M117x1 collimation ring up for sale in the classifieds - won't ever need that again. I'll be sure to post some photos here when it's all together ready to collimate.