Mickes adapter is still being made, but to answer a few of your questions, If you want to do the install your self, I will supply a threaded collar, threaded inside and out, it will screw onto the original m90 thread on the back of the scope, and my adapter will thread over this. This ensures it and the original thread are concentric with each other. Once its screwed down and in the correct orientation, you can center punch the drill holes in the back plate, through the 9 clearance holes in my adapter, they can then be drilled and taped. This is the basics of it, but I will supply a link to video instructions with everyone's units.
I have attached a couple of pictures for you to see the basic design. Note, Michael didn't want the tilt adapter version of this adapter as he is using a separate tilt adapter, but for people who want a tilt adapter built into this, I can supply that also.
That looks great Joshua!
I also have the tilt thingie for collimation, it came with the near new CF RC I bought off a member here, used 3 times I believe (the scope).
I do have a question, I see how this system bolts to the rear housing/cover. but I've a little confused because currently the focuser mount ring attaches directly to the mirror. This is the thread this 90mm collar screws onto, I understand that part but I have to detach the original collar from the mirror first.
In saying this I better read again, I think I just somehow confused myself and maybe answered my own question at the same time.
Migraines do this to me, too frequently sadly.
Quote:
I will supply a threaded collar, threaded inside and out, it will screw onto the original m90 thread on the back of the scope, and my adapter will thread over this. This ensures it and the original thread are concentric with each other.
OK, that is what I read. I haven't pulled my RC down but I'm guessing detaching the original collar from the mirror shouldn't be a major problem.
Drilling and tapping the end cover shouldn't be a big problem either but what is the material it will be attaching to?
I guess I have a magnet here and can check that myself, I haven't looked. If it's carbon fibre is that easy to drill (and more importantly, tap?)
Oh OK, my son just said he believes it's alloy, that's easy.
The adaptor does look nice, really itching to try it out.
An interesting point that Joshua pointed out while doing the design is that in the basic GSO setup, the complete baffle tube + mirror + image train assembly, which would weigh a few kilos and be upwards of 600mm long, is attached to the OTA via only the 3 (three!) 4mm mirror collimation hex screws, leading to the possibility of collimation change due to flexure as OTA elevation varies. You can see the three (inner) screw holes in the attached photo.
That's why his adaptor uses NINE attachment points to the backplate, ensuring the image train is solidly mounted to it while totally offloading it from the mirror assembly, so the mirror collimation screw load is significantly reduced to just the mirror and baffle tube.
I believe Joshua's adaptor should provide significant improvement to the overall collimation stability and imaging load carrying performance of the unit.
Yes, I am quite perplexed how everything is supported on those 3 screws, with only about 3.8mm of thread depth. Anyone who knows about thread sheer stress, knows aluminium threads are required to be 2.5 x thread diameter for steel bolts to withstand the stress that might be placed on the bolt... This is why I have 9 bolts.
Some people might say, 9 x m6 cap head bolts is a little overkill, and I know it is, But there is flex in everything, and I mean everything (not refering to GSO here) but metal fixtures and plates will always flex minor amounts, its a matter of minimising it. So 9 bolts will go a long way to keeping flexure at the camera interface to a minimum.
I like over engineered, I've spent my entire life doing it from specialist forklift attachments to what I called "a spider", a collapsible steel (and plank) structure to aid in safe assembly of silos and never had a device fail.
Just a quick update for those who may be following the RC8 major upgrade. I mentioned in an earlier post that I was going to install the baffle tube extension as recommended, and it arrived a few days ago from FLO UK, (cheapest postage).
Very lightweight 3d printed, with good non reflective surface inside and out.
It's a good medium friction fit into the baffle tube, and seems quite secure without need for glue or screw fastening etc. Some pics attached.
Mike I don;t believe the extension is necessary for the later model unit I have. I haven't been game to strip mine as of yet, deciding to wait till an adapter is available and do collimation only once. Plus I may get it out and use it in the interim till the adapter is available.
I'lll have to set up my mill to drill and tap the holes unless I get my engineer to do them, not sure yet.
It seems I have a lot happening in different areas of my life at the moment and I have no idea when I might even get to it once I have the upgraded rear plate.
I would guess Google is the best way to find out. Cloudy Nights, Stargazers Lounge or FB RC user group being the immediate suggestions. My RC8 was also bought used back in 2011, and IIRC, the corrected baffle version came out much later than that, but I don't remember when.
I sent you dimensions of my baffle on P2 of this thread, but I guess you have to remove the rear assembly to get at the baffle and see if yours is the same. If it's longer, then I would suspect you have the newer version.
As I also mentioned earlier, I don't even know if I had any of the bright-star reflection problems, just decided to put in the extension as insurance while I had the scope in pieces.
I also think that with a little determination, the ~10g extension could be inserted from the front without any disassembly.
Hi Guys,
Mikes rear cell has been sent back to him, I have attached some photos from along the way.
I am currently working on 2 others, one having a tilt attachment built in (Mike opted to not have the tilt version as he has a separate tilt adapter). I will post this over in the dedicated thread for these parts (hopefully a duplicate is alowed)
The RC8 backplate with adaptor has arrived from Joshua, he did a super job and it looks even better than the photos. A photo with the RC spacers and my tilt adaptor attached follows.
Now to document the assembly and collimation. First task is to clean the primary mirror, which is still sitting upside down on a towel in the obs since the disassembly. Better late than never.
I'll make another post to list the steps in assembly and collimation.
