Hello all.
I have a QHY 294M-Pro, CFW3M-SR, and OAG-M fitted to my Vixen R200SS newt. I have been battling tilt with my 294M ever since I bought it, and have been stumped by the lack of suitable tilt adjusters available on the market (especially in M54). The only two almost workable solutions were the Gerd Neumann CTU-XT, Photon Cage, or the Octopi Astro tilt adjusters - some of which are astronomically expensive or didn't fit backfocus requirements. I also considered just selling my whole QHY setup and getting the PlayerOne IMX294 equivalent system or using this as an excuse to upgrade to a full-frame system, but then that would have necessitated 2" filters... meaning more $$$... I thought 'surely I can make something myself'...
My design was inspired by the Gerd Neumann CTU-XT, however as myself and several users have found out, it is too large to fit under the QHY OAG-M at 99mm OD. It also doesn't feature the M3x62mm PCD mounting pattern used by QHY's medium camera adapter system.
So I custom designed a tilt adapter that is smaller in diameter (93mm OD) to fit under the OAG-M, and is side-adjustable. I couldn't get a rear-adjustable design to work due to the limited backspacing I had available with the CFW3M-SR, and the limited mounting screw locations given to us from QHY on the 294M's front plate. The design is lightweight at only 129g. It uses the same belville washer spring system as the CTU-XT, using a stack of 5x M5 belville washers to provide a restorative force against the tilt adjusting grub screws. Turning the grub screws into the tilter causes the tilter to expand in that side.
The tilt adapter consumes 11mm of back-focus when fully closed, and opens to approximately 12mm. Total stackup from QHY294M sensor, CFW3M-SR, OAG-M and M54 adapter is approximately 53.5mm, allowing 1.5mm for a standard M54 t-ring to adapt to your focuser drawtube and coma corrector:
(note the quality of back-focus specifications of QHY's equipment is appalling and/or entirely incorrect online, I had to painstakingly reverse engineer/measure and model every one of these QHY parts to make sure the backfocus dimensions worked out.)
Some compromises had to be made:
I had the tilter parts machined by PCBWay, and specified the parts to be Aluminium 6061-T6, bead-blasted and anodised black. They came out to around $140USD shipped to me in Western Australia.
I would recommend spending the extra money for hard-anodising instead of standard anodising; the tilt adjusting grub screws chew up the soft aluminium pretty quickly. This thing probably wouldn't survive hundreds of uses. Perhaps it even needs to be made from 7075, or stainless steel or something... but for a prototype the 6061 worked well enough and it is very cheap compared to market alternatives.
I have archived the machining and assembly drawings as PDFs and .x_t parasolid files which you can download here:
M54-Mini-Tilter-Files.zip
You can send these files to a machinist to have them make the parts for you, or machine them yourself if you are so inclined.
You will need to purchase:
Disclaimers:
I have no interest in selling these as I am located in Australia and couldn't reasonably compete with anyone international due to exchange rates and shipping etc. If you would like one of these please download the files and get them machined locally. I am making these files available in case it helps anyone else obtain a tilt adjusting solution for their QHY medium camera setup. I do this as a hobby. I am not responsible if these parts do not fit your equipment or cause damage - do your own checks first on your equipment!
If you have made one of these and it helped you - please let me know! drop a comment. It would be cool to see someone else getting some use out of this work.
I have appended assembly pictures and some test shots from NINA's abberation inspector from some tests last night. Unfortunately it has just clouded over and I will be unlikely to get some more test shots for a while. It took me just an hour or so of fiddling and I have already managed to get most of the tilt out of my system. It is remarkably improved from what it used to be, and shows promising results. I hope I can get some more testing time soon to add before/after star pictures, but first impressions are that the corners of my images have improved substantially from what they used to be.
Assembly photos:
Assembly of Part B to filterwheel (note the M3 CSK fasteners become captive once the tilter is fully assembled)
Also note you will need to remove the stock dovetail adapter that comes with the QHY filterwheel and camera, and fit QHY 020063 adapter to mount the camera directly to the EFW.
Final assembly of the tilter onto the filterwheel
Final stackup complete with 3mm QHY 020070/ 020079 (6xM3 to M54) adapter on the OAG-MM:
As-installed on my Vixen R200SS, with a Moonlite 2.5" focuser.
I custom machined an M68-M54-M56 T-ring with an M68 locking collar. The T-ring holds the Vixen Coma Corrector PH inside the focuser drawtube, and the M68 locking collar allows some rotation adjustment of the camera if I need to adjust framing. Of course this messes with the tilt adjustment, but I rarely need to rotate my camera. This is the same methodology as the stock Vixen focuser and t-ring system.
NINA/Hocus Focus Abberation Inspector plots from last night's testing:
Before:
After about an hour of fiddling with the tilt adjusting screws:
I have a QHY 294M-Pro, CFW3M-SR, and OAG-M fitted to my Vixen R200SS newt. I have been battling tilt with my 294M ever since I bought it, and have been stumped by the lack of suitable tilt adjusters available on the market (especially in M54). The only two almost workable solutions were the Gerd Neumann CTU-XT, Photon Cage, or the Octopi Astro tilt adjusters - some of which are astronomically expensive or didn't fit backfocus requirements. I also considered just selling my whole QHY setup and getting the PlayerOne IMX294 equivalent system or using this as an excuse to upgrade to a full-frame system, but then that would have necessitated 2" filters... meaning more $$$... I thought 'surely I can make something myself'...
My design was inspired by the Gerd Neumann CTU-XT, however as myself and several users have found out, it is too large to fit under the QHY OAG-M at 99mm OD. It also doesn't feature the M3x62mm PCD mounting pattern used by QHY's medium camera adapter system.
So I custom designed a tilt adapter that is smaller in diameter (93mm OD) to fit under the OAG-M, and is side-adjustable. I couldn't get a rear-adjustable design to work due to the limited backspacing I had available with the CFW3M-SR, and the limited mounting screw locations given to us from QHY on the 294M's front plate. The design is lightweight at only 129g. It uses the same belville washer spring system as the CTU-XT, using a stack of 5x M5 belville washers to provide a restorative force against the tilt adjusting grub screws. Turning the grub screws into the tilter causes the tilter to expand in that side.
The tilt adapter consumes 11mm of back-focus when fully closed, and opens to approximately 12mm. Total stackup from QHY294M sensor, CFW3M-SR, OAG-M and M54 adapter is approximately 53.5mm, allowing 1.5mm for a standard M54 t-ring to adapt to your focuser drawtube and coma corrector:
(note the quality of back-focus specifications of QHY's equipment is appalling and/or entirely incorrect online, I had to painstakingly reverse engineer/measure and model every one of these QHY parts to make sure the backfocus dimensions worked out.)
Some compromises had to be made:
- The tilter cannot be rotated, and one of the 3 tilt adjuster grubscrews can only be accessed with a long allen key alongside the bottom of the filterwheel (this is only a mild inconvenience and I easily found a long enough allen key to adjust it)
- This design provides less theoretical tilt resolution compared to the CTU-XT or photon cage due to the smaller tilter diameter and standard pitch M5x1.0 tilt grub screws
- The tilter must be fit in front of the CFW, meaning more weight hanging off the tilter vs other designs which mount directly to the camera.
- The tilt-locking screws are very difficult to access, however I haven't actually needed to use them so far. I have just left them loose
- You lose the rotating dovetail feature that comes with the QHY system - the only way to rotate the camera comes from a locking collar on my focuser's M54 T-ring.
- I couldn't get a 4-screw tilting system to fit between the 6xM3 PCD, so it is a 3-screw tilt system. Mildly annoying if you are using NINA and the Hocus Focus abberation inspector, or other packages that only output a 4-corner adjustment recipe, however I got it to work just fine.
- If opened too wide, it could introduce a light leak. In practice I have not found this to be an issue, perhaps wrap some tape or a hair scrunchy around it if it does cause an issue. Due to the OD and ID limitations I just couldn't fit any further light seal geometry in the design.
- The backfocus stackup with a 1.5mm t-ring measure exactly 55.0mm, which allows zero adjustment under 55.0mm (if your coma corrector's ideal backfocus setting is <55mm due to manufacturing variance).
- The M3 CSK screws holding the tilter to the CFW are captive inside the tilter - you have to disassemble the tilter in order to assemble it to the filterwheel first before assembling the rest of the imaging train. Make sure you get the screw length right the first time!
I had the tilter parts machined by PCBWay, and specified the parts to be Aluminium 6061-T6, bead-blasted and anodised black. They came out to around $140USD shipped to me in Western Australia.
I would recommend spending the extra money for hard-anodising instead of standard anodising; the tilt adjusting grub screws chew up the soft aluminium pretty quickly. This thing probably wouldn't survive hundreds of uses. Perhaps it even needs to be made from 7075, or stainless steel or something... but for a prototype the 6061 worked well enough and it is very cheap compared to market alternatives.
I have archived the machining and assembly drawings as PDFs and .x_t parasolid files which you can download here:
M54-Mini-Tilter-Files.zip
You can send these files to a machinist to have them make the parts for you, or machine them yourself if you are so inclined.
You will need to purchase:
- The two tilter machined parts (Parts A & B)
- QTY 3x M5x20mm grub screws to modify (turned down to a point for the tilt adjusting mechanism)
- QTY 15x M5 belville washers (10mm OD)
- QTY 3x M5x9mm wafer head torx screws
- QTY 6x M4x6 SHCS
- Various M3 countersink screws in various lengths
- QHY 020070 / 020079 (or 020089 spacer kit?) M54 to 6xM3 adapter to adapt OAG-M to M54 threads, 3mm thk.
- QHY 020063 6x M3 camera adapter plate
Disclaimers:
I have no interest in selling these as I am located in Australia and couldn't reasonably compete with anyone international due to exchange rates and shipping etc. If you would like one of these please download the files and get them machined locally. I am making these files available in case it helps anyone else obtain a tilt adjusting solution for their QHY medium camera setup. I do this as a hobby. I am not responsible if these parts do not fit your equipment or cause damage - do your own checks first on your equipment!
If you have made one of these and it helped you - please let me know! drop a comment. It would be cool to see someone else getting some use out of this work.
I have appended assembly pictures and some test shots from NINA's abberation inspector from some tests last night. Unfortunately it has just clouded over and I will be unlikely to get some more test shots for a while. It took me just an hour or so of fiddling and I have already managed to get most of the tilt out of my system. It is remarkably improved from what it used to be, and shows promising results. I hope I can get some more testing time soon to add before/after star pictures, but first impressions are that the corners of my images have improved substantially from what they used to be.
Assembly photos:
Assembly of Part B to filterwheel (note the M3 CSK fasteners become captive once the tilter is fully assembled)
Also note you will need to remove the stock dovetail adapter that comes with the QHY filterwheel and camera, and fit QHY 020063 adapter to mount the camera directly to the EFW.
Final assembly of the tilter onto the filterwheel
Final stackup complete with 3mm QHY 020070/ 020079 (6xM3 to M54) adapter on the OAG-MM:
As-installed on my Vixen R200SS, with a Moonlite 2.5" focuser.
I custom machined an M68-M54-M56 T-ring with an M68 locking collar. The T-ring holds the Vixen Coma Corrector PH inside the focuser drawtube, and the M68 locking collar allows some rotation adjustment of the camera if I need to adjust framing. Of course this messes with the tilt adjustment, but I rarely need to rotate my camera. This is the same methodology as the stock Vixen focuser and t-ring system.
NINA/Hocus Focus Abberation Inspector plots from last night's testing:
Before:
After about an hour of fiddling with the tilt adjusting screws:
