CGEM HYPERTUNE

[Explorer 190 MN]

Well after fighting with guiding all winter and not really enjoying my mount I decided to pull it apart to see what I could find and this is what I found.

1. Lose OTA saddle. (apparently this is common) (=BACKLASH)

2. Paint spots inside RA ring gear housing and also blemishes in the housing. (=FRICTION)

3. Both RA and DEC ring gear slightly over sized. (=FRICTION)

4. Stiff worm shaft bearings due to incorrectly adjusted retaining rings. (=FRICTION)

5. Incorrectly adjusted RA and DEC retianing rings. (=FRICTION)

6. Incorrectly adjusted DEC motor spur gear. (BACKLASH)

7. Alt adjustment Handel moulded on adjustment bolt out of line. (CAN BE USED AT GREATER THAN LAT 60)

8. Alz. Pin on tripod lose. (= EASY TO UPSET POLAR ALIGNMENT)

9. Incorrectly adjusted spacing for correct worm gear to ring gear meshing. (BACKLASH)

10. Incorrectly set DEC marker (causing first alignment star to be out I field of view.)

11. Incorrectly set spirit level on mount.

12. Holding pins in the motor gearbox out of true and grease thick like glue. (FRICTION AND LOSS OF MAX CAPACITY)

I ordered a DIY Hypertune kit from Ed Thomas a very informative DVD aprt from the DVD almost all the tools and materials needed to do the job were included. You need a vernier gauge and not a (micrometer as he calls it) and a C clip remover. I would advise anyone with a CGEM to do this upgrade or at the very least check the tightness of the retaining rings at the end of each axes and also the worm gear bearing retaining ring. My mount now is very smooth and has only 1mm of movement at the end of the counter weight bar and about the same for DEC. I would also recommend adjusting the motor spur gear for a better fit to the worm gear spur gear it helps minimize the backlash a bit.I pulled my RA motor gearbox apart to find out why it was stiffer than the DEC when moved by finger to find dark brown thick grease in there and to find the pins the gears sit on wern´t round but slightly triangle and I think this is causing stiction in there. I cleaned out the thick grease and put in some superlube instead and all though it runs better I am going to order a new one anyway. Its really hard to explain the difference in the mount now. I am really happy with the results and cant wait to do some PE runs as soon as its dark enough here in Sweden. I may even offer a European hypertune service in some months.

Well I am of to make a new more suitable cable for my Lodestar a shorter cable of better quality and also going to pull the Handcontrol and GPS unit apart to add longer cables to them so they actually reach the mount head with out pulling at the mount head in certian positions .I add a piller to my mount so when I am using my 8" MakNewt it doesn´t run it to the mount whilst I am asleep.

Well that all folk I´ll write a little update in a month or so when it is dark enough to do some PE runs.

[billhinge]

Out of curiosity did you get new ceramic worm bearings and pfte washers?

[Explorer 190 MN]

Out of curiosity did you get new ceramic worm bearings and pfte washers?

I got the PTFE spacers and bought the ceramic bearings locally much cheaper for me, they are a standard size easy to come by. But the PTFE bearings which are more correctly called shims are necessary for getting the correct spacing for the worm gear to ring gear meshing. Ed calls quite a few things by a wrong name and kinda drops stuff and forgets stuff which was kinda worrying whilst watching the DVD but in all its handy having it for reference. I would definitely recommend measuring the motor spur gear distances from housing using the spur gear inspection hole before taking the mount apart and to honest the allen keys in the kit work but they are not ideal for the job. I would also add this. When putting the motor allen screws back in put a dab of grease in the screw head and that will make sure you dont drop the screw inside the casing. As for the ceramics bearings and the original bearings there wasnt so much difference in it just a tinny little bit. Did I think hte kit was over priced yes did it work yes. My father comes to visit me in a few weeks and he has been the head engineer on oil platforms for many years Ill pull it aprt when he is here to show him how it ticks to see if he can think of any improvments. I have been thinking about replacing the spur gear with a belt driven system.

[Martin-Devon]

Nice post - the hypertune kit/video from Ed Thomas is very popular with the USA CGEM users, and many folks there post on the Yahoo CGEM users forum & are very positive in their comments on the benefits of this. I think you'll find a lot of interest from many European CGEM users if you can offer servicing, hypertuning & repairs for this mount. Please keep the SGL forum updated if you proceed down this route.

[continuum]

Coincidentally I have recently "Hypertuned" my CGEM following Ed Thomas' video. I didnt buy the kit which I thought was grossly overpriced especially when taking account of the postage, duty and VAT involved.

So I didnt have the Teflon shims or the ceramic bearings. Otherwise I followed the videos and I must say that the mount is so much freer. Unfortunately the weather has been so bad I have yet to try in earnest at night.

I would agree with Exploer 190 MN re the faults found so all in all I would recommend tuning.

Ron

[Explorer 190 MN]

Coincidentally I have recently "Hypertuned" my CGEM following Ed Thomas' video. I didnt buy the kit which I thought was grossly overpriced especially when taking account of the postage, duty and VAT involved.

So I didnt have the Teflon shims or the ceramic bearings. Otherwise I followed the videos and I must say that the mount is so much freer. Unfortunately the weather has been so bad I have yet to try in earnest at night.

I would agree with Exploer 190 MN re the faults found so all in all I would recommend tuning.

Ron

Actually I think the problem lays in the retaining rings on the RA and DEC axes and possibly the worm gear retaining rings. I did see some minor scratches on the the ring gears indicating slight contact but nothing too bad. And if it is true that the retaining rings are too tight then you don´t really need to pull the mount apart to sort this out and the other main problem is definitely the contact between the motor gearbox spur gear and worm gear drive gear I am sure this causes a fair amount of periodic error I plan on changing these out to a belt driven system found some parts here I just need to work out the right sizes http://www.hpcgears.com/products/pulleys_belts.htm and that should definitely take care of backlash there.

As for the backlash in the motor gearbox well I was thinking change out the pins the gears sit on to a better quality round bar that is actually round and not slightly triangular.

There is replacement motors for anyone with that problem these are cheaper to buy than from Celestron the gearbox is the same ratio but you need to transfer the nylon safety gear from the original and also the Encoder will need to be changed over. I think if and well actually when I go down this road Ill just change over the gearbox as thats where the problem lays I think. Its because the gears are lose on the mounting pins. I did see some rough spots on these pins I am guess they are forged on rollers and I am guessing just now and then the odd gearbox gets a bad bit of bar the gearboxes have that old sticky brown grease in them they are the same as the CG5GT advanced series motor. I have also read it is possible to piggy back mount a new motor drive chip on top of the old one to give it the same va va voof as the CGEM DX mount thus increasing motor power and max payload. I dont think my soldering skills are up to the job though. I may try to wangle a DX control board some how depending on price.

Has anyone out done the AMD OTA saddle conversion? I am thinking in term of weight reduction are they lighter??

Has anyone any good ideas for getting better performance from the CGEM?? I think I have taken it as far as I can go apart from the ring gear/ worm gear upgrade and I have read that these £1000 parts are all they say they are on the box and a £1000 lotta cash!!

[Explorer 190 MN]

BTW the ceramic bearings for the worm gear are 608 zz ABEC-5 ceramic

Dimensions are 8 x 22 x 7

It is required to take the mount apart to do this job so unless you are taking it apart anyway I would just skip this part.

As for the Teflon shims well I am not sure of how much gain there is to be had apart from getting better gear meshing reducing backlash a bit further. I think by reducing friction in the entire drive train gives you the possibility to tighten the worm gear meshing up just a bit so the motors fight against that and not friction. Ill see what my father has to say about the Telfon shims and if there is a better solution than that. He has worked as head engineer on oil platforms for 20 years and should know of better lubricant and material for shimming the worm gear meshing. Final note for anyone intending to do this measure the the spur gear spacing from the inspection hole in the before taking it apart Ed suggests trial and error which well is just annoying to say the least. These mount are not that complicated just be careful !!

I´ll post some torqure setting later from my reference paper as I am sure bolts that have different amount of torque will warp the alu casing just a bit I am a bit of a torque wrench addict but that comes from maintaining my bikes...

Good luck!!

[billhinge]

Thanks for the info

Incidentally the 608 ceramics are the same size as skateboard bearings - I originally incorrectly assumed the the CG5 had the same size bearings and bought a set of bones reds

I agree with you about the benefits of reducing friction being that you can tighten the meshings. I tuned my CG5 up (by taking it apart and seeing how it worked) - I replaced my slightly smaller CG5 worm bearings with ceramic bike bearings and lubricated all my surfaces with tungsten disulphide (ws2) and this allowed me to get the various meshings a lot tighter than with grease. I just set the correct tensions by running the motors and tweaking the tension up until it was just right

I had looked at the hyper tune kit but decided it was too expensive so I went down the diy route

If I had the dosh I would probably get a CGEM or DX but I can't afford it till perhaps next summer - already bought this years major toys

Don't know if the CGEM has a vixen or losmandy saddle but I fitted the ADM losmandy to the CG5 and it makes a big difference. In conjunction with a hypertune and berlebach tripod it supports a C11 reasonably well so it gets a thumbs up from me

[Explorer 190 MN]

Yeah I done a CG5GT DIY hypertune and had 16kg on it doing 600sec unguided subs actually worked better than my CGEM dose hopefully did and not does.... No I am sure it will work real good now.

[billhinge]

I can believe it, my OTA has a baader focuser, camera plus big dew shield so over 30lbs but its good enough for planets even in moderate breeze - but I admit it is still a bit of work at times

Sure the CGEM will be great, can recommend the wooden tripods if you ever get the chance

[Explorer 190 MN]

I can believe it, my OTA has a baader focuser, camera plus big dew shield so over 30lbs but its good enough for planets even in moderate breeze - but I admit it is still a bit of work at times

Sure the CGEM will be great, can recommend the wooden tripods if you ever get the chance

I have seen wooden tripods whats the advantage?

[MoT Man]

I have seen wooden tripods whats the advantage?

The larger Berlebach wooden tripods are sturdier than the standard CGEM tripod, they also have better vibration absorbing properties too. Good info on the DIY Hypertune. When i did mine i also found that the dec/ra retaining rings were cranked up way too tight. I went for the ceramic upgrade bearings and teflon spacers. I didnt change the bearings in the end, just cleaned up the originals with a citrus based degreaser and reaplied with superlube. Replaced standard spacers with the teflon ones. Also cleaned, sanded and polished the ring gears. Made worm adjustments without any weight on the mount and then final fine adjustments with mount fully loaded. What a difference

[billhinge]

I swapped out the standard steel tripod for a Berlebach UNI and it is stable and damps vibration quickly even on concrete

everyone says you can't mount a C11 on a CG5 or even think to use a camera, well with a Berlebach and a Losmandy dovetail and a hypertune you can

Individually they wont cut it but together they do, tripod is a key part of this chain. It even stays solid when focusing and damping is to my satisfaction

I've probably spent enough to get an NEQ6 overall but I'm stubborn/stupid and like a challenge, I've no doubt a CGEM on a berlebach Planet would be a great combo (expensive thought)

[Explorer 190 MN]

I swapped out the standard steel tripod for a Berlebach UNI and it is stable and damps vibration quickly even on concrete

everyone says you can't mount a C11 on a CG5 or even think to use a camera, well with a Berlebach and a Losmandy dovetail and a hypertune you can

Individually they wont cut it but together they do, tripod is a key part of this chain. It even stays solid when focusing and damping is to my satisfaction

I've probably spent enough to get an NEQ6 overall but I'm stubborn/stupid and like a challenge, I've no doubt a CGEM on a berlebach Planet would be a great combo (expensive thought)

hmmm just when I thought I was done......... wooden tripod huh?? .... surly am done then..... well apart from I might whack my DSI IIIc in my 9 x 50 finder scope just for alignment purposes and a electric focuser oh yeah some kinda scope for wide field too or a hyper star unit tough one or maybe not imagine guiding something around 400mm fl with 2032mm fl on a OAG interesting...

Hardware

Edge 8HD or Skywatchers 190 MN DS PRO

Atik 314L+

TS OAG 9mm

Starlight express Lodestar

DIY Hypertuned CGEM

Celestron GPS

Kendrick Dew shield with built in heater band

Kendrick Heater control

Orion Piller extension

Polar alignment scope (time saver)

Kendrick astro tent

Logitech wireless gamepad

TS 2" monorail Dual speed focuser (not installed yet)

HP elitebook 2730p Tablet PC 2.3 Ghz 8GB RAM Touch screen, external battery 16h running time

2 x 12v 120 amp marine batteries

Customised hand control cable

Software

MaxIm DL connected to Nexromte

Artimis captue

Pemp Pro

CCD Inspector

[x6gas]

Thanks again for the info in your two threads on tuning up the CGEM. I've just finished a strip down and rebuild of my mount. I have to say that with the benefit of the threads on here and AstroBaby's guide on the EQ6 / Orion Atlas (which is pretty similar) I didn't find the process too difficult. I did take my time though and did the job in several sessions.

I replaced the worm carrier bearings with ceramic ones from SMB Bearings (available on ebay, cost me £14.50 inc postage) and used Badfish Barracuda Tungsten Disulphide Grease (which is black so looks a bit gloopy, but seems to do the job!). To be honest, though, the mount seemed to have fairly decent lube in it and the original bearings span freely enough so while I'm pleased with the results I would agree that I'm not sure replacing the bearings and / or lube is absolutely necessary.

However, here is what I found needed correcting / tweaking on my mount:

• Loose OTA saddle
  
• Retaining rings on both worm gears a bit tight (I am actually not sure if this made a huge difference)
  
• Spur gear on the RA worm wasn't square (wobbled when spun) which I guess was generating PE and would presumably have increased wear over time.
  
• RA taper bearing way too tight.
  

It's the last point that, I am sure, has made the most difference. The taper bearing wasn't particularly well lubricated and the retaining ring pushing it up was on so tight that some of the roller bearings that make it up were seized... I have no idea why the person who put this mount together orginally felt the need to have it so tight but as mentioned above this is pretty easy to address without striping down the mount (it's two allen grub screws and a retaining ring).

Anyway, thanks any for the info which gave me the confidence to give this a go. Not a difficult job as long as you are careful and take your time. I'll be interested to see if this solves the issues I've had trying to autoguide at 2800mm focal length!

[Explorer 190 MN]

Thanks again for the info in your two threads on tuning up the CGEM. I've just finished a strip down and rebuild of my mount. I have to say that with the benefit of the threads on here and AstroBaby's guide on the EQ6 / Orion Atlas (which is pretty similar) I didn't find the process too difficult. I did take my time though and did the job in several sessions.

I replaced the worm carrier bearings with ceramic ones from SMB Bearings (available on ebay, cost me £14.50 inc postage) and used Badfish Barracuda Tungsten Disulphide Grease (which is black so looks a bit gloopy, but seems to do the job!). To be honest, though, the mount seemed to have fairly decent lube in it and the original bearings span freely enough so while I'm pleased with the results I would agree that I'm not sure replacing the bearings and / or lube is absolutely necessary.

However, here is what I found needed correcting / tweaking on my mount:

• Loose OTA saddle
  
• Retaining rings on both worm gears a bit tight (I am actually not sure if this made a huge difference)
  
• Spur gear on the RA worm wasn't square (wobbled when spun) which I guess was generating PE and would presumably have increased wear over time.
  
• RA taper bearing way too tight.
  

It's the last point that, I am sure, has made the most difference. The taper bearing wasn't particularly well lubricated and the retaining ring pushing it up was on so tight that some of the roller bearings that make it up were seized... I have no idea why the person who put this mount together orginally felt the need to have it so tight but as mentioned above this is pretty easy to address without striping down the mount (it's two allen grub screws and a retaining ring).

Anyway, thanks any for the info which gave me the confidence to give this a go. Not a difficult job as long as you are careful and take your time. I'll be interested to see if this solves the issues I've had trying to autoguide at 2800mm focal length!

You are wellcome!!! there is a new stage to be done read below

[Explorer 190 MN]

Well the long darkless summer nights have passed now in Scandinavia and as promised the update:

As I have been pre occupied with adjusting other things like PHD camera attachment, cable drag ect ect I havent had the chance to do any Pempro runs well actually I have to good nights but I just wanted to use the mount and grab a picture.

So during my hypertune experience I learned the Ring gears aren´t actually as round as one might hope for so what I done was to make them as tight as I could with out binding I was lucky enough to have enough rotation in my ring gear with out it binding until it was almost at the of the tracking cycle.

So whilst adjusting PHD parameters and capturing NGC 7380 I noticed the mount was about at the end of its cycle were it was about to bind just ever so slightly I was waiting for the worst when well the tracking graph on PHD went almost flat the RA osc. dropped to 0.16 and RMS 0.15 and the star shape confirmed this was right.

This got my thinking a bit so much so I just had to do something about it. DEC guiding was giving me a headache due to backlash (and guiding parameters) So what I thought I would do was to tighten the DEC mechanical backlash up until it was binding a bit more but not enough for the motor to struggle. I started trying to work out where the tightest posts were to keep them out ot the tracking range of DEC like I done with RA and after sometime I noticed the motor wasnt dropping in revs which would make sense as the ring gear is brass and the worm gear stainless steel. So I tightened everything up just a tad more and ran the motors until it was bedded in again and kept on going for over an hour and now there is absolutely zero backlash and no tight spots I may do this just one more time. I done the same for RA over and over and the same there although there is still just a bit backlash. I will have another go at this tomorrow until it is as smooth as DEC this is a revolution in tuning the CGEM, Because the worm gear is a solid bit of stainless steel and the ring gear brass the ring gear can only get moulded by the linear shaped worm gear and any faults therefore can be smoothed out with PPEC tuning using pempro. The spur gear unfortunately are out of round on mine too and I guess its the same for all CGEM´s including the DX as the only difference really is the moto control board chip for delivering power to the motors.

Do not over tighten the backlash causing hard binding it just has to bind ever so slightly and work it back and forth until it sounds smooth you absolutely must have OTA and counter weights mounted for adjusting RA backlash or you may strip the safety nylon gear in the gearbox. (It is possible to order new motor/gearbox unit)

My mount has become so quite and smooth since this last adjustment.

I TAKE NO BLAME IF YOU BREAK something this is what I done by feel and ear and I have been around engines and things since I could walk. This is not a hard procedure just use conmen sense... I´ll post some pics soon next time I am at my mount which will be tomorrow after work. I´ll attach a 35 min sub from last night. The purpose of this sub was for testing only!!! taken through thin cloud.. It was debayered, one stretch and converted to jpg I know it has artefacts in it from the conversion but its just a test pic...(the heart of the heart IC1805)

[Explorer 190 MN]

Hang on people where did my actual hypertune instructions Go?

[Explorer 190 MN]

Here is the drill then including small details the lawyer missed (Ed)

Tools:

1.5mm Allen key (go get some good T-Handel type allen key)

2.5mm Allen Key

5 mm Allen key

C clip remover ( a good quality one)

Pump grips

Old spanner which you will need to grind down. ( I got a tool in the kit)

Plain screw driver

Philips screw driver

A vice

Digital vernier gauge

Plastic mallet

Wooden blocks

Fine plastic brush (in the kit)

De-greaser

Wet and dry sand paper from a bit coarse to really fine (in the kit)

Metal polish (in the kit)

Synthetic superlube you want something that will work at low temperatures preferably with Teflon base or better

Leaving the mount head on the tripod

1. Take off your OTA saddle lay it to the side and replace the three screws in the top of the DEC axes

2. Remove the Polar finder scope

3. Remove Polar finder scope cover

4. Remove the little silver spur gear inspection screws and messure the distance from the housing to the spur gear write it down! insert screws again so you dont lose them.

5. Look to where the counter weight bar attaches to the mount you will see a small hole there turn the DEC axes and you will see 3 grub screws 1.5mm allen screws I think it was. Slacken these off a good bit dont need to remove them

6. Use your C clip remover to unscrew the DEC retaining ring almost until it is off.

7. Loosen the DEC worm gear adjustment screw

8. remove the DEC worm gear housing holding bolts

9. Place your hand over the DEC taper bearing and gently pull the DEC axes up, if its stuck just gently tap it with plastic bearing hammer. Now when the DEC axes comes up a bit the tapper bearing will fall out to keep you hand over it (infact place a towel or something soft under the mount to cushion the fall of parts just in case)

10. Place the DEC assembly aside watch for plastic spacers and where they come from.

11. Where your Polar finder scope sits under that plastic cap is your RA retaining ring and this is the same as the DEC retainer but 4 allen screw to slacken off. I took my mount head of the tripod went to the shed and with two wooden blocks gently held the retaining ring in the vice and turned to housing to losen this of then back into the house back on the tripod and continued to un-screw the retaining ring here agian place your hand over the tapper bearing and gently pull the RA housing out. Put it aside.

Ok now to DEC again here is the fun part

Carefully lift the ring gear assembly up out and off the DEC shaft do this with care and do it gently if it get even just a little bit stuck STOP! look to see which side is higher than the other and gently press it down failing that just tap it down gently until it sits in place again and start over I was lucky mine came strait off the first time. If there is a bearing left in the top of the DEC housing gently but firmly tap the end of the DEC shaft down ward onto your wooden block I used my hand at first but that get sore after a while

Now you have almost disassembled you DEC assembly.

DEC worm gear housing

Ed says to remove both plastic caps and retaining rings not necessary.

Look closely at the plastic caps and you´ll see a little indent a dart or even a little screw driver and prise off the plastic cap be careful under here you´ll find the

DEC worm gear retaining ring.

You´ll need to remove this with you C clip remover to screw this out to uncover the

Bearing retaining ring, this is where you need your ground down spanner Ill attach a youtube link where this is explained later in my post.

Losen the the two spur gear grub screws

If the worm gear doesn´t come out clean/easily check the grub screws are lose enough failing that find a suitable long punch and very gently tap out your worm gear please be very carefull with it you really don´t want to damage that, really don´t don´t fret to much its stainless and the housing is cast alu.

Congrats !! DEC dismantled.

Now clean all parts do not try to dry fot any part or they will get seriously stuck trust me..

Polish your ring gear by holding it loosely in one hand with your wet and dry and just twist it to try to fine slip it down. Don´t go mad! and then change to a finer grade with water and finally polish it up. Now take little superlube and smearer just a tiny amout all the way round the ring gear.

Check your DEC housing for blemished and paint in my case make sure it is clean and very carefully/slowly place your ring gear in there if there is even a hit that it might be sticking STOP gently pull it out or it will get stuck very stuck.

The whole point of this fine sanding of the ring gear is to be able to put it in and out of hte housing with out it getting stuck I spent some time on this and was able to get it to spin very freely with out grease. I dry fitted mine right of the bat and almost got it stuck once.

Clean of and worm gear and spur gear only with soft cloth and soft plastic bush I used a business card to clean the worst out and a microfiber cloth and de-greaser for cleaning motocross airfilters poisonous stuff but works good not ever to be pured down toilets or drains or near any water it is poisonous!!

Ok time to replace bearing if you like to the ceramic ones tap em out press in the new ones just a tiny bit of grease there on the out side of the bearing back in with your worm gear and on with your spur gear tighten up grub screws on spur gear now worm gear retaining ring look to see when it meets the bearing. Spin the worm gear with your finger until it spins just right, use your head you´ll know when it is tight enough a dab of thread lock glue and now check the spur gear distance which you wrote down earlier. Now lube up your worm gear.

In with your plastic shims or telfon if you bought them

Same procedure for RA and then put it all back together

When you tighten up your retaining rings use commen sence I just made mine hand tight and tightened the grub screws checked for play. I think by only releasing the pressure on this retaining rings would make loads of difference.

Don´t tighten the worm gear housing screw too much just nip them. Adjust the RA and DEC backlash with adjustment screws until just a little bit of play is felt.

Best way to fine adjust backlash there is by ear go back and forth until it sounds smooth all the way from left to right tighten up worm gear housing screws and re-check for free running from side to side, do not try to make this adjustment with un-balanced mount you will damage the gearbox.

After its all together again place the mount on it side and remove the motor control board pull the plugs out and now loosen the motor allen screws place mount back on tripod balance it with OTA ect plug plug in the motorboard again, remove the spur gear inspection screws by using the direction keys look foe backlash between the gears this can be adjusted by moving the motors up and down carefully with a big screw driver and run the motors and listen there is a very fine balance here between too much and too little. You will hear the diffrence.

This is just a very rough guide and I assume no responsibility if it all goes pair shape.

The heart of the hypertune kit is the DVD that follows with the kit although Ed drops stuff calls it by the wrong name and forgets things its a good guide.

I would just slacken of the retaining rings a bit first and and tighten them to see if that helps if not pull it apart. I am glad I went all the way with mine.

Good luck!!

[x6gas]

So tonight I disassembled my mount to finish my hypertune by reshiming the RA axis to ensure proper spacing of the worm gears. I followed Astro Baby's guide http://www.astro-baby.com/EQ6-Supertune/EQ6%20Super%20Tune%20Guide.php for the EQ6 / Orion Atlas as it is exactly the same for the CGEM / CGEM DX.

I had sourced some PTFE shims but after careful measuring my RA was perfect (and I mean absolutely perfect) with no bottom shim at all. The bottom RA axis bearing seats against plastic so I figure that I am OK with no shim. Put everything back together; setting up the worm gear meshing was a piece of cake (nip the 'positive engagement' adjuster up and then back off by an eighth of a turn, then nip up the opposite grub). I now have no slop at all in either axis and yet both rotate freely with the clutches disengaged.

Very, very happy with the results so far and can't wait for first light under the stars!

[x6gas]

Got first (proper) light following my DIY hypertune. Guiding at this focal length (2800mm) with an OAG I think I am going to have to live with an RMS value of ~ 1.5 in PHD... can't seem to do much better than that, though I am still tuning the settings. Anyway, the important thing is nice round stars. This is a 600s luminance sub of the bubble nebula:

I am quite happy with that...

[Explorer 190 MN]

Seems to be working ok I have a RMS of .35 to max .50 I am replacing the RA motor on mine just waiting for it to come in the post....

[x6gas]

Seems to be working ok I have a RMS of .35 to max .50 I am replacing the RA motor on mine just waiting for it to come in the post....

At 2800mm with PHD? Wow - so come on, share your settings!

I'm down to <1 RMS now (but not between .35 and .5 that;s for sure!

[Explorer 190 MN]

Thats a nice sub, I am not sure my settings would help you. Depending on what I am imaging with they change but my best advice is to make sure you have the right calibration step size. I have my autoguide rte set to 99% and use short pulses for guiding with the hyperstar system at 425mm and when guiding with 2023mm OAG I use 10% autoguide rate and short pulses. I also decrease the autoguider exposure intervals until PHD dosent keep up with the drift anymore Most of the time I try to keep my exposures to 2 seconds to even out the seeiing