ChrisEll Posted February 17, 2018 Share Posted February 17, 2018 Here's a quick guide to adjusting the tightness on the Dec and RA axes on the AVX mount. Freeing up the axes means better guiding, less wear on gears and motors (some gears in the drivetrain are plastic), lower worm PE and you will be able to balance more precisely. Dec axis: Remove the counterweight bar and cup to reveal the tension ring. To adjust this first loosen the 2 grub screws at its side... there is a small access hole at the side of the housing. You'll need a tiny allen key to do this. Then use a slightly larger, stiffer allen key and insert this into the access hole and against the grub screw so that the tension ring is wedged tight against the allen key - this serves to hold the tension ring in place as you turn the axis, no need for a special tool! Now rotate the mount saddle anti-clockwise to loosen the tension ring until you feel some vertical play (grab hold of the saddle and move up and and down to test). Slowly tighten until there's no play. Tighten grub screws. RA axis: Remove the plastic cup at the end of the axis. The RA tension ring has 3 grub screws and the access hole is hidden by the control panel cover (3 screws hold this in place). My RA axis was very tight and needed a few turns of the axis before I got any vertical play. For those wishing to improve their AVX further I recommend adjusting the worm housings in both axes. 6 Link to comment Share on other sites More sharing options...
knobby Posted February 17, 2018 Share Posted February 17, 2018 Top man, much appreciated ! 1 Link to comment Share on other sites More sharing options...
Rob63 Posted February 18, 2018 Share Posted February 18, 2018 I posted some info about AVX disassembly before but this seems like a good thread to add them again. http://rocketsparrow.blogspot.co.uk/2017/01/how-i-made-better-celestron-avx.html (note the comments at the bottom about removing the RA tensioner there are 3 grub screws to loosen first and it needs a very small allen key as shown above) https://www.flickr.com/photos/10605262@N04/sets/72157646742806679/?ytcheck=1 This guide is for the older but similar CG5 http://astronomyboy.com/cg5/ https://www.cloudynights.com/topic/578878-celestron-avx-rebuild/ I replaced the RA bearing with an angle bearing although it does leave a slight gap as mentioned in some threads but it made a HUGE difference to RA stiction http://www.ebay.co.uk/itm/SKF-32007XQ-Metric-Single-Row-Taper-Roller-Bearing-35x62x18mm/130940248658?hash=item1e7ca5a252:m:m3AAqpQNFsFJgnN6vqioQOw It's easier than I thought I didn't even need to remove the RA from the mount part. It certainly made things less sticky and balancing became a lot easier although guiding performance wasn't much better. In the end I bought an EQ6-R which has been a massive improvement. Rob. 1 Link to comment Share on other sites More sharing options...
ChrisEll Posted February 18, 2018 Author Share Posted February 18, 2018 Those are all useful links which I have visited many times! Link to comment Share on other sites More sharing options...
ELEMENT22 Posted April 7, 2019 Share Posted April 7, 2019 (edited) I just wanted to say thank you. My DEC axis was pretty stiff and I never felt confident that I was balanced properly. It's worlds better now and much easier to balance. Thank you! Edited April 7, 2019 by ELEMENT22 1 Link to comment Share on other sites More sharing options...
Astrowal Posted January 31, 2020 Share Posted January 31, 2020 I realize this is an old thread, but iam about to try out this method. But before I do, has anyone actually gotten better results guiding after doing this? Link to comment Share on other sites More sharing options...
ChrisEll Posted January 31, 2020 Author Share Posted January 31, 2020 There are many reasons not to have the axes too tight... you will be able to balance better, less stress and load on the motors, gears, and bearings and yes it may improve guiding. Link to comment Share on other sites More sharing options...
Astrowal Posted January 31, 2020 Share Posted January 31, 2020 Thanks for replying Chris. One more thing, when loosening the RA axis should I follow the same method of rotation (anticlockwise) then pull/push then adjust so that there is no play then tighten the grub screws? Just an insight, Iam a newbie to astronomy but very passionate about seeing this through. Also just recently tried astrophotography and I can safely say iam addicted! I was warned about the Avx mount but chose not to listen. Appreciate all the help though on anything to help make guiding smoother. Link to comment Share on other sites More sharing options...
newbie alert Posted January 31, 2020 Share Posted January 31, 2020 Avx are great mounts, but as with everything massed produced you get good and bad ones... Link to comment Share on other sites More sharing options...
ChrisEll Posted January 31, 2020 Author Share Posted January 31, 2020 38 minutes ago, Astrowal said: Thanks for replying Chris. One more thing, when loosening the RA axis should I follow the same method of rotation (anticlockwise) then pull/push then adjust so that there is no play then tighten the grub screws? Just an insight, Iam a newbie to astronomy but very passionate about seeing this through. Also just recently tried astrophotography and I can safely say iam addicted! I was warned about the Avx mount but chose not to listen. Appreciate all the help though on anything to help make guiding smoother. That sounds fine to me. Yes I got addicted to imaging but now finished my journey. The AVX is capable of good results, just needs some tweaking which is probably true of all of the cheaper GOTO mounts. Link to comment Share on other sites More sharing options...
Astrowal Posted January 31, 2020 Share Posted January 31, 2020 For the most part it's been pretty accurate visually. I do have a Celestron 9.25 sct attached to it. Could be the weight of the scope that's throwing it off for astrophotography. It is quite stiff though, so stiff that I could balance it with my eyes closed. Link to comment Share on other sites More sharing options...
Astrowal Posted January 31, 2020 Share Posted January 31, 2020 Awesome! That's good to know. Thanks for help Chris. Iam gonna give the tweaking a shot. I'll update my results. Clear skies. Link to comment Share on other sites More sharing options...
ChrisEll Posted January 31, 2020 Author Share Posted January 31, 2020 13 minutes ago, Astrowal said: For the most part it's been pretty accurate visually. I do have a Celestron 9.25 sct attached to it. Could be the weight of the scope that's throwing it off for astrophotography. It is quite stiff though, so stiff that I could balance it with my eyes closed. That's a big scope for imaging on the AVX... I had a 8" SCT and it was a struggle! I then got a SW ED80 refractor which was an improvement, being lighter and having a shorter focal length. Link to comment Share on other sites More sharing options...
Astrowal Posted January 31, 2020 Share Posted January 31, 2020 Iam actually looking into a smaller refractor to mount on the Avx. Was told the 9.25 was a bit on heavier side for the Avx, at that point though I was just interested in visual only. Guess I am gonna have to pay the price. Link to comment Share on other sites More sharing options...
ChrisEll Posted February 1, 2020 Author Share Posted February 1, 2020 For those wishing to tune their AVX further check out my other mod: Link to comment Share on other sites More sharing options...
Astrowal Posted February 1, 2020 Share Posted February 1, 2020 Hi Chris, I just have to thank you again, I managed to do the tweaks and it's just so much better, a massive improvement compared to its previous state. Gonna give guiding a try tonight, hopefully register some improvements in that area as well. 1 Link to comment Share on other sites More sharing options...
iapa Posted August 3, 2022 Share Posted August 3, 2022 There has been a number of comments regarding trying the previous adjustments; but no feedback as to success with tracking/PEC results Link to comment Share on other sites More sharing options...
newbie alert Posted August 6, 2022 Share Posted August 6, 2022 On 03/08/2022 at 21:27, iapa said: There has been a number of comments regarding trying the previous adjustments; but no feedback as to success with tracking/PEC results Doubt it would change any of the pec( period error correction) With any of the synta mounts those locking nuts are all over tightened , it has the effect of sandwiching up the ring bearing and locking up the axis... Best to have it loose but not to a point that you have play ( up/down) in the axis..once tightened I'd go as far to say the grubscrews need equal tension You can go further and adjust the height of the worm/ ring gear as from factory that's also usually wrong.. but that needs teflon washers and the whole mount dismantled, so while you're doing that you may aswell change the bearings in the worm and it's tension as again that's usually again wrong You can get to fettle and adjust most things but just know that you void your warranty as soon as you start taking it apart.. just depends on how far you want to go Link to comment Share on other sites More sharing options...
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