A few weeks ago I was scouring the internet for various things and I came across someone who had modded their heq5 with belts. They were claiming lower PE (any from the transfer gear) elimination of all backlash, and far greater goto's. This intrigued me because one of the issues I currently face is being a portable imager setting up every night and re framing images.
I contacted the guy who had done it and he was very helpful. I ended up ordering the parts and today they arrived. Here are a few images of what I have done so far. I have tested it indoors and it sounds a lot healthier ( no crunching as the motors speed up and slow down). I took a PE measurement before and still have the data, so I will do one after and post it here in case it interests anyone.
These looks like the belts/pulleys that i have.
Did you machine them down like the instructions (that i have) said to do?
If not then i am very interested on how yours goes.
If it works well ill swap mine over - i never got around to machining them down to what was stated, and the amount of meat left on the smaller pulley was only 1-2mm!
I actually purchased the parts from a shop who would machine all the parts for me. So all of the specs were already met when they arrived. I know that the 5:1 ratio set were very tight on machining, This is a 4:1 (15 tooth and 60 tooth).
The only thing I need to do now is get a smaller set of allen keys to tighten the grub screws on the 60 tooth (which is tiny!). and make myself a spacer for the cover as the new drive sticks out slightly more.
Because I am a creature of convenience the parts set me back around 100 bucks ( from the UK sent machined) the raw parts were not much. I got some time out tonight to test how she runs. The first thing you notice is there is no more crunching as it speeds up and slows down. I decided with my limited time out tonight to do a polar alignment and a periodic error run so didn't get to test the goto accuracy.
Here are the two graphs, one from before the belt mod and one from after. I didnt record for long enough for the before belt modding run however at a minimum it displays 26 arc seconds peak to peak error. The belt drive run is showing 14.8 arc seconds peak to peak error.
Interestingly the "transfer gear" error in the pre belt drive run had a peak around 10 arc seconds in magnitude, so it seems that the belt mod has eliminated this error.
I would love to see what this mount could do with PE applied but being portable makes this impossible.
I am very happy with the mount and the mod, an error of around 15 arc seconds peak to peak is very good for this class of mount in my opinion.
15s peak to peak is better than my G11 in its standard configuration.
An excellent mod, and it would be very interesting to see what it could do with PEC applied.
That is very encouraging.
Mine is exhibiting errors in ra. I sometimes see round stars and the next exposure would have elongated stars in the E W direction.
Could you post a link to the site with the details of the mod?
Any reason you can't get these timing pulleys here? They look standard enough. I usually get mine from Naismith engg and they can machine it as well.
Hook us up with some links to the mod pete, seen this around awhile back but never new the belts and gears would be that easy to get a hold of. For $100 just to lose the crunch would be nice lol, also eqmod already has the adjusted setting for the mod w00t.
This is the site where I got my information, he has a guide on there but its for a 5:1 ratio. I emailed him for the information and got the specs for a 4:1. There is absolutely no reason you could not get your parts from here, I was just lazy and when he linked me to a site I just bought from them.
He also has a video on his site so you can hear how non crunchy it is. The only thing I have to do now is fabricate a spacer for additional clearance on the cover as the pulleys stick out futher. A project for the weekend I think.
I have just installed the belt drive modification for my HEQ5 but I am concerned about the grub screw that secures the pinion to the motor shaft. Has anyone had any problems with the pinion slipping? Any other problems I need to look out for with the new mod?
Cheers
Why can't you do PE sorry Peter? As long as you park/unpark religously and don't suffer any crashes on the mount or controlling PC you should keep the motors in sync with your PE curve. I run PE routinely on my EQ6, and have done so in the past for the HEQ5Pro (but not currently).
Having an HEQ5 & wanting to mod to a belt drive for a while. I've found three options so far. I wish to continue to use my Synscan hand controller, so that cancels out the 4:1 ratio option. I am very used to the Synscan unit & don't wish to spend time adapting to the EQMOD system for now. I am glad that the EQMOD is available, but I don't want my hand to be forced, & my portable controller to be redundant.
Of the remaining two options, the Rowan Astronomy looks the better of the two. The use of an idler wheel in place of the spur gear gives two obvious advantages.
1. It wraps the belt further around around the pulleys. This may not matter much for the 47 tooth pulley, but will provide surer engagement on the 9 tooth pulley.
2. The belts are identical length, which means that carrying a spare belt could be a good option, as it could replace the belt on either axis, in the unlikely event of a failure.
There is a new Yahoo group for HEQ5 owners. It is fully moderated, so it will not become a spam dump like the last one. At the moment there are only 4 members, so any HEQ5 owners are welcome to swell the ranks. It is not meant to supplant this excellent site, but provide a specific adjunct to it for HEQ5 owners.
One more item, I came across a site for a machining mob that make high precision worm drives & ring gears among other things, including replacement units for some Skywatcher gear. I will contact them to see if they can make replacement worm & ring gears for the HEQ5. That would complete the drive train upgrade for this mount. I'll get back to you when I know, but if anyone else knows of these people, & what their work is like, that would help.
Just joined the Yahoo HEQ5 group Peter , just awaiting approval .
Brian.
Quote:
Originally Posted by peterskye
Having an HEQ5 & wanting to mod to a belt drive for a while. I've found three options so far. I wish to continue to use my Synscan hand controller, so that cancels out the 4:1 ratio option. I am very used to the Synscan unit & don't wish to spend time adapting to the EQMOD system for now. I am glad that the EQMOD is available, but I don't want my hand to be forced, & my portable controller to be redundant.
Of the remaining two options, the Rowan Astronomy looks the better of the two. The use of an idler wheel in place of the spur gear gives two obvious advantages.
1. It wraps the belt further around around the pulleys. This may not matter much for the 47 tooth pulley, but will provide surer engagement on the 9 tooth pulley.
2. The belts are identical length, which means that carrying a spare belt could be a good option, as it could replace the belt on either axis, in the unlikely event of a failure.
There is a new Yahoo group for HEQ5 owners. It is fully moderated, so it will not become a spam dump like the last one. At the moment there are only 4 members, so any HEQ5 owners are welcome to swell the ranks. It is not meant to supplant this excellent site, but provide a specific adjunct to it for HEQ5 owners.
One more item, I came across a site for a machining mob that make high precision worm drives & ring gears among other things, including replacement units for some Skywatcher gear. I will contact them to see if they can make replacement worm & ring gears for the HEQ5. That would complete the drive train upgrade for this mount. I'll get back to you when I know, but if anyone else knows of these people, & what their work is like, that would help.
Just joined the Yahoo HEQ5 group Peter , just awaiting approval .
