George

https://www.facebook.com/groups/345004195931930/?ref=share

Thought the 3D printing brigade would like this 😉

Managed to find one on Astroboot for £83.00......now to double check all the electrics in the observatory

Been slowly returning my observatory to use this week after being mothballed for 7 years.

Powered the EQ6 pro up today and nothing, no led but the area surrounding the power connecter was warm to say the least:

So any experts think this is repairable or am I looking at a £120 replacement 😩

Worth book marking for cheap Arduino parts

https://www.fasttech.com/search?arduino

Ive used them a few times and postage is free

4 in mesh sounds about right for the small pulley, I also had to make the motor plate slot a few mm larger for adjustment, it takes a minute or two with a jewellers file.

Hi George,

I just read your answer, thank you.

I'm still tempted to opt for a 60T pulley: I should be able to enlarge the worm housing.

Could you suggest me the right (MXL) belt length?

Thank you again and Clear Skies!

Armando Beneduce

I think this link has been posted somewhere in this discussion, it will be trial and error until you actually get the pulleys fitted as being a few mm out in your calculations can mean the difference between a few teeth. I think originally to save on postage I opted to get a size either side of my calculations.

The 60t pulley won't fit unless you enlarge the slot, you would also have to machine out the worm housing too using a mill or possibly a stand drill.

Sent from my GT-I9300 using Tapatalk 2

Malcolm, any chance of a brief summary of the advantages the belt drive delivers?

At the beginning of the thread somewhere I posted before and after tracking screenshots, also some data that Chris analysed and commented on. The verdict was very much in favour of a good return to the mounts performance for a quite small outlay.

I had my first pulleys done by a so called experienced amateur lathe freak of a friend of mine....he made a right mess of the small pulley, it was wobbling like a drunk who'd just had 10 pints. I ended up buying a mini lathe and doing my own, the mini lathe has started a whole new hobby

Very sad news indeed, SPM inspired countless to take the astronomy route and entertained those that didn't.

He had a good innings and is now amongst the stars he loved.

RIP SPM

Baader cleaning fluid is the best product widely available however I use disposable wipes. Using the same cloth over risks bringing contaminates over from over cleaning sessions. Even if washed the cloth could absorb hard particles from all manner of sources.

Sorry to be OCD on this but I always vacume close to the surface of the glass to lift any hard particles to ellimate them being wiped across the coatings with the cloth. A combination of this and a fine camel hair brush and a blower works well before the cleaning fluid and cloth is used.

If in any doubt Leave Well Alone! Dust on optcis does not defrade the image however finger smudges are worth considering removing as the natural acids present could permanently mark the coatings.

Just my experience and opinion YMMV

Hope this helps

Paul

Methanol is cheaper and nearly all the lens cleaners are based on this. Ive used it for years with no effects on both telescopes and DSLR lenses.

No doubt the purists will cringe

Sara, you should drift align anyway.

But separate guidescopes nearly always suffer from flexure to one degree or another.

There is a method you can determine the cause of the eggy stars, detailed here:

http://deepskystacker.wikispaces.com/Measuring+differential+flexure

Interesting link Tim....thanks very much.

Hi Neil,

I found putting a flat bladed screwdriver between the motor and body casting and twisting until it "felt right", keeping it there until the socket head bolts are tight worked.

Exactly how I adjust mine, you can get quite a feel for doing it this way.

These belts are pretty unbustable. I raced model cars for years and most of the 4wd models were belt driven.... belts lasted forever, and I am sure in a model car it is subjected to much more abuse that it would in a EQ mount....

The rubber focuser grips on my ED80 fell to bits in less than 12 months, the rubber O rings that I replaced them with didn't last much longer. Im not saying these belts we have used for the modification are flimsy by any means BUT you have to remember (if its permanently mounted in a observatory) that they will be subjected to all sorts of temperature extremes (-25C here in winter 2009/10 & 45C+ in summer), I doubt RC cars and model helicopters suffer the same climatic abuse a telescope mount does

Time will tell.

Makes you wonder why a belt drive is not factory fitted....

I should imagine because its not consumer friendly, at some point those belts would either wear or snap and need replacing. Realistically how many non mechanically minded people could dismantle a mount (ignorant of the likes of Astrobabys site etc etc) to replace belts whereas gears will probably outlast the user

Commercially tho I'd imagine the belt driven route would be cheaper to manufacture.

I used (shock horror) fine grinding paste I connected a drill to the worm shaft and ran it 10 times in each direction and then checked progress using a magnifiying eye glass. This was repeated 3 or 4 times until I got a polished and easy to turn worm, it was then washed off with white spirit and then another thorough washing with degergent and a nail brush.

Provided you don't go mad and take your time and make those inspections I don't see what it matters what you use as a grinding medium, Ive heard good reports about Solvolautosol (think that's how its spelt) which is a alloy wheel polish.

Neil, sorry for hi-jacking this thread... I was going to post the question regarding different ratios on the HEQ5 thread I started, but then Chris had outlined all the settings and aspects of different ratios in this thread...

As for kits..the one thing I've found is it can be either difficult to find a decent machinist that will bore out and turn them down to the correct size properly (so they don't wobble or rub), and /or find a machinist that doesn't charge the earth to do the work (I was charge £40 which was more than I paid for the parts). The other factor for looking at "kits" is that purchasing in bulk reduces the cost of the parts, thus "hopefully" makes it cheaper for other members. It also make for a convenient solution for other members who haven't got the time to get the parts machined.

I'm sure if I do end up persuading the boss that I need this lathe, and then have the capital to bulk buy the pulleys etc then I'll also offer them for EQ6 owners.

Having said that, I'm sure there are other members with access to or own lathes etc and could well do the same... It would certainly save me a lot of bother and the expense of a lather and all the gubbins that go with them

Actually Ive given this a lot of thought and I'm actively looking at lathes and looking at supplying ready to use kits , if you can service the EQ6 then doing the mod is a doddle.

The 12 tooth pulley is the biggest problem in its present form ie aluminum with a steel shaft insert as there is very little of the steel left after machining as a few of us have found out. Im in the process of making inquiries with suppliers on either a solid aluminum or steel 12 tooth pulley. Alternative would be to have custom pulleys fabricated or oversize the bore and use a bore reducing insert (which Ive had todo with my focuser pulleys) if the demand is there putting together a reasonably priced belt conversion kit should not be a problem.

Watch this space

RA is sounding wonderful but with a slight rubbing sound from the belt....i may try to adjust it a bit but it should be ok as it is.

I can't stop popping into the garage and running the motors just to see the belt go round and hear the noise it makes ;-D very sad i know!

Press....wwwwwhhhiiiiirrrrrrr....Press....whhhirrrrrr..

Press.....

Have you tried adjusting the stepper pulley up or down the shaft as this will give you a little adjustment, think I moved one of mine further up the shaft by a couple of mm's or if you have a dremmel you could open the slot a little.

Nice to hear your having fun with your "NEW" mount

When rebuilding the mount remember to add the belt onto the worm.....i'm just saying....not that i forgot on the RA.

I'm not that silly...noooooo

Neither am I , I did it 3 times

I put mine with the slight wobble on the DEC, don't think a wobble is a crucial with belts as it is gears.....think my graphs speak for that

Finally got 6 hours of imaging in last night.

Hi George,

Strictly speaking it is actually rather hard to pin down the biggest culprit on the worm alone - all we can say is that those components moving at the worm speed combine to give the biggest error. In your mount this means the worm and the worm pulley.

The overall level of PE is around half that which is typical for an EQ6Pro and the PE now almost entirely consists of elements that are harmonic with the worm. PEC should be quite effective should you ever feel the need for it.

Attached is my interpretation of the data.

I'm not sure why you should have experienced an improvement in goto accuracy unless you had a bad backlash problem before. It is true that the reduced PE amplitude will allow for greater accuracy when synching on alignment points but wouldn't have thought that would have had a significant effect unless you're observing at a long focal length, high mag.

Anyhow, all in all it looks a very successful mod and I must admit to being tempted to give this a go myself (with a bit of luck I'll find a happy EQMOD user with a lathe willing to do me a favour ).

Chris.

Thanks for taking the time to peruse my data and write a report its much appreciated

My mount certainly feels & tracks 50% better than pre-converstion, as Ive said in other posts above my main reason for changing to belts was to try rid the mount of backlash particularly in the DEC axis, as you have said this was probably affecting my gotos and certainly affected tracking with wild swings in the the form of bounce.

I also took the trouble of polar aligning to the best of the mounts mechanical ability (ie pitchs on adjustment bolts are far too coarse for minute adjustments) and spent many hours getting that last arc second adjustment.....it certainly paid off and is probably responsible for some of the goto's extra accuracy Also lapping the worm & gear must have helped smooth things to some degree.

In hindsight to pinpoint any gains it would have been better to get data after every step but with limited clear skies in the UK that would have taken months

I hope this thread and documentation helps others to go ahead with a worthwhile modification particularly to imagers who are always after that last bit of accuracy from their kit.

Regards to everyone who has helped.

George ( a happy bunny)

Well my main reason was to rid the mount of backlash which the conversion has done admirably, anything else was a bonus.

So to recap so far:

1. Backlash non existent.

2. GOTOS far superior.

3. Guiding has vastly improved.

4. Mount is much quieter on fast slew.

5. I'm much happier & confident with my mount.

Point 5 is perhaps the most important, I've never been happy with my mounts performance and I was constantly fiddling/dismantling and even contemplating a replacement.

Well at last we had a clear night and it was time to play

Spent an hour tweaking the polar alignment with EQalign and eventually got the green & red circles merged as one even after 20 minutes of tracking. Ive marked the pier head and mount up now with some tippex so in the future if I have to remove the mount from the pier it will be a doddle to get everything up and running quicker.

I then parked the scope up and resynced the steppers and created a new point list, after the first 3 stars I got every slew in the centre of the crosshairs on the QHY8. Slewing accuracy has definitely improved with the belts so a big plus there for the conversion.

Now it was time for the unguided PHD data

Fired PHD up disabled guide output and slewed to my chosen star, I wanted something bright that would show thru some high level cloud at the time.

Guide scope ST80 FL400mm

Guidecam QHY5 Pixel size 5.2x5.2

Object name: Enif

Magnitude: 2.38

Equatorial: RA: 21h 44m 47.291s Dec: +09°56'02.723"(current)

Equatorial 2000: RA: 21h 44m 11.158s Dec: +09°52'30.041"

Horizon: Azim: 227°03'59.883" Alt: +37°50'48.433"

Bit bright for guiding really but I didn't want any cloud losing me any data Must say even with perfect polar alignment (well as perfect as I could get) after the first few minutes PHD's guide graph started some horrible mountaineering and I couldn't watch and left it todo its thing, came back an hour or so later & the target star was still more or less centred in PHD's bullseye.....here's my PECprep graph.

Looks pretty horrible unguided

I edited my pecprep ini and added the mechanical modifications as Chris suggested, on the above graph they are ticked to highlight their contribution which to my untrained eye looks negligible.

The biggest culprit still appears to be the worm which I checked for runout while everything was dismantled, runout was 0.001mm which in engineering terms is as perfect as you will get.

Ive attached my unguided log perhaps Chris can comment

PHD_log_28Oct1_testdata.txt

Well, my machinist has worked his magic and i have everything back and ready. Now where is that extra small allen key...er....that really small easy to lose Allen key....oh darn it.

And none of the shops have one that small..

I hate mechanical thingies...

I couldn't find mine either but I have one of those micro screwdriver sets and found a flat bladed one I could jam in

Chris I want to thank you for taking the time todo this , hopefully when the weather cooperates I can grab that important data (to me at least) and find out how much improvement I have gained. But TBH I'm more than happy to have turned a dog mount into something that has no more backlash and tracks better than I could have imagined.

Hopefully at some point belt modded EQ6/HEQ5 users will reach critical mass when they realise that a simple modification can overcome one of the mounts most fundamental shortcomings.

I'm pretty sure a belt driven mount would have been cheaper to manufacture than a geared mount god knows what Synta was thinking.

Thanks again from a EQ6 user for EQmod and all the secondary programs that run with it

Hi George,

There are some configurations changes you will need to do to for PECPrep to properly handle your modded mount.

First open up the marks.def text file in notepad (this is in the PECPrep install directory) and add the following to the bottom.

Use tabs as separators. This file determines what periods are significant for your mount - you can add more entries to the list if you discover new characteristics you want to quickly identify.

With PECPrep running go into the Mount menu and select edit types - a new window will appear. Select one of the "undefined" slots and fill it the data in as shown below.

Then hit the Apply Changes and then when you close the window your modded mount should appear in the PECPrep mounts menu.

Chris.