AstroEQ, what i was looking for.

[simonmc]

Having a search round the net earlier as the reason i have my machine shop is that quite a few yaers ago i quite liked mel bartels system for controlling a telescope. i even but a dob mount and electonics for my first 114mm telescope. Well as time has moved on a bit and the availability of arduinos and the like i thought i would look and see if there is something similar but involving less 'hassle', when i came across this on another forum:-http://www.astronomyshed.co.uk/forum/viewtopic.php?f=35&t=14666&p=103034&hilit=diy+eqmod#p103034

Tom Carpenter's system looks exactly like what i was after, a fully customisable telescope driver, which apart from a couple of motors and drivers i have all the hardware for, and is EQMOD compatible. If also incorperated into something like the yesyes spc mod could really produce a one usb cable control system. This going very high on the list of things to do, as it has so much potential.

Simon

[simonmc]

Well i have managed to win a eq5 mount on ebay and ordered a few stepper controllers as well. I think this mount will be solid enough for the mak, so will it will be a very handy addition to the collection. If it all works as i hope it does i can start thinking about a mount for my 10" GSO with this system. This will be fully home made however as i want it really solid. I also have been given permission for a permanent pier from SHMBO very near the site of where she would like a summer house. All very nice and handy.

I may need to get some nema 17 motors as i think the nema 25's i have will be too large for the eq5. I will be going for a belt drive system with a reduction of about 4:1 as suggested in the above link. Handly one of the model engineering mags i get just did a couple of articles on machining timing gears so i will be re-reading them..

Also due to the chinese new year i may have to wait a while for bit to arrive, which could be a good thing with the amount of projects i have on the go.

Simon

[simonmc]

The EQ5 turned up today and it was exactly as advertised. The Nema 17 motors are on order from a chap in Southampton so they should arrive fairly quickly and they come with very long leads which is handy. On thing has got me wondering though. The polar scope was advertised as being cracked. Turned out that the reticule is cracked but in one peice. It looks useable but it is an annoyance. Looking on the forum my polar scope looks slightly different from the standard ones, and the replacement ones from various vendors. Its illuminated and does not have any grub screws holding the reticule. See pics below. If it is a replacement does anybody have any ideas as to what make?

Polar Scope,

Quick pic through it.

Its obviously been a bit abused judging by the scratches and gouges on the body but i quite like it and it would be nice to get a new, or possibly make a new reticule for it. I did find an interesting site about doing exactly this earlier on. Will have to re-find it and give it a proper read.

Its does look like the mount it has has been well treated with only a few wear and tear scratches on it, mainly on the setting circles and a bit of age related flakey paint. Some nice anodised alloy replacements will be made for it at some point and maybe a natty paint job!

Simon

[simonmc]

I stripped and regreased the mount today. It had been done before as the grease was white but it must have been a while ago as it was still abit dirty inside. Also some of the bolts had been replaced with the incorrect ones, so i was unable to set the dec worm up correctly until some replacements arrive. I also have to think about how i want to mount the scope. I really dont like the current arragement of a bolt and one at 45^ to it. I will probably machine up some sort of shoe to stop the dovetail on the scope getting all messed up. I followed the guide from astronomy boy to strip the mount but found that althogh it has the same casting as described on the site as the later eq5 there were no bearings in it at all.

The stepper motors also arrived, ive dug out an arduino mega, so all im waiting for is the stepper boards to arrive. I may purchase the pullys rather than make them just to speed this project up a bit.

Simon

[Gonzo]

The project sounds very interesting and promising, but it's a lot of work. All the best with it

[simonmc]

Thanks, To be fair it hasnt been that much work yet, but as im still waiting for the drivers, i havnt really been able too!

Simon

[simonmc]

After some thinking i decided to buy the timing gears rather than make them. 2 60t and 2 15t gears at at least 2 passes per tooth meant at least 150 cuts if i ganged them together. So i ordered them from a company called Motionco off the net. 2 60t, 2 15t and 2 mxl drive belts came to just over 35 quid. Costs are starting to stack up abit but i have still less than £120 tied up in this, including buying the mount. I need to make some motor mounts now. I am wondering weither to make them from steel or from aluminium angle. I probably have the steel to hand but i think i would prefer aluminium.

Simon.

[Gonzo]

When you'll do the circuit board, give me a shout please.

[simonmc]

When you'll do the circuit board, give me a shout please.

Im using an arduino mega and some bought in stepper controllers, so should not need to make a board. If however you want a board i think Tom Carpenter who wrote the software is having some made so it may be worth getting in touch with him. I personally have not been in touch with him yet as i wanted to get the mount hardware together first. There is also a good writeup on converting a an EQ3-2 in the eqmod yahoo group, where the authour bought all necessary bits for £122 and did a very neat job.

Simon

[Gonzo]

Just joined the eqmod yahoo group, would you have the direct link to the eq3-2 write-up please?

found it http://tech.groups.yahoo.com/group/EQMOD/files/Hardware%20Tinkerers/

[simonmc]

Its a pretty good write up and some nice machining went into those mounts. I managed to find some steel brackets that i had on hand to make up some mounts. They already had some holes in but all in the wrong places, but are exactly the right size. I drilled them out for the steppers with a battery drill and a step drill, rather than use the bigger equipment I have on hand, just to check its possible. I do sometime find it annoying when looking at sites that show a 'simple' modification to something that requires a £1000 piece of machinery to do it correctly! That said, if this all works out ok i will be machining up some nice alloy ones. I would like to give anodising (sp?) a go.

Simon

[Gonzo]

If you do machine up some brackets...

[simonmc]

From your sig your running an EQ3-2. I will be using an EQ5 and looking at the document above the stepper mounts may be different. I am going to be using the standard fixing points on the mount to attach the motors so that no modifications to the mount will be necessary. Can the same be done with your mount?

Simon.

[Gonzo]

I think the motor brackets are different. I've also contacted the author to find out if there's an ST4 port.

[chrisshillito]

An ST-4 port isn't essential as the AstroEQ hardware/firmware requires EQMOD anyway to provide the telescope/mount control - so you can use ASCOM pulseguide for guiding.

Chris.

[simonmc]

An ST-4 port isn't essential as the AstroEQ hardware/firmware requires EQMOD anyway to provide the telescope/mount control - so you can use ASCOM pulseguide for guiding.

Chris.

Thanks for that. I thought that was the case but wasnt sure.

Simon

[simonmc]

Well, just a short update. The Belts and pulleys turned up. I have bored one of each out to size but weirdly the other 2 clocked abit out and i will need to set up the 4 jaw chuck to bore out the other 2. I may be being picky but i might as well do the job properly, and get the OD concenteric with the bores. To be fair they are only a few thou out. I also had 2 lots of anodising dye turn up, so i can give that a try at some point. I bought red and black. :laugh:

Im still waiting for the stepper drivers which i think will hold this project up.

[JamesF]

I've come to this project late having somehow missed it before, but it looks very interesting. Now I just need to work out how to get Yahoo to let me log in again. I only do that once every couple of years and it seems to forget I exist.

James

[Gonzo]

I've come to this project late having somehow missed it before, but it looks very interesting. Now I just need to work out how to get Yahoo to let me log in again. I only do that once every couple of years and it seems to forget I exist.

James

If you have a Google account, it's easy

[JamesF]

If you have a Google account, it's easy

How does that help?

James

[simonmc]

MMM. Looks like the 75 tooth belt may be a better choice for the drive belts for an eq5 rather than the 80 tooth. However im glad i made 'prototype' mounts out of the steel brackets AND i have a milling machine. Made short work of the required 'fetteling'. Now to fit the dec axis then will post some pics.

James,

I found this post here which originally got me interested. Its by the author of the software and quite informative. He is also quite helpful.

Simon

[JamesF]

That's very interesting. And I've got back into Yahoo so I can look at the EQ3-2 doc, too.

James

[simonmc]

Well my bits from astroboot turned up today. I got a tripod head for an eq mount with the idea that if its big enough i could modify it to fit. Well its a perfect fit for the legs i already had, but needed some modifications to fit the head. It was a simple matter to chuck it up in the lathe and modifiey it to suit.

I need to make up a tray and some sort of large cup washer to mount the actual head to the tripod. I think this will be ok for testing as even without the tray it feels pretty solid.

I also mounted up one of the steppers to the RA and made a tiny boring bar to bore out the remaining 2 pulleys. I may redo the first 2 pulleys as im not really happy with the centering of the bores of the first 2 i did. Also the flash makes the belt look as though it needs a bit more tension.

I also made up a bar to fit the DEC stepper, eventually i will make some alloy mounts. The larger pulleys are over wide and i may have a play with them in the lathe to pretty them up. This will be after i have proto-typed it all up and confirmed its working. Maybe anodize them red after i have done a few test pieces and happy with the process.

Im still waiting for the stepper drivers so i have plenty of time to tidy all this up.

Simon

[simonmc]

Has anybody got any data on how accurately an eq5 will track assuming its all set up correctly? Im just wondering as i would like to compair this modification to one with a comercial goto upgrade and need a baseline to aim for, or more importantly so i dont go chasing my tail looking for improvemets that just are not possible. I would like to get this tracking as accurately as possible, but realise i will be limited by the mount itself.

Simon

[JamesF]

I think if you get the GOTO upgrade for the EQ5 then it includes new gear wheels with more teeth to improve accuracy, but I'm not certain about that. Of course it doesn't have belt drive so perhaps one will offset the other.

James