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Getting started: maybe


Helmut Fritz
 

Hello,
This project is quite interesting from two points: economy and just a plain interesting project.  First thanks to the creator and those helping to keep it going (contributions and showcase!).

I do not believe I would have any issues with the electronics, it seems there are plenty of helpful hints, instructions, etc. to get that part done.  My trepidationis connecting the motors to the actual mount.  I am not a machinist by any stretch and do not have the tools to fabricate much.  I am also not sure I would have the means ($$$) to have something fabricated nor tell someone what I actually need fabricated.

I would like to target a CG5 class mount, but if there is something easier to tackle to start with (EQ3-2, CG4, other?) I am up for that as well.  I do not yet have a telescope, but am planning on a smallish short tube refractor (80mm) or reflector (114 or 130mm) so things should be fairly lightweight to start with.

In general I would like to have all the goodies available; guiding, bluetooth/wifi come to mind but I am sure there is a lot I do not at all know about.  I would like to start with e mega 2560 (have one) but am concerned about the lack of accuracy in the clock.  It seems I can surmount this by going with a different "mainboard", and some of those have faster CPU, etc.  Can an external clock be added to the mega2560 to address its shortcoming there?  Suggestions for the easiest route are quite welcome.

Regarding the electronics assembly, I am sure I can manage it as I have done similar to create a DCC controller for model railroading, although this is a bit more involved.  That project does use the mega2560 and a motor shield and soem other bits.  It was not at all difficult, but I did not have to venture into the code to change things based upon options.  However, I have been in IT and IT Engineering for over 20 years and am not afraid of mucking my way through code.

Thank you in advance for suggestions, help, etc.

Helmut


Khalid Baheyeldin
 

On Thu, Sep 3, 2020 at 01:52 PM, Helmut Fritz wrote:
My trepidationis connecting the motors to the actual mount.  I am not a machinist by any stretch and do not have the tools to fabricate much. 
Many here share your sentiment. I am one of them.
I got a friend who has tools and skills to drill the hole in the flanges so I can fit the motors.

I would like to target a CG5 class mount, but if there is something easier to tackle to start with (EQ3-2, CG4, other?) I am up for that as well.  I do not yet have a telescope, but am planning on a smallish short tube refractor (80mm) or reflector (114 or 130mm) so things should be fairly lightweight to start with.

The CG5 is the most popular mount with OnStep. They are readily available, fairly inexpensive (when bought used), and a known quantity when it comes to the conversion.

There are 3D printed mounting for the motors, as well as mounts for 3D printers that can be adapted.

In general I would like to have all the goodies available; guiding, bluetooth/wifi come to mind but I am sure there is a lot I do not at all know about.  I would like to start with e mega 2560 (have one) but am concerned about the lack of accuracy in the clock.  It seems I can surmount this by going with a different "mainboard", and some of those have faster CPU, etc.  Can an external clock be added to the mega2560 to address its shortcoming there?  Suggestions for the easiest route are quite welcome.
Skip the Mega2650. It is no longer a good option given there are better ones out there.

Start with the ESP32 W32 with the CNCv3. It is much faster than the MKS Gen-L.
It does not require a lot of soldering, and is very cheap.

Regarding the electronics assembly, I am sure I can manage it as I have done similar to create a DCC controller for model railroading, although this is a bit more involved.  That project does use the mega2560 and a motor shield and soem other bits.  It was not at all difficult, but I did not have to venture into the code to change things based upon options.  However, I have been in IT and IT Engineering for over 20 years and am not afraid of mucking my way through code.
You should not need to modify any code, nor should you do it, as it makes upgrades messy.
Use the Online Configuration Generator to get a basic working configuration.

Ask more questions as you progress with your build ...


George Cushing
 

The CG-5 and what we cal the EQ-5 class mounts are IMO the most straight forward to convert. Fabrication of the motor mounts can be done with a drill motor, hack (metal) saw and 4mm and 6mm threading taps. See:  https://onstep.groups.io/g/main/message/24242

Electronic kits available at  https://www.stmbluepillkits.com/


Helmut Fritz
 

Thank you guys!  I will do more investigating and see about targeting a CG-5/EQ-5.  Are there versions of those to stay away from?  Conversely, are there versions of those that are more desired?


Khalid Baheyeldin
 

On Fri, Sep 4, 2020 at 03:50 PM, Helmut Fritz wrote:
Are there versions of those to stay away from?  Conversely, are there versions of those that are more desired?
The Vixen Great Polaris (GP), GPD and GPDX are the best.
They have lower periodic error, and better manufacturing quality.

In fact, they are the originals that the CG5/EQ5 are clones of.


Ant No
 

Is the Vixen Super Polaris equal, better or worse than the Great Polaris?

Ant👣


On 4 Sep 2020 22:06, "Khalid Baheyeldin" <kbahey@...> wrote:
On Fri, Sep 4, 2020 at 03:50 PM, Helmut Fritz wrote:
Are there versions of those to stay away from?  Conversely, are there versions of those that are more desired?
The Vixen Great Polaris (GP), GPD and GPDX are the best.
They have lower periodic error, and better manufacturing quality.

In fact, they are the originals that the CG5/EQ5 are clones of.


Mike Ahner
 

I have a Vixen GP2 and it's very good. I think the difference is mainly in the manufacturing process and refining the ergonomics of the design. Also, the mounting foot to the tripod changed some where along the line, but the rated load is still 15 lbs / 7kg for both. 


Mike Ahner
 

Here's a short comparison & history of the Super Polaris & Great Polaris series.
http://www.company7.com/vixen/mounts/gpegem.html


Ant No
 

Is GP2 another name for Super Polaris?

I'm aware that the Super Polaris has two versions with different motor mounting.

Ant👣


On 5 Sep 2020 08:03, "Mike Ahner" <mahner@...> wrote:
I have a Vixen GP2 and it's very good. I think the difference is mainly in the manufacturing process and refining the ergonomics of the design. Also, the mounting foot to the tripod changed some where along the line, but the rated load is still 15 lbs / 7kg for both. 


Ant No
 

Ah so the Super Polaris was the forerunner. To the Great Polaris and is good but not quite as good.

Losmandy rules apparently.

Ant👣
On 5 Sep 2020 10:28, "Ant No" <cmpaqp1100@...> wrote:

>

> >

> Is GP2 another name for Super Polaris?
>
> I'm aware that the Super Polaris has two versions with different motor mounting.
>
> Ant👣
>
>
> On 5 Sep 2020 08:03, "Mike Ahner" <mahner@...> wrote:

>

> >>

>> I have a Vixen GP2 and it's very good. I think the difference is mainly in the manufacturing process and refining the ergonomics of the design. Also, the mounting foot to the tripod changed some where along the line, but the rated load is still 15 lbs / 7kg for both. 


Mike Ahner
 

Here are pictures of the Vixen GP2. It seems there is no real difference from a GP except color scheme.
https://www.vixenoptics.co.uk/Pages/gp2_mount.htm

I'm planning to rework my OnStep RA motor assembly to allow me to reinstall the blue cover.


George Cushing
 

If you can ace a Bressler EXOS-2 (Explorer Scientific in the U.S.) without any drives, that would be good. A Meade LXD-75 is the same mount. Or any Skywatcher EQ-5 made in the last 5 years should be OK. The Celestron ASCG-5, Meade LX70 are the same mount. Earlier Synta (Skywatcher) have widely varied reviews. 

For example; Decided to totally break down the current donor mount to get an RA worm drum for someone on CN. Prior owner had apparently disassembled, cleaned and reassembled with some form of lithium grease. The axles could not be rotated by hand there was so much striction. Once I removed the hugely over tightened retaining nuts they freed up, but the RA crown was jammed into its seat to point it wouldn't rotate. I didn't want to damage it in an attempt to free it, but was at a loss as to how to do it.. Then I remembered I have a collection of exhaust pipe expanders. The 2.5-4" was a good fit in the drum. Once snug inside, I got a 30" pipe wrench on the body of the expander and the gear came free with some effort. Then it was easily removed by hand. 

You don't want to start your project looking for an exhaust pipe expander.


Helmut Fritz
 

There is a used LXD75 available now, sounds like that might be a good one to grab if still available?


Helmut Fritz
 

NM - it is gone.  I will keep looking for one of these mounts.

Is it worth working on a CG4/EQ3-2?  Currently I plan on small refractor (ST80  or similar with DSLR, or just DSLR and lens) weight loading, and if I move to something larger (if I decide i REALLY like doing this EAA and astrophotograhpy) would decide to invest in heavier duty equipment.  Or am I just asking for issues with a lower capacity setup?  Or is the CG4/EQ3-2 class more difficult to get drives onto?

As an aside, Do the CG5/EQ5 mountes need to be drilled and tapped to mount motors, or are there enough "mount points" to attach the brackets that need to be made?

Thank you all!


Helmut Fritz
 

For instance, would a Vixen Polaris be OK (not sure what class mount that is, EQ3?)?

If there is a reference I can use to figure out what mounts are similar to other mounts (i.e. is the EQ3 the same as Vixen Polaris, for example) I could use that pointer instead of bugging you all with all of these posts, so please let me know.  That said, you all aslo are likely to know pitfalls with particular mounts.


Khalid Baheyeldin
 

On Sat, Sep 5, 2020 at 03:05 PM, Helmut Fritz wrote:
Or am I just asking for issues with a lower capacity setup?  Or is the CG4/EQ3-2 class more difficult to get drives onto?
People have converted both EQ5 class and EQ3 class mounts, with good results.
Just set your expectations right: e.g. don't expect a C11 on the former (although one member did it for visual).
For DSLR or an 80mm refractor, either should be fine, depending on what else you put on it (size of guide scope, ...etc.)

As an aside, Do the CG5/EQ5 mountes need to be drilled and tapped to mount motors, or are there enough "mount points" to attach the brackets that need to be made?
Usually, the EQ5 have enough mount points, and they don't need to be drilled.
Not sure the EQ3 is the same.

Again, the showcase on the Wiki has actual conversion that people did, and the images are helpful.


Helmut Fritz
 

Thx Khalid.  Will dig in deeper to the showcase.


George Cushing
 

Well, I suspect the last GPs were made in China. Otherwise there is very little difference in the two models. Any individual unit will vary reflecting on how it's been treated and the extent of any wear. A later ASCG-5 or EXOS-2 with ball bearings may be a better choice. 


Helmut Fritz
 

Thank you George.  When you say the two models, are you referring to GP and EQ5/CG5?


Helmut Fritz
 

All,
it looks like a couple of LXD75's have become available again.  I looked at the showcase reports on these, and the things I am most fearful about is not covered very well - mounting brackets for the stepper motors.  it sounds like stock aluminum angle was used?  can someone give me ahint of what I would be looking at?  i am mostly finding pics of the finished motor/mount copmbo on the mount itself, not separate pics of the brackets. etc.

as an aside - are the LXD75's good?  or should i target a great polaris instead?  it seems I could possibly get both right now.  should i just go for the cheapest?

believe it or not, my wife is saying i should spend more (!!!) and get a working mount such as an az-gti to start with.  i cannot believe she said that.  ;)  (i know it has a much lower payload capacity, but i am starting with dslr only, later may add an ST80 of equivalent - for now).