lenscap

Hi Peter,

I think the SW Goto kit is very overpriced.

If you are into DIY you could build an Onstep Goto system with equivalent performance (and including new motors) for about  one third of that cost.

https://onstep.groups.io/g/main/wiki/3860

If you click on the "Showcase" section you will find  info on several Vixen GP conversions.

11 minutes ago, Tomatobro said:

Thanks for the tip. I just had a quick look but I think this is only for equatorial mounts.

No, Onstep software can be configured for any type of mount that can be driven by steppers including Alt/Az.

Examples of Dobsonian conversions here.

https://onstep.groups.io/g/main/wiki/4414

11 minutes ago, Tomatobro said:

We tried Malc-c we really tried to get the go to working. I do a lot of work with PIC's but in the end we went for our tried and tested Alt/Az system.

Have you considered building an OnStep Goto controller?

Since you have the motors in place it would be straightforward & inexpensive.

https://onstep.groups.io/g/main/wiki/3860

I just searched the Onstep forum for "Fullerscope" and got 54 hits.

https://onstep.groups.io/g/main/search?p=recentpostdate%2Fsticky%2C%2C%2C20%2C2%2C0%2C0&q=fullerscope

Should be some useful info there.

I made my own based on a design in Sky@Night magazine;

It cost nothing because I used timber that I found in a skip/dumpster, but don't tell anyone. 😉

https://www.skyatnightmagazine.com/advice/build-an-observing-chair

1 hour ago, Rodd said:

Here is a more relaxed version--not sure which I like better.  

 

". . . . oh my God! . . . . it's full of stars. "     David Bowman,   "2001: A Space Odyssey",   Arthur C. Clarke

On 14/05/2021 at 06:53, astrosathya said:

looks like if i need to use my 8729 drivers i need to wire up M0 and M2 on the CNCV3? or am i getting it wrong?

Hi Sathya,

The LV8729 data sheet includes the microstepping table; https://wiki.fysetc.com/LV8729_V1.0/

For 64 microsteps you need to hold the ms2 and ms3 pins high on each driver. [ Just to cause confusion the CNC uses  different terminology (m0, m1,m2 instead of ms1,ms2,ms3). ]  To achieve this all you need to do is shunt the m1 & m2 pairs under each driver with something like these; 2-54mm-0-1-PCB-Header-Jumper-Link

As said above you don't need to wire anything to the SPI bus since you are using LV8729's.

Hi @malc-c,

I posted a question about whether or not OnStep will run on the UNO,  on the OnStep forum and here is the reply from one of the developers;

Just completed my second OnStep (WeMos D1 R32/CNC V3) when a colleague pointed out that according to this section of the Wiki;   https://onstep.groups.io/g/main/wiki/19670 , OnStep will run, albeit with limited features, on an Arduino UNO with CNC V3 shield. I'm sure I've read somewhere that it won't. So my question is (just out of interest) will Onstep run on an UNO or not? Thanks for all the great work.

Reply  Like  More

Khalid Baheyeldin May 10   #33543     No, the Arduino UNO will not run OnStep. That page should be reworded to remove any reference to the UNO. In the Arduino family, only the Mega2560 will run OnStep because it has the required 256K flash storage to hold the OnStep program image. Even the Mega2560 is the slowest of the boards that run OnStep, and suffers from an inaccurate clock, which needs to be mitigated with an RTC. You are better off with the R32 which has a much faster microcontroller.

Have a look at this guide;

http://newsroom.meadeuk.com/2016/06/autostar-and-audiostar-explained.html

20 hours ago, astrosathya said:

Regarding the drivers, I now have 2 different sets, the DRV8825's and the A4988's, so i will have choice on which to use as both will work.

Your Config looks good except for the microsteps. The DRV8825's are limited to 32, and the A4988's to 16.

For 64 microsteps you will need the LV8729 drivers.

1 hour ago, malc-c said:

If I was starting on this project I would simply follow the advice given here and get the recommended CNC shield, drives and UNO

Thanks Malcolm,

To clarify one point, the WeMos D1 R32 has exactly the same footprint as the Arduino UNO, but the UNO is not used here because it has insufficient memory to run OnStep.

1 hour ago, astrosathya said:

Meanwhile i found a seller with the Wemos D1 8266 board. Hope this will work. What do you think please? The CNC shield is also available with the same vendor. If you think they are the right ones, i'll order them right away. Thanks again for your help and guidance. 

 

Hi Sathya,

I believe you need a Wemos D1 R32 board which has an ESP32 processor and not the item you link to which has an ESP8266 chip.

You need the CNC V3. I think you may  link to an earlier version . Not sure if it will be OK.

I strongly urge you to study the Wiki until you are familiar with it. It has all the info you need including links to most of the main components and it explains the reasons for choosing various options. Keep the questions coming.

.

This is my Wemos R32, CNC V3 build before I put it in a case;

The lower board (that the power jack plugs into) is the R32.

The CNC (with all the yellow headers) just plugs into it. It only fits one way.

The two stepper drivers (with the blue heatsinks) plug into the CNC.

Just connect the  power &  the motors & you have a basic functional Onstep controller that can be directed by the Onstep app and/or Skysafari via Bluetooth or by Stellarium/CdC/Kstars etc by USB.

Hi Sathya,

Have you considered OnStep;

https://onstep.groups.io/g/main/wiki/3860

The OnStep project is very active and, while you can use  a Mega2560 if you wish, you have the choice of several other boards, most of which which are  more capable than the Arduino.

Hi Capt Slog,

Select Ocular view, then click on the spanner icon.

Select the eyepiece tab & add an "eyepiece" called "6x30 RACI" or similar.

Tick the Binoculars box

Set the AFOV to 7 degrees, the Mag to 6 & the diameter to 30.

That should give the view for your finder.

Hi eswardn12,

This is the Skywatcher 17Ah powertank;

   https://www.firstlightoptics.com/batteries-powerpacks/skywatcher-powertank-17ah.html

Some people use a car jump starter which can be cheaper;

  https://www.ebay.co.uk/p/2077213952

I use a scooter/leisure battery like this;

   https://www.amazon.co.uk/HQ-Universal-Sealed-Rechargeable-Battery

With the car or scooter batteries you may need to make up a lead to connect them to your mount.

The above are examples, you may be able to find other brands from local suppliers. These are all lead/acid batteries. You could also use Lithium power packs/batteries which are much lighter, but also much more expensive.

Good luck.

Hi, and welcome to SGL.

This is from a local dealer's website for your scope;

"Power Requirement: 12v DC Power Supply (Tip Positive). Sky-Watcher 17Ah Power Tank Recommended"

A 17Ah battery (and it doesn't have to be a Skywatcher brand) should run the scope for an all-night session before needing re-charging. If using a lot of electrical accessories you might need a larger battery.

Good luck!

1 hour ago, David Millen said:

longitude and latitude ( N 50:41:46 W 3:13:53)

Hi David,

Problems like this are almost always settings errors, even though everybody double-checks them 😀

Lat & Long must be entered in degrees and minutes so you should have entered;       50:41 N    and    003:14 W

Since the shutdown has happened with two different power tanks the cause is likely to be with the handset or the mount rather than the battery. Can you try a different power supply such as a 12v car battery. If the behavior persists you will know that the handset or mount is faulty.

33 minutes ago, Chris Jones said:

I measured the current with a multimeter and the highest current I got was 3.1 A, at which point the device shut down.

This current seems high.  My 200p/EQ5 draws just under 1A with both axes slewing at Goto speeds. (It is Onstep, not Synscan but the motors are similar).

This suggests a mechanical or electrical fault in the mount/handset which is causing the mount controller to draw too much current & shut down.

BTW is the mount under warranty or second hand?

Hi,

If you click on "Customer Care" on the RigelSys.com site there appears to be an email link.

Alternatively, they list our sponsor First Light Optics as one of their UK dealers. (link at top of this page)

Working inside the hemisphere I would make a rectangular frame, sphere half-chord by 1 metre in size. (so that it touches the dome at two points)

I would pivot one end of this on the horizontal polar axis of the hemisphere.

Rotate this frame from the horizontal to the vertical and the outer corners would scribe the observation slit.

52 minutes ago, michael8554 said:

The Celestron spec says it will supply 5 Amps, which is what the EQ5 spec says is required.

Actually the EQ5 Pro spec says it requires 2A, so a 5A supply will be plenty.

I found this statement in the Power Tank Lithium Pro spec;

"Battery shuts off automatically when insufficient current flow is detected to prevent you from inadvertently draining your battery"

Perhaps the low current shut-off on the power tank is faulty. Could you try a known-good supply such as a 12v car battery to see if the fault is in the power tank or the mount?

11 minutes ago, Louis D said:

It should scare us informed voters that many, if not most, voters are completely uninformed or worse, misinformed, on most topics, and yet they choose our representatives via their votes.

To paraphrase Churchill  " . . . democracy, the worst form of government, apart from all the alternatives . . ."

Unless the supplier told you that it was faulty, and that it was being sold without warranty and you agreed to buy it on that basis, he is talking through his hat. You are entitled to a full refund. Whether it was "on sale" or not is irrelevant.

Does the vendor really want thousands of SGL members & guests to know that he is trying to pull a fast one?

Hi doublevodka,

To use 2" EP's you need to remove the bronze coloured 1.25" eyepiece adapter and replace it with the 2" eyepiece adapter that usually comes with Helios/Skywatcher 200p's. Perhaps the previous owner still has it and the knurled ring with the grubscrews that it fits in.