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SimpleDreamEQ3


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Hi, I am picking up a cheap eq3-2 tomorrow and am considering cheap goto upgrade options.

Does anyone have any experience of using SimpleDreamEQ3?

Primary usage would be for EEVA and some light imaging. 

Thanks

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Posted (edited)

Just got this picture from my friend. This is how it looks like when installed on mount. Do note it's a micro GoTo. 

Screenshot_20210709_103213.jpg

Edited by Tan Zhi Qi
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Thanks for that.  Must say I emailed astro-tech to see if it supports plate solving late last night and had an email back within a few hours saying yes.  So that's promising.  Just got my eq3 but maybe next month I can buy this.  Trying to do AP as cheap as possible!

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Hi Greg,

I'm sure you're aware that the maximum slewing speed of the Simple Dream is 60x siderial which is much too slow to be practical for long slews. ( Typical Goto systems slew at 600x to 800x or more. At 60x a meridian flip would take about 15 minutes ! )

So you would have to loosen the clutches and push the scope close to your target before engaging the Simple Dream "micro Goto"  and a planetarium app to zero in.

If you are handy & want a full-speed Goto you could build an OnStep Goto system using Nema 17 motors for around £100.

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

Good luck.

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Thanks @lenscap. Not too confident with the DIY thing but appreciate it's a good cheap way to go. Do you know if anyone sells pre-built versions of these? 

As for micro goto I realise its more push then goto.  I do have a az-gti in eq mode.  Would you happen to know what the x60 compares to on the 1-9 scale in synscan? 

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@Gmx76 I did managed to find some pre built version of Onstep for EQ3-2 mounts in a China second hand market, should cost around 100 USD. Maybe if you can find some agent in your country that could help you get those stuffs? Planning to get one for myself too (be getting an EQ3-2 mount soon!) :)

Edited by Tan Zhi Qi
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I should think that a GoTo that slews at 60x siderial would be fairly useless.   And if you de-clutch it you will have lost the GoTo alignment.

If you don't want to invest £300+ in the Skywatcher Synscan upgrade, a more sensible option on a low budget might be not to have GoTo at all, but to motorise the RA and Dec axes.  You can do planetary imaging perfectly well with a RA motor drive, and you don't need GoTo for guided imaging, though admittedly the performance of guided GoTo mounts is said to be better.  And you should be able to do EVAA without GoTo provided you can actually find the objects, for which I recommend a good RACI finder + a red-dot finder.

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On 09/07/2021 at 18:56, lenscap said:

Hi Greg,

I'm sure you're aware that the maximum slewing speed of the Simple Dream is 60x siderial which is much too slow to be practical for long slews. ( Typical Goto systems slew at 600x to 800x or more. At 60x a meridian flip would take about 15 minutes ! )

So you would have to loosen the clutches and push the scope close to your target before engaging the Simple Dream "micro Goto"  and a planetarium app to zero in.

If you are handy & want a full-speed Goto you could build an OnStep Goto system using Nema 17 motors for around £100.

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

Good luck.

Hi @lenscap I saw in another post that you have built your own onstep for eq3. I'm not that handy but now thinking about it, one of my friends teaches electronics, so could get some help. Would you mind sharing how you did your onstep please? 

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On 10/07/2021 at 22:59, Gmx76 said:

Hi @lenscap I saw in another post that you have built your own onstep for eq3. I'm not that handy but now thinking about it, one of my friends teaches electronics, so could get some help. Would you mind sharing how you did your onstep please? 

All the info you need to build an Onstep Goto is in the Wiki, which can be confusing because there are at least 10 microcontroller boards to choose from, ranging from  custom designed pcb's to which you solder each component, to off-the-shelf modules that require little or no soldering.

I built my first Onstep for my EQ3-2 a few years ago using the Arduino Mega 2560/Ramps 1.5 board. This works fine but better boards are now available. I've recently finished an Onstep for my EQ5 using the WeMos D1 R32/CNC V3 board. This is the controller before I put it in a case.

WemosD1R32CNCv3power.thumb.jpg.8e091937a916ef2ebc9a9ae3dd890df2.jpg

The lower board (that the power jack plugs into) is the WeMos D1 R32 microcontroller board which runs the Onstep software.

The CNC V3 shield (with all the yellow headers) just plugs into it. It has sockets for the stepper drivers, and pins to which you can connect various optional bells & whistles.

The two stepper drivers, (I used LV8729's, with the blue heatsinks) plug into the CNC V3 without the need for any wiring.

Just configure & upload the Onstep software to the WeMos, 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 from your phone, or by Stellarium/CdC/Kstars etc by USB from your laptop.

https://www.ebay.co.uk/itm/152975590787

https://wiki.keyestudio.com/Ks0160_keyestudio_CNC_Shield_V3

https://wiki.fysetc.com/LV8729_V1.0/

I'll post some notes on the mechanical side of the build tomorrow.

 

 

 

 

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Drive Trains for an EQ3-2 Onstep conversion.

I suggest NEMA 17, 400 step , bipolar steppers using 32 microsteps with 3:1 belt drives. Each motor needs at least 50 ounce.inches of torque.The RA worm ratio on the EQ3-2 is 130:1 so the tracking resolution will be 0.26 arc sec which is similar to a Synscan system.

(360 x 3600) / (130 x 3 x 400 x 32)  = 0.26

The Dec worm ratio is 65:1 so if you are guiding you could use 64 microsteps on the Dec for symmetry if you wish.

Motors;  https://www.omc-stepperonline.com/nema-17-stepper-motor/nema-17-bipolar-0-9deg-44ncm-62-3oz-in-1-68a-2-8v-42x42x47mm-4-wires.html

Pulleys;  16 tooth & 48 tooth GT2 pulleys will give you a 3:1 ratio. 6mm wide belts will be adequate. Select bores to suit the motors (5mm) and the worm shafts (6mm).

https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2499334.m570.l1311&_nkw=gt2+timing+pulley&_sacat=0

You could use these brackets. One of them will mount the Dec motor.

You could use 2 of them in a "U" or "Z" arrangement to mount the RA motor. There are other options. I used 1 angle bracket & a diy hardwood block for the RA on my EQ3-2. (see pic) . Or search for EQ3 on thingiverse for 3D printed brackets. Angle Brackets

Dec

EQ32DecFront.jpg.bdfbaafa8a2a60a0d6e385b9e30f7683.jpg

Dec

EQ32DecSide.jpg.000172d799d16c4d6d012fc00941bb9d.jpg

RA

EQ32RAFront.jpg.f997482c56ce297c991a06515a258c8d.jpg

RA

EQ32RASide.jpg.d94cb45e1ba2829b7a54c15b74d29848.jpg

Those are the main items. If you go ahead with the build post as many questions as you like.

Hope this is enough to get you started.

 

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thanks so much, think I am actually going to do it. It might take a little time but I appreciate the support , cheers

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I emailed AG yesterday asking about the slew rate on the EQStarPro EQ3 for my CG-4, which admittedly is twice the cost of the Simple Dream, but it works with Stellarium and several other PC-based software packages.  I was unsure if the go-to speed was reasonably fast or not.  The product info does not list that info, whereas the simple dream does (60x).  If I'm correct in my figures, even at 60x you're only covering .4 degrees / sec.  Well...last night he emailed me back:  

--------------------------------------------

Hello,

GoTo speed (rotation speed of the mount when searching for objects) for the EQStarEQ3 is 600x. GoTo speed for SimpleDreamEQ3 is 60x. Therefore EQStarEQ3 is better than SimpleDreamEQ3.

Best Regards,
Alexander.
www.astro-gadget.com 

---------------------------------------------

$279 seems pretty reasonable, doesn't it?  For smartphone or PC control...guiding compatibility...?

Erks me too...because I just bought the Celestron motors a month ago. 

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