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Video on the tools I use to tune my mounts for better guiding numbers


Glennbloke

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Also great for Mesu friction drive mounts. Do you know if it has DC cables plugs 2.1 or 2.5 mm ?

PS: On their website they do have 2.1-2.5 mm option for plugs. Looks like a great way to balance a mount. Some high end mount have something similar in their own software 

Edited by dan_adi
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5 hours ago, CraigT82 said:

one of these can do the job for a lot less money

I'd question that.

The one in the Amazon link plugs into AC mains power. The device in the video looks like it measures the DC current to the mount.

Something your digital multimeter will do, once you have the correct cabling for it.

Edited by pete_l
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Doesn’t matter if you measure on the AC side or the DC side… the current varies with the power consumption  just the same. You just get a smaller value for current on the AC side as the voltage is higher. 
 

Here is a (rubbish) video I made using the one I linked to:

 

Edited by CraigT82
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Three quid will get you one of these off E-bay

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Measures 0-999mA, or 0- 10A  (or higher) - so very well suited to measuring the typical current draw of the steppers used in most synscan mounts.  

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Something to think about when figuring out the cost difference would be the things other than the simple amp meter itself. These cheap plastic trinkets are far from weatherproof, tugproof on a mount, accidental bump proof and you need to wire them yourself so if you're a clutz with the process you brick the mount. Obviously a DIY man can build a casing for the ebay meter and wire it properly to go between the mount and the powersupply but its no longer obviously much cheaper. Okay its still a lot cheaper if you buy some obscure ebay components for everything or crack out the saw and do some woodwork for the casing but anyway its not for everyone.

The AC plug meter is quite convenient looking though. Shame i dont use AC to power the kit so cant really use that. Think im going to order the Prologic one unless i find some easy solution that i could plug into my existing kit.

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9 hours ago, ONIKKINEN said:

Something to think about when figuring out the cost difference would be the things other than the simple amp meter itself. These cheap plastic trinkets are far from weatherproof, tugproof on a mount, accidental bump proof and you need to wire them yourself so if you're a clutz with the process you brick the mount. Obviously a DIY man can build a casing for the ebay meter and wire it properly to go between the mount and the powersupply but its no longer obviously much cheaper. Okay its still a lot cheaper if you buy some obscure ebay components for everything or crack out the saw and do some woodwork for the casing but anyway its not for everyone.

The AC plug meter is quite convenient looking though. Shame i dont use AC to power the kit so cant really use that. Think im going to order the Prologic one unless i find some easy solution that i could plug into my existing kit.

That's true, but once you have used this "tool" to set up the balance its removed and put away, it doesn't remain attached to the mount.  My guess is that the unit featured in the video is something that they developed, possibly using their own PCB to fit the shiny case and drive a standard 4 digit display.  But by reinventing the wheel it's just an expensive ammeter.

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I have a Pegasus Power Box Ultimate which reads out voltage and current draw. Also have a multi meter that can loop around a cable, like the one Cuiv uses in his video. Both of those aren't accurate at all and the figures jump around the place. The PBB was £500! I was a bit put off the £65 price tag on the ProLogik but decided to get one anyway after I rebuilt my mount. I have no regrets about buying the ProLogik. That £65 is long forgotten when you see those guiding graphs.

 

1181319433_Screenshot_20220612-210622_VNCViewer.thumb.jpg.7310a7a4cb374f875ccd649885ef7a77.jpg

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5 hours ago, david_taurus83 said:

That £65 is long forgotten when you see those guiding graphs.

I you have the cash and are happy to spend it that’s great.

My point - and the whole reason I chimed into this thread- is to point out that there is an alternative, thrifty way of getting the same end result. Not trying to knock anyone’s way of doing things. 


Plenty of us on this forum who like to save the pennies where we can. 

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50 minutes ago, CraigT82 said:

I you have the cash and are happy to spend it that’s great.

My point - and the whole reason I chimed into this thread- is to point out that there is an alternative, thrifty way of getting the same end result. Not trying to knock anyone’s way of doing things. 


Plenty of us on this forum who like to save the pennies where we can. 

I agree.  Same goes for me.  Not knocking the product, but just pointing out that there are lots of cheaper alternatives that do the same thing.  

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Given the prices in astro gear this 60 ish pounds is nothing 😄. I did try the cheaper stuff, but as mentioned above, I also found the variation was too great to make precise balance. From the video the gadget seems pretty stable when measuring, also it has a  metal case and good cables. 

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Just occasionally these Sangemo Western ammeters come up for sale on Ebay. I paid £10 for this one and apart from a clean and some adjustment works well. When I got it the calibration certificate was dated February 1949 and it said that at 20 degrees C you had to multiply the readings by 0.0008

Inside is a work of mechanical art and heaven knows what it cost new

IMG_20220616_180730.jpg

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On 13/06/2022 at 19:17, malc-c said:

I agree.  Same goes for me.  Not knocking the product, but just pointing out that there are lots of cheaper alternatives that do the same thing.  

I dont agree that the alternatives offered in this thread are the same thing as the Prologic meter. I think i laid out at least decent reasoning in my previous comment as to why the price is (justifiably) higher. Can you link a well made and durable meter that does the same but for cheaper?

Its not a rhetorical or snarky question, i would genuinely be interested in one that does the same (and does not need AC power).

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1 hour ago, Tomatobro said:

Just occasionally these Sangemo Western ammeters come up for sale on Ebay. I paid £10 for this one and apart from a clean and some adjustment works well. When I got it the calibration certificate was dated February 1949 and it said that at 20 degrees C you had to multiply the readings by 0.0008

Inside is a work of mechanical art and heaven knows what it cost new

IMG_20220616_180730.jpg

That’s a nice bit of kit, wouldnt have looked out of place bolted to my old Fullerscope mk3 (with it’s deadly 240v synchro motors!) 

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59 minutes ago, ONIKKINEN said:

I dont agree that the alternatives offered in this thread are the same thing as the Prologic meter. I think i laid out at least decent reasoning in my previous comment as to why the price is (justifiably) higher. Can you link a well made and durable meter that does the same but for cheaper?

Its not a rhetorical or snarky question, i would genuinely be interested in one that does the same (and does not need AC power).

If you don’t have the DIY skills to make something for a DC supplied mount then your best bet would be the prologik meter.  

You could try a cheap clamp ammeter which can be had for £25 but even then you’ll need to split the positive wire out of the power supply lead. Also like others have said the readings may not be very usable either. 

I’m half tempted to buy a big bag of panel ammeters, project boxes and a reel of cable and start making… I reckon I could undercut the Prologik guys quite significantly. 

 

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36 minutes ago, CraigT82 said:

That’s a nice bit of kit, wouldnt have looked out of place bolted to my old Fullerscope mk3 (with it’s deadly 240v synchro motors!) 

Yeah, our robust equatorial mount built for Astrophotography by @Tomatobro in the late 1980’s I recall had 240v synchronous motors, don’t go poking around the mount in the dark!

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13 hours ago, ONIKKINEN said:

I dont agree that the alternatives offered in this thread are the same thing as the Prologic meter. I think i laid out at least decent reasoning in my previous comment as to why the price is (justifiably) higher. Can you link a well made and durable meter that does the same but for cheaper?

Its not a rhetorical or snarky question, i would genuinely be interested in one that does the same (and does not need AC power).

I thought I had... there are plenty of digital panel meters that measure DC current and are powered by battery or have significant low current draw that they can be powered from the same DC source they are measuring.  My point was that the Prologic meter is a nice piece of kit, looks the part, and if you want to get that finicky on setup then it will do the job.  But like most things, cheaper alternatives still exist.  Now they may be of a lesser quality, lack the refinement or have little or no aftersales service compared to the Prologic device, but that may be why the Prologic device is priced at such.

I use a £20 BEVA digital multimeter when working on electronics projects, it reads voltages or measures current just as good as a Fluke costing five times as much.  You may also find that there are digital multimeters in poundland that do the same as my meter, but will lack some of the protection built in, which in the case of Fluke, is why they cost so much more.

The other thing is that these tools and their usage depends on the individuals needs.  If you are mobile then having something that aids balance, and does so in a timely fashion is an excellent tool to have.  If you have a permanent set up in an observatory then these things, like a polemaster are just a one off use as once set there is no need to use them again unless the mount or scope is accidently moved, so the investment in such tools becomes questionable.

As I stated, I'm not knocking the Prologic device.  There are lots of things that dictate the selling price, not always profit margins.  Now if they had taken a £4 module, added a couple of leads and stuck it in a cheap plastic box and sold it for £80 because it had an astro theme then that would be taking the P**s....

 

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