May 31, 2017: The Orion Sirius Pro AZ/EQ-G mount, Part One – Power Troubles

Well, I finally broke down and bought it, and now it’s here!  And my first impression of this mount?

Damn, this thing is HEAVY.  

Don’t get me wrong.  This is a good mount.  But in comparison to my puny little SLT mount, this thing is massive.  But heavy is good.  Right?  RIGHT?  I mean, there are two reasons for heavy – one is to be able to support heavy scopes.  The other, more important reason, is to remain steady while supporting all that weight – to suppress vibrations.

To briefly recap how I got here, I have long been enamored of the iOptron series of alt-az mounts, which had the capability of handling two scopes simultaneously, using one scope as a counterweight to the other.  However, when I learned of an opportunity to buy this Sirius Pro at a heavy discount, I couldn’t resist.  (The discount is now only $280 instead of $200.)  The Sirius Pro is supposedly capable of carrying 33 lbs. of telescope on each side.  Even if the actual capacity is in reality 20% less than that, that’s still plenty enough for me.

I unboxed the mount and proceeded to set it up.  This process was not quite intuitive.  I had to go through the setup instructions carefully, one-by-one, but the instructions were clear and well-illustrated.  Finally, the mount was setup and ready.  But uh-oh; how to power it?  I was stopped dead in my tracks in getting to use my new mount.

The mount did not want to play well with others.  Other sources of electricity, that is.  It comes with what looks like to be a very proprietary plug with a dozen prongs inside of it.  The only adapter/cord it comes with has a cigarette plug on one end, you know, that plugs into your car.  I have been using small 4000 mAh lithium-ion 12V powerpacks with little 2.1mm x 5.5mm plugs to power my SLT mount ever since I bought it 2 1/2 years ago.  Indeed, the very first little powerpack I bought is still working and doing just fine.

Talentcell Rechargeable 6000mAh Li-Ion Battery Pack For LED Strip And CCTV Camera,12V DC Portable Lithium Ion Battery Bank With Charger,Black
This 6000mAh unit is similar to what I have; it’s roughly the size of an over-sized deck of children’s playing cards.

The recommended power source for this mount is a powertank.  These are big, heavy lead-acid batteries, like a battery in a car.  But you have to be married to them, making sure that they’re fully charged once a month, every month, like Eddie Murphy’s Porsche in 48 Hrs., or else they’ll be a big dead brick that won’t be able to be rejuvenated.  While I loves me some Eddie Murphy, I don’t like being a baby-sitter to a battery.  No, thanks.

Instead I (of course) cheaped out, and bought an adapter that accepts the mount’s cigarette adapter plug on one end, and my lithium powerpack’s standard 2.1mm plug on the other.  After some annoying delivery mishaps, it finally arrived about 10 days later.  Then the clouds settled in.

Finally, I got to try it out a few days ago.  And there were problems galore.  The mount offers two ways to align.  One is “brightest star”, which includes planets.  You pick an octant of the sky (north, northeast, east, etc.) and it will figure out what the brightest thing in that part of the sky is.  Then you point the scope there and align.  Repeat that until you have three align points.  I was observing off of my balcony, which only has a slice of about 30 degrees of the southern sky in it, so this is difficult for me.  Yes, I could have shlepped the mount and the scope on up to my roof for a much larger view, but this was all about testing, not observing, and I wanted to test it out first.

The second way to align is the tried and true method I’m familiar with:  two-star align.  The mount offers you the choice between whatever 1st magnitude stars are up at the time.  Fortunately, at around Midnight – 1am, you’ve got Spica, near Jupiter in the southwest, and Altair way over in the east.  Perfect – practically opposite sides of the sky, as recommended by the manual.

I started with Spica first, aligned, and then pressed the buttons for the mount to slew over to Altair.  It stutter-stopped the whole way – slewed a little, stopped, slewed a little more, stopped.  That was weird.  Then it didn’t get all the way to Altair – it stopped far short.  I used the manual control buttons to get it the rest of the way, then got some sort of Caution error message.  This was no good.

But, okay, so it’s aligned now, right?  Nope.  Punching the buttons for it to show me Jupiter did not get it back in the southwest sky – stopped short again.   Worse, the quiet hum of the tracking motor was going on and off.  A few seconds on, a few off.  That’s no way to track.  Tracking should be continuous.  What the hell was going on?

One option on the handset is for it to display the voltage being supplied.  And this certainly seemed to be the problem.  It would fluctuate continuously, going down to about 9 1/2 volts when it was “tracking”, and then back up to about 11 1/2 while it was “taking a break”.  Maybe the battery wasn’t fully charged?

I have two of these little powerpacks; the newer one is only about 16 months old.  I thought they were both charged up.  Maybe not 100% charged, but at least 70-80%.  Like I said, they work fine on my SLT mount.  So, out of an abundance of caution, I recharged both of them until they were full.  However, that did not take all that long, meaning that they weren’t discharged in the first place.  Normally, when the battery is really discharged it takes around 14 hours to recharge it.  One battery was recharged in less than 2 hours; the other newer battery, which I used much more with the new mount, took something less than 6.  Again, this wasn’t making sense.

But by now it was the next day, and I was clouded out again.  Finally, another break in the clouds last night:  clear skies and freshly charged batteries, so out to the balcony I returned.  Same two-star alignment procedure; same two stars, Spica first, then click on the handset to move to Altair.  There was an immediate and noticeable difference in how the mount reacted to the 100% charged battery – it slewed the whole way all in one go.  And then, it landed on Altair, putting it just outside the field of view.  A small adjustment to center it, and bang, it was aligned.

Back to Jupiter now, near Spica.  Hmmm, it stopped once on the way back; but again, it made it all the way there.  Jupiter was practically centered in the field of view, and the low hum of the tracking motor was continuous.  Very nice!  Okay, what else is up now that I can see in my 30-degree sliver of sky?  How about M5, a nice glob.  Uh oh, more stops and starts, but again, it made it there, and just off center.

Good.  But how does it track?  I didn’t notice as I walked away, but it had begun the stutter track again.  And when I returned 10 minutes later, M5 was nowhere to be seen.  I pressed the handset to get M5 again.  Zip, zip, and it’s done – back in the field of view.  That’s interesting – the mount knows that it’s not pointing in the right direction, even though the tracking is off.

But this time I sat and watched it.  And within 5 minutes, with the on and off tracking, it was gone, slipping out the bottom of the field.  Slewing to Saturn, the same thing happened – Saturn was there, and then after a few minutes, gone.

Notably, both Jupiter and Saturn looked just terrific, and even without dark-adapted eyes, M5 was decent.  I think that the seeing was probably pretty darn good, but I think another thing is at play as well – less vibration transmitted to the scope through the mount, and also – maybe – a more smoothly tracking mount which leads to steadier views.  If true, and if I’m not just encouraging my own placebo effect, that would be very nice!

This is a major power supply problem.  These little powerpacks are just not working, even though I can’t see any reason why they shouldn’t.  Christopher Sullivan has this same mount in the Skywatcher flavor. To avoid the battery babysitting problem, he recommended the Celestron Lithium Powertank, which is a powerful Lithium Iron Phosphate battery.  Much smaller and lighter than a regular lead-acid powertank at only 2 1/4 lbs., but significantly more capacity than the powerpacks I had been using.  Importantly, no baby-sitting necessary – it will maintain a charge for years.

However, another astro-buddy, Mark, recommended a different – and vastly cheaper – approach:  create my own powerpack out of rechargeable AA batteries.  I had looked into this option waaaay back when, right after I first bought the scope.  Rechargeables operate at 1.2V instead of the regular 1.5V that alkalines work at.  So, where 8 x 1.5V batteries will get you to 12V, you need 10 x 1.2V to get there.  He uses such a ten-pack of AAs to operate his iOptron Mini-Tower Pro, and tells me it works great.  Notably, while the Powertank is $139, this 10 AA battery holder, complete with the appropriate 2.1mm x 5.5mm 12V DC plug, was only $7 shipped.  Obviously, this had immense appeal to my innate cheapitude.

But let’s see what Orion customer service had to say about these two options.  Once I explained the problem to them, they hit on it pretty instantly – my powerpack batteries weren’t putting out enough continuous amperage.  This mount requires not just 12 volts, but also 3 amps to work correctly.  The powerpacks most likely only output about 2 amps of continuous power, and probably even less – and that’s just not enough.  Regular rechargeable AAs would probably do the same.  But that LiFePO4 powertank is specifically rated at 3 amps; it should do fine.

I checked with Tom, an engineer friend of mine.  He concurred – AAs wouldn’t put out enough amps either; perhaps rechargeable D cells would, but they’d be expensive.  And due to my generalized lameness when it comes to being handy, I prefer the prepackaged solution over one that I was assembling myself anyway.

Celestron Lithium Powertank it is!  Will be here Friday, and then I’ll take the mount up to the roof and really put it through its paces.  Can’t wait!


All four of my Jeopardy shows have now aired, and those that watched them know that I won!  Yes, I am now officially a Three-Time Jeopardy Champion, and you’d better believe that that phrase will come up right at the end of every discussion I’m ever involved in for the rest of my life.  (I kid, I kid.)  If you’d like to watch my shows, here are some links:

May 25, 2017

May 26, 2017

May 29, 2017

May 30, 2017

Unfortunately, even though I was on the show in February, I still won’t be getting my prize money until October, which is more than a little annoying.  Seven-month wait!!! But $77K sure is a nice haul.  And lifelong bucket list item firmly crossed off, to be sure.  What fun!


3 thoughts on “May 31, 2017: The Orion Sirius Pro AZ/EQ-G mount, Part One – Power Troubles

  1. Congratulations on the Jeopardy wins. You did a great job. While the Celestron Powertank in the 17ah form costs over $100, Harbor Freight sells a 17ah version with two cigarette sockets and a 5v usb socket for around $40. I use a Battery Tender, plugged in through one of the cig sockets, to keep it charged up. Lithium power packs have their own issues. They store best between 50% & 80% charged. Don’t like to be maintained at 100% charge for any length of time. Don’t like to be stored above about 85 degrees. These all affect the longevity of the battery. I’ve got a couple 36v – 11ah packs for our e-bikes, and they require as much attention as the lead acid power pack for the telescope, just in a different way. For safety reasons, the common wisdom is to not charge any lithium power pack in the house while unattended or away, due to the risk of fire. Lead acid power packs don’t pose the same risk.

    Side note, I was a member of DAS 20 years ago when we lived in Denver for a couple of years. It’s where I caught the astronomy bug.


    1. Thanks! I’m not too concerned about tending to a Lithium battery, or the safety concerns. When I charge mine up fully, to 100%, it’s usually because I’m about to use it. And then, when I use it, it goes down to, say, 80%, and then into “storage”, which is inside the house – and certainly less than 85 degrees.

      More importantly, I had $70 on an Amazon gift card, so the cost of the battery to me is about $70. I’ve read some good things about it, so I’m sure it’ll be fine.


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