iOptron AZ Mount Pro

[+bryand]

I wanted one mount that I could use with my 9 ¼”SCT, 4” refractor and binoculars so at the risk of making my other mounts redundant, I got an iOptron AZ Mount Pro, and their Tri-Pier to put it on.

 

Support

The Tri-Pier is a very solid support.  It is actually slightly lighter than the 2” tripod for my SCT, but it is really rock solid.  The lower legs, which are not retractable, are chromed steel: the rest is aluminium.  Levelling adjustment is by moving the legs inward slightly and the range is restricted.  But then you wouldn’t be setting up on a slope anyway.  Vibration suppression feet are attached to the bottom of the legs – a nice touch.

The central pier (which houses the chrome legs for transport) slides up and down within oversize scope rings, being held in place temporarily by spring-loaded balls which click into holes in the pier.   This arrangement keeps the rings in place long enough to screw up the clamps, locking the column in place.  To adjust the height, you slacken off the screws and hoick the column up, tossing-the-caber style until it’s at a suitable height.

I added the woodwork to provide some eyepiece stowage and somewhere to keep the laptop off the ground.

 

Balancing

You need to balance the load quite carefully in both Azimuth and Altitude before levelling the mount.  This is best done as a dummy run in daylight.  I use masking tape to record the balanced positions so I can set them again without further adjustment.

Balance in Azimuth is awkward because there is no clutch, so you can:

a)    Work out (weight x distance) for the scope with accessories and for the counterweights.  The values for each side should be within 7 lbs (3.2 Kg) of each other, OR

b)    Use the Rule of Thumb that scopes < 5 Kg don’t need any counterweight; between 5 and 10 Kg need one of the 4.7 Kg counterweights and > 10 Kg scopes need two weights, OR

c)    Rotate the scope so it is pointing exactly between two legs of the Tri-Pier.  Then weigh each of the two legs.

Balance in Altitude is easier because you can undo the Altitude lock and allow the scope to swing, which makes finding the balance point easier.  It is recommended to have the scope slightly objective-heavy (i.e. falling downwards slowly) to put pressure on the Altitude clutch and prevent it slipping.  In fact, with the ‘capstan’ levers on the Altitude lock, there is no slipping anyway.

 

Levelling

The top rim of the column has three brass levelling screws that the mount sits on, and a central 12 mm bolt to hold the mount in place.   My experience with the mount levelling process is that it’s best to start off with the brass screws almost all the way out i.e as high as possible, and to level the mount by lowering one or more screws.  The central bolt should be only loosely fitted at this stage. The bubble level is quite sensitive, but you soon get used to which way to turn the screws to centralise the bubble.   You need a head torch to do this at night, but the bubble is easy enough to see.  Having got the bubble centralised, make sure all three screws are contacting the mount, so there is no rocking.

Tightening the central screw, and adding payload both alter the levelling.  The heavier the load (scope and/or counterweights) the more difficult it is to re-adjust the levelling, and you need to keep the centre bolt screwed in but loose until the mount is levelled.  Little tweaks to the brass screws and the centre bolt work best.

Once levelled, remember to fully tighten the centre bolt – on one occasion I found it was quite loose after 2 hours or so.  Can’t remember whether I failed to fully tighten it or whether it had worked itself loose.

 

 

Alignment

When you switch the mount on, it does a pirouette so the onboard compass can find South.  It then moves to its Zero (“Home”) position, which is facing South with the scope pointing at the zenith.  It may ask you to confirm Daylight Savings time etc, and it will probably beep to announce it has GPS lock.

Then it slews to the brightest object in the sky (mine seems to like Mars) and asks you to:

a)    Align the target in Azimuth.  This is a final correction for the South position.  I tend to use my Telrad for this, since the target may not be within the eyepiece’s field of view yet; then

b)    Use the Altitude and Azimuth controls to centre the target in the eyepiece  i.e. perform a one-star alignment.

And that’s all.  No faffing around with Polaris, or picking random targets.  Using a reticuled eyepiece for the alignment, I found that the mount keeps its alignment for several hours’ use, to the extent that the Telrad and RACI finderscope are redundant.

 

I turned the saddle 180° so that the clamp knobs are at the bottom, which is where your hands are when fitting the scope to the saddle.  You do need to ensure the dovetail rail is fully engaged with the saddle clamp before you let go of the scope.

The saddle is 6” long and seems to vibrate less than the Celestron mount’s single-screw clamp.

Strictly speaking, the SCT needs a second counterweight.  I plan to fit one of iOptron’s battery counterweights.

 

 

It’s all very well having an internal Lithium battery to power the mount, but you still need to power the dew heaters and mounting the battery on the CW shaft not only helps the balance, it prevents cable-wrapping problems.

Edited September 26, 2018 by bryand
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[Tweedledee]

Very nice write up, and a very nice visual setup. Love your woodwork, it looks great. ?

 

I'd be interested to know what in particular persuaded you to go for the iOptron?

 

Did you consider any other similar mounts, like the SW AZEQ5 or 6?

 

The iOptron Tri-Pier certainly looks very stable whereas the az mount pro itself looks quite small in comparison to the SkyWatcher mounts. Perhaps that is not the case as we can't see them side by side. 

[+Bino-viewer]

Looks good.

I've always thought what a neat idea a 'battery counterweight' is.

 

[+bryand]

1 hour ago, Tweedledee said:

I'd be interested to know what in particular persuaded you to go for the iOptron?

Did you consider any other similar mounts, like the SW AZEQ5 or 6?

I already have an iOptron CEM25P equatorial mount, so I appreciate the standard of their engineering but have grown to dislike the hassle of setting it up.  (The best mount is the one you use most often... etc)

Dual-mode mounts look like they were designed by a committee and I suspect perform like that too. 

At its simplest, I wanted a mount that goes where you point it, not in some arbitrary arc that makes perfect sense to a geodetic specialist but nobody else.

There really aren't that many higher-end Alt-Az mounts out there.  If I could afford a Panther TTS, I'd have one.

[Tweedledee]

Cheers, that makes a lot of sense. 

 

So it looks neat and does exactly what it's meant to do. ?

 

I'd never really looked too closely at iOptron, but will have a closer look now.

[BAZ]

That's an interesting read Bryan, thanks for sharing it.

[+Streetbob]

Thanks Bryan; interesting read.  I have an earlier version of the iOptron CEM25GT.  My main reason for buying was because of its relative lightweight, and though it is a good bit of kit it is still hassle to set up as you say.  I revert to my 200 dob for ease.

I also have the battery counter weight, again because it is relatively light, but they are expensive.

[+seven_legs]

Just found this post and finding a great help as I brought this mount with a altair starwave  f5.9 6"  refractor,  but as not yet had chance of setting it up due to a forced  move of house.

Maybe be bothering @bryand with questions and tips if that's ok😀

[+bryand]

No problem Tony.  I'll be getting out to Wymeswold as soon as it clears for long enough.