Geoff Lister

It is also possible that the mount requires the mechanical load of the optical tube, so that the motor has something to work against. In an earlier life, I worked on aerospace control systems; and some control loops are unstable without their designed load.

Hello Chris, and welcome to SGL. My Skymax 127mm Mak. has a similar mount. These are some of my power sources:- These are some current measurements:- Geoff

I know it is counter-intuitive, but would the (old) thicker grease help dampen-out any resonances in the gear train?

I'm not sure that my Skywatcher Dob mount would be much quieter at max slew rate with the gear covers off.

Hello Gary, I have the 250mm (10") version, and have not needed an extension tube with any of my 1.25" eyepieces. I do need a 40mm extension if I use my Meade 2" 56mm Plossl eyepiece. The 1.25" adaptor supplied with my 'scope fits directly into the rear of the focuser drawer tube. The 2 eyepiece adaptors - both have the same diameter tapered flange, and are clamped in place by the 2 thumbscrews (roughly 9 and 1 o'clock positions in above photo) Geoff

Modifications for dual OTAs. For lighter OTAs, the mount uses the locking knob in place of the counter-weight shaft. With the heavier OTAs, the balance is achieved with the counter-weight shaft, and a counter-weight roughly equal to the weight of the OTA. By adding a dovetail clamp to the locking knob, I can now mount 2 equivalent OTAs with the same overall weight as 1 OTA + 1 C-W. I drilled and tapped the locking knob, giving it a 1/4" - 20 UNC (standard tripod) internal thread. My dovetail clamp has a similar thread, but I wanted a clearance hole, so drilled this out to 6.5mm. A suitable slotted, cheese-head, machine screw + star washer, sits in the clamp's well and attaches the clamp to the knob. Alignment of the 2 clamps is done with a "pound shop" spirit level. This shows the altitude drive interface and the modifications. The bronze sleeve is just a very thick washer, with a metal-to-metal coupling on its inside face, so I am experimenting with replacing it with a couple of thick fibre washers to give a variable altitude clutch action. Heritage 130P OTA (now correct way up) and 127mm Mak. OTA (with RACI finder in alternative position) in balance on a piece of 2cm x 2cm wooden "rod". Geoff

My Ioptron mount came with an RS232 lead. The computer end is the standard 9-way "D", and the other end is RJ9 (4P4C), and goes into the 8408 "Go2Nova" handset. The handset connects to the mount's "HBX" (Handbox) port via a curly lead with RJ11 (6P4C) jacks at both ends. The manual mentions ASCOM drive protocol for computer control, and Ioptron do a USB to RS232 adaptor lead (part# 8435), but no mention of the FTDI chip-set. There is also a "StarFi" wireless adaptor available (part# 8434). Geoff

Hello Tom, I have the Ioptron SmartStar CubePro (designed as AZ/Alt, but EQ modes available if on a wedge) mount. If it helps, the counter-weight shaft has a diameter of 19.3mm and works well with weights designed for the SW SkyTee 2 mount. The underside of the CubePro has an almost flat base and has an internal 3/8" - 16 UNC thread (as used on the Virtuoso Dob. mounts). This thread-form is very similar, but not quite identical, to that of the SkyTee 2 top to tripod long bolt. Geoff

The larger diameter part of the clamp body is riveted to the bottom of the upper tube. This makes it very difficult for most people to replace - hence no after-sales spares. Even if you managed to get a replacement clamp, it is unlikely that you would be able to attach it with a fixing that permitted the inner tube to retract, or look "as new". So I would repair. Based on your photo:- (1) remove the white traces of duct tape glue. (2) get some single-strand wire 0.5 to 1.0 mm diameter, copper or steel - the green coated wire sold in garden centres would be fine - even nylon chord or fishing line would probably work; and wrap it as a coil, starting at the top, to pull the two broken surfaces together ( Google "whipping end of rope" to show the best way to stop it unraveling). (3) coat your coil with "superglue" or epoxy-resin glue, penetrating the gaps between the turns of the coil, so the coil is attached to the plastic - just make sure it does not flow through the split to get inside the clamp and lock the lower tube. (4) when the glue is set, paint with black paint if you want the repair to be less noticeable. You may want to do the same to the other 2 clamps to stop them splitting in the future. It's much easier to "beef up" an intact clamp, than repair a split one. Geoff

Good. This implies that the basics are operational, and the software "thinks" it's tracking. If you set the mount looking at a distant earth-bound object, the tracking should make the eyepiece view change slowly (give it a few minutes). The next thing to try is slewing at intermediate speeds. Try pushing the "2" or "3" buttons prior to using the up/down/left/right buttons. You will have to look closely to see the mount move, it is easier to set the 'scope pointing at a distant object and look for movement in the eyepiece. If that works, try "4" and then the max. slew rate, "5" - this will be the best test for good power connections. Geoff

Let's start with the basics. I have 2 of the mounts (90 Mak. and 114 Newtonian) and both are very reliable. This implies that it initially worked for you when you first used it. Is this correct? When you turn the power switch to "On", does the mount make a (very quiet) double "Beep" sound about every 2.5 seconds, with simultaneous flashing of the keyboard back-lighting (only visible in a subdued light)? If not, (1) check that all the batteries are making contact in the holder, or (2) if the external 12V socket has a battery disconnect contact when a plug is inserted, it is possible that something is stopping it making a proper contact between the battery pack and board electronics. Geoff

I bought this mount, from FLO, at the beginning of January 2020. https://www.firstlightoptics.com/ioptron-mounts/ioptron-smartstar-cubepro-az-mount.html These comments are after a month's occasional use. I already have a selection of Celestron & Skywatcher (Synta) GoTo mounts, but I wanted something smaller for a grab-and-go with quick setup. Overall I am very pleased with my choice. The GPS locks in a few tens of seconds, and the mount emits a short "beep" to indicate the lock (the top-right corner of the display also changes from "ON" to "OK"). Provided that the mount is pointing towards its designated starting Az & Alt positions, (see below), the automated slew to the selected target is accurate and, after final centring, tracking is excellent. It is very quick and easy for solar white-light observing when there is a gap in the clouds. The single object alignment (2 and 3 object alignment is also available) is ideal for daytime, when only the Sun is visible. The mount incorporates a holder for 8-off 1.5V AA cells, and there is a socket for a 12V, 2.1mm ID/5.5mm OD power jack. I have measured the current consumption. Initially (no tracking) it is between 75 & 90mA; whilst tracking, between 90 and 130mA; 2-axis slewing at maximum rate, up to 470mA; and 2-axis slewing at 128x standard rate is about 155mA (about 10mA less if only 1 axis). Generally, the standard zinc/manganese dioxide "alkaline" cells have a capacity between 1700 and 2850mAh. The manual indicates a supply range of 10V to 14V and >1.5A (the supplied PSU is rated at 1.5A - so, in theory, out of spec!). The mount has a 3/8" - 16 UNC internal thread (heavy duty tripod), and is coupled to the top of the tripod by a long, captive, bolt. The tripod's legs are locked in position by rotating a plastic tray (with holes for 3 off 1.25" eyepieces) similar to the Synta ones. There are a few areas with significant differences to my other Celestron and Skywatcher mounts, and other "features" of note:- (1) The Cube's dovetail clamp is on the right, whereas on the Synta mounts it is on the left. Thus any Synta OTA is going to be upside down on the cube. This is not a problem with most focusers, but the finder is now bottom right, and A RACI with eyepiece facing downwards, is unusable. The OTA from my Heritage 130p has the helical focuser pointing directly downwards (I believe it is possible to remove and reverse the truss tubes, but then that would make the OTA incompatible with my other mounts). The 127mm Mak from my Skymax system is right at the top end of the mount's OTA-weight range, and I have glued a second finder shoe at 180 degrees to the original, so I can use my 6x30 RACI finder. I have a Celestron C90 Mak. spotting scope, designed to go on a tripod, and this works fine with the cube - the finder moving from top left to top right. (2) The supplied system includes a 12V 1.5A mains PSU. This supply is a small block with a permanently-attached mains input lead. This lead has a "European" small, round-pin, (incompatible with standard UK socket) mains plug. It has similar spacing to the plugs supplied with UK shavers and electric toothbrush re-chargers, but, the pins on the supply are of a smaller diameter. I tried the plug in two plug-in shaver adapters; there was no problem with electrical contact, but it was far too easy to dislodge the plug with a small movement of the lead; easy to disconnect in the dark (leads and supply are black). I cut off the plug and fitted a UK BS1363 square-pin plug. (3) With my Synta AZ/Alt systems, the default starting position is with the OTA pointing North and the OTA level or pointing to the NCP (Virtuoso Dob. mount). With the Cube The default starting position is with the mount facing South, and the OTA/dovetail clamp, vertical. This makes it far more difficult to attach the OTA. With a horizontal dovetail clamp, the clamp supports most of the weight of the OTA, and just requires a gentle push to adjust the OTA's dovetail plate position in the clamp. With a vertical clamp, you have to support the full weight of the OTA + any clamp-to-plate friction. I have found a solution that seems to work for me. Unlike the Synta system, the Cube remembers the mount's position at power-down. So, at the end of a session, I slew the mount to AZ 180 degrees, Alt to 0 degrees, and then power down. The mount seems to accept this as a starting point for the next session. (I have yet to try the Az at zero [= North] end/restart setting). (4) The initial "South" starting point is more difficult than North, (no Polaris equivalent) and the mount has a strong stray magnetic field, so you cannot use a magnetic compass near it. I have found the best method is to use a compass to identify an object (roof/tree/pole) roughly due South, point the OTA's finder at the object, tighten the tripod's mounting bolt, swing the OTA vertical (spirit level across objective end shroud/ dew shield), and tighten the Alt knob/balance weight shaft. Remove spirit level - its a long way down to a concrete paving slab when the mount slews! (5) The Cube mount relies on a level tripod for its initial accuracy. However, the little bubble level incorporated in my mount was not well aligned. With a leveled tripod, using a "good" builder's spirit level, the mount's bubble was off-centre, with one edge of the bubble touching the black line. I got round this by putting a Tipp-ex white blob on the level's glass, positioned to just cover a properly-leveled bubble, and leveling is now just a game of "Hide the bubble". (6) Some of the advertising photos show the handset as though it is attached to one leg of the tripod. There is no way of doing this with the supplied kit. The handset has a little lanyard, and there is a small raised "button" on the North face of the Cube. The lanyard slips easily over the button, and is a reliable "dock" for the handset. However, both the lanyard and the button are black, so in the dark, it is difficult to find the button, and ensure that the lanyard's loop is open and correctly positioned. I made a tripod-leg docking clamp, similar to the ones supplied with the Synta tripods. I find the lanyard is best for daytime solar, and the (home made) docking clamp for night use. (7) The Alt axis drive is from a sleeve on the main Alt shaft. The coupling is performed either by the locking knob, or by the end of the balance weight shaft. In both cases, the drive is through metal-to-metal friction with the end of the drive sleeve. There is no compliance in this coupling, so a minor release movement completely unlocks the drive. I have added a thin fibre washer (of a type often used in plumbing joints) to absorb any minor changes due to temperature or a nudge on the OTA. It's still not the same as an adjustable clutch, but it seems to stop inadvertent release (and associated loss of alignment). When I have a few suitable photos, I will add these as an edit. Photos now added. 90mm Mak from Virtuoso system and Ioptron-supplied 1.4kg counterweight. Note "glow-in-the-dark" tape added on mount's lanyard attachment button, handset, eyepiece tray and tripod legs. DIY docking clamp for handset - in dark, easier to use than lanyard. Skymax 127mm Mak and 3.5kg counterweight from SkyTee mount. Note, extra finder shoe (the black one) on OTA, so RACI finder works. 127mm Mak in "zero" position. Note that you are fighting gravity when sliding the OTA into the dovetail clamp. Cosmos 90mm refractor and 1.4kg counterweight. Note upside-down position of RDF and focus adjustment shaft. Heritage 130P OTA showing focus tube facing downwards. Geoff

Yes, but only at night. Geoff

With its 4m diameter primary mirror, they can also cook lunch 😎. Geoff

Also a first for me. I used my 90mm Mak with solar film and Solar Scout 60mm Ha, and the white light view was more impressive. Geoff

I have just had a look at the cable on my Skyliner 250 (10") mount, and the cable is pin 1 to pin1, pin 2 to pin 2, etc. up to pin 8 to pin 8. To achieve this, the cable outer has its central injection moulding line on the pin side at one end (the one that has the ferrite clamp), and the moulding line is on the retaining clip side at the other end. If you hold the cable with both plugs having the pins facing you, the colour sequences are identical. Geoff

Depending on the magnification of your optical path, you may need to set a lower slewing rate to make it easier to set the final position. Press the "Rate" key, then "3" or "4" then "Enter" Geoff

Hello Ivor, Under the "Utility" menu, Synscan has a "PAE" function. Once you have centred an object, you activate PAE, and this improves the GoTo accuracy in a small (I believe it is about 5 degrees) patch of sky round that object. This can be done for various regions of the sky during a session. To avoid using old, inaccurate, pointing data, it is also worthwhile using the adjacent "Clear PAE Data" function at the start of a session. I hope that this helps. Geoff

This is where you have to do your homework. My experience is that the initial suggested 2nd star is often behind houses/fences/trees, and, if you select that star and realise the problem, and stop the slew, you have to start again with a first star. It is better to step through the list of suggested second stars, to get one that you are fairly sure that you can see (and recognise in its constellation). The "Brightest star" alignment also gives you the option of a 'planet + 2-stars'. This requires a manual slew to the planet, (Venus is good for me at the moment), and does an automatic slew to both alignment stars. Geoff

I managed to get a set of small Allen keys for a quid at my local "Pound Shop". Geoff

When I bought my first GoTo system, the Skywatcher Skymax 127 with Synscan handset, I found it hard to get good alignment; adequate, but not as good as I would have liked. I think I now know what is needed. In an ideal world, the azimuth axis (mechanical, or the digital model in the handset) has to be perfectly vertical. To get the mechanical axis vertical, the top surface of the tripod (or the Dobsonian base of my Skyliner) has to be horizontal. The bubble level glued into the Skymax's tripod is a good indication, but the one on mine was not quite level. I used a good builder's spirit level to get the tripod level, and marked the position of the bubble with a spot of Tipp-ex, about the same size as the bubble. Now, tripod leveling is a simple game of "hide the bubble". Provided that I do not kick the legs, attachment of the mount and OTA does not seem to shift the bubble. At power-up, the mount's digital model starts at zero (level and pointing North). I usually try to start with the mount's altitude pointer at zero and the OTA pointing roughly North (compass, or if it is dark, Polaris and then lower the OTA back to zero). Assuming that your tripod/mount/OTA is not "perfectly" level, the azimuth axis will be leaning over, and this will affect altitude accuracy. It will be accurate at 2 points, 180 degrees apart, and most inaccurate at 90 degrees to these points. However, at this stage, you, and the digital model, do not know where these points are. The digital model, assuming that you have set up time/date/location correctly, does know where the important stars are. The manual slew, and final eyepiece centring on the first star will give the digital model a fairly accurate azimuth and altitude calibration, including the component of the azimuth axis "lean" in that direction. If you choose a second alignment star close to 90 degrees in azimuth from the first, and preferably with a different altitude, the digital model will have calculated the direction and magnitude of the "lean", and so can compensate for it when using tracking or GoTo. It may be my imagination, but I have found that, if I can minimise the time duration between starting the slew to the first star and centring the second, the GoTo accuracy is better. By using the brightest stars, easily visible from your observing location (not too high, but high enough to be well clear of houses, trees and fences), it is possible to speed up the process. A bit of prior homework (I use "Stellarium" on my PC) to identify the 'best' stars, is worthwhile. I went to the next stage, and produced a table of 14 stars by the 12 months of the year, and for the middle of each month, at dusk, I selected 3, 4, or 5 stars with good separation, and noted their rough direction and altitude. For an Az/Alt mount, Polaris is just as valid as any other star. The above is for Az/Alt mounts; EQ mounts are not so reliant on a level tripod, but substitute that for good polar alignment. Geoff

The setting of tripod/mount level and OTA horizontal takes out most of the errors. The GoTo alignment on 2 stars, centred in the eyepiece, should remove the final errors in your initial settings. The first star takes out most of the errors, and the second adjusts the final values. Geoff

If you have an Az/Alt mount, again, level the mount first. This reduces any cross-coupling between the altitude and azimuth axes. If you have a GoTo mount, this reduces the corrections that the alignment calculations have to make, and so reduces the pointing error when the mount slews to the second alignment star. Geoff

Although not a replacement for the book, some of its information is now available online, at https://www.cambridge.org/turnleft Geoff

Good advice. The details on the Jessops web page do not give the eyepiece diameter. The FAQs have an answer that the mount does not take a motor drive. Geoff