Jarno_c

Although it's no longer needed here, mousepads can also work near miracles. Place it upside down (non-slip side up), hold it firmly in place, push the frozen part onto it with gentle pressure, and rotate. The mousepad provides so much friction that in many cases the part comes right off and more than once I've been able to remove stuck filters or extension rings this way. Alternatively you can wrap the mousepad around the part and see if that provides enough grip. I always have a mousepad in my astro goodies bag for just this purpose. Jarno

Well, Avalon indeed came to the table but not entirely voluntary. I sent them the defective belts and they confirmed they're the incorrect type. They then wanted to charge me for the shipping costs (at 3 times what it cost me to send the defective belts to them) and I really had to nag to get them to honor their promise . Their response here quite clearly says "In the case of a defect not due to misuse or natural wear, but, as in the case of non-compliant belts supplied to us by the manufacturer, the customer will not be charged of any cost, even if the repair exceeds the warranty period." We'll see if and when the replacements arrive, and perhaps these blasted clouds will finally have moved away by then... Jarno

Update: Avalon has now confirmed there's indeed a small number of belts in circulation that do not comply with their specifications. Rather than steel reinforcements the manufacturer used Kevlar or something similar. I'm not sure this is indeed the root cause because that has now been confirmed to be hydrolysis: degradation of the polyurethane by coming into contact with moisture. The symptoms are cracking, an oily appearance and finally complete disintegration of the material. However if one part of the belts is not up to spec, the remainder might also not be. In case anyone is having problems caused by this wrong type of belt, Avalon will replace them free of charge, even if the mount is out of warranty. It took some prodding and pushing but eventually Avalon did (in my opinion) the right thing. I've received an email asking me to return the failed belts and if they're the faulty type (and they are, the wires indeed aren't metal) Avalon will send me replacement belts free of charge. Of course the weather gods will consider those belts to be new equipment and send in the mandatory three weeks of clouds, so I apologize in advance. 😉 Jarno

Is the wifi on the plus omnidirectional? On the pro the signal strength can vary wildly depending on its orientation, before slewing to a target I can have full strength showing and after slewing it's "connection lost". Jarno

Thank you Julian, finding replacement belts will not be a problem. They're standard industry belts with MXL profile and they cost next to nothing, which is why Avalon's attitude annoys me so much. I'm just debating whether to go for glass fiber or steel reinforced belts. In theory the steel belts should have less flex but the elasticity of the reinforcing material is probably an order of magnitude less than the polyurethane teeth, so I doubt it makes a difference. Jarno

Hi all, I've been lurking here for the last couple of years. A long time ago I promised to post a review of the Avalon Linear mount and I've finally gotten around to it, so here goes. The good First, a little background. The Avalon Linear is an equatorial mount which doesn't use any gears, instead it's completely based on belts and pulleys. The rationale behind this is that while it won't necessarily reduce periodic error, it'll make it much smoother and more gradual so it can easily be guided out. The belts also are completely free of backlash and don't require lubrication of maintenance. Mechanical The mount head itself is completely made of machined aluminum with very tight tolerances, there are barely any gaps between the parts. The head is attached to the tripod with two screws which unfortunately aren't captive, which means you have to hold the mount head with one hand while putting in the screws with the other. This is made easier by the handle conveniently placed over the center of gravity but I'd still have like those screws to be captive. The mount electronics are all suspended underneath the RA axis so they act as a counterweight. This means you can use less actual weights but the downside is that all the connections move as the mount slews around the sky. Speaking of counterweights, those are stainless steel of the same finely machined quality as the mount head. The counterweight rod is another hefty 30mm thick piece of stainless steel which is inserted into the mount head and then held in place with a screw that falls into a safety slot. As long as you don't have too many counterweights on it, you can leave them on and attach and remove the counterweights as a single assembly. It's one of several things that makes setup faster and easier than with other mounts. The saddle clamp is another machined part (I don't think there are any castings anywhere on this mount) and it fits Losmandy type plates. It has a single clamping screw and personally I'd have preferred two, but it holds even heavy OTA's securely enough. There are several types of polar scopes in circulation, mine is apparently the same one Synta uses but I can't confirm that since I've never used or owned a Synta mount. It seems functional enough but I've never actually used it since I prefer to use a Polemaster and later the Asiair to polar align. And finally, the alt-az adjustment screws. These have knurled knobs which are easy to grip even with thick gloves on. Movement is smooth so the mount can be polar aligned very precisely. This is what it looks like, all set up: Drive and electronics Avalon mounts can be provided either with the Synscan system, or Avalons own StarGO system. The main difference is that where Synscan is mostly a standalone system, the StarGO requires an external device like a laptop or tablet to run its software. I chose the StarGO since I'd be bringing along a laptop for guiding and camera control anyway. The mount by itself has little to no "intelligence" built in: you can slew it, you can control a Baader Steeldrive focuser and that's pretty much it. There's no goto, no PEC, no platesolving, no polar alignment routine, nothing. All that is handled by the StarGO software which is very intuitive to use although the first versions were a bit on the basic side. I understand it now includes things like a polar alignment routine and plate solving but back then it didn't, and I've switched to an Asiair since then. Since I no longer use the Avalon software I can't really comment on how it performs nowadays. Goto's were executed smoothly and in 90% of the cases placed the target near the center of the FOV. In the remainder of the cases the target was off to the side but it never was completely outside the FOV. A sidenote here is that the mount doesn't have encoders so goto accuracy is highly dependent on how accurately the mount is polar aligned and placed in the home position. There are laser engraved markings on the mount to help with this. Because of the belt drives the mount is very quiet. You can hear a soft whine from the motors when they're at full speed but it's hardly audible two meters away and won't wake the neighbors even in the quietest places. For those interested, the mount used a four-step reduction system. The first three steps use opaque yellow belts which aren't tensioned, the fourth and final step is a much larger translucent belt which has a tensioning mechanism. All this will become relevant later. Here's an overview of the mechanism with the steps color-coded: I've heard from others that the belt mechanism is more sensitive to wind but I've not noticed that myself. Usually when the wind picks up at my observing site, it's strong enough to cause problems for all but the very heaviest mounts. Weaker gusts are immediately compensated for since the mechanism is indeed almost free of backlash and guiding can be set pretty aggressively. The stars may become a bit bigger but it's rare to have any trails. Overall I would say the mount is well suited to mobile astrophotographers. It's very easy to set up and tear down, and tracks and guides very well. Or at least it used to... The bad On my last couple of sessions I noticed that guiding in RA was worse than in DEC and sometimes would go completely off-track. Since I'm using an Asiair to control the mount, and this has its fair share of software issues, I didn't think much of it. I usually returned the mount to its home position, reset the Asiair and all was well again. But two days ago it happened again and this time, when I sent the mount to the home position it started making loud grinding noises. I immediately stopped the slew and noticed there was a lot of play in the RA axis. I called it a night and when I opened up the mount the next morning a handful of debris came falling out, much to my shock and surprise. As it turns out one of the belts has completely disintegrated. The reinforcing wires are still intact but the polymer around it is just crumbling away: I inspected the other belts and those are showing cracks and damage as well: [ Obviously this shouldn't be happening with a mount that's just over 5 years old so I contacted Avalon. The ugly I informed Avalon of what had happened and included photos of the destroyed and damaged belts. Their reply was that the mount would have to be returned to Italy and then they would give me an estimate of the repair costs. This surprised me because obviously there's a production fault with these belts since only the yellow opaque belts are affected and the larger transparent belts are just fine. I asked another Avalon user to inspect the belts on his mount and he's seeing cracks in the belts as well so it's not something unique to my mount, or caused by something I did. This is not what you'd expect from a mount in this price range. I told Avalon as much and they agreed to send me replacement belts for 98 euros per axis, excluding VAT and shipping. I'd already looked up the belt manufacturer and this type of belt costs less than 10 euros! So total cost for both axes would be around 60 euros while Avalon wants to charge over 200, and for something that should never have happened in the first place. I don't expect them to send the belts for free, the mount is out of warranty after all, but in my opinion the proper response would've been "Apologies, this isn't the quality you should expect from us and we're sending replacement belts at cost + shipping." I mentioned that another user has also seen cracks in the belts, he made a movie of the belt moving so you can see what's happening for yourself and judge if this is normal for a mount costing over 5K: https://youtu.be/OF7oVwpDk4w While I still like the mount I'm extremely disappointed with Avalons customer service. I'd recommend that all Avalon owners regularly check their mounts belts and at the first sign of cracks, notify Avalon immediately. Jarno