RR RST-135 Goto Mount

[Ouroboros]

@nfotis They’re designed? 😉  Yes, you make a good point. It’s a very different technology. Sometimes when companies want to develop in a particular direction they acquire another company with the required expertise. 

[Highburymark]

On 16/05/2021 at 16:40, Ouroboros said:

 I must admit I am tempted. I see another one has just been bought from the FLO site

That was my order from FLO I think. Brilliant though the SW AZGTi and Solarquest mounts are, I’ve had to admit I need something stronger. After searching everywhere, had to conclude there was nothing else on the market that ticked all my boxes. Think there’s room for a beefed up AZGTi-type mount, with a 7kg payload, solar-friendly, that can operate on a robust camera tripod, and be easily packed away for travel.

[Ken82]

I would be very interested in one of these for my grab and go setup. I’d like to see some guiding results below 1” accuracy thought. For this price point I’d expect it to consistently guide below that figure. 

[Ouroboros]

1 hour ago, Highburymark said:

That was my order from FLO I think. Brilliant though the SW AZGTi and Solarquest mounts are, I’ve had to admit I need something stronger. After searching everywhere, had to conclude there was nothing else on the market that ticked all my boxes. Think there’s room for a beefed up AZGTi-type mount, with a 7kg payload, solar-friendly, that can operate on a robust camera tripod, and be easily packed away for travel.

I hope it meets your expectations.  It’s quite a price hike.  Let us know how it works for you. 

[Deadlake]

2 hours ago, Highburymark said:

That was my order from FLO I think. Brilliant though the SW AZGTi and Solarquest mounts are, I’ve had to admit I need something stronger. After searching everywhere, had to conclude there was nothing else on the market that ticked all my boxes. Think there’s room for a beefed up AZGTi-type mount, with a 7kg payload, solar-friendly, that can operate on a robust camera tripod, and be easily packed away for travel.

I’m sure a TSA-120 or maybe a FSQ-106 ( at F5 it would do wonders for your NV intensifier, help with the gain setting) would also look good on it. Let me know how the alignment works out, hopefully no need to use a pole master???

[Davey-T]

On 15/05/2021 at 13:08, Highburymark said:

Have you used yours much in alt az mode Dave? I’ve got a 135 on order - one of reasons is to handle a front heavy solar Ha scope on camera tripod - will mainly use alt az for imaging and visual. But not many reports out there on alt az performance. 

Not used it at all in Alt Az Mark, the only reason for the counter weight is to balance it in Alt AZ, I made a counterweight bar and a couple of stainless steel weights for mine as the Rainbow one is a bit overpriced, also made a pier extension for the same reason.

Dave

 

[Highburymark]

Thanks all. Weights look great Dave. 

I shall report back on alt-az performance. Main uses will be TV85 (almost 4kg) with nearly 2kg of solar filters on the front. Impossible to balance perfectly for imaging without adding extra weight to the back. For visual, with a binoviewer and two eyepieces (another 1kg+), it’s reasonably balanced. Then my other scope for this mount is Tak Epsilon 130 - around 6-6.5kg fully laden. The 135 will carry these scopes without breaking sweat, but it’s go-to and tracking accuracy that remains to be seen.

[tonyowens_uk]

On 16/05/2021 at 19:06, nfotis said:

That would require sourcing robotic mechanisms, which are an altogether different market. And that would mean depending on another supplier (it's my understanding that Synta prefer to be vertically integrated as much as possible, in order to be able to control costs and quality themselves).

That makes me wondering: how much of the materials and parts in the Skywatcher mounts and telescopes are in-house designed and built?

N.F.

 

From what I've seen, Skywatcher (Nantong Schmidt Instrument Company) have enormous manufacturing operations of their own, for optics, tubes, machined parts, worm wheels, finishes, assembly, test and many other things. Obviously they dont make their own PCB's, castings, small lenses and so forth. No OEM does. Such things come from specialist suppliers. But they do have an excellent design engineering team, who are very much involved in the latest developments, and plenty of resources.

So far as harmonic gears are concerned, as used in the compact mounts referred to on this thread, these all come from specialist companies who serve the automation/robotics/semiconductor processing equipment markets. The technology has been around for decades, but it is difficult to master, as it involves materials, heat treatment, motion control, creep-grinding and structural analysis expertise of a high level all under one roof. At the hobby level,harmonic gears are 3D printable, but for ultraprecision uses such as imaging telescope mounts, neither Nantong Schmidt nor anyone else is going to be producing their own!

It is worth mentioning, that for all their advantages (compactness, low backlash, low friction losses), harmonic drives have many disadvantages too (indifferent linearity (large periodic error), lack of torsional stiffness, cost). When autoguided by fast guide optics and star centroiding software with with good response, they should track fairly well. But they will not match the accuracy and low PE of a good set of machined and ground worm gears, never mind friction drives. 

[Ken82]

13 hours ago, tonyowens_uk said:

But they will not match the accuracy and low PE of a good set of machined and ground worm gears, never mind friction drives. 

A little disappointed with this, for the price point I would have hoped the guiding accuracy would be the same as traditional mounts. 
 

So the big advantage is the low weight ?  But the second critical point of guide accuracy will likely be worse than traditional mounts 🤨

[tonyowens_uk]

4 hours ago, Ken82 said:

A little disappointed with this, for the price point I would have hoped the guiding accuracy would be the same as traditional mounts. 
 

So the big advantage is the low weight ?  But the second critical point of guide accuracy will likely be worse than traditional mounts 🤨

I need to qualify my comment Ken. The comparison would be against quality antibacklash worm gears, not fixed-centre gears. Remember that many traditional mounts have neither ground worm gears, nor precision-grade worm bearings, nor antibacklash provisions. And in some cases not even proper environmental sealing of the oily bits. There is a huge quality spread across the hundreds of models of worm geared mounts available.

 

Tony 

[Highburymark]

4 hours ago, Ken82 said:

A little disappointed with this, for the price point I would have hoped the guiding accuracy would be the same as traditional mounts. 
 

So the big advantage is the low weight ?  But the second critical point of guide accuracy will likely be worse than traditional mounts 🤨

The weight’s a big advantage (3.3kg), but the other key benefits for me are compactness/portability, payload up to 13.5kg without counterweights, and no need to worry about perfectly balancing your scope. Also GPS and wi/fi, as I’ll be using Sky Safari via IPhone. But accept I’m an atypical buyer - not so concerned with eq performance

 

[Highburymark]

Well, it’s here. Found a counterweight and adm saddle which both fitted. Just time to power up and have a quick look at the Moon. Throws around the Epsilon and FC-100 beautifully. Have another 50 pages of the manual to absorb before I test go-to and tracking accuracy. 

[Ouroboros]

@Highburymark  Looks good.  
 

Does it feel stable enough on that sort of tripod?  Stable enough for DS imaging I mean. In photos I often think this mount looks a bit top heavy on a camera tripod.  I wonder whether a metal tripod of the SkyWatcher or iOptron variety might be more stable, albeit marginally less portable. 

[UKRoman]

I've just swapped out my RT90C tripod for an Avalon T-Pod 90. The RT90C was fine for my Tak FSQ-85, but I'm planning on moving that on for an FSQ-106 soon and was a little uncomfortable that the rig would be top heavy. The T-Pod 90 is a bit heavier but I can still pick the whole rig up quite easily to move it outside. It does feel a lot more stable now though.

 

[Ken82]

1 hour ago, UKRoman said:

I've just swapped out my RT90C tripod for an Avalon T-Pod 90. The RT90C was fine for my Tak FSQ-85, but I'm planning on moving that on for an FSQ-106 soon and was a little uncomfortable that the rig would be top heavy. The T-Pod 90 is a bit heavier but I can still pick the whole rig up quite easily to move it outside. It does feel a lot more stable now though.

 

That looks really nice, a similar setup to what I will be getting for my grab and go (just need to decide on the mount)

What do you average for guiding accuracy ? RMS total ? 
 

Ken 

[UKRoman]

The guiding has been nothing to write home about, so far, t.b.h. The ASIAIR Pro has been reporting around 1.3" RMS average. Although the images I've been getting seem to be fine, so I haven't worried about it too much. That said, the new multi-star guiding in PHD2 (also implemented in the beta firmware for ASIAIR Pro) is supposed to transform the RST-135's guiding capabilities and bring it well under 1". I have the ASIAIR beta firmware installed but it's been cloudy since I installed it, so I haven't been able to confirm it yet. I'll report back the next time I get chance to do some imaging.

Edited May 20, 2021 by UKRoman

[Highburymark]

10 hours ago, Ouroboros said:

@Highburymark  Looks good.  
 

Does it feel stable enough on that sort of tripod?  Stable enough for DS imaging I mean. In photos I often think this mount looks a bit top heavy on a camera tripod.  I wonder whether a metal tripod of the SkyWatcher or iOptron variety might be more stable, albeit marginally less portable. 

Feels fine on Gitzo (25kg payload) so far but it’s early days. Definitely feels safer with counterweight in alt az with carbon fibre tripod.

[Ken82]

3 hours ago, UKRoman said:

The guiding has been nothing to write home about, so far, t.b.h. The ASIAIR Pro has been reporting around 1.3" RMS average. Although the images I've been getting seem to be fine, so I haven't worried about it too much. That said, the new multi-star guiding in PHD2 (also implemented in the beta firmware for ASIAIR Pro) is supposed to transform the RST-135's guiding capabilities and bring it well under 1". I have the ASIAIR beta firmware installed but it's been cloudy since I installed it, so I haven't been able to confirm it yet. I'll report back the next time I get chance to do some imaging.

1.3” isn’t at all bad although not seeing limited. Let us know how you get on, I think 0.8” would be a very nice result if it was consistent. 

[Ken82]

28 minutes ago, Highburymark said:

Feels fine on Gitzo (25kg payload) so far but it’s early days. Definitely feels safer with counterweight in alt az with carbon fibre tripod.

👍

Which gitzo model is that please ? 

[Highburymark]

1 hour ago, Ken82 said:

👍

Which gitzo model is that please ? 

It’s a 4552 TS. Replaced by another model in Gitzo’s range now I believe. It’s my only tripod, so hoping it will prove robust enough for the new mount.

[Highburymark]

First couple of sessions with the 135 in alt az only. Tried go-to (solar) with the Rainbow hand controller and near 7kg solar scope, and it was bang on, and kept the Sun centred for 10 minutes before skies clouded over. Also good first time accuracy with Sky Safari via iPhone. This mount is a joy to use. 
Only one annoyance - my Lynx Astro 12DC mains cable doesn’t fix securely to the mount, and keeps cutting out. So on the hunt for a better mains solution, using the supplied 5.5x2.1mm jack - also need to buy a mobile power pack.

[Davey-T]

One thing that worried me Mark when imaging on dewy nights was the vulnerability of the connections on the top face of the mount, even more so in alt / az mode, the on off switch appears to have nothing to stop water running into it, a simple rubber hood is all that's needed so don't know why they don't fit one as you can buy toggle switches with them on, the ST4 socket likewise, I put the blanking plug out of a ZWO camera in mine again a simple thing they could do in the factory.

Dave

[Highburymark]

1 hour ago, Davey-T said:

One thing that worried me Mark when imaging on dewy nights was the vulnerability of the connections on the top face of the mount, even more so in alt / az mode, the on off switch appears to have nothing to stop water running into it, a simple rubber hood is all that's needed so don't know why they don't fit one as you can buy toggle switches with them on, the ST4 socket likewise, I put the blanking plug out of a ZWO camera in mine again a simple thing they could do in the factory.

Dave

Good point - will have to come up with a solution. The South Korean climate’s clearly a bit different to ours

[Ken82]

On 20/05/2021 at 20:02, Highburymark said:

It’s a 4552 TS. Replaced by another model in Gitzo’s range now I believe. It’s my only tripod, so hoping it will prove robust enough for the new mount.

Sounds fine with me

Was the tripod 3/8” standard ? How is it adapted for the rst mount ? 
 

Thanks 

[Highburymark]

20 minutes ago, Ken82 said:

Sounds fine with me

Was the tripod 3/8” standard ? How is it adapted for the rst mount ? 
 

Thanks 

Yes to 1st question. RST-135 has 3/8” adapter as standard, but I’ve ordered a specific Rainbow Gitzo plate which will provide a stronger connection