115 replies to this topic

[lwbehney]

I have noticed that several companies have joined into competition with the Rainbow Astro mounts:  HOBYM, ZWO, Ioptron, Artesky, and Pegasus Astro and have I left anyone out?

I spoke to ONE vendor, who told me that they had sold 3500 of the Rainbow Astro mounts. That to my mind was well, astronomical! Apparently, nearly every customer was pleased with them also. 

If you look on the forums, you will find threads with hundreds of responses regarding this class of mount. 

If you look at the history of amateur astronomy equipment, the thing that stands out is the never-ending effort to get the most out of the smallest weight and volume. My examples:  the long focus Newtonian is placed into a Dobsonian mount to make it more portable and the focal ratios of the mirrors are reduced, and this is so popular, that accessories like the Paracorr are manufactured. Then the SCT competes to provide aperture in an even smaller format. In the midst of this comes the apochromatic refractor, not just because it has better control of chromatic aberration, but mostly so you can avoid having to have an f/15 focal ratio to gain that control. Another example is Ioptron with their Center-balanced-equatorial mount and greater payload to mount weight ratios and Losmandy with their modular GM811G mounts. 

Now Rainbow Astro has caused another move in that same direction and many companies are following suit. 

If you take the NYX-101, for example, the 6.4 Kg mount can carry a 20 Kg payload without counterweights. No counterweights means lighter weight tripods can be used. This means that trips to darker skies with our favorite telescopes just got twice as feasible. 

The amateur astronomy community I know are mostly older men, who do not want to lift anything heavier than 30 lbs. 

For those who live in ideal skies and have observatories, there is no need to move to this type of mount. For everyone else, I think this is where we are all headed.

The new harmonic drives will take the "strain" out of the practice of amateur astronomy. 

 

I enjoy watching history unfold in the present.

 

-Larry

 

[petert913]

I still don't see how you can have so much weight on one side of a mount with no counterweight.    It's Voodoo !

[steveward53]

I still don't see how you can have so much weight on one side of a mount with no counterweight.    It's Voodoo !

I've just watched a video on a Rainbow mount , looks very clever right up until the guy slews it and the weight is between two legs when it becomes very unstable in my opinion and would easily topple over if knocked .

 

The tripod has very far spread legs in an effort to counter this but also looks vunerable to these eyes as there's nothing taking the strain to prevent it 'doing the splits' so's to speak.

 

Looks a bit of an 'emperors new clothes' situation to me unless you're only mounting tiny 'scopes on it , I wouldn't dream of loading it to capacity.

 

Maybe its a case of ''we've made it because we can'' , a trait that has filled the planet with needless things over the last few years .

[lwbehney]

You make an excellent point. If the tripod were resting on ground, you could use a dog leash screw to secure the tripod legs, which would grip much better than a tent stake. If the tripod is resting on concrete or asphalt or a tarp, then it would be necessary to either have counterweights on the legs of the tripod or a tripod with a very broad base. 

Might be a good idea to buy the counterweight option regardless, just for protection from tipping over.

[psandelle]

I've just watched a video on a Rainbow mount , looks very clever right up until the guy slews it and the weight is between two legs when it becomes very unstable in my opinion and would easily topple over if knocked .

 

The tripod has very far spread legs in an effort to counter this but also looks vunerable to these eyes as there's nothing taking the strain to prevent it 'doing the splits' so's to speak.

 

Looks a bit of an 'emperors new clothes' situation to me unless you're only mounting tiny 'scopes on it , I wouldn't dream of loading it to capacity.

 

Maybe its a case of ''we've made it because we can'' , a trait that has filled the planet with needless things over the last few years .

In my four years of using Rainbows (off-and-on), I've never had the thing tip over. Just sayin'.

 

Paul

[azcubs76]

I totally agree that these strain wave mounts have the potential to overtake the mount industry. They have some obvious issues like the large PE requiring very fast guiding intervals but it looks like the ones with built in encoders can tame that quite a bit. I'll wait for the version 1 bugs to be worked out but these seem like great visual, EAA and short focal length mounts. If you can get similar performance and price at half the weight, what's not to like?

[Linwood]

It would appear that all of these sacrifice tracking error for weight at present, with really large (and not periodic) tracking error. That makes them best for portability and shorter focal lengths and (possibly aggressive) guiding, and less good for unguided imaging and long focal lengths.

 

I think there are three sorts buying them now: 

 

- Those who love to be on the bleeding edge (including some who live there to do videos, which is their real hobby) 

 

- Those who want serious portability

 

- A few who buy into some of the hype and marketing images and really expect a C11 at 2800mm to work well with tracking error of 50". 

 

The latter drop out fast.   

 

The middle group though is a LARGE if nascent audience.  The Unistellar audience is a harbinger of that, people who like to set up in 10 minutes, push a button and like magic are getting images quickly, then can break it down into a backpack in another 10 minutes.  These strainwave mounts are an upgrade to this, portable but with more expandability and flexibility if less automation.

 

My guess is there are a lot of people who may move into this hobby if they can get a reasonably good OTA and mount in a backpack and hike to their favorite dark spot. 

 

I consider my setup portable (an AP1100 and C11), but we are talking carrying 100 pounds or so of counterweights and shaft, 25 pounds of heavy tripod (yet light for the size), 55 pounds of mount, and then all the pieces, parts, OTA, etc.  "Portable" means "Fits in a BIG SUV" for me.  For those where "Potable" means "fits in a backpack leaving room for food and sleeping bag"... well, classic mounts will struggle. 

 

And bear in mind -- current limitations are serious, but absolute encoders can work wonders. They will add a LOT of cost (and are hard to get right now), but the (relatively huge) error inherent in them can be mitigated.  Maybe.

[KJL]

For a visual-only observer, I would love an alt-az version that is even lighter-weight than the RST-135 and contains a LiFePO4 battery to boot.

 

Something like the iOptron AZ Mount Pro but only 5-10 lbs all-in.

 

There's still room for such a mount, I feel.

[psandelle]

For a visual-only observer, I would love an alt-az version that is even lighter-weight than the RST-135 and contains a LiFePO4 battery to boot.

 

Something like the iOptron AZ Mount Pro but only 5-10 lbs all-in.

 

There's still room for such a mount, I feel.

Gotta tell ya, the RST-135 set to Alt/Az with a 9ah LiFePO4 battery and some APM 100mm 90 degree binocs is a SWEEEET and light setup. I'm NOT a fan of built-in batteries.

 

Paul

[rgsalinger]

Given what the Rainbows are currently able to do, my bet is that these become the goto (haha) mid-priced mounts for most portable imagers using short focal length, modest weight systems. Period. There's nothting bleeding edge about the technology at all. What's bleeding edge is whether or not ZWO (for example) can build mounts. So, if I was going to buy one, and I'm really tempted to do so, I'd go with the iOptron offering or one from another experienced mount making company as a hedge. IMHO and YMMV.

 

Rgrds-Ross

[Linwood]

Given what the Rainbows are currently able to do, my bet is that these become the goto (haha) mid-priced mounts for most portable imagers using short focal length, modest weight systems. Period. There's nothting bleeding edge about the technology at all. What's bleeding edge is whether or not ZWO (for example) can build mounts. So, if I was going to buy one, and I'm really tempted to do so, I'd go with the iOptron offering or one from another experienced mount making company as a hedge. IMHO and YMMV.

 

Rgrds-Ross

I would agree with that viewpoint in bleeding edge, though I might include Pegasus in there, I do not think they will release garbage, though whether they can ramp up to the volume is a question.

 

But I think the other bleeding edge aspect is trying to get a handle on the error in these. Wide field, short exposures is one thing, but getting that under control is going to take (I think) encoders.  From what I understand (certainly have not tried it) the error is not periodic, at least not short term periodic, so it is not easily removed with simply a PEC curve being built and loaded.  That's why I think the future of these for longer focal lengths will have encoders (and I think some do, though it is not clear they are adequate resolution to really fix the problem). 

 

Which sort of defeats the idea of being mid-priced (depending on your definition of "mid"). 

 

I just wish they wouldn't show them with C11's on them, it's misleading. 

[calypsob]

I would agree with that viewpoint in bleeding edge, though I might include Pegasus in there, I do not think they will release garbage, though whether they can ramp up to the volume is a question.

But I think the other bleeding edge aspect is trying to get a handle on the error in these. Wide field, short exposures is one thing, but getting that under control is going to take (I think) encoders. From what I understand (certainly have not tried it) the error is not periodic, at least not short term periodic, so it is not easily removed with simply a PEC curve being built and loaded. That's why I think the future of these for longer focal lengths will have encoders (and I think some do, though it is not clear they are adequate resolution to really fix the problem).

Which sort of defeats the idea of being mid-priced (depending on your definition of "mid").

I just wish they wouldn't show them with C11's on them, it's misleading.

The problem in harmonic drives is how often you need to correct. If you use an oag that requires 4-5s exposures and you are sampling at or above 1:1 a worm driven eq mount will do fine where a harmonic drive relies on rapid corrections. Even encoders do not help much there. 20 minute Ha subs through an oag on a c14 at full focal length are difficult enough on a normal mount, I am not sure it would work on harmonic drive.

Imo a strainwave is a good mount if you need more than 1 mount and have more than one scope. I plan to buy one to use with every scope but my newtonian. Which essentially means when I do finally get emailed about an ap1100 it will primarily be used for the 12” newt. I guess that will be incentive to buy more long fl ota’s. But for day to day use I will probably go with an am5 once we see how people are getting them to perform. If zwo can step up its customer service I see no reason why the am5 wont be a solid option. The testers have been getting great results even on a c9.25 platform.

[rgsalinger]

Well, for visual use, the stated weight capacity might actually be reasonable, but no one is going to use one of these puppies with a C11 doing long exposure AP. Maybe planetary though. 

 

From what I've read, you simply need a rapid guiding cadence to control the non-periodic error. To me that plays back into the short focal length idea as there are tons of stars in my OAG's when using either of my two shortish refractors that are of sufficient brightness to give me an excellent SNR. With a guide scope it's going to be really moot. 

 

My bet is, though, that encoder versions will quickly follow at higher price points. The premium on the iOptron mounts is maybe 1500 USD (?), so that would put these in the 4K range. All fun speculation until I get to see one of them in the wild. 

 

Rgrds-Ross

[psandelle]

Although I doubt they'll do it, if 10Micron put a couple of absolute encoders on something like this, I'd pay true premium price for that (as I LOVE me some 10Microns, and making them small, whooeeee!).

 

Paul

[rgsalinger]

The iOptron Hybrid model now comes (now means sometime soon I guess) with encoders for 3200 tripod is I think 300.. So, if you can accept a mount that has only the RA axis using a harmonic drive and can balance your OTA in DEC you've got a very nice under 4K highly portable system. 

Rgrds-Ross

[Swanny]

As a visual person strictly, this mount (or Rainbow, ZWO) on a Gitzo carbon tripod makes for a great system to not have to break the back over setting up.  And I am just using a 130mm F7 so this and all other harmonics should have no issue with handling such a scope I would think.

[Poochpa]

Harmonic drive mounts, such as the Hobym Crux and Rainbow Astro RST-135 have been around for 4 years, so hardly bleeding edge. I'm in my mid-60s with a bad back. Three years ago, I sold my beloved Tak EM-200 Temma2 that I had for a decade and bought the Rainbow Astro RST-135. The Tak mount was 33 lbs., 50 lbs. in its case. The RST-135 is 7 lbs.  It's been an AP hobby-saver for me and my back, especially when coupled with a lightweight tripod such as the Innorel RT90C and small refractors. The advent of multi-star guiding effectively mitigates the large PE inherent in harmonic drive mounts.

Mike

[joshman]

As someone that currently has to setup and pack up everytime I want to image, "Portability" is high on my priority list, but more importantly, it has to be a setup that is quick to set up and take down, I generally work long-ish hours and need my setup to be something that is quick and easy to setup. I've got it to a point that I can grab-and go my setup - i can walk in my door from work or whatever and be completely setup and taking images within 20 minutes.

[andysea]

There is one issue that is giving me pause. These mounts have no clutches. In case of a pier collision, the drive is so strong that it could potentially cause a lot of damage to the OTA, Camera or whichever part collides with the pier. 

I am surprised that no manufacturers have come up with a safeguard to prevent this from happening. With my normal mounts, the clutches can mitigate possible damage.

[Patrick]

 

I enjoy watching history unfold in the present.

 

-Larry

It will be interesting to see what happens.  I imagine that we will be seeing a lot of images of large DSO's taken with these mounts and small refractors.  And then there will be images of smaller DSO's taken with longer f/l instruments, but not as many. 

 

Personally, I want to have the option of moving my scope manually when I want to, and actually look through the optics.     I definitely think it's a generational thing.  

 

Patrick

[lwbehney]

Sky&Telescope had an article this year about live stacking and reduction of read noise to the point that very short exposures of a few seconds will become commonplace. The technology may improve to the point that an Alt/Az mount would be totally sufficient for AP.

I actually chose to order the NYX-101 just for its light weight and compact size, lack of need for counterweights, which makes it very portable and it has a matching small light weight carbon fiber tripod.  It can be top-loaded in Alt/Az mode, which makes attachment of a heavy refractor much easier and safer. 

[dciobota]

There is one issue that is giving me pause. These mounts have no clutches. In case of a pier collision, the drive is so strong that it could potentially cause a lot of damage to the OTA, Camera or whichever part collides with the pier.
I am surprised that no manufacturers have come up with a safeguard to prevent this from happening. With my normal mounts, the clutches can mitigate possible damage.

I hear you Andy. I posted in another thread what happened to mine the very first time I used the am5. Luckily it was a bracket that hit the wedge base, making a nice gouge in it before the cog belt slipped. The mount is supposed to have "collision detection" but my guess is it's just a simple current limiter, and since it's set to allow large unbalanced payloads, the mount can pack a large amount of force before it stops.

The rst135 I believe has slew limits which imo help immensely. The only downside to the rst135 is it has no brake, so you can still experience backdrive after a power loss.
I don't know what the hem27 has. Nor do I know much about the pegasus. But I hope they can do better.

Actually I keep hoping for an am5 firmware update to allow slew limits and maybe also allowing changing the "collision detection" force limits. Luckily all this should be possible in firmware.

[andysea]

I hear you Andy. I posted in another thread what happened to mine the very first time I used the am5. Luckily it was a bracket that hit the wedge base, making a nice gouge in it before the cog belt slipped. The mount is supposed to have "collision detection" but my guess is it's just a simple current limiter, and since it's set to allow large unbalanced payloads, the mount can pack a large amount of force before it stops.

The rst135 I believe has slew limits which imo help immensely. The only downside to the rst135 is it has no brake, so you can still experience backdrive after a power loss.
I don't know what the hem27 has. Nor do I know much about the pegasus. But I hope they can do better.

Actually I keep hoping for an am5 firmware update to allow slew limits and maybe also allowing changing the "collision detection" force limits. Luckily all this should be possible in firmware.

Daniel, 

I did not read your post but what you describe is exactly my fear with these mounts. An OTA with a full frame camera and filters can easily be well over $10k in value. I would not want to risk that.

[lwbehney]

I remember reading that the Pegasus Astro NYX has slew limits built into the controls to prevent collisions with tripods. Word out is it may be two more weeks before this mount starts being delivered. 

[dciobota]

I think you're right. So does the ioptron and rst135. Zwo is supposedly beta testing new firmware for the am5, which I hope will include slew limits. I haven't heard any details tbh. Makes no sense not to put it in there, costs them nothing but some software development.