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New Hybrid iOptron HEM27 Harmonic/ Worm gear


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Posted (edited)
2 hours ago, Stu said:

Looks very interesting.  Presumably it will take two scopes side by side in Az mode? Way out of my price range but looks well designed.

That’s a good question, I do not know.

Rumoured price is around $3000.

This is close to RST-300 in load capacity, 20 kg, so why not two scopes?

Edited by Deadlake
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Interesting to see yet another harmonic drive enter the market.  Pity they seem to have kept with the azimuth hex bolts.  

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13 hours ago, Deadlake said:

This has no AltZ mode and no brake at all?

I'll wait for the Pegasus to come out, built with a Swiss harmonic gear.

https://pegasusastro.com/nyx-101-harmonic-gear-mount/

It does mention a brake, but I guess you might have to wait for a manual to be published to get any detail about alt-az mode.

Unique friction brake to safely stop movement during a planned or unplanned power interruption (from https://www.ioptron.com/product-p/h272a.htm)

 

 

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On 15/05/2022 at 20:33, Deadlake said:

This has no AltZ mode and no brake at all?

I'll wait for the Pegasus to come out, built with a Swiss harmonic gear.

https://pegasusastro.com/nyx-101-harmonic-gear-mount/

The design and likely QC of the Pegasus NYX appears to be pretty good for the price they are posting. Very competitive and looks much more coherent than the iOptractor. 

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Looks like there is a shift in the mount market from traditional worm gears to harmonic drives. Hopefully, the competition means we get high performing competitively priced options. 
 

I am quite surprised about the example Pegasus posted to promote mount performance though. Imaging at native 2800mm FL with a C11 edge and QHY268m with an image scale of 0.28”, they show a PHD2 graph with 1.32” RMS error 🤷🏻‍♂️ They also show an unguided 120s exposure purportedly showing round stars but the only conclusion you could draw from that based on the guiding performance is that they are bloated round stars. 
 

Pretty sure the mount can carry the load they claim but they’re hardly proving adequate imaging performance at that FL. 

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Posted (edited)
7 hours ago, Icesheet said:

They also show an unguided 120s exposure purportedly showing round stars but the only conclusion you could draw from that based on the guiding performance is that they are bloated round stars. 

I put a cropped and re-saved picture from the Pegasus web site through Astrometry.net and ended up with an image scale of 1.97 arc-s/px (note. I don't think that'll be the same as the original in view of the additional image manipulations, but the stars should scale proportionately). Looking at these two stars

1427221951_Pegtest2.thumb.jpg.7f34a2d5257ebbc784cdb30b00ff9f3c.jpg

I get approximate widths of 6 and 14 arc-s. So, if my logic is correct, that might support Icesheet's doubt. Please correct me if I am wrong. Mind you, given that is unguided, perhaps it's a pretty good result, bloated stars or not. I don't think other manufactures would recommend using their mounts unguided, let alone with a 2800mm fl scope! Incidentally, they are using a 2 second guide exposure, which implies a relatively slowly changing PE, not really what one would expect from strain-wave gearing.

I'm not trying to slate the Pegasus product here, or cast doubt on their credibility, just trying to get a handle on what performance might be, from the sparsely available information from manufacturers. In fact, neither the new  iOptron nor the Pegasus mount have any hard and fast real-use measurements of performance, and neither are quoting the PE. To be fair to ZWO, they at least have published the PE curves, so you know what one might expect, and there is now some real-use reports on the ZWO mount Facebook site. The Rainbow, of course, has been available for some while and there will be user reports.

Ian

Edited by The Admiral
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8 hours ago, Icesheet said:

Looks like there is a shift in the mount market from traditional worm gears to harmonic drives. Hopefully, the competition means we get high performing competitively priced options. 
 

I am quite surprised about the example Pegasus posted to promote mount performance though. Imaging at native 2800mm FL with a C11 edge and QHY268m with an image scale of 0.28”, they show a PHD2 graph with 1.32” RMS error 🤷🏻‍♂️ They also show an unguided 120s exposure purportedly showing round stars but the only conclusion you could draw from that based on the guiding performance is that they are bloated round stars. 
 

Pretty sure the mount can carry the load they claim but they’re hardly proving adequate imaging performance at that FL. 

More discussion here:

https://www.cloudynights.com/topic/818409-pegasus-astro-nyx-101-harmonic-mount/page-4#entry11901336

However the gist is that the results where due to poor seeing due to African dust flying into Europe. 

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If the Pegasus can run at 2s guide exposures then I can only assume they have somehow reduced the axial flutter that other strain wave designs suffer from. Has there been any clarification how they have done this? Bearing design and location perhaps? 

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1 hour ago, 900SL said:

If the Pegasus can run at 2s guide exposures then I can only assume they have somehow reduced the axial flutter that other strain wave designs suffer from. Has there been any clarification how they have done this? Bearing design and location perhaps? 

It does, which would be surprising given the nature of these gears, but I think for all these new mounts we need a lot more data based on real user experience to make a decent appraisal. 

Ian

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  • 4 weeks later...
5 hours ago, knobby said:

I can't wait to see some of these being used ! I'm resizing to lighter kit due to the old back getting creaky ...

Exactly what I'm doing. I've pre-ordered the ZWO but I can't afford to wait for all the user reviews to come out, I'll end up being too old! 😀. And with all these new players in the game it'd never end! I know I'm taking a bit of a gamble but on the other hand it should play nicely with the ASIAir. The Rainbow is just too expensive.

Ian

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On 15/05/2022 at 21:44, Deadlake said:

That’s a good question, I do not know.

Rumoured price is around $3000.

This is close to RST-300 in load capacity, 20 kg, so why not two scopes?

 

Price on two well known UK sites is now £2450 which seems very reasonable

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Cheers Steve, that's what I was saying in my dodgy Essex boy English ...

The HEM27 is in stock at FLO but not in stock without the Ipolar 🙂

Edited by knobby
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Really not your fault Steve ... Even my wife struggles to understand me sometimes 🤣

Can't wait to see some real user feedback on the mount though .

Apparently Ioptron have found a way to have PEC ?

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1 hour ago, knobby said:

Thanks Icesheet !

Very promising looking guided performance ...

HEM27EC_Guiding.jpg

Shame that's the EC version though 😞

I'm waiting for some more stats on the base model.

I would hope the performance of the base model is not too far off this at the focal length they’re showing anyway. I think the encoders are more for unguided or guiding at long FL.

 

Never sure how much to trust these marketing graphs but even if it’s 0.6-0.8" range I’d be happy

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