Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

New ZWO AM5 Harmonic Drive Mount

  • Please log in to reply
1280 replies to this topic

#526 andysea

andysea

    Fly Me to the Moon

  • *****
  • Posts: 5,589
  • Joined: 03 Sep 2010
  • Loc: Seattle, WA

Posted 15 June 2022 - 11:25 PM

I watched a very thought provoking YouTube video on guiding - or maybe better described as: why we should abandon the thought of having to guide.  Worth a watch as we begin to think about this mount.  A bit long, but worth a watch.  Here’s the link:  https://youtu.be/p4bpFJSdHDY  

What Richard is saying makes sense with a few caveats as he describes. I think it would applicable to the AM5 and most other mounts.



#527 dciobota

dciobota

    Vanguard

  • *****
  • Posts: 2,445
  • Joined: 07 Aug 2007
  • Loc: Sitting in a corner in southeast Arizona

Posted 16 June 2022 - 07:53 AM

Yeah, fair point. I wonder too if these initial units have gears that have been cherry picked, or if they managed tighter tolerances. Time will tell. What is encouraging is that each mount comes with a measured PE graph so at least you'll know right away if you have a dud and maybe return it. I can definitely see some folks cherry picking these mounts based on their graphs.

#528 Glass17

Glass17

    Vostok 1

  • -----
  • Posts: 138
  • Joined: 02 Feb 2022

Posted 17 June 2022 - 11:02 AM

Arny Feldman (AM5 Facebook users group) did 30 seconds unguided on Zenithstar 360mm and for me it looks very bad. Ind I would say it is what I expected. From beginning I am planning to use 80mm guidescop with 0.5 second intervals.

#529 psandelle

psandelle

    Skylab

  • *****
  • Posts: 4,265
  • Joined: 18 Jun 2008
  • Loc: Los Angeles

Posted 17 June 2022 - 11:09 AM

Arny Feldman (AM5 Facebook users group) did 30 seconds unguided on Zenithstar 360mm and for me it looks very bad. Ind I would say it is what I expected. From beginning I am planning to use 80mm guidescop with 0.5 second intervals.

If this is anything like the Rainbows I've used, I NEVER want to try any unguided. There's a reason it guides well at 0.5 seconds.

 

Paul



#530 Mike Sandy

Mike Sandy

    Apollo

  • *****
  • Posts: 1,343
  • Joined: 29 Aug 2003
  • Loc: SF Bay Area, CA

Posted 17 June 2022 - 11:54 AM

I didn't want to imply that the AM5 was a great candidate for this, but having just watched that video and returning to this thread with all the concern about guiding, it just struck me.  We have all kinda accepted that guiding is just something you do - it is how you image.  We may not be there yet - but the technology exists today to break that paradigm in some applications.  If the demand is there, the software will improve more quickly.  Live stacking isn't as good today as stacking during post processing -  but it could use more of the available GPU capability to analyze and select the best sub-exposures, do some of the initial processing, and stack them in real-time (well maybe).  I can only imagine the possibilities- but that is for some future state, I guess.  But we are - way off topic again. 

 

On topic:  The highlight and low light of my day is checking my email each morning.  I look with great expectation to find the ZWO email saying my AM5 mount is on the way - and then comes the disappointment when it isn't there.  Yes - what a shallow and materialistic life I lead bawling.gif   Of well - like the monkey said as he backed into the fan - it won't be long now!  


  • Markovich and psandelle like this

#531 dciobota

dciobota

    Vanguard

  • *****
  • Posts: 2,445
  • Joined: 07 Aug 2007
  • Loc: Sitting in a corner in southeast Arizona

Posted 17 June 2022 - 01:26 PM

I feel your pain. Mine won't likely be in the late June batch, and hopefully will be in the next batch which might be mid July. This means it won't be delivered to me until August. So I gave up checking my emails on that.

But to talk about unguided in the context of the am5 and similar mounts. It's doable, provided they're equiped with encoders. The encoder version of the rst135 shows pretty low or actually. Encoders are still expensive, but if they eventually scale up in production, I can see them coming down to maybe a couple hundred bucks. Then it would be worth incorporating them into these lower prices mounts. I think ioptron is doing that already.

If encoders can lower pe to a couple arcsec peak to peak then unguided is definitely doable at the shorter focal lengths.

But I'll be honest. I'm a sloppy polar aligner. If I spend more than a couple minutes with the asiair nailing down pa then I get impatient. A couple arcmin error is good enough for me. Guiding hides a multitude of sins, which is why it's so useful. And it's dead easy once you're dialed in. Even with cantankerous mounts like the azgti. I think the entire guide kit cost me maybe $250.

Edited by dciobota, 17 June 2022 - 01:28 PM.

  • Mike Sandy and psandelle like this

#532 Mike Sandy

Mike Sandy

    Apollo

  • *****
  • Posts: 1,343
  • Joined: 29 Aug 2003
  • Loc: SF Bay Area, CA

Posted 17 June 2022 - 03:03 PM

Polar alignment is certainly a contributor to your tracking error, along with atmospheric refraction, differential deflection, and all the errors in the drive system (and I'm sure there are others contributors that I'm not thinking of right now).  Encoders need to be absolution encoders to really do the job (maybe you could argue that point) and they are expensive with accuracy that we need.  But encoders can only correct for the errors in the drive system.  So we guide by tracking a star that is dancing about, sending questionable correction signals to the mount hoping that the sum of most of these corrections will make things better - it is a imprecise method to achieve precise movement.  Yes it works, and the more accurate the mount is (fewer variables) the better it works - but is there a better way? 


  • psandelle likes this

#533 Mike Sandy

Mike Sandy

    Apollo

  • *****
  • Posts: 1,343
  • Joined: 29 Aug 2003
  • Loc: SF Bay Area, CA

Posted 17 June 2022 - 03:10 PM

Mike, I think Simon (or maybe TJ) did some unguided exposures at shorter focal lengths (maybe an fra400?) and they looked pretty good.  But, I don't know at what part of the gear cycle those were taken, so I'm not sure the percentage of keepers at that point.

I intrigued enough to try to find out what the unguided limits are.  Of course  imaging at 1.62"/pixel in a area where seeing is rarely very good may not be much of a test. 



#534 licho52

licho52

    Messenger

  • -----
  • Posts: 414
  • Joined: 15 Dec 2020

Posted 17 June 2022 - 06:46 PM

This mount is a bad a candidate for guideless astrophoto as you can actually find.

 

That said I find the whole concept ridiculous, guiding is such a simple thing while trying to get rid of it is, at this point, an example of cure being worse than the disease.


  • Joe Bergeron likes this

#535 Mike Sandy

Mike Sandy

    Apollo

  • *****
  • Posts: 1,343
  • Joined: 29 Aug 2003
  • Loc: SF Bay Area, CA

Posted 17 June 2022 - 07:24 PM

That said I find the whole concept ridiculous, guiding is such a simple thing while trying to get rid of it is, at this point, an example of cure being worse than the disease.

I guess I agree then.  Guiding is the answer, there no merit in looking at any other options.  So sorry I brought it up - carry on.



#536 alphatripleplus

alphatripleplus

    World Controller

  • *****
  • Moderators
  • Posts: 130,681
  • Joined: 09 Mar 2012
  • Loc: Georgia

Posted 18 June 2022 - 05:56 AM

Moderator Note:

 

Everyone please remember to stay on topic. A number of off topic posts have been removed. Thanks for your future co-operation.



#537 calypsob

calypsob

    Cosmos

  • *****
  • Posts: 7,607
  • Joined: 20 Apr 2013
  • Loc: Virginia

Posted 18 June 2022 - 02:08 PM

Now that the lockdown is easing up, these are going to flood out of production.

#538 Zambiadarkskies

Zambiadarkskies

    Vostok 1

  • -----
  • Posts: 158
  • Joined: 17 Nov 2021

Posted 21 June 2022 - 08:22 AM

As far as I can see this is pretty much the first independent review. I haven't even watched it yet, just wanted to get the link out. I find his videos excellent and am looking forward to watching this:
https://youtu.be/EOpemZB64EA

#539 Northernguy

Northernguy

    Mariner 2

  • -----
  • Posts: 225
  • Joined: 11 Nov 2021
  • Loc: Southeast MN, USA

Posted 21 June 2022 - 08:36 AM

As far as I can see this is pretty much the first independent review. I haven't even watched it yet, just wanted to get the link out. I find his videos excellent and am looking forward to watching this:
https://youtu.be/EOpemZB64EA

I watched it this morning, and am worried now that it won't be the best choice for what I like to do. maybe I should cancel my order until it's more clear. However, I don't really understand the problem with why only one PC program can access the mount control through ASCOM at a time. This is an issue for me, as I like to use NINA for imaging and PHD2 for guiding. Even if only one program can communicate with the mount, why couldn't we simply use ASCOM device manager as a server of sorts, and then just have other programs connect to the ASCOM manager as a go-between? That seems to work with the EXOS2 mount, which is a serial communications device.

I guess the other issue is that if I like to image at higher focal lengths and not bother with guiding (for short subs and EAA, as I do) then he says this is not the mount for me because of the high error rate. Too bad, as I really like the idea of no counterweights to mess with



#540 licho52

licho52

    Messenger

  • -----
  • Posts: 414
  • Joined: 15 Dec 2020

Posted 21 June 2022 - 09:22 AM

That review is a bit of a reality check, I must say.  The excursions make guiding numbers better than they really are.  Stars are trailing @250mm FL Redcat, that's completely unacceptable.



#541 arbit

arbit

    Viking 1

  • -----
  • Posts: 554
  • Joined: 19 Feb 2012

Posted 21 June 2022 - 09:32 AM

As far as I can see this is pretty much the first independent review. I haven't even watched it yet, just wanted to get the link out. I find his videos excellent and am looking forward to watching this:
https://youtu.be/EOpemZB64EA

Theres one on the facebook page after 2 weeks of usage. The user there is quite happy. C9.25 all night guiding at 0.4-0.5 in good conditions, 0.8 with wind of 15-20 kph.

 

He also describes the workaround to 1 app at a time issue by using the ASCOM hub.


Edited by arbit, 21 June 2022 - 09:40 AM.


#542 Glass17

Glass17

    Vostok 1

  • -----
  • Posts: 138
  • Joined: 02 Feb 2022

Posted 21 June 2022 - 09:48 AM


The first honest review, and exactly match my expectation.

It is not vision issue. Random atmospheric turbulence wouldn't make  starts prolonged, but rather smooth the stars shape, make them bigger.

Worst of all ZWO was very (let say) inaccurate with their method of calculation max drift per second by dividing PE to period in seconds.

Knowing the nature of the issue ZWO from beginning mentioned they are not recommending FL more than 900mm.

 

 

On my current EQ5 I moved to 80mm guide-scope and .5 seconds intervals as soon as pre-ordered AM5 (to prove it works for me).

I never doubts VERY short guiding intervals MUST be for AM5.



#543 arbit

arbit

    Viking 1

  • -----
  • Posts: 554
  • Joined: 19 Feb 2012

Posted 21 June 2022 - 09:56 AM

Heres a text review  https://www.facebook...__tn__=,O,P-y-R

 

Guiding seems better - he did say it took some time to figure out the best settings. Plus he used a CW with the C9.25 which may have helped.

 

The ASCOM driver issue is just embarassing, imo.


  • licho52 likes this

#544 Glass17

Glass17

    Vostok 1

  • -----
  • Posts: 138
  • Joined: 02 Feb 2022

Posted 21 June 2022 - 10:12 AM

Heres a text review  https://www.facebook...__tn__=,O,P-y-R

 

Guiding seems better - he did say it took some time to figure out the best settings. Plus he used a CW with the C9.25 which may have helped.

 

The ASCOM driver issue is just embarassing, imo.

I saw reports about average 0.49-0.62 ArcSec, But in most cases it was big spikes on graphs time to time.

Zwo counted max 0.074 Arcsec in their example, and they trying to say other result is imperfection of our setups, visual conditions, winds, name it, but not mount issue...

Difference in shape of starts with 1.5 second guiding intervals and 1.0 seconds guiding intervals (300mm FL) clearly prove the issue is the nature of harmonic drives.
This what we have to discuss, how low interval we have to go for different focal lengths.

 


 



#545 Glass17

Glass17

    Vostok 1

  • -----
  • Posts: 138
  • Joined: 02 Feb 2022

Posted 21 June 2022 - 10:15 AM

I saw reports about average 0.49-0.62 ArcSec, But in most cases it was big spikes on graphs time to time.

Zwo counted max 0.074 Arcsec in their example, and they trying to say other result is imperfection of our setups, visual conditions, winds, name it, but not mount issue...

Difference in shape of starts with 1.5 second guiding intervals and 1.0 seconds guiding intervals (300mm FL) clearly prove the issue is the nature of harmonic drives.
This what we have to discuss, how low interval we have to go for different focal lengths.

 

PS We need to understand thru max drift per second.
I think PHD2 can provide logs with per interval report of distance from initial position. Probably we can extract max drift for period from this logs?

 

 



#546 HxPI

HxPI

    Vanguard

  • -----
  • Posts: 2,071
  • Joined: 05 Sep 2013
  • Loc: Virginia Beach, VA

Posted 21 June 2022 - 10:22 AM

I canceled my order. It’s a nice mount but it did not meet my needs for visual use and it’s too expensive for just using with Redcat51. It definitely doesn’t adequately replace my CEM60. Plus requiring the hand controller for Wi-Fi is annoying. Waiting for the Pegasus NYX-01.


Edited by HxPI, 21 June 2022 - 10:25 AM.

  • TomTom2509 likes this

#547 licho52

licho52

    Messenger

  • -----
  • Posts: 414
  • Joined: 15 Dec 2020

Posted 21 June 2022 - 07:59 PM

I am also close to giving this a pass, 0.8" as best guiding result, 1" average with a Redcat 250 and eggy stars.  I kinda felt this was coming when first non-sponsored reviews appeared.  But actually it's worse than I expected with ridiculous ASCOM limitation that passed all tests since every tester was (perhaps was required to be?) using AsiAir (which I own and I think it's great but for my traveler setup, not the main scope).



#548 arbit

arbit

    Viking 1

  • -----
  • Posts: 554
  • Joined: 19 Feb 2012

Posted 21 June 2022 - 09:35 PM

The ASCOM issue is disappointing. Yes, there is a workaround by connecting NINA and PHD through the ASCOM hub instead of directly, but it shouldn't be needed in the first place.

 

On the guided performance though, its probably too early to write it off. As far as I can see, there are 3 non-ZWO data points - Roro, Stars and Stuff (referred to in Roro), and the FB user (the most detailed and longest usage).

 

Roro: 1 night usage, 1-1.3 sec, bad stars with Redcat 51. S&S: longer usage, 0.6-0.7 as, good stars with C9.25, FB user - 2 weeks usage, 0.4-0.5 as, 0.8 with wind, good stars with C9.25. It could be optimization, effect of tripods / counterweights, equipment lottery, or something else. Too early to conclude anything imo.

 

Edit: Make it 2 reviews. Just saw the starsnstuff and the FB user are the same smile.gif


Edited by arbit, 21 June 2022 - 09:47 PM.


#549 BlakPhoenix

BlakPhoenix

    Sputnik

  • -----
  • Posts: 49
  • Joined: 28 Jan 2019

Posted 21 June 2022 - 10:24 PM

Hi all, thought I'd jump in here as I am the YouTube reviewer Astro With RoRo. I also personally know the FB text reviewer and we have talked quite a bit about the mount and our feelings on it before posting to make sure that my views was not too distant from his own experience.

 

As I called out in the video, the guiding numbers I got and mention are higher than you would see if you were in a field / open space. I had only 2 days with the mount, and limited time under the skies during this 2 days so was stuck to imaging from my apartment balcony. The seeing is poor compared to skies you can get away from the city & I have buildings near me that can cause interesting seeing/wind movements which amplify guiding numbers somewhat. In general Prasun and I agree that the mount will perform solidly so long as you are able to guide it at sub 1.5s intervals as I mention in the conclusion. If you are not able to do this, then yes this mount is probably not for you. The mount can definitely hold a good payload (as you can see through Prasun's setup) and with fast guide exposures you can get some nice looking stars (note he uses a 174 for guiding and he did not think a 120 or 290 could OAG fast enough). I was disappointed to see the star trails in my wide focal length images, but I think Prasun's image shows that with time, tweaking of settings, the right environment, etc, you can absolutely obtain very good images from the AM5.

 

I don't want to take away from what ZWO has created here, it's a great piece of hardware that competes well with many other harmonic mounts. I do think they were being greedy to think that not releasing proper integration with non-ASIAIR hardware wouldn't come back to bite them. With time this should be resolved though and after that this mount, just like many others will serve many users well over the coming years.

 

Happy to answer any other questions I can.


  • sctchun, StarDust1, charles.tremblay.darveau and 1 other like this

#550 arbit

arbit

    Viking 1

  • -----
  • Posts: 554
  • Joined: 19 Feb 2012

Posted 21 June 2022 - 10:54 PM

Hi all, thought I'd jump in here as I am the YouTube reviewer Astro With RoRo. I also personally know the FB text reviewer and we have talked quite a bit about the mount and our feelings on it before posting to make sure that my views was not too distant from his own experience.

 

As I called out in the video, the guiding numbers I got and mention are higher than you would see if you were in a field / open space. I had only 2 days with the mount, and limited time under the skies during this 2 days so was stuck to imaging from my apartment balcony. The seeing is poor compared to skies you can get away from the city & I have buildings near me that can cause interesting seeing/wind movements which amplify guiding numbers somewhat. In general Prasun and I agree that the mount will perform solidly so long as you are able to guide it at sub 1.5s intervals as I mention in the conclusion. If you are not able to do this, then yes this mount is probably not for you. The mount can definitely hold a good payload (as you can see through Prasun's setup) and with fast guide exposures you can get some nice looking stars (note he uses a 174 for guiding and he did not think a 120 or 290 could OAG fast enough). I was disappointed to see the star trails in my wide focal length images, but I think Prasun's image shows that with time, tweaking of settings, the right environment, etc, you can absolutely obtain very good images from the AM5.

 

I don't want to take away from what ZWO has created here, it's a great piece of hardware that competes well with many other harmonic mounts. I do think they were being greedy to think that not releasing proper integration with non-ASIAIR hardware wouldn't come back to bite them. With time this should be resolved though and after that this mount, just like many others will serve many users well over the coming years.

 

Happy to answer any other questions I can.

Thanks for that.

 

My first mount was the SmartEqPro+, with a PE of +-30as, or 60as p2p, i.e., way more than the AM5. PHD didn't do well even with a Redcat 51, resulting in eggy stars, but Metaguide absolutely did. I got roundness of 0.9 or so with 5 min exposures.

 

Just a thought - maybe high frequency guiding for this mount would do better with a different guiding approach like Metaguide?




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics