Harmonic Mounts Vs Seeing in the UK (Any harmonic mount users in the uk able to give feedback)

[Northernlight]

Hi All,

I just ordered a Ioptron HAE69C mount but i'm starting to second guess myself.  I'm going to be using it pier mounted in an obs, but the thing that keeps bothering me is the 0.5-1.0s guiding. In the uk the seeing isn't the best, so I wondered if there are any harmonic mount owners in the UK that could give feedback.

I'm just worried that the poor seeing will result in terrible guiding or if it will be fine using multistar guiding.

So if there are Harmonic mount users from the UK, would really appreciate your feedback, especially on harmonics without encoders.

 

Many Thanks,

Rich.

[geeklee]

16 minutes ago, Northernlight said:

HAE69C

16 minutes ago, Northernlight said:

especially on harmonics without encoders.

Hi Rich - will you be guiding at all with a mount using encoders?

FWIW, my ZWO AM5 (no encoders) currently guides fine and usually always below 1" (except when pointing at low altitude).  That's on the carbon fibre tripod instead of something really sturdy.

Edited February 2 by geeklee

[iantaylor2uk]

I use an rst-135 and guide at either 0.5 secs or 1 secs, and the guiding is usually well below 1" but will depend how good polar alignment is and what load is on the mount. The mount is in an innorel RT90c carbon fibre tripod.

Edited February 2 by iantaylor2uk
Typo

[Elp]

Hem15 at around 120-200mm guidescope FL guides around 0.6-0.8 at best at 0.5s exposures 7Kg odd payload close but not exactly balanced in Dec (hem only has hd on the RA), guiding at 1-2s it usually goes up to 1.2 or more. Images however look fine despite the impact it might have on FWHM. Find little difference mounting on CF tripod or Berlebach Uni.

Edited February 2 by Elp

[fireballxl5]

Seeing in the northwest isn't so great and using a RST-135E here carrying an RC6,  so with encoder, on an AstroTrac pier.  Guiding usually at 1s currently via a 70mm/270mm finder, with multistar enabled.  The mount gives consistently good results,  with any guide variation not seemingly affecting the final sub. Love this mount😍

[Bivanus]

@Northernlight it sounds like you have some worries about the mount being a harmonic type ? They are actually better as far as I know , if the price was right I would jump on one too😄 This type of drive has already a long history in robotical mecatronic , maybe a short clip will apease your worries 

 

[Northernlight]

Hi all.

Thanks for the feedback. My imaging scale ranges from 0.6" to about 1.91" depending on the scope/camera combo i use so it sounds like under best case scenario i'll be borderline with a harmonic mount.

[Elp]

The Warp servo hd mounts are supposed to guide/correct exceptionally well (see Cuivs review of the larger WD20, theres also a smaller 17S). Likely RST135 equivalents at much more affordable prices.

[The Admiral]

48 minutes ago, Elp said:

The Warp servo hd mounts are supposed to guide/correct exceptionally well (see Cuivs review of the larger WD20, theres also a smaller 17S). Likely RST135 equivalents at much more affordable prices.

But do note that although Cuiv mentions encoders, IIRC, I understand that this is essential for servo motor control in a feedback loop. It is not I believe the same as encoders used at the output from the harmonic drive, so it wouldn't correct for the variations which are characteristic of the harmonic drive. To be fair to Cuiv, this is really what he says.

Anyway, I am no expert in guiding nor do I have extensive experience with my AM5, but like others I've found guiding generally in the range 0.5"-0.8" using a 50mm x 200mm guide scope, multi-star guiding, and with a 0.5s guide exposure. The load is only about 5kg, and I use the carbon fibre tripod with a ballast of a few kilos. It is advised to use a short guide exposure of 0.5-1.0s guide exposure on account of the rapid switch-backs one can get with harmonic drive errors, though I've seen folk using longer without a problem. I haven't tried longer exposures myself.

Ian

Edited February 5 by The Admiral

[fwm891]

I'm using an HEM27 (no encoders) with a RASA 8 mounted no counterweights, tripod mounted (braced surveyors tripod) camera asi2600MC Duo so guiding at 400mm subs are usually < 0.8" on good nights circa 0.5" using 1 - 1.5 second guide exposures with no filters. Narrow band filters require longer guide subs of 2 - 2.5 seconds but still around 0.8" guiding. I do balance the dec carefully and avoid using a dew shield if possible. I keep the tripod legs as low as possible and locked out once levelled.