Starlight Xpress Active Optics

[Petergoodhew]

does anyone have experience of the SX AO that they can share?

[swag72]

I had one of these a few years ago and if I'm honest I didn't really get on with it..... I thought it would be the shangri-la to better images, the panacea  to sharper and clearer images. Honestly I didn't get that. I wasted literally loads of nights trying to get it working well and even when it was working I still found that after a night it would run out of adjustment and would have stopped working half way through when I was fast asleep...... I didn't bother carrying on and gave up.  It wasn't even correcting for a bad mount as at the time I had my Avalon Linear.

Did I gain anything from it? I certainly didn't feel like I did. Did I produce sharper images? No. Was it worth the nights and hours of hassle? Absolutely not.

I did quite a bit of research before I got it...... spoke with quite a few folks and the majority really rated it, so perhaps it was just me!!! Take my thoughts with a pinch of salt, but I thought I'd share them for some balance!!!

 

[Whirlwind]

I suppose the question is for what purpose are you thinking about an SX-AO?  I see you have two 10 Micron mounts and if it is used for refractor imaging on these I'm not sure there is much point.  They are primarily there to correct for tracking issues in mounts with poorer corrections (or backlash) as you don't have to correct the whole mount and just using the SXAO to correct over time.  It can also help with mirror based systems as they can be more reactive to mirror movement.  This system is not the same as the adaptive optics professional observatories use to correct for seeing.  You might get a small improvement at the fastest correction but in that case you need bright guide stars and they can be hard to come by.

As for experience I have one of the older versions (Serial) and have the following comments to make:-

For faster corrections you need a sensitive guide camera (binning also helps)
It worked very well for me in Astroart and never had the problems Sara mentioned (pretty much plug and play)...but
I found issues with it when using MaximDL.  I could never get it to calibrate it properly and always tried to sit on a bright pixel in the lodestar (even after dark subtraction - was a non linear blighter).  MaximDL didn't also allow me to select a star in AO mode (it would just jump back to the bright pixel).  As such it never really corrected properly and on the rare occasions I found a brighter star than the pixel I also experienced the same calibration issues in that it wouldn't bump the mount.  That I never got the same issue in AstroArt made me believe it was a MaximDL software issue and not something fundamentally wrong with the SXAO.  This was a few years ago now as I use a Mach1 now and tended to find with refractors that I ran out of backfocus with those that needed flatteners as my CCD size increased.  Things may have hence changed (both with Maxim and AstroArt). I am not sure whether this could relate to Sara's issue above.

 

[swag72]

6 minutes ago, Whirlwind said:

......... never had the problems Sara mentioned (pretty much plug and play)...but
I found issues with it when using MaximDL.  I could never get it to calibrate it properly and always tried to sit on a bright pixel in the lodestar (even after dark subtraction - was a non linear blighter).  MaximDL didn't also allow me to select a star in AO mode (it would just jump back to the bright pixel).  As such it never really corrected properly and on the rare occasions I found a brighter star than the pixel I also experienced the same calibration issues in that it wouldn't bump the mount. ......

 

I was using Maxim DL at the time, and really struggled to find guide stars that were bright enough to use the AO unit at quick speeds, and as I remember all of the above that you mention was applicable to me!!!

[Whirlwind]

10 minutes ago, swag72 said:

I was using Maxim DL at the time, and really struggled to find guide stars that were bright enough to use the AO unit at quick speeds, and as I remember all of the above that you mention was applicable to me!!!

I could of course be cynical a given that MaximDL and SBIG were very close (and now bought out).  Given that SBIG also have their own AO system I couldn't possibly see any potential conflict in a competitors product (especially as there are only two such systems)!

[Petergoodhew]

Thanks to you both.  I'm contemplating an SX AO for two reasons:

1. I'm just setting up a Celestron C11 here at home, in part for planetary/lunar (for which the AO will of course be useless), but also to leverage the 2880 focal length to try to capture small planetary nebulae in narrowband (the light pollution here is dreadful). But I also have pretty bad seeing in London - so the theory is that AO might help address that. The 10Micron seems to track perfectly unguided.

2. I'm setting up a triple rig at e-Eye in Spain, including 2 APM TMB 152 Refractors. Almost everyone I know with dual rigs has hit differential flexure issues - especially with long tubes and heavy cameras. I've heard of an SX AO being a solution to flexure on the slave scope (the primary scope having an OAG just in case it's needed).  It's early days - I hope to start testing the rig next week - but as it's a remote robotic rig I'm trying to anticipate every possible problem and corresponding solutions.