Max sensible load for a Vixen SXW Sphinx?

[Rich MedRev]

I'm seriously considering a Vixen Sphinx, however what in Newtonian terms is the largest tube assembly it could sensibly handle, some imaging would be on the cards?

I know everyone likes APO's for imaging, I'm a died in the wool Newtonian fan and will be using the setup for plenty of visual work as well.

Therefore what aperture can I hope to mount??

[E621Keith]

I heard Sphinx running early version of Starbook software are not suitable for imaging at all. Initially the mount lacked PEC and ability to accept autoguider, but these have been added in later firmware update. There are also reports of random DEC axis movement. There is an aftermarket 3rd party upgrade call NexSXD which replaces all the electronics in the Sphinx and uses a Celestron hand controller instead of the Starbook.

Here is a review I found for the heavier SXD.

Vixen Sphinx SXD

It showed a 20 arcseconds p2p periodic error when loaded with a C8. It's up to you to decide whether this is good enough for you.

[Geys1987]

I think Orion Optics had a line of newton telescopes up to 12" that came with an optional Vixen Sphinx (perhaps someone else can give some more information). On CN there's a review of someone with a 10" newton on a Vixen Sphinx.

Btw, I own a Vixen Sphinx and do some imaging with it. The latest firmware works great with an autoguider (I've got the QHY5). I had a problem with periodic DEC-movement a few months ago but it turned out that it wasn't the mount.

[pete_gamby]

When Orion was selling its AG Newts with Vixen mounts, it recommended the SXW for up to its 10" model (which weighs in at 12kg sans eyepieces, camera etc and is 810mm x 300mm in size). For 12" it recommended the SXD and above that the Atlux.

In the US, the Vixen distributor quotes the max payload as 16kg which is 4kg above the Vixen factory spec. The guys there have confidence in the figures they publish based on installed equipment.

Regarding the issues mentioned by Keith, the DEC 'jumps' are related only to the use of the Starbook alignment process. I also had some information that in fact it is related to the software updating the Starbook screen i.e. when the screen is off, the DEC jumps don't occur even when the mount has been through the alignment process.

The recommendation I've seen from a number of owners is that the mount should be very accurately polar aligned only to avoid any possible hiccup from the DEC motor.

The NexSXD solution does drive the mount more smoothly and more quietly. We are confident enough in the quality of the product that we've told existing SXW and SXD owners that we will honour any remaining Vixen warranty if they decide to install the NexSXD board as an upgrade.

HTH

Cheers, Pete

[ollypenrice]

I wonder why you fancy the Sphinx? I've met a number of less than delighted owners, though their grumbles were software rather than hardware and if these have been addressed then well and good.

Olly

[Whirlwind]

I think the rated loading is 12kgs and 15kgs for the SXD. I've had the SXD for a while and have comfortably imaged with it at a focal length of about 500 to 600mm (there is an example here M42 | Flickr - Photo Sharing!). I never really came across the reported dec jumping issue, but i never properly synced the starbook - just polar align then used a planetarium program, which may be why. The dec jump did seem to be software related, which is why it appears the NexSX upgrades appear successful. Realistically I think you could go to 50 - 60% of the rated weighting capacity for imaging, and 100% for visual.

The real advantage of the sphinx is its light weight. Because of its layout you need less counterweights to balance, so if you have to set up, tear down after every session it's really easy just pick up and move.

The starbook software is immature and lacks Vixens support - especially as they seem to moved onto Starbook 10 now, but you can guide and use PEC (note its not PPEC though) with current firmware editions without paying extra (that was an early oddity).

Also be aware that new version of the sxd mount is now coming out with Starbook 10 as standard in the new year.

Hope this helps

Ian

[Rich MedRev]

Thanks for the reply's so far, as for why I'm considering the Sphinx it was more due to the fact that I've been offered one for a good price and wondered if the time has come to join the AP party!

The version I have been offered is 2006 and will no doubt require some serious software updates to correct the DEC issues and PEC, am I better to look at the NEQ6?

[ollypenrice]

Thanks for the reply's so far, as for why I'm considering the Sphinx it was more due to the fact that I've been offered one for a good price and wondered if the time has come to join the AP party!

The version I have been offered is 2006 and will no doubt require some serious software updates to correct the DEC issues and PEC, am I better to look at the NEQ6?

I would say so, yes. The iOptron IEQ45 is also very competent.

Olly

[Rich MedRev]

I would say so, yes. The iOptron IEQ45 is also very competent.

Olly

Thank you Olly, which of the two would you get if it was your personal choice?

I've looked at the IEQ45 before and wasnt sure whether it was worth the additonal expenditure over the NEQ6.

I also have been intrigued by the LX80, however previous Meade mounts seem to have had mixed reviews.

I have declined the Vixen.