Orion 250mm F/6.3 SPX

[dweller25]

Hello,

Would like to hear from users of the 10" Orion Optics F/6.3 SPX scope.

I will be using it for visual planetary only.

My question is at 1600mm focal length will an EQ6 be stable enough or does it require something larger ??

Thanks

[John]

Sorry you've not had any replies do far.

I have an OO Europa 10" but it's a F/4.8. I have noticed that OO OTA's are a little lighter than their Skywatcher equivilents - my 10" is quite comfortable on the CG5 mount for visual.

An F/6.3 is a lot longer of course and tube length seems to put even more of a strain on mounts than weight does - it's that "moment arm" force that's to blame !.

Sorry I can't be of more help. Maybe OO themselves would be worth a call ? - I spoke with a chap called John there today about a small issue and he was very helpful.

[Roger_Laureys]

Hi,

I am sure for visual use and planetary imaging the mount will be OK. Martin Mobberly has the same combination ( see his website and review on Cloudy Nights)

For Deep Sky imaging you should go to a heavier mount.

I am waiting for my 350 SPX which will be mounted on a G11.

Enjoy,

Roger

[Chris H]

Here is a link to what Roger mentioned

Orion Optics 250mm f/6.3 SPX Newtonian - Review

[dweller25]

Thanks for all the comments.

I am very seriously considering the 10" SPX on an EQ6 now my back has improved.

[brianb]

tube length seems to put even more of a strain on mounts than weight does - it's that "moment arm" force that's to blame !.

And the wind pressure on the longer tube ....

There's little doubt that the SPX 10" f/6.3 is a killer planetary scope but I do have doubts about stuffing it on an EQ6. The Vixen Atlux is a great deal steadier despite being similar in weight to the EQ6, unfortunately it's also a great deal more expensive. But I'd consider the Atlux / Losmandy G11 / Celestron CGE (the big one, not the cut-down CGEM version) to be a better match to a large tube like a 10" f/6.3 Newtonian than an EQ6.

[John]

And the wind pressure on the longer tube ....

There's little doubt that the SPX 10" f/6.3 is a killer planetary scope but I do have doubts about stuffing it on an EQ6. The Vixen Atlux is a great deal steadier despite being similar in weight to the EQ6, unfortunately it's also a great deal more expensive. But I'd consider the Atlux / Losmandy G11 / Celestron CGE (the big one, not the cut-down CGEM version) to be a better match to a large tube like a 10" f/6.3 Newtonian than an EQ6.

Aside from the obvious tracking issues, how would this OTA fare on the OO dobsonian mount do you think ?.

[brianb]

how would this OTA fare on the OO dobsonian mount do you think ?.

Apart from the obvious tracking issues ... very well ... but perhaps the shorter tube would work better at the low powers usually employed with Dobsonians. Serious planetary work demands magnification in excess of x200 and tracking becomes more essential than a mere convenience IMO.

[psjshep]

I have used the F/4.8 SPX 250 for a couple of years and even with extra tube rings to reduce flex in the tube (Skywatcher ones which were fairly hefty) the EQ6 handled it just fine. I have since put the mirrors in a carbon fibre tube, but this was for the thermal & rigid properties.

I used to run it in the obsy with it mounted side-by-side with a Skywatcher ED80, using one of John Rose's m3 mounting systems (not light in itself, but very sturdy) - needed 3 x standard skywatcher weights. I would say this is at the limit of the mount, so just an SPX250 on it's own is just fine. As has been said, there is a little flex in the mount, but I have imaged like this for some time... maybe bouncing an eye of the eyepiece is a different matter?

Phil.

[dweller25]

Phil - Flex in the tube ????? that has my attention - does it hold collimation ?

[psjshep]

Phil - Flex in the tube ????? that has my attention - does it hold collimation ?

Bear in mind I do 99.9% imaging... which is extremely sensitive to any flex; focuser, imaging hookup, tube, secondary, etc.

OO tubes are nice & light and THIN. Figure out what happens when a 10" mirror + CNC mirror cell one end is chucked about on a mount when the tube is a piece of thin ally. It also means you cannot tighten the spider too much else the tube gets pinched. For my scope (maybe not typical with other OO's ?) It would shift collimation between one side of the meridian and the other.

Phil.

[John]

OO tubes are nice & light and THIN. Figure out what happens when a 10" mirror + CNC mirror cell one end is chucked about on a mount when the tube is a piece of thin ally. It also means you cannot tighten the spider too much else the tube gets pinched. For my scope (maybe not typical with other OO's ?) It would shift collimation between one side of the meridian and the other..l.

My OO 10" is 2007 vintage and also has a thin tube. As a visual observer I've not noticed the impact of any flex and the scope holds collimation well however with imaging things are more critical.

My scope being an F/4.8, the rigid tube end rings and the 2" wide tube rings (tube bands really) keep the tube rigid however I'd accept that this could be an issue with a longer tube.

I recall that tube flex used to be an issue years ago when PVC / fibreglass tubes were used and back then folk used to employ a number of tube bands to minimise that.

[psjshep]

I recall that tube flex used to be an issue years ago when PVC / fibreglass tubes were used and back then folk used to employ a number of tube bands to minimise that.

exactly.

Although mine was ally, as I mentioned, I too used some extra tube rings to make it more rigid - this did mostly work, but the 2" focuser with extra weight of camera & filterwheel did make it flex at that point. I ended up bracing everything; either side of focuser, spider went thru a ring placed at the top.... For visual, I am sure everything is ok, but for imaging (& I did discuss with Barry & John @ OO I would be doing this 99% time ) I was disappointed.

Phil.

[dweller25]

This has me concerned.

My philosophy was to pay for the 1/10th wave optics to give me the best possible planetary views, but what's the point in having ultra precision optics if the tube will flex ?

To me it will negate the advantage of the optics.

Or am I wrong ?

[johninderby]

If you're concerned about tube flex just ask OO to use a heavier gauge tube, or if you've got the funds the carbon fibre tube. A lot of people don't realise that OO custom builds each OTA to order and so you can have them make pretty well any changes that you want.

For visual use I've not found any problems with flexing and collimation is held very well.

John

[nitram100]

Not noticed any flex in my OO 10" F4.8 and mine is an old one from around 2000 and it holds collimation really well despite only using a 3 point cell.

[psjshep]

Not noticed any flex in my OO 10" F4.8 and mine is an old one from around 2000 and it holds collimation really well despite only using a 3 point cell.

That is great to hear. This isn't meant to be a "scare mongering" thread... This is just my personal observations.

For me, the combination of the heavy secondary *ever-so-slightly* flexing, with the heavy SXV-H9+Filterwheel+focuser, along with a thin aluminium tube, causes slight shift which can be detected with an image - mine is an f/4.8 system don't forget..... quite fast & collimation is critical.

I use a Cat's Eye system which *precisely* collimates...ANY shift is detected.

As has been said, visually I would be very suprised if you detect it.

I went to carbon fibre BOTH for sturdiness AND the thermal properties.

[psjshep]

Not noticed any flex in my OO 10" F4.8 and mine is an old one from around 2000 and it holds collimation really well despite only using a 3 point cell.

John,

I was not made aware by the OO boys that I could have had a more hefty tube, else I would have asked for one... interesting.