Big GEM decision CGE or Altux

[Ian Robinson]

I looking at putting my 10" newt (f4.7) onto a bigger and more capable mount .... into long exposure 35mm astrophotography .... yes I know I'm a dinosaur and have not migrated to a DSLR (getting a Canon 40D shortly too).

I need to make a decision on the right GEM for me ....

As I see it , it's a choice between a CGE , a G11 + GEMINI , a Vixen SDX with Starbook , or a Vixen Altux (also with Starbook).
Hey , if I am going to spend all this money .... I might as well go whole hog and get a computerised GOTO mount .... I've never had GOTO before .

The Atlux eats all these for breakfast wrt maximum load capacity but the Vixen Duralum tripod looks a bit flimsey and wobbly cf the CGE's massive tripod.
Scrub the SDX.
I'm not terribly impressed with the Losmandy or what I've read about it, and would have to buy some extras to put my scope in top of it (new dovetail).

Anyway I am having a hard time finding any objective field tests by advanced users (that don't read like infomersals designed to sell this or that GEM).

I've read some bad stuff about Losmandy and Celestron quality issues which have my warning bells ringing.

I can get a CGE or an Altux ready to go for near the same price (but have to wait several weeks for the Vixen).

Nitty gritty : can anyone give an indication

peak to peak tracking precision (raw (no PEC) and with PEC on) anyone know this (or measured it) for the Altux and the CGE ?
Some people say they get pp tracking precision better than 11 arcsec with PEC for the CGE but this is variable from what can see.
I have read a claim the Atlux is in a class by itself cf the CGE and the G11 , reported better than 3 arc seconds (peak - peak ?? with PEC)
Can I believe these claims ?

pointing precision once electronically aligned ?
Atlux seems superior to CGE and G11 GEMINI but can't find any comparative testing.

When I've looked at the Vixen website the Starbook makes me cringe a bit , looks too much like a game console and I have so reservations about a big bright display screen will do wonders for my dark adaption when I using it .... but I can learn to live with that (or put a bit red plastic sheet over the display , maybe you can make the display go red like I can my Laptop when running GUIDE.

pointing precision if properly (by visual polar alignment the old way) ?

What would you buy ? (both CGE and Atlux will cost me about the amount ... bought locally with local warantees).

Any advise or feedback offered or better (actual user experiences with these GEMS) will be greatly appreciated.

[g__day (Matthew)]

The CGE will carry more load than the Atlux – but from my research I’ve read of CGE with raw PE of +/- 22 arc seconds – that can get 3-4 times better with tuning! (A Dr Clay service).

Many folk here to very good work on Losmandy G11 + Gemini – don’t write them off – just make sure they are really well balanced. I have heard from folk here that the G11 gears are better machined than the CGE.

The Atlux has raw PE of +/7 arc seconds and corrected +/- 3. My Atlux raw PE is about +/- 4 arc seconds – see post by Julien, trained I last recall it was about +/- 2.1 (must re-verify)! http://www.iceinspace.com.au/forum/s...ad.php?t=30307

Pointing wise I have it under MaxPoint point to +/- 34 arc seconds (and no wosre than 90 arc seconds) within target all over the sky, raw I’d say its within +/- 2-3 arc minutes of target if your alignment was well done (regardless of whether you are polar aligned or not). On a C9.25 I have at best done 10 minute shots at 2300mm focal length with no guiding or PEC and have round stars – at best! It also has a very nice power on and recall all last pointing alignment set up for permanent mounts that I absolutely love!

I am surprised you can find a CGE (generally about $5,500) for the same price as an Atlux (list $7,200) – well done!

Yep - I think the Starbook is a crazy step back in power versus the SkySensor-2000-PC!

With the Atlux it’s said you don’t need it to be closer than 20 degrees of the polar to track stars – its smart enough to run both motors to compensate for drift and refraction in polar unaligned mode (which doesn’t then provide PEC – you need to be in Polar Aligned mode for PEC to be active). I can vouch for that under 5 degrees in polar unaligned mode via the SS2K-PC it track very well, but I have never tried it 20 degrees of the pole!

[Ian Robinson]

Yep .... it's a very good deal on the Atlux, too bad it comes with Starbook and not SS2000PC which from what I heard was a great system. Rumour has it the chap who was coding the SS2000PC at Vixen left the company.

I'll still procastinating (it's a lot of money !!!) but plan on biting the bullet in the next week or two , it might come down to coin flip Atlux or CGE.

I know of a 2nd hand SS2000PC that is for sale complete with goto drives (which I don't need but might fit my old CG5 , maybe).

How do you find the Vixen Atlux duralum tripod ? .... is it robust and good at rapidly dampening vibrations (caused by the breeze or little bumps (like changing eps)) ?

I am very impressed with the tracking precision for the Atlux in shown in the link .... thanks , that was interesting , bit worried about the Starbook bugs mentioned and the solidness of the Altux tripod.


BTW sources I've seen say :
capacity less cweight for a CGE is 42 pounds load (65 pounds incl cweight)
capacity less cweight for an Atlux is 45 pounds load (75 pounds incl cweight)(have Vixen beefed it up a tad maybe in the new version ???)
Not a big difference , but it might mean better tracking with the piggybacked guidescope or a camera with a fat telephoto.

Another question : relates to autoguiding the Atlux .... if I can get my hands onto a Orion TS autoguider or a secondhand Meade autoguider (on the cheap via Ebay maybe) will these work with an Atlux Starbook setup ?
Is autoguiding overkill if PEC will get me tracking precision better than 4 arc seconds ?

Will take a bit of getting used to not using setting circles ....

I have to visit a darker site for my astrophotography as I have a neighbour who keeps his outside back light on perpetually (one of those horrible compact fluorescent globes)and so my backyard is too brightly lit up , he refuses to turn the light off. (The local council wont do anything). From what I have read , moving a CGE around will build up my muscles ..... !!

[g__day (Matthew)]

The Vixen Atlux tripod looks very solid to me - but I have only used it once - I am on a permanent pier!

I have 22kgs of counterweight on my rig – and the Atlux doesn’t seem bothered by this load when imaging…

[Ian Robinson]

Thanks for that , it's very helpful .... one less issue to procastinate about.

[Julien]

Hi Ian,

I'm also looking for a new mount (I currently have a Vixen GP with a SS2KPC).
And I think that an Atlux could be a good solution for me. But the bad point is the Starbook (SB). I have read a review ( http://www.groupeastronomiespa.be/SSvsSB_V1.02.doc.pdf ) about it and it seems that a lot of the SS2K's functionalities are not in the SB. But the review has been writen in 2005. And since, several update have been released. I have writen to the review's authors to know which "new" functionalities have been released. I'm waiting for their answer.

For the PE of different mount, have a look there : http://demeautis.christophe.free.fr/ep/pe.htm . It's in French but the graphics (all without PEC) are easy to read .

Atlux : http://demeautis.christophe.free.fr/ep/atlux.htm
CGE : http://demeautis.christophe.free.fr/ep/cge.htm
G-11 : http://demeautis.christophe.free.fr/ep/g11.htm

The last two G-11 are around +/-5" because their RA worm have been changed by a french company (http://www.ovision.com/Losmandy_PresentationNS.html)


In fact I have rapidely give up the Losmandy possibility. It's a good mount but the quality don't seems to be as good as other mounts (Atlux, Takahashi, ...). And its PE is not very smooth. I think it's a good mount but you have to tune it very carefuly.


For my new mount I have three choices :

- Atlux (if the last SB's versions are good)
- Takahashi EM-200 (a very good mount but I would like to have a higher capacity)
- Astro-Physic 900GTO (if I can buy it in the USA)

[Ian Robinson]

Hi Julien,

I am liking the Atlux more and more.

You might be able to simply swap the Starbook for your existing mount's SS2000PC controller.

I looked at the Taks too and the prices are too high.

I think the build quality of american made GEMS is pretty ordinary.

[g__day (Matthew)]

The G11 has quite a following on this forum - and many folk do impressive things with one. I am unclear on where their so called suspect reputation comes from!

[robgreaves]

Originally Posted by Ian Robinson

...I think the build quality of american made GEMS is pretty ordinary...

Interesting thoughts.

I've certainly owned and used more mounts than perhaps most people, and the American designed/manufactured Astro Physics AP1200GTO is the best mount I've ever owned and used, period.

I've owned its smaller sibling too, the AP900GTO, as well as the American-made Paramount ME 4000MKS. Ah - also the G11, that's American too! Owned one of those also for a while. American mounts have always done the job as far as I'm concerned...

Incidentally, I think the best 'value' mount I'd ever owned was actually the Synta EQ6 Pro. PE out of the box absolutely horrible - but!... it guided perfectly. It responded properly to guide commands, so all guiding was flat-lining perfectly. Much better than some mounts 3 times its price.

I personally would plump for a CGE over an Atlux, if I was offered a choice. The CGE seems more 'tuneable' to end up with a good mount than the Atlux does.

Also - what about the Losmandy Titan? Does that fall in your budget? Probably worth a look.

Regards,
Rob.

[Julien]

Originally Posted by Ian Robinson

You might be able to simply swap the Starbook for your existing mount's SS2000PC controller.

Unfortunatly not. The mecanic parts of the Atlux SB is exactly the sames than the Atlux SS2K one. But the electronic has changed, and the SS2K can't be use with this new electronic.

[Ian Robinson]

Titan is outside my price range , and I would never be able to justify it (unless I win the $25million AusLotto or the $19million Saturday Lotto .)

Astrophysics GEMS I looked at but getting one at an acceptable price is impossible.

Originally Posted by robgreaves

Interesting thoughts.

I've certainly owned and used more mounts than perhaps most people, and the American designed/manufactured Astro Physics AP1200GTO is the best mount I've ever owned and used, period.

I've owned its smaller sibling too, the AP900GTO, as well as the American-made Paramount ME 4000MKS. Ah - also the G11, that's American too! Owned one of those also for a while. American mounts have always done the job as far as I'm concerned...

Incidentally, I think the best 'value' mount I'd ever owned was actually the Synta EQ6 Pro. PE out of the box absolutely horrible - but!... it guided perfectly. It responded properly to guide commands, so all guiding was flat-lining perfectly. Much better than some mounts 3 times its price.

I personally would plump for a CGE over an Atlux, if I was offered a choice. The CGE seems more 'tuneable' to end up with a good mount than the Atlux does.

Also - what about the Losmandy Titan? Does that fall in your budget? Probably worth a look.

Regards,
Rob.

[Ian Robinson]

Bummer .... (Hope that is acceptable language here , if not .... sorry if I offended).

Originally Posted by Julien

Unfortunatly not. The mecanic parts of the Atlux SB is exactly the sames than the Atlux SS2K one. But the electronic has changed, and the SS2K can't be use with this new electronic.

[robgreaves]

Hi Ian

I'm not sure what prices you've been seeing, but a used Losmandy Titan will always be less than an AP1200 on the used market. or were you looking at the AP600 sized mount?

It might sound obvious, but the biggest market for the AP and Losmandy mounts is the USA, so keep an eye on AstroMart. There are some bargains to be had.

Regards,
Rob.

[Ian Robinson]

Been there done that : bought a second hand CG5 (last year to use as a camera platform and to mount my old Dob on) from a guy in the USA.

Never again , he made claims the mount was in good working order and when it arrived , after about 3 months , I found it was unuseable , the RA worm gearing was stuffed and it was had worn bushes.

When I tried to contact him , he refused to respond. He was great before he got my money.

Fortunately I was able to get my PayPal transaction reversed when I complaigned to Visa via my building society. (I considered the transaction to be fraudulent ,and so did my building society who leant on Visa , since PayPal refused initially to reverse the transaction.)

Never again.

I'm still willing to buy SMALL secondhand items like filters , eyepieces , etc , from overseas but will not consider expensive (secondhand) items unless I can check them out first or have someone I trust check them out.

I now take the same attitude to secondhand GEMS that I take to secondhand cars , that is don't buy them unless you have no choice , and if you do , it's buyer beware.

As to AP and Losmandy , they are over-rated.

Originally Posted by robgreaves

Hi Ian

I'm not sure what prices you've been seeing, but a used Losmandy Titan will always be less than an AP1200 on the used market. or were you looking at the AP600 sized mount?

It might sound obvious, but the biggest market for the AP and Losmandy mounts is the USA, so keep an eye on AstroMart. There are some bargains to be had.

Regards,
Rob.