Vixen SXD2 or iOptron GEM45? - Forums

Topic starter

Nov 6, 2022

I recently wanted to upgrade my mount and looked up information on related products.
My needs are to be able to be carried by car, as well as a load of 15kg or more, and to be used for deep sky photography. So I noticed that vixen's sxd2 and ioptron's GEM45 fit my needs almost perfectly.
The price of these two mounts is almost indistinguishable in Japan, and the similar spec confused me in choosing.
I hope anybody can give me some advice. Of course, if you can have other recommendations, please also let me know. (EQ6R is too heavy).

andrea tasselli

Frequent contributor

Nov 6, 2022 · Edited: Nov 6, 2022

I'd go for a Vixen mount any time over the IOptron ones. I had/have 3 Vixen mounts so far and not one disappointed me. I can't say the same of my GEM28. More to the point their spec's can be believed in and if anything their quoted max payload is on the conservative side. Good luck with your quest.

Reg Pratt

Nov 6, 2022 · Edited: Nov 6, 2022

I've owned 2 GEM45 and they served me well between dual refractorm 8" RC, and 10" Newtonian setups. I would not hesitate to buy another one if I ever found myself needing a mount in that weight class again.

daywalker

Nov 6, 2022

I have a gem45ec . It has very little stiction and so requires a good balance on all 3 axis. Newtonians tend to be mounted in rings so that's easy enough to sort out as you can spin it in its rings as well as sliding back and fourth for fine balance adjustments. Tidying up the install i.e getting rid of all trailing cables from the saddle made a big difference in guiding consistency aswell.
I have two 10kg counter weights which are now almost right at the botttom of the counterweight shaft so not ideal but it guides @ around 0.5 rms on average.
0.45 on a goodnight 0.6-0.7 on a bad one.

I also like the alt/az adjustment, and also the usb ports and 12v dc output on the saddle.

I did have a faulty switch on the main board,but it was easy to access to remove and ioptron sent me replacement board very quickly.

I think it looks cool too

Helpful

Lynn K

Nov 6, 2022 · Edited: Nov 6, 2022

I owned a Vixen SDX. It was a well made mount and very light. The aluminum tripod is very sturdy. I used a AT111ED refractor. I used the mount for astrophotography and sold it after a few months use. THIS IS WHY. Vixen in ther wisdom programed a feature that automatically adjust the DEC for any polar alignment arror. It does that periodically. That might seem like Great feature and probaly is for visual use. But for astrophotography it made the mount un-useable. The mount would be guiding very well and for no apparent reason the guide star would go completely off the guide screen. That was due to the programed polar misalignment adjustment. Ther was no way to turn off that feature off. It became the main topic of discussion on the Vixen Yahoo group at the time. The mis-polar alignment adjustment was based on how far the DEC had to slowed to center the last alignment star. Vixen US said the work-around was to loosen the DEC clutch and hand move the mount to align/center the final alignment star. That would fool the mount into thinking there was no polar mis-alignment. I felt that was too problematic.

A third party in Portugal created a circuit board that preplaced the Vixen one and converted the mount to the Celestron NexStar operating system. I think it was called Nex Sphinx or something like that. Many took that approach and was well pleased wit the performance. It was tempting, but I thought the third party one person show was not long term reliable.

/ IMPORTANT TO NOTE. The SDX2 version may have solved that problem. I do not know if it did. CHECK TO SEE. If it did, then I would highly recommend the mount. The #10 StarBook with its numbered keys is a big advantage over the original StarBook I had. I found the built-in planetarium useless. Too small and too limited of objects.

In my openion Vixen never designed this mount for astrophotography. It was designed as a very light GoTo mount not needing A separate computer. With today's phones and pads, it has made the Vixem StarBook system obsolete. The more expensive SXP was/is Vixen's answer to a astrophotography designed mount . I have thought about looking for a used SXP, for Dark sites, but bought a used Astro Physics 400 instead. A much better choice, with outstanding support and operating system upgradeable.

Lynn K.

Helpful Engaging Supportive

Supeng Liu

Topic starter

Nov 7, 2022

I have a gem45ec . It has very little stiction and so requires a good balance on all 3 axis. Newtonians tend to be mounted in rings so that's easy enough to sort out as you can spin it in its rings as well as sliding back and fourth for fine balance adjustments. Tidying up the install i.e getting rid of all trailing cables from the saddle made a big difference in guiding consistency aswell.
I have two 10kg counter weights which are now almost right at the botttom of the counterweight shaft so not ideal but it guides @ around 0.5 rms on average.
0.45 on a goodnight 0.6-0.7 on a bad one.

I also like the alt/az adjustment, and also the usb ports and 12v dc output on the saddle.

I did have a faulty switch on the main board,but it was easy to access to remove and ioptron sent me replacement board very quickly.

I think it looks cool too

Thank you for the detail of gem45.
Do you think the ec part is necessary even though I have auto-guiding?

Supeng Liu

Topic starter

Nov 7, 2022

Lynn K:
I owned a Vixen SDX. It was a well made mount and very light. The aluminum tripod is very sturdy. I used a AT111ED refractor. I used the mount for astrophotography and sold it after a few months use. THIS IS WHY. Vixen in ther wisdom programed a feature that automatically adjust the DEC for any polar alignment arror. It does that periodically. That might seem like Great feature and probaly is for visual use. But for astrophotography it made the mount un-useable. The mount would be guiding very well and for no apparent reason the guide star would go completely off the guide screen. That was due to the programed polar misalignment adjustment. Ther was no way to turn off that feature off. It became the main topic of discussion on the Vixen Yahoo group at the time. The mis-polar alignment adjustment was based on how far the DEC had to slowed to center the last alignment star. Vixen US said the work-around was to loosen the DEC clutch and hand move the mount to align/center the final alignment star. That would fool the mount into thinking there was no polar mis-alignment. I felt that was too problematic.

A third party in Portugal created a circuit board that preplaced the Vixen one and converted the mount to the Celestron NexStar operating system. I think it was called Nex Sphinx or something like that. Many took that approach and was well pleased wit the performance. It was tempting, but I thought the third party one person show was not long term reliable.

/ IMPORTANT TO NOTE. The SDX2 version may have solved that problem. I do not know if it did. CHECK TO SEE. If it did, then I would highly recommend the mount. The #10 StarBook with its numbered keys is a big advantage over the original StarBook I had. I found the built-in planetarium useless. Too small and too limited of objects.

In my openion Vixen never designed this mount for astrophotography. It was designed as a very light GoTo mount not needing A separate computer. With today's phones and pads, it has made the Vixem StarBook system obsolete. The more expensive SXP was/is Vixen's answer to a astrophotography designed mount . I have thought about looking for a used SXP, for Dark sites, but bought a used Astro Physics 400 instead. A much better choice, with outstanding support and operating system upgradeable.

Lynn K.

Hi Lynn

Thank you for the detail about SXD.
Vixen released a new version of SXD2. It doesn't have SB10 but has a wifi unit for mobile phones.
As you say, maybe SXD2 is mainly designed for visuals, not photography.

Su

daywalker

Nov 7, 2022

Supeng Liu:
I have a gem45ec . It has very little stiction and so requires a good balance on all 3 axis. Newtonians tend to be mounted in rings so that's easy enough to sort out as you can spin it in its rings as well as sliding back and fourth for fine balance adjustments. Tidying up the install i.e getting rid of all trailing cables from the saddle made a big difference in guiding consistency aswell.
I have two 10kg counter weights which are now almost right at the botttom of the counterweight shaft so not ideal but it guides @ around 0.5 rms on average.
0.45 on a goodnight 0.6-0.7 on a bad one.

I also like the alt/az adjustment, and also the usb ports and 12v dc output on the saddle.

I did have a faulty switch on the main board,but it was easy to access to remove and ioptron sent me replacement board very quickly.

I think it looks cool too

Thank you for the detail of gem45.
Do you think the ec part is necessary even though I have auto-guiding?

Necessary.. No.I have it turned if off for guiding.Also PHD2 can make allowances for periodic error in your mount gear mechs.

Astrophoto Seba

Nov 7, 2022

I have quite new GEM45 (without encoders), bought it 6 months ago.

Can't get it work correctly in RA axis. There are some random peaks, which looks more or less like some sticktion issues, adjusting worm does not help at all. Tried i guess all possible things, balance it differently, rearrange cables 10 times, adjusting worm gears following mount manual, checked all screws, wedge, recording PEC, no luck.

I've lost my patient and going to contact the seller. Regret my choice, should have bought the some of the EQ6 mounts.

Supeng Liu

Topic starter

Nov 7, 2022

Astrophoto Seba:
I have quite new GEM45 (without encoders), bought it 6 months ago.

Can't get it work correctly in RA axis. There are some random peaks, which looks more or less like some sticktion issues, adjusting worm does not help at all. Tried i guess all possible things, balance it differently, rearrange cables 10 times, adjusting worm gears following mount manual, checked all screws, wedge, recording PEC, no luck.

I've lost my patient and going to contact the seller. Regret my choice, should have bought the some of the EQ6 mounts.

Thank you for your experience.
Has the seller solved this problem? I heard from my Chinese friend that this is a usual problem.

Astrophoto Seba

Nov 7, 2022

What was the solution?

For me no response yet, still waiting for some actions.

daywalker

Nov 7, 2022

Astrophoto Seba:
I have quite new GEM45 (without encoders), bought it 6 months ago.

Can't get it work correctly in RA axis. There are some random peaks, which looks more or less like some sticktion issues, adjusting worm does not help at all. Tried i guess all possible things, balance it differently, rearrange cables 10 times, adjusting worm gears following mount manual, checked all screws, wedge, recording PEC, no luck.

I've lost my patient and going to contact the seller. Regret my choice, should have bought the some of the EQ6 mounts.

Sorry to hear your troubles. so you got it perfectly balanced so that no matter what position you place it in with the clutches disengaged it doesnt move?

Astrophoto Seba

Nov 7, 2022 · Edited: Nov 7, 2022

Sorry to hear your troubles. so you got it perfectly balanced so that no matter what position you place it in with the clutches disengaged it doesnt move?

Yes, tried also balance it towards the side which is "pulled" and still no luck. Maybe i need to balance in 3rd axis but I use RC with OAG so basically all the weight is in line of DEC.

daywalker

Nov 7, 2022

i have never had much luck balancing east heavy. I dont think that works well with these mounts.
For a long time i was having frustrations with this mount i must admit when using this with my SCT. When i got a newtonian things improved because even though the newtonian setup was heavier i could rotate it in the rings so that a much better balance could be achieve in all 3 axis.

I went from consistently guiding well above 1 arc sec to consistently guiding well below.
Last night was 0.4 with probably 16-17kg load.

I use to also have my powerbox and mini pc resting in the tripod eyepiece holder so that cables were trailing down from camera etc to that.
I did this because i didnt want to have the extra weight ontop of the mount i thought that would degrade performance even more but since i installed it all ontop of the scope making the cable management more compact and eliminating trailing cables hanging down from top of scope this improved the guiding noticably.

Im sure youve checked your polar alignment multiple times , if not use phd2 guiding assistant to check what polar alignment error it gives.

For a long time i was convinced it was a poor performer and that i had bought a duff… but it was just me.Thats not to say yours isnt faulty but its worth checking the basics

Helpful Supportive

Pariah

Dec 10, 2023 · Edited: Dec 10, 2023

Lynn K:
I owned a Vixen SDX. It was a well made mount and very light. The aluminum tripod is very sturdy. I used a AT111ED refractor. I used the mount for astrophotography and sold it after a few months use. THIS IS WHY. Vixen in ther wisdom programed a feature that automatically adjust the DEC for any polar alignment arror. It does that periodically. That might seem like Great feature and probaly is for visual use. But for astrophotography it made the mount un-useable. The mount would be guiding very well and for no apparent reason the guide star would go completely off the guide screen. That was due to the programed polar misalignment adjustment. Ther was no way to turn off that feature off. It became the main topic of discussion on the Vixen Yahoo group at the time. The mis-polar alignment adjustment was based on how far the DEC had to slowed to center the last alignment star. Vixen US said the work-around was to loosen the DEC clutch and hand move the mount to align/center the final alignment star. That would fool the mount into thinking there was no polar mis-alignment. I felt that was too problematic.

A third party in Portugal created a circuit board that preplaced the Vixen one and converted the mount to the Celestron NexStar operating system. I think it was called Nex Sphinx or something like that. Many took that approach and was well pleased wit the performance. It was tempting, but I thought the third party one person show was not long term reliable.

/ IMPORTANT TO NOTE. The SDX2 version may have solved that problem. I do not know if it did. CHECK TO SEE. If it did, then I would highly recommend the mount. The #10 StarBook with its numbered keys is a big advantage over the original StarBook I had. I found the built-in planetarium useless. Too small and too limited of objects.

In my openion Vixen never designed this mount for astrophotography. It was designed as a very light GoTo mount not needing A separate computer. With today's phones and pads, it has made the Vixem StarBook system obsolete. The more expensive SXP was/is Vixen's answer to a astrophotography designed mount . I have thought about looking for a used SXP, for Dark sites, but bought a used Astro Physics 400 instead. A much better choice, with outstanding support and operating system upgradeable.

Lynn K.

My reply:

.The SXD2 is a significant .
upgrade on the SXD. It is very well made, has improved bearings, worm gears and can carry 15kg imaging load. The SB10 controller is excellent for visual, and it makes a great mount for imaging (simply connect a network cable to the SB 10 LAN port and you can control from PC or ASI Air)

I've used an SXD2 for two years, worked out of the box and no issues in service. Tracking, dither, goto, all AOK

Gianfranco GAV TOP

Mar 22, 2024

Lynn K:
I owned a Vixen SDX. It was a well made mount and very light. The aluminum tripod is very sturdy. I used a AT111ED refractor. I used the mount for astrophotography and sold it after a few months use. THIS IS WHY. Vixen in ther wisdom programed a feature that automatically adjust the DEC for any polar alignment arror. It does that periodically. That might seem like Great feature and probaly is for visual use. But for astrophotography it made the mount un-useable. The mount would be guiding very well and for no apparent reason the guide star would go completely off the guide screen. That was due to the programed polar misalignment adjustment. Ther was no way to turn off that feature off. It became the main topic of discussion on the Vixen Yahoo group at the time. The mis-polar alignment adjustment was based on how far the DEC had to slowed to center the last alignment star. Vixen US said the work-around was to loosen the DEC clutch and hand move the mount to align/center the final alignment star. That would fool the mount into thinking there was no polar mis-alignment. I felt that was too problematic.

A third party in Portugal created a circuit board that preplaced the Vixen one and converted the mount to the Celestron NexStar operating system. I think it was called Nex Sphinx or something like that. Many took that approach and was well pleased wit the performance. It was tempting, but I thought the third party one person show was not long term reliable.

/ IMPORTANT TO NOTE. The SDX2 version may have solved that problem. I do not know if it did. CHECK TO SEE. If it did, then I would highly recommend the mount. The #10 StarBook with its numbered keys is a big advantage over the original StarBook I had. I found the built-in planetarium useless. Too small and too limited of objects.

In my openion Vixen never designed this mount for astrophotography. It was designed as a very light GoTo mount not needing A separate computer. With today's phones and pads, it has made the Vixem StarBook system obsolete. The more expensive SXP was/is Vixen's answer to a astrophotography designed mount . I have thought about looking for a used SXP, for Dark sites, but bought a used Astro Physics 400 instead. A much better choice, with outstanding support and operating system upgradeable.

Lynn K.

My reply:

.The SXD2 is a significant .
upgrade on the SXD. It is very well made, has improved bearings, worm gears and can carry 15kg imaging load. The SB10 controller is excellent for visual, and it makes a great mount for imaging (simply connect a network cable to the SB 10 LAN port and you can control from PC or ASI Air)

I've used an SXD2 for two years, worked out of the box and no issues in service. Tracking, dither, goto, all AOK

what are you talking about friend? That was more than 10 years ago, you cannot compare old models with problems with current models that are more accepted, I have an SXD2 and it works like a Swiss watch, guided in good nights with less than 0.5 rms and with not so good ones in 0.7 rms , key the GOTO in an excellent way, all the material is anodized steel, it has no plastic parts except the azimuth and altitude knobs, I don't understand why people talk about problems from 20 years ago, things change, improve and evolve.

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