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Celestron VX mount

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#201 orlyandico

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Posted 26 January 2013 - 12:54 AM

I have no experience with the AVX. My acquiantance is not an experienced imager either (neither am I). I think someone who is experienced with the mount, knows its issues and how to get around them, would get better performance.

I did use an Orion 100ED f/9 on a Vixen GP. That was not a suitable setup.

Here's another. I've revisited my CGEM and have been trying to make it work more precisely. One of the things I did was loosen the worm mesh. This improved the PE slightly and made the mount a lot quieter. But, it also increased the backlash in both axes.

I noticed last night that the wind can cause the scope to move back and forth due to the not-to-tight worm mesh. If you tighten the worm though you will get increased PE, noise, and might burn out your motors or motor board. This was a CGEM with an AT90EDT (which admittedly is heavy, but not as heavy as an ES127).

For these reasons... I would not try imaging with the ES127 on the AVX. I think it's more of a CGEM class tube, and even there would not be trouble-free. I actually think the C8 with a reducer would be a better bet. With the Starizona reducer you're at 1500mm which is a bit more than the ES. But a much shorter tube.

#202 orlyandico

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Posted 26 January 2013 - 12:57 AM

All for imaging of course. I think for visual the ES127 would be OK-ish (if the AVX is anything like the Vixen GP, I didn't really enjoy the Orion 100ED on the GP even for visual).

p.s. folks on here might be thinking I'm excessively conservative about mount capacity. But I know people imaging with FSQ-106's and AP130EDF GT's on G11s, Mach1s, and PMXs. That is massive mount overkill by the conventional wisdom, but it pays off in zero subs thrown away and very good tracking even over very long exposures. Much less hair loss all around :grin:

#203 dr.who

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Posted 26 January 2013 - 01:29 AM

Cheers Orly, And thank you again.

For what it's worth I use the 127 on the CG5 with ZERO problems for visual and this new mount seems in my limited use of it to be at the mid point between the CGEM and CG5. It glides on the CG5 with no strain at all.

I finally gave up on my CGEM because at the end of the day it was just too darn heavy and too many trips to get setup for the majority of the times I had time to image since said time was very limited and I didn't want to spend it setting up and tearing down. With this mount and the CG5 I can carry the entire primary setup out in one trip with only a follow on or two for misc. gear

I knew going in that I was facing a trade off by giving up on the CGEM but I don't think it was a bad choice. I gave the 80mm a try but like I said in my mind it was going to end up being ultimately too wide for what I wanted to shoot. There are only so many times you can take a photo of Orion or M31. ;)

Ideally I would like a 700 FL 102mm APO like the one I sold (STUPID STUPID ME!) and then the SCT with the reducer at 1500 (by the way the one from Starizona won't work it's for standard C8's not the Edge) and ultimately the SCT at f/10 2032 for truly deep shots but there are no 102's out there in the price range I can afford at f/7 and there won't be for at least a couple of months.

So I was hoping to see if I could get the 127mm (also a great FL at 900ish) to fly on this mount...

Oh and I am not worried about having to toss some subs if I have to.

#204 cn register 5

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Posted 26 January 2013 - 05:27 AM

I'm thinking of getting a 6" GSO RC for my AVX. It's a bit bigger than the 80mm and is at a price I can afford, even if I have to get a focal reducer - although will probably try a SCT FR and see how it goes.

The RC, with an Atik camera, filter wheel, and ST80 with another Atik camera as a guide scope, and mounting rings should give it a bit of a work out.

Chris

Chris

#205 George N

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Posted 26 January 2013 - 12:49 PM

Cheers Orly, And thank you again.

For what it's worth I use the 127 on the CG5 with ZERO problems for visual ......


I use an ES127ED on the CG-5 and have had three rather minor issues:

At times the diagonal hits the tripod legs when the scope points too close to the zenith, and this sometimes happens unfortunately during moving to find the set-up stars. A friend with the same rig solved the problem with a pier extender from Orion, but that adds more weight (and cost).

The mount often stops during a slew…. waits up to 10 seconds, and then continues on to its final position. It sometimes does this *twice* before getting to the right spot. It never does this with less weight.

There is a little more shake during focus than I’d like, even with vibration pads under it.

On the other hand, I have successfully done deep sky imaging by limiting my exposures to 30 seconds (no guiding). I find that using a lit crosshair eyepiece to center stars during set-up and polar alignment improves slewing and tracking accuracy.

Of course putting the ES127 on my Mountain Instruments MI-250 is an entirely different world, but that can mean taking that beast to star parties, when I’m already dealing with a 20-inch Dob and the refractor is “just my secondary scope”.

#206 dr.who

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Posted 26 January 2013 - 01:21 PM

Cheers Orly, And thank you again.

For what it's worth I use the 127 on the CG5 with ZERO problems for visual ......


I use an ES127ED on the CG-5 and have had three rather minor issues:

At times the diagonal hits the tripod legs when the scope points too close to the zenith, and this sometimes happens unfortunately during moving to find the set-up stars. A friend with the same rig solved the problem with a pier extender from Orion, but that adds more weight (and cost).


I apologize George I should have also put in that I have it on the pier as well. It does add weight to the tripod but not the mount and really not that much and the cost was about $80 if I remember right. I had the same problem as well as needing to almost lay down when things were at zenith.

The mount often stops during a slew…. waits up to 10 seconds, and then continues on to its final position. It sometimes does this *twice* before getting to the right spot. It never does this with less weight.


Now that is interesting! And sounds like a possible problem with the mount... I have never seen this happen even with my all up 34 lbs Celestron C11 on it...

There is a little more shake during focus than I’d like, even with vibration pads under it.


Oh. That would be a problem. I was hoping the pads would take care of that. Thank you.

And thank you for the post.

#207 landshark99

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Posted 26 January 2013 - 10:42 PM

Which Orion pier the skyview pro or atlas and does it need to be modified to use with the VX

#208 orlyandico

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Posted 26 January 2013 - 11:18 PM

well of course with 30 second subs a lot can be forgiven :D

#209 dr.who

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Posted 26 January 2013 - 11:23 PM

Skyview pro is what I use and it will not work with the VX. The base on the mount is now different on the VX than the CG5 with the base being wider which in theory means more stability.

Orly- Sure ;). But I am aiming for 5 minute subs or greater as I plan to do narrow band...

#210 landshark99

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Posted 26 January 2013 - 11:36 PM

Thanks,so at this point there does not seem to be a pier option for the VX

#211 dr.who

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Posted 27 January 2013 - 01:34 AM

Unfortunately no mate. Unless you want to have one fabricated you are going to be out of luck. I am thinking about it but not too much at this point because I still have my CG5 so there isn't much point to it.

#212 cn register 5

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Posted 27 January 2013 - 04:58 AM

I've done three minute exposures with the AVX with no problems. I can see no reason why it could not do 5 minutes or more.

I've attached an image, this was about an hour of 3 minute exposures. I've had to crop it to get it below the CN size limits. I'm not a good astrophotographer (as this shows), it was stacked using deep sky stacker and some light curves applied, that's it.

Chris

Attached Files



#213 orlyandico

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Posted 27 January 2013 - 05:14 AM

Chris, what scope? if it's a C8 or similar that's fine, that scope has a much shorter moment arm than the ES127.

#214 cn register 5

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Posted 27 January 2013 - 05:27 AM

Oynx 80EDF and a ST80 mounted side by side on a massive Al plate. It's reasonable heavy, especially once two ccd cameras are added.

Chris

#215 orlyandico

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Posted 27 January 2013 - 06:29 AM

ahhh... there's the thing. an ED80 is quite in a different class from an ES127... although its an SBS with a heavy plate, the moment is still fairly concentrated near the scope axes.

not like the ES127 which is a triplet ( = heavy cell ) at the end of a 1-meter long tube.

#216 cn register 5

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Posted 27 January 2013 - 08:42 AM

Just send me the ES127 and I'll try it and let you know :)

Chris

#217 orlyandico

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Posted 27 January 2013 - 11:07 AM

it's not mine :D

#218 dr.who

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Posted 27 January 2013 - 11:15 AM

Sure Chris. No problem! Right after you send over $1,600 US... :lol: Seriously thank you though for the image. I am not so much worried now about the weight it is sounding more like it's going to be a problem with vibration than weight due to size of tube. Looks like the only way to find out is to just bloody well man up and try it! :lol:

#219 bunyon

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Posted 27 January 2013 - 05:51 PM

The image is nice. The main question I have is whether or not the declination axis on the vx has less (or no) stiction/backlash trouble relative to the cg5. Those of you with the mount, can you comment on that?

#220 tiptip

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Posted 28 January 2013 - 12:34 AM

For anyone looking to buy the advanced VX mount, check this:

http://www.youtube.c...h?v=T03G0DZMJ9E

We need more reviews and videos about it.

#221 Ray Gralak

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Posted 28 January 2013 - 09:06 AM

Just so you know, the AVX has a 144 tooth gear so the worm period is 598.362 seconds.

PECTool handles this with no problem, PEMPro may need a bit of juggling to set the right period. I've let Ray know so.

Chris


The latest build of PEMPro V2 (Build 131) now supports the AVX. Anyone who wants to try it just use the Check for Updates feature in PEMPro's help menu.

-Ray

#222 zawijava

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Posted 28 January 2013 - 10:59 AM

I can say this Paul, I contacted Celestron Tech Support on Jan 14th 2013 and asked for clarification regarding the VX Dec Axis design, bearings or no bearings(?). After 4-5 days of no response I sent a followup email that got their attention. Their response: "Thank you for contacting Celestron Technical Services. I am sorry that it is taking a little longer than anticipated for a response. I have sent an email out to our engineering staff regarding your inquiry. We have not been given the full details of this product yet, so I am waiting on a response from our engineering team. Thank you for your patience." That was on Jan 18th....still nothing :shrug:

I'm not that impressed at this point :bangbangbang:

The image is nice. The main question I have is whether or not the declination axis on the vx has less (or no) stiction/backlash trouble relative to the cg5. Those of you with the mount, can you comment on that?



#223 bunyon

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Posted 28 January 2013 - 11:15 AM

Well, I don't really care if it has bearings, no bearings or little magical leprechauns inside it. I just want to know if it moves better in Dec than the CG5.

I really like the CG5 and have had a lot of (for me) success with it. The ONLY thing I don't like about it is the Declination axis. It moves terribly and is essentially useless in guiding. By polar aligning carefully, I can avoid needing to guide in Dec. I would be interested in changing mounts if, and only if, I get the same performance in all other areas but can turn my PhD guiding Declination axis back on.

I am surprised you aren't getting faster feedback from them.

#224 zawijava

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Posted 28 January 2013 - 12:06 PM

FWIW I sent another email to Celestron Tech Support a sort while ago, it prompted an almost immediate response:

Hello Tim,

I am just as disappointed as you are. Unfortunately, it also looks like the new mounts also do not have bearings in the DEC axis. Again a apologize for such a long delay.

Best regards,

[name removed]

Celestron Technical Services Representative


Well, I don't really care if it has bearings, no bearings or little magical leprechauns inside it. I just want to know if it moves better in Dec than the CG5. I am surprised you aren't getting faster feedback from them.



#225 cn register 5

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Posted 28 January 2013 - 03:58 PM

I posted an image of a PHD graph on this thread. It's back a bit, about page 5 I think. It shows a consistent PEC error with a variation of a fraction of a pixel. I'm able to get nice images with round stars, I posted an image of M33 a bit back. I've never managed to get such good guiding with so little effort.

I think that Celestron have delivered what they say they have; improved Ra and Dec guiding with better motors, gearboxes and drive software.

Chris






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