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Celestron AVX mount w/ 9.25": Any visual users?

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#1 AstroTrev

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Posted 23 May 2018 - 10:28 PM

First some background. I've been very active in astronomy for about 8 years now, including being a board member in the local club for many years, traveling to star parties, and doing outreach. I started off with a 120mm refractor with a non-go-to Skyview Pro, then got an old late 80's Meade 10" Newtonian mirror around which I designed and built from the ground up my own dob. The refractor is not APO and is lacking the aperture I desire, and my homebrew dob has a really long setup time because it is designed to be stored as compactly as possible (whole thing collapses into the mirror box). I'm looking for something that can give me decent aperture, have increased portability, decreased setup time, and I'd like to finally get a go-to mount. I started looking at the Celestron Evolution line, but thought the flexibility of a GEM would better suit my needs which are strictly visual (Too many of our club members take really nice photos for me to make the investment! I'll just look at theirs!).

 

I've dug through countless reviews of Celestron's 9.25" SCT on all sorts of mounts, and have not really found any that fit my situation. They are all either beginners, interested in imaging, etc. I feel like going from my 10" dob to an 8" would be disappointing from an aperture perspective, and going to something like a C11 is really outside of my price range. The 9.25 on the AVX seems to fit the bill, but there seems to be huge disagreement on whether or not the mount is actually capable of handling the load. I plan to replace the straight through finder with a red dot, add the Baader 2" visual back and diagonal so I can use my 2" eyepieces (the Nagler Type 4 line + the 31mm and a couple Delos), and a heated dew shield. My back of the napkin math comes to about 24#, assuming I'm using the 31mm grenade, and the mount is rated to 30#. Really just looking for some people who have experience with a similar setup to confirm or deny that the AVX mount paired with the 9.25 is suitable for visual, if I'm better off going with the Evo and giving up the flexibility of a GEM, or if I should just take a pill for aperture fever and get the 8".



#2 Axunator

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Posted 23 May 2018 - 11:23 PM

You will likely receive replies that are both pro and against. The reason being that sensitivity to vibration in visual setup is a very subjective thing. I use C9.25+2” diagonal+heavy 2” eps on HEQ5, which is quite comparable to AVX in terms of payload capacity - if something, it’s a bit heftier. It works, but I consider my setup undermounted and am planning to upgrade the mount. I like the scope to be stable when I focus at high power, and this setup doesn’t provide that. Yet many others would not be bothered by minor shakes lasting for 1-2 sec. My setup is also a bit too sensitive to wind, IMO.

Tripod, balancing and arrangement of counterweights affect stability as well. You could e.g. just upgrade the tripod, or get a clamping spreader (check TPIAstro.com) or anti-vibration pucks if you want to use AVX head but improve the stability of the overall setup.

But yes, AVX would work - but whether it’s good enough for you, you can only know for sure by trying.

#3 tonyt

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Posted 23 May 2018 - 11:24 PM

. The 9.25 on the AVX seems to fit the bill, but there seems to be huge disagreement on whether or not the mount is actually capable of handling the load. 

For visual use the AVX is perfectly fine carrying a C9.25.

 

Whether you go for the Evolution/AVX and C8/C9.25 just comes down to personal preference, with significant differences in portability. 



#4 tonyt

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Posted 23 May 2018 - 11:26 PM

In stock form the AVX is probably less vibration prone than the HEQ5 simply because of the different tripods (I've owned both).



#5 aa6ww

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Posted 24 May 2018 - 04:05 AM

I'm not impressed with the AVX mount for any SCT larger then an 8". I've looked through a 9.25" on an AVX with 2" eyepieces and a 9x50 finder and it was more than the mount could handle. Settling time was annoying. To me, any settling time is bad. I don't like the feeling of any scope that feels unstable on an undersized mount. 

 

The AVX is over rated at 30 pounds for a person actually using the mount. Its fine for the bean counters who say the mount can safely handle the weight, but these smaller mounts are unrealistically rated for people who actually use them.

 

The AVX mount is no more steady then my GP-DX mount with is rated at 22 pounds. The 9.25 is the shortest scope for that weight that can be mounted and the mount is undersized. 

 

The GM8 for example, is rated at 30 pounds, and it can support a C9.25 and 2" eyepieces with no issues. 

 

Personally, if I had an AVX mount, and a C8 wasn't enough aperture for me, I'd still get the 9.25". Id have to. At some point I would break down and sell the C9.25 and get a C8, or keep the 9.25" and get the CGEM mount instead.

 

...Ralph


Edited by aa6ww, 24 May 2018 - 04:06 AM.


#6 CHASLX200

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Posted 24 May 2018 - 05:16 AM

It would be pushing it for my taste. I have a SW 150 Mak and it was just a little too much for my GP mount.  I bought a G8 and it is much better.  Bigger mounts mean not so much a grab and go and they weight more.



#7 macdonjh

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Posted 24 May 2018 - 07:51 AM

A friend of mine used a C9.25 on an AS-GT (predecessor of the AVX) for several years.  A capable combination for visual.


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#8 ckhorne

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Posted 24 May 2018 - 08:05 AM

I used my C11 on my AVX for a few months without any trouble for visual. I wouldn't recommend it for DSO astrophotography, but it can carry a 9.25 without too many issues. Would a heavier, more capable mount work better? Sure. But the AVX is capable.


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#9 bikerdib

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Posted 24 May 2018 - 08:32 AM

Everyone will have their own opinion.  I use my 9.25/AVX as a remote location travel scope.  I ordered the scope with the larger CGE saddle ("D" series) and replaced the saddle on the AVX with the ADM Accessories saddle and highly recommend this combination because lots of the focus vibration people talk about comes from the smaller "V" series dovetail that the stock AVX requires.

 

It gives nice views, of course nowhere near what my 14" Edge does but the 14" and CGE PRO are MUCH more work to travel wiith.  The standard 9.25 is my choice over the 9.25 Edge because the flattener/FR for the standard is much cheaper and by having it the 9.25 is really versatile.  You can use it native for long focal length high power views or put on the FR and get pretty decent widefield views.

 

I use a Williams Optics 2" dielectric diagonal and 2" eyepieces without issue.  Like has already been said, since the weight is near the rated capacity of the AVX, balanceis important but easily doable.

 

Good luck with whatever you choose.



#10 gfstallin

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Posted 24 May 2018 - 12:00 PM

For visual and planetary imaging, I have not had any issues at all using an AVX (with upgraded ADM saddle - personal preference, not necessary) and regular tripod. The photo below was taken with a C9.25 on an AVX. Tracking was fine.

 

17
Album: Planetary Images
1 images
0 comments

 

Vibrations are fine for my taste, but vibration toleration is a highly personal thing. No, it is not as rock solid as my iOptron Tri-Pier/EQ-6 setup, but I also keep my planetary imaging at a minimum when tropical depressions are rolling over my area at the same time we are experiencing earthquakes. I generally do not dance around the tripod or practice drums on the OTA while looking through it. A little care goes a long way toward avoiding unnecessary vibrations with this setup. 

 

George


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#11 Mitrovarr

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Posted 24 May 2018 - 02:07 PM

People routinely underestimate the AVX. I use mine with a 10" Meade and it's fine.

#12 dr.who

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Posted 24 May 2018 - 02:15 PM

Used mine with a 11” EdgeHD for visual no problem.



#13 AxelB

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Posted 24 May 2018 - 02:47 PM

Maybe you’ll miss the field of view. The shorter length of a C8 will show a bit more field, even if there will be some vignetting from the narrower baffle tube while using the 31mm Nagler. Visually it may not botter you.

Edited by AxelB, 24 May 2018 - 02:47 PM.


#14 Cpk133

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Posted 24 May 2018 - 05:48 PM

Been using the 9.25 AVX combo for a few years now so I can offer some impressions and a short dissertation:  I consider the 9.25 to be the max I'd want to put on this mount.  The longer aspect ratio of the 9.25 (due to its superior f2.3 primaryblush.gif) places the balance point further aft relative to its brethren.  Mounted on a GEM, it translates into a larger working envelope for the eyepiece.  It's not like using a refractor, but it does make you move around a bit more (count on using an adjustable observing chair).    The other downside of the C9's optically superior primary, is that added length means you have a longer moment arm.  Heavy accessories, and dew shield create more forces for the mount to overcome and more vibration.  To mitigate these effects, I used a China marker to mark the center of the saddle and to mark the dovetail balance points for the OTA in various configurations (dewshield with diagonal and eyepiece, no dewshield and eyepiece, binoviewer....etc).  If I'm doing specialized observing, I'll bias or match that config.  Now the positives.  The mount isn't a total wimp.  The motors have a good bit of torque.  Most nights, I split the balance points and just plug and play without issue.  I customized the slew speed to 1.5 deg/sec.  Its not fast, but it handles the load no problems.  It's also much quieter at that speed (no coffee grinders please).  Damping time is couple seconds max.  When it's windy, I'll usually forego the dewshield and it does fine.  With dewshield, it doesn't take much of a breeze to make thing so shake.  Pointing accuracy is somewhat variable.  Some parts of the sky are perfect, others are off by a degree.  Would the C9 be happier on a CGEM or a CGX, you bet.  I originally ordered a 11edge CGEM, but changed my mind when I started thinking about schlepping it around all the time.  The AVX is very strong for its weight.  I carry the mount and tripod as an assembly right out the door, down the deck stairs, up the stairs, with no effort.  I'll let you in on a little secret about the AVX.  The RA and DEC bushings are plastic (at least I think they are) and they have a bit of stiction.  Some people complain that it's difficult to balance as a result or they try to oil / fix them.  It's the way the mount is designed.  So here's the secret.  You can mount a grab n go refractor or small compound scope, balance it, plop it down roughly polar aligned, and use it as a push to grab and go.  Once you acquire your target, all you have to do is push on the counterweight shaft and that stiction will hold things when you let go.  It's a beautiful thing.  No batteries or cords.  As far as C8 vs 9.25 goes, for visual, go with the C9.25.  Standard disclaimers apply YMMV.

 

ps: I'm going to be in Cleveland this weekend.  If I wasn't spending a couple days at a travel soccer tournament, I'd bring the scope for you to try.  Hot cars and SCTs aren't  good combo.frown.gif


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#15 gnowellsct

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Posted 25 May 2018 - 01:06 AM

One of the finest combinations in amateur astronomy is a 9.25 on a G11.
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#16 AstroTrev

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Posted 25 May 2018 - 07:29 AM

Thanks for taking the time to provide some responses. It has been very helpful. I keep looking back to my original purpose with this, which was portability for outreach events and quick backyard observing, and it seems like mostly any option using the 9.25 will decrease portability. I'm thinking about the Edge 8 on the AVX mount as a happy medium. I can get the better optics for a little less cost than the 9.25, be comfortable that the mount can handle it, and will be filling that portability gap. When I was really thinking about it, any trips I take to dark sky sites, like Cherry Springs next month, I'll be taking the dob for to most light grab anyway. I'm not trying to replace my dob, more fill a gap in usability. I'm still going to do so more thinking, so comments still welcome!


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#17 Jim4321

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Posted 25 May 2018 - 08:18 AM

Comments still welcome?  Okay, here's one.... If  primary considerations include portability and quick setup for outreach, consider the Celestron Evolution, in 8", 8" Edge, or 9.25".  I'd argue that it is about 75% easier to get up & running than a GEM, if you just want to do visual.  With Sky Portal / Sky Safari, the wifi connection and initial alignment are quick and easy, or if you're a bit of a technophobe, the hand control is plenty easy to use.  Being strictly a visual observer doing frequent outreach, I literally haven't had my old GEM out of the closet in almost 4 years.

 

You can add the StarSense, and the Evo becomes almost self-aligning (I haven't bothered, since 'manual' alignment with the app is so easy).

 

 

Jim H.


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#18 John SC

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Posted 25 May 2018 - 08:38 AM

I would agree with Jim - the Evo / 9.25 makes a GREAT outreach pair, and it comes with a much heavier weight tripod than either an Evo / C8 or the AVX / 9.25 combinations.  It is much quicker to set up and align than the AVX, and if you ever want to get polar aligned (i.e., develop an interest in AP) there are two different wedges you can add to this combination to allow that.  The better optics might be valuable for you, but the extra light of the 9.25 will be the improvement that the outreach visitors will notice.  And a focal reducer would take care of the field of view concerns that were addressed above.

 

Note - I have both mounts.  I have not yet put the 9.25 on the AVX (they are in different states, hope to get them together soon!) but I do intend to try that later in the year.  

 

John P.



#19 AstroTrev

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Posted 25 May 2018 - 09:01 AM

I had written off the Evolution because I was concerned clearance along the bottom with a 2" diagonal and eyepieces/weight management on a single arm side mount. It looks like there is a lot of space under there, but hard to tell what would/wouldn't fit from a photo.



#20 Jim4321

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Posted 25 May 2018 - 09:16 AM

My solution (9.25 with 1.25 diagonal) for assurance in the dark while well-balanced was to create a 'rear-handle delete' model, but I did it after the warranty expired:

2lc4p5e.jpg

It goes vertical, no issues.

 

Of course, if there's something up there that you really want to see, another solution is to just wait a hour....wink.gif

 

Jim H.


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#21 Cpk133

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Posted 25 May 2018 - 08:34 PM

They should sell the 8edge evo with the heavy duty mount.  I'd be inclined to go with the 8" on the evo for clearance.  It's a better match for a quick outreach setup either way.  No counterweights to fuss with.


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#22 ewave

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Posted 25 May 2018 - 08:46 PM

For outreach I highly recommend the EVO Alt-az mount with a C8 edge. It is hard to beat, especially if only being used for visual.

Now for astrophotography/sct combo I wouldn't recommend using an AVX mount, however for visual only I highly recommend the AVX for something like a C9.25.  My C9.25 edge rides on top of the AVX easily without breaking a sweat.



#23 AxelB

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Posted 28 May 2018 - 05:12 PM

For outreach I highly recommend the EVO Alt-az mount with a C8 edge. It is hard to beat, especially if only being used for visual.

Now for astrophotography/sct combo I wouldn't recommend using an AVX mount, however for visual only I highly recommend the AVX for something like a C9.25.  My C9.25 edge rides on top of the AVX easily without breaking a sweat.

 

How much counterweight do you need on the avx to balance the c9.25 Edge (with dew shield, heavy 2" eyepiece and 9x50 raci finder)?



#24 Poconut

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Posted 28 May 2018 - 05:32 PM

If you are strictly visual, the AVX will be just fine on the 9.25".  I even have a buddy that does astrophotography on the exact setup and he seems to be happy.



#25 robbin

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Posted 28 May 2018 - 06:41 PM

You didn't mention the CPC line--its heaviest piece is generally heavier than any one piece for the EVO or AVX and so may be the reason you are not considering it.  It is, however,  in my experience rock steady.  I have looked through an evo 9.25 and while certainly usable, it definitely shakes during normal focusing which the CPC's don't, to any appreciable degree. 

 

Also the GEM motions of the AVX will move your eyepiece around as you know quite a bit more than the alt az setup of the CPC's or Evo's--both of which I have found very comfortable when observing.  For purely visual I don't see an advantage to the gem in goto configuration, alignment is a bit more fussy in addition to having the larger eyepiece motions.

 

If you don't mind a bit of jiggle (or are very careful when focusing or purchase a motorized focuser) the EVO sounds like it fits your needs very well. If you don't mind the added weight, the CPC's I think are solid and comfortable.  And of course if you want to be aligned directly with your sky atlas coordinates the AVX is great too.

 

Curious what you decide to do but all sound workable.


Edited by robbin, 28 May 2018 - 06:42 PM.



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