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Equipment Discussions >> Mounts

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mclewis1
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Reged: 02/25/06

Loc: New Brunswick, Canada
Re: CGE Pro: Anyone have a good one? new [Re: James Cunningham]
      #5366594 - 08/13/12 02:39 PM

Quote:

A friend just purchased a 14 inch SCT on the CGE Pro mount. The instructions say nothing about how to get a Polar alignment. It just says pick the all star and let the scope slew to the first star. The manual also says nothing about where to orient the scope. It does not even mention the Polaris star. How do you srart to get an alignment with the CGE Pro mount? Thanks.



There is a good write up on the All Star Polar alignment in the manual. It's not in the hand controller section but more towards the back. It's in the Astronomy Basics section under Polar aligning the mount.

You don't use Polaris with ASPA ... that's why it's called "all star".

You don't care about initial positioning the otas since the CGEPro has home position switches.

You do an initial alignment then you do an ASPA. For visual work you usually (like with all Celestron gems) don't need to do any form of polar alignment ... doing the initial alignment will give you accurate gotos.

It would be best if your friend first read the manual and then opened up a posting with his questions ... it's not going to work well if you are "translating" for him Jim.

Edited by mclewis1 (08/13/12 02:43 PM)


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Daniel Mounsey
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Re: CGE Pro: Anyone have a good one? new [Re: James Cunningham]
      #5366607 - 08/13/12 02:43 PM

Quote:

A friend just purchased a 14 inch SCT on the CGE Pro mount. The instructions say nothing about how to get a Polar alignment. It just says pick the all star and let the scope slew to the first star. The manual also says nothing about where to orient the scope. It does not even mention the Polaris star. How do you srart to get an alignment with the CGE Pro mount? Thanks.




It starts on p.38 Here's a PDF to help just in case.

http://www.telescopes.com/images/pdf/CELE319.pdf


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KDizzle
scholastic sledgehammer


Reged: 09/12/08

Loc: Woodinville, WA
Re: CGE Pro: Anyone have a good one? new [Re: Jared]
      #5366613 - 08/13/12 02:47 PM

Quote:

Here is the disadvantage to AO... You need a bright guide star in the field of view. If you really want to adjust things on the order of 2-5 Hz or even faster, that requires either an extremely fast scope or a very short focal length scope (in which case even a moderate quality mount can probably handle things without the help of AO).
...
Now I'm imaging at 2,000mm+ and I just don't see how to make AO work.




Jared, I think we have the same scope here at 2m fl -- the AT10RC. I never have issues finding guide stars with LRGB if I use very slow guide times like 3-5 sec. This is what I'd say is typical for the average autoguider anyway, and I'd argue it would still be better than moving hundreds of pounds of mass. (Note the above 30 min frames were done with an OAG at 2.5s on the CGE Pro.)

Now, If I use faster guiding (like subsecond) it can become an issue but usually only requires rotating the camera or slewing to somewhere "near" my target that doesn't perfectly center it. I wouldn't call this "a challenge" as much as I would "wow that chip is huge and I'm going to crop it anyway". This is with the AO-L and STL 11k, so I don't know how this compares with your AO-7 experience.


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KDizzle
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Reged: 09/12/08

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Re: CGE Pro: Anyone have a good one? new [Re: David Pavlich]
      #5366620 - 08/13/12 02:52 PM

Quote:

A good topic, OAG, but if we could, get this back on the CGE Pro topic? Thanks!




CGE Pro is an inexpensive mount. With good OAG or AO, despite having "apparently poor" peak-to-peak PE, it will run with the best of them. Chances are you're going to use using OAG or AO (or at least a guidescope) if you're doing imaging and therefore it's a helluva deal, easy to use, transportable, and well supported.


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KDizzle
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Reged: 09/12/08

Loc: Woodinville, WA
Re: CGE Pro: Anyone have a good one? new [Re: James Cunningham]
      #5366629 - 08/13/12 02:57 PM

Quote:

A friend just purchased a 14 inch SCT on the CGE Pro mount. How do you srart to get an alignment with the CGE Pro mount? Thanks.




Lots of good responses here already but here's my wisdom on the topic. BTW, now I actually use my 50mm guidescope to do the alignment, centered with my eyeball to it, so even though my alignment is never perfect, it's set up extremely fast.

Anyway:

Quote:


Perform a two-star alignment. I added one calibration star. (In my case, I used Algenib in Pegasus as a calibration star.)
At the end of this alignment, press the “Align” button again and select “Polar Align” -> “Align Mount”. When you do this, the scope is going to move (from the star it was pointing at, Algenib) to “where it would be if it were properly aligned.”
Recenter the same star with the Alt/Az controls on the mount. The handset will tell you in big letters: “DON’T USE THE HAND CONTROLLER TO MOVE THE MOUNT”. Remember, the idea here is that we want to get polar alignment which means the actual axis of the mount must move!
The manual falls a bit short of emphasizing how important it is then to go back and recalibrate for the GOTO’s to work. At this point, you’re tracking, but you’re not GOTO’ing! So I went back and re-found my original two-star alignment stars and replaced them with their new positions. Of course, it’s okay to use the hand controller at this point.





Some people turn off the scope and turn it back on to see how well they did here also.


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freestar8n
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Re: CGE Pro: Anyone have a good one? new [Re: Alph]
      #5366645 - 08/13/12 03:05 PM

Per the moderator's request - please spawn a separate thread if you want to discuss this further.

Frank


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psu_13
sage


Reged: 05/30/10

Re: CGE Pro: Anyone have a good one? new [Re: freestar8n]
      #5366672 - 08/13/12 03:14 PM

This is what I used to do to set up my CG-5 with all-star polar align. The process should be the same for a CGE.

http://atelescopeinthecity.blogspot.com/2011/10/grab-and-go.html

Note the use of a video camera for this is of course optional.

Somehow I did forget to mention that you should always center starts with the UP and RIGHT keys on the pad. I might have an earlier page where I did that.

Also, I think my general experiece was that doing the pointing alignment over again after shifting the polar axis is probably a good idea even though the system is supposed to compensate. My mount would sometimes be "off" after a polar align. Was never sure why.


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KietTran
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Reged: 05/14/12

Re: CGE Pro: Anyone have a good one? new [Re: freestar8n]
      #5367630 - 08/14/12 12:46 AM

Frank,

I have been mostly a lurker on some Y! groups and in fact this is my first post here. I'm in the market for a mid range telescope mount like the CGE-Pro.

You have some very compelling arguments below. Which AO units have you tried and on which mounts?

-kt

Quote:

Quote:

Every time these PE discussions come up, AO never seems to enter the discussion. Doesn't it make sense to move a tiny refractive element super fast without a giant pile of weight on it? Or still everyone thinks it's best to move a huge mass ever-so-slightly while combating the manufacturing challenges of pi?




I consider AO to be proven technology that will make a mid-range or even lower grade mount perform, in terms of fwhm, like a high end mount - but it has many disadvantages.

Results from AO provided evidence for me many years ago that tighter guiding was possible with low latency and a good centroid. AO for amateurs was originally intended (I believe) to help correct seeing in the 10-20Hz range, but the benefits with mid-range equipment were obvious even when used at around 1 Hz, and much slower than seeing. I could tell from images I saw on the web whether an lx200 shot used AO or not - even when it was correcting at 1 Hz or slower.

If you go from a small guidescope to AO you are not only getting the lower mechanical latency of a small moving element - you are switching to OAG and low latency corrections without a shutter. But there is nothing that prevents a mount from responding in less than one second. So - as long as the autoguider feedback is prompt, a mount can achieve similar tightness of guiding without the need for added complexity of AO.

AO has several flavors nowadays - reflective or refracitive; guiding before the filters or after. But for correcting mid-range mounts (not seeing) I think you can get nearly the same benefit in the 1 Hz range with tight guiding and OAG.

Unfortunately there are "expert" web pages on autoguiding that say you should make as few corrections as possible because each correction introduces "noise." I would say instead that you should make corrections at the optimal rate - whatever it is - that is needed for your mount. If you steer a cruise ship across the Atlantic you probably don't want to jerk the steering back and forth rapidly - but if you are off-roading in a jeep you had better keep your hands on the wheel.

Also unfortunate - many people using OAG are not dialing in the brightest guide star available and instead they just expose longer - perhaps 5 seconds - until they can see a guidestar that happens to fall on the chip. This is fine for high end mounts because they are truly smooth over this time frame - but for mid-range mounts it will prevent prompt corrections to faster terms. I recommend dialing in the brightest guidestar available with OAG. This points out the inherent benefit of high end mounts, in that such details and added care may not be needed. But similar results can be obtained when added effort is made in directions that actually yield smaller fwhm.

Frank




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freestar8n
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Re: CGE Pro: Anyone have a good one? new [Re: KietTran]
      #5367704 - 08/14/12 03:33 AM

Quote:

Which AO units have you tried and on which mounts?




Hi and welcome to CN.

I have tried zero - none - of the AO devices myself, but I like to go by actual images that people post and I can see clear benefit of AO with mid-range mounts even when run at "slow" rates of 1 correction per second.

I don't know the full range of AO options nowadays but for narrow band work I would certainly want one that allowed guiding on the unfiltered star.

My main points, regarding AO and mid-range equipment, aren't specific to the cge-pro - and they don't really promote AO either - since AO adds cost, complexity, uses back focal distance, and it could break. My main point is that comparisons based on PE alone aren't very meaningful, and that optimal guiding with a good OAG centroid can make mid-range mounts yield results more comparable to high end ones. Data supporting that conclusion are in the cge/cge-pro images on the MetaGuide site.

Frank


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Bowmoreman
Clear enough skies
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Reged: 09/11/06

Loc: Bolton, MA
Re: CGE Pro: Anyone have a good one? new [Re: freestar8n]
      #5368267 - 08/14/12 12:36 PM

Lets please at least *try* and keep this thread On Topic...

thanks!


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KietTran
member


Reged: 05/14/12

Re: CGE Pro: Anyone have a good one? new [Re: freestar8n]
      #5368726 - 08/14/12 05:00 PM

Quote:

Quote:

Which AO units have you tried and on which mounts?




Hi and welcome to CN.

I have tried zero - none - of the AO devices myself, but I like to go by actual images that people post and I can see clear benefit of AO with mid-range mounts even when run at "slow" rates of 1 correction per second.

I don't know the full range of AO options nowadays but for narrow band work I would certainly want one that allowed guiding on the unfiltered star.

My main points, regarding AO and mid-range equipment, aren't specific to the cge-pro - and they don't really promote AO either - since AO adds cost, complexity, uses back focal distance, and it could break. My main point is that comparisons based on PE alone aren't very meaningful, and that optimal guiding with a good OAG centroid can make mid-range mounts yield results more comparable to high end ones. Data supporting that conclusion are in the cge/cge-pro images on the MetaGuide site.

Frank




Frank, from what I've read on the web (and by the subject of this thread) the quality and capabilities of mounts seems to vary significantly. So how many different CGE-Pro mounts have you used and what's your opinion on the quality of them from your personal experience? Again, I ask because from your posts you seem to know a lot and so I am hoping to glean enough information to make an informed decision on a CGE-Pro mount for imaging.

Thanks,

kt


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orlyandico
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Re: CGE Pro: Anyone have a good one? new [Re: KietTran]
      #5368763 - 08/14/12 05:35 PM

KT, well the "new" CGE Pro's are "guaranteed" by Celestron to be +/- 3".. but as the OP pointed out, there seems to be a dearth of reports from "new" CGE Pro owners..

and as Frank points out PE isn't everything..


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freestar8n
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Re: CGE Pro: Anyone have a good one? new [Re: KietTran]
      #5369475 - 08/15/12 03:32 AM

I'm just talking personally about one dang cge and one dang cge-pro, but my approach to autoguiding applies generally to mid-range mounts from all manufacturers. If I can make even one such mount guide well, without AO, I consider it sufficient to demonstrate that the inherent components and PE are not fundamental limitations in terms of what matters - which I consider to be long exposure, well-guided fwhm.

What are you imaging with now - and do you have a web page of example images? Where are you located and what kind of skies do you have? What do you want to image and with what OTA?

Frank


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KietTran
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Reged: 05/14/12

Re: CGE Pro: Anyone have a good one? new [Re: freestar8n]
      #5371338 - 08/16/12 10:03 AM

Frank,

I have no mount, nor even a CCD camera yet. I'm trying to determine which mount would be good to get. I've had a few other hobbies where I've made the mistake of buying something cheap then being sorry about it. I want to do my homework and find a good mount that I will be able to use for a long time and be happy with it. I'm not sure what kind of imaging I will like but since I live in a metropolitan area I might be restricted to planetary and narrow band imaging.

From what I have read there seems to be a tremendous variation in mounts, even in the same model from the same manufacturer. It seems the more you spend the greater the chance that you won't get a lemon and the less effort you have to put into getting a mount to work well. Even you say that to get a mid-range mount to act like a high-end mount you have to guide at 1-second intervals or use an AO device. If this is what is required to get consistently good images with the CGE Pro then I think I might want to consider a higher end mount.

Thanks again for your valuable feedback,

kt

Quote:

I'm just talking personally about one dang cge and one dang cge-pro, but my approach to autoguiding applies generally to mid-range mounts from all manufacturers. If I can make even one such mount guide well, without AO, I consider it sufficient to demonstrate that the inherent components and PE are not fundamental limitations in terms of what matters - which I consider to be long exposure, well-guided fwhm.

What are you imaging with now - and do you have a web page of example images? Where are you located and what kind of skies do you have? What do you want to image and with what OTA?

Frank




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EFT
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Re: CGE Pro: Anyone have a good one? new [Re: KietTran]
      #5371361 - 08/16/12 10:19 AM

Quote:

From what I have read there seems to be a tremendous variation in mounts, even in the same model from the same manufacturer. It seems the more you spend the greater the chance that you won't get a lemon and the less effort you have to put into getting a mount to work well.




This is actually only partly true. Higher end mounts may be more consistent in quality but they are notoriously more difficult to use. The consumer level mount companies spend a lot of time making their hand controllers and mounts relatively easy to use and user friendly. In general, the high end mount companies tend to spend more time on the mount and less time on the user friendly side. So if you purchase a mount from one of the big two, you are likely to get it out and working fairly quick while a high end mount will have a much steeper learning curve. It can be an important difference, especially for someone just starting out. Some mount control programs can even this out but the software is neither cheap nor always easy to use. The general assumption with high end equipment is that most people already know a lot about what they are doing so that the ease or difficulty of the mount's use is not as much of an issue.


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Jared
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Re: CGE Pro: Anyone have a good one? new [Re: KietTran]
      #5371688 - 08/16/12 02:31 PM

Quote:

Frank,

<snip>

From what I have read there seems to be a tremendous variation in mounts, even in the same model from the same manufacturer. It seems the more you spend the greater the chance that you won't get a lemon and the less effort you have to put into getting a mount to work well. Even you say that to get a mid-range mount to act like a high-end mount you have to guide at 1-second intervals or use an AO device. If this is what is required to get consistently good images with the CGE Pro then I think I might want to consider a higher end mount.

Thanks again for your valuable feedback,

kt






There is one other factor at work as well which often gets overlooked... The difference in expectations. You'll get visual users, for example, saying a mount is wonderful if it is easy to setup and use, doesn't vibrate (or dampens vibrations quickly) when focused, and has accurate go-to slews.

For an astrophotographer, this is just the starting point. The mount also needs to track well under load--with smoooooth periodic error--and needs to be easy to guide, either through the inclusion of an ST-4 port or similar capabilities in the hand controller. It's not at all uncommon for visual users to report that a mount is wonderful while an astrophotographer provided with the same mount would say it is terrible and/or overrated in terms of carrying capacity.

Finally, even within astrophotographers there are fairly significant variations in expectations. Lots of astrophotographers are happy with 3.5" FWHM stars and 30 second unguided exposures as long as the stars appear round. Others expect fifteen minute guided exposures with 2" FWHM stars in all subs. These are dramatically different standards, and a mount/scope/guiding combo that easily meets the 3.5" FWHM threshold can be very challenging to get to the 2" FWHM range. It's all about expectations.

So, when evaluating feedback on particular mounts keep the context in mind. Is it an astrophotographer complaining about difficulties guiding? A visual user might not care. Is the person stating how wonderful a mount is using an 80mm refractor or a 10" Mak Newt? Depending on what you intend to do, the feedback can be accepted at face value or may need to be weighted according to the use.


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KietTran
member


Reged: 05/14/12

Re: CGE Pro: Anyone have a good one? new [Re: EFT]
      #5371984 - 08/16/12 06:24 PM

Quote:

Quote:

From what I have read there seems to be a tremendous variation in mounts, even in the same model from the same manufacturer. It seems the more you spend the greater the chance that you won't get a lemon and the less effort you have to put into getting a mount to work well.




This is actually only partly true. Higher end mounts may be more consistent in quality but they are notoriously more difficult to use. The consumer level mount companies spend a lot of time making their hand controllers and mounts relatively easy to use and user friendly. In general, the high end mount companies tend to spend more time on the mount and less time on the user friendly side. So if you purchase a mount from one of the big two, you are likely to get it out and working fairly quick while a high end mount will have a much steeper learning curve. It can be an important difference, especially for someone just starting out. Some mount control programs can even this out but the software is neither cheap nor always easy to use. The general assumption with high end equipment is that most people already know a lot about what they are doing so that the ease or difficulty of the mount's use is not as much of an issue.



Yes, I do realize that that higher priced mounts will be more sophisticated and likely have a steeper learning curve. I am not sure that is much of a drawback for me because I think I want a mount that I could grow with for many years. I think this is maybe a better alternative (for me) than a mount I would have to tinker with, changing gears or having to do 1-sec autoguider cycles, all in search of better tracking.

So, to keep this on topic, what features does the CGE Pro have that would make it easier to use than a higher end mount?


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freestar8n
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Re: CGE Pro: Anyone have a good one? new [Re: KietTran]
      #5372005 - 08/16/12 06:40 PM

For a beginner I recommend a simple mount and a small refractor guided by a guidescope. Very forgiving and should make nice images so you can get experience with how this stuff works and decide what you want to do - and if you even enjoy imaging in the first place.

Frank


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KietTran
member


Reged: 05/14/12

Re: CGE Pro: Anyone have a good one? new [Re: Jared]
      #5372015 - 08/16/12 06:48 PM

Quote:

There is one other factor at work as well which often gets overlooked... The difference in expectations. You'll get visual users, for example, saying a mount is wonderful if it is easy to setup and use, doesn't vibrate (or dampens vibrations quickly) when focused, and has accurate go-to slews.

For an astrophotographer, this is just the starting point. The mount also needs to track well under load--with smoooooth periodic error--and needs to be easy to guide, either through the inclusion of an ST-4 port or similar capabilities in the hand controller. It's not at all uncommon for visual users to report that a mount is wonderful while an astrophotographer provided with the same mount would say it is terrible and/or overrated in terms of carrying capacity.

Finally, even within astrophotographers there are fairly significant variations in expectations. Lots of astrophotographers are happy with 3.5" FWHM stars and 30 second unguided exposures as long as the stars appear round. Others expect fifteen minute guided exposures with 2" FWHM stars in all subs. These are dramatically different standards, and a mount/scope/guiding combo that easily meets the 3.5" FWHM threshold can be very challenging to get to the 2" FWHM range. It's all about expectations.

So, when evaluating feedback on particular mounts keep the context in mind. Is it an astrophotographer complaining about difficulties guiding? A visual user might not care. Is the person stating how wonderful a mount is using an 80mm refractor or a 10" Mak Newt? Depending on what you intend to do, the feedback can be accepted at face value or may need to be weighted according to the use.



This topic is something I haven't quite got a handle on. In reading posts it has become clear that virtually every mount and scope has different performance characteristics. Also there is local seeing, which can vary dramatically. There are tube currents and issues of accurate focus and tracking. Because of all these conditions how can anyone compare the performance of their scopes in an apples-to apples way?


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psu_13
sage


Reged: 05/30/10

Re: CGE Pro: Anyone have a good one? new [Re: KietTran]
      #5372158 - 08/16/12 09:06 PM

My progression through mounts is documented here in the posts here:

http://atelescopeinthecity.blogspot.com

I started with the CG-5 to learn the basics relatively inexpensively. Then, since I could afford it, I jumped over the mid-end stuff to something that I knew would work and work really well (Astrophysics). Admittedly not everyone can or needs to do this.

It seemed to me that the mid-end stuff, between $1500 and $5000 is in a sort of no man's land. It's not cheap enough to be really affordable but it's also not enough better than the lower end equipment to make the jump in cost and weight and bother worth it. I didn't want to end up buying (say) a CGEM or CGE and then two years later turn around and get the Mach-1 anyway.

Also: While it's true that the consumer mount software has some nice features (like the all star polar alignment) after you gain some experience the non-consumer hardware, if you will, is not that much more complicated to run and the improved mechanics count for a lot. Polar alignment on an AP mount might seem more complicated at first, but the hardware is so ergonomic that it actually turns out to be a lot easier.

Just my experience. YMMV. etc.


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