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Does CGE Have A Future?

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#1 Jeff55

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Posted 19 January 2009 - 09:05 PM

With both the CGEM and soon to be available CGE PRO filling high and low end of the mount market for Celestron...what's the future of the CGE.

#2 Strgazr27

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Posted 19 January 2009 - 09:35 PM

As of the last update it's fine and will continue to be offered by Celestron. It fills a gap between the CGEM (EQ6 Class) and the CGE Pro (AP900 Class) mounts and does it aamzingly well at that. I don't think you'll see it go away anytime soon. There are a few small things that could use a going over and perhaps that is what Celestron is in the process of doing. I'll tell ya this if they could fix those few small things, design it to look like the Pro I think they'd be hard pressed to keep them in stock.

#3 HaleBopper

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Posted 20 January 2009 - 07:07 AM

What are some of the small things that would need to be looked at, (improved), in the CGE? I have never used one, but won't rule out the possibility of getting one.

Thanks.

#4 rmollise

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Posted 20 January 2009 - 08:09 AM

What are some of the small things that would need to be looked at, (improved), in the CGE? I have never used one, but won't rule out the possibility of getting one.

Thanks.

Mainly the external cables--like the dec cable. Because of the cable material used and the way they are connected, these are a source of constant trouble. Also, the limit switches. Other than that, especially with the new software, not much to nitpick about.

#5 Strgazr27

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Posted 20 January 2009 - 08:16 AM

What are some of the small things that would need to be looked at, (improved), in the CGE? I have never used one, but won't rule out the possibility of getting one.

Thanks.

Mainly the external cables--like the dec cable. Because of the cable material used and the way they are connected, these are a source of constant trouble. Also, the limit switches. Other than that, especially with the new software, not much to nitpick about.


:waytogo:

I'd like to see the clutch levers redone perhaps but that is about it.

#6 HaleBopper

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Posted 20 January 2009 - 08:20 AM

I'll assume that one can buy better quality cables from somewhere? I suppose that won't change how they are connected to the mount. Do they simply get in the way of operation?

What are the limit switches and how do they work or not work? What do you do to get them going?

Thanks.

#7 Jeff55

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Posted 20 January 2009 - 11:26 AM

Bobby;
Has there been discussion of a revised or updated GCE...I especially agree that if they changed the design to be a smaller, lower cost version of the CGE PRO...that would be a mount to want.

#8 MichaelW

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Posted 20 January 2009 - 11:37 AM

Funny Jeff, I sent an email to Celestron asking more or less the exact same thing. I loved my CGE. There was some what I considered minor issues, but the mount itself was fantastic. I still think it has a great future and a little tweaking would make it a long time fixture.

#9 Strgazr27

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Posted 20 January 2009 - 11:53 AM

Bobby;
Has there been discussion of a revised or updated GCE...I especially agree that if they changed the design to be a smaller, lower cost version of the CGE PRO...that would be a mount to want.


Jeff,

Not that I am aware of but it seems like a logical step with the release of the CGEM as well as the Pro. It would seem like a logical step for them to take and if any Ceelstron reps are listening.........Have at it! :)

#10 Tapio

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Posted 20 January 2009 - 12:04 PM

How about the meridian flip with CGE ?
Can you avoid it now ?

#11 Strgazr27

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Posted 20 January 2009 - 12:14 PM

How about the meridian flip with CGE ?
Can you avoid it now ?


Tapio,

Welcome to CN's!

The meridian flip can not be avoided with the CGE due to it's limit switches. Although this can be an inconvenience even the mighty Paramount ME needs to do a flip ;)

#12 TheMenace

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Posted 20 January 2009 - 12:28 PM

They would sell a lot more cge's if the price was $500 cheaper.
Not many people need a $3000 mount.

#13 Bowmoreman

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Posted 20 January 2009 - 01:07 PM

What are some of the small things that would need to be looked at, (improved), in the CGE? I have never used one, but won't rule out the possibility of getting one.

Thanks.

Mainly the external cables--like the dec cable. Because of the cable material used and the way they are connected, these are a source of constant trouble. Also, the limit switches. Other than that, especially with the new software, not much to nitpick about.


:waytogo:

I'd like to see the clutch levers redone perhaps but that is about it.


I would weigh in with a better hand control that would be more functional in really cold conditions... the LCD display is pretty much useless (and hence the entire mount) if/when temps get much below -5C or so...

I've asked my wife to knit me an HC cozy with holes for buttons and screen and into which I can easily slip a hand/toe warmer pack...

Other nits, not yet mentioned: the cable between the HC and the Pier needs to be about twice as long, and about 4 times as flexible (again in cold conditions).

Otherwise, its a great mount and pretty hard to beat in its price range...

Mine will probably ultimately get sold when I either go with an AP900/Mach1GTO or this beautiful looking CGE Pro model!

clear enough skies

#14 bseltzer

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Posted 20 January 2009 - 09:35 PM

What kind of PE are you guys getting out of your CGE mounts out of the box? Seems to me that PE would be a pretty big factor in the selection on a mount for AP. Certainly more of a factor than cables, clutch knobs, and other such issues that can be addressed with little time, effort or expense.

I have no first hand experience with CGE's, but I do have a strong interest in imaging. That's why I'm asking.

Regards,
Bert

#15 SleepIsWrong

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Posted 20 January 2009 - 10:08 PM

I have two CGE mounts - they run about 15-25" peak-to-valley PE uncorrected. Using the PECTool I get about 5" P-V PE.

Mike

#16 rmollise

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Posted 21 January 2009 - 07:25 AM

I'll assume that one can buy better quality cables from somewhere? I suppose that won't change how they are connected to the mount. Do they simply get in the way of operation?

What are the limit switches and how do they work or not work? What do you do to get them going?

Thanks.


You can, but part of the problem is that the way they are wired means the shields are used as conductors, which causes problems, no matter what kind you use. They fail.

Limit switches are just that, microswitches used to indicate positions during setup/alignment. They tend to fail/get out of alignment.

#17 bseltzer

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Posted 21 January 2009 - 09:41 PM

I have two CGE mounts - they run about 15-25" peak-to-valley PE uncorrected. Using the PECTool I get about 5" P-V PE.

Mike


Really? Is this typical of CGE's? I've thought they'd do better than that.

Regards,
Bert

#18 LarsZ

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Posted 22 January 2009 - 04:51 PM

I got my CGE last summer and it had a PE of 12.6 peak-to-valley (+- 6.3) out of the box. I learned that another buyer got a PE of 12.4 which means that at least our 2 are very similar.

I have read that older CGE:s have a larger PE, so it seems that Celestron has made some improvements over the years.

Regards
Lars

#19 Lane

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Posted 22 January 2009 - 10:24 PM

Since I have never done astrophotography I probably should not even be commenting but I thought the amount of PE made no difference if you are using a CCD Autoguider. I thought the only problem is when you have a sudden big change in PE that can't be corrected quickly enough by the Autoguider. Isn't that true?

#20 Alph

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Posted 23 January 2009 - 04:29 AM

I have read that older CGE:s have a larger PE, so it seems that Celestron has made some improvements over the years.



Not really. That's urban legend. I have one year old CGE and it has a PE of 20 arcsecs peak-to-valley.

#21 MichaelW

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Posted 23 January 2009 - 09:50 AM

Since I have never done astrophotography I probably should not even be commenting but I thought the amount of PE made no difference if you are using a CCD Autoguider. I thought the only problem is when you have a sudden big change in PE that can't be corrected quickly enough by the Autoguider. Isn't that true?

I have done a little astrophotography and I agree with your comment to a degree. There is a point where an autoguider cannot keep up with the significant change in the image. But the severity of the impact also depends on other factors such as focal length, sensitivity of the CCD and the overall time not on target. Most autoguiders can be set to specific intervals to sample for correction and if the sampling rate is high enough I would suggest that you can overcome most PE errors up to a specific focal length. Now what an autoguider cannot over come isn't PE error perse unless it is truly radical but a mount error where the mount stops tracking and therefore when you attempt to correct, correction isn't possible due to the mount not tracking.

At least this is the premise and understanding I run under and part of my justification of being able to go from a AP1200 with freaking unbeleiveable tracking back to the CGE (soon to be purchased) for me to re-enter imaging using refractors and shorter focal lengths with my ST-2000. And to be able to do so with confidence that the CGE will do the job I will ask of it.

#22 Jared

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Posted 23 January 2009 - 04:13 PM

Since I have never done astrophotography I probably should not even be commenting but I thought the amount of PE made no difference if you are using a CCD Autoguider. I thought the only problem is when you have a sudden big change in PE that can't be corrected quickly enough by the Autoguider. Isn't that true?


Yes, I believe that what you say is true--and I have some evidence to back it up (though the evidence is not from the most controlled environment). Below are two separate pictures taken on different nights using the same refractor and the same camera and the same exposure duration. The only differences are the mount and the night (and therefore, of course, the seeing and the focus). In both cases the mount was autoguided, and in both cases the autoguiding appeared to work well--meaning the the guide star was never lost and the mount was not chasing the seeing conditions.

The picture taken with the Mach1 GTO is significantly sharper than that taken with the Losmandy GM-8 (itself no slouch as a mount). Now, you could attribute it to better focus in one image, or better seeing conditions on one night, but that wouldn't explain why I see the same result in image after image.

Autoguiders can adapt to mounts with very large overall periodic error--as you can see in the picture with my Losmandy GM-8, the stars are nice and round--but they can not correct for rough tracking. An autoguider is, by its nature, reactive. It adjusts for error after it has occurred. I think that a lot of us using mounts that don't have very smooth tracking are throwing away some of the resolution our scopes are capable of. We may not know it since the stars are still shaped properly, but there is more detail there to be had.

The particular guiding software I use keeps track of the RMS error that it is guiding out. With my Losmandy GM-8 on nights with average or better seeing I typically saw values in the 0.4 to 0.6 pixel range (which is 1.2 to 1.8 arc seconds with my scope/camera combination) between guide exposures. With my Mach1 GTO I typically see values in the 0.00 to 0.05 pixel range (which is so small it may well be due to rounding issues in the centroid calculations rather than any second-to-second variation in tracking). That makes for a noticeably sharper image.

BTW, I'm not suggesting that the CGE isn't capable of very good tracking. I have never used one for imaging, so I simply don't have the experience to say what it might be able to do. However, those who point to low periodic error as in indication of good tracking ability (as well as those who point to high periodic error as an indication of a good tracking ability) are missing the point that in a system that is autoguided, the major issue is not overall periodic error but smoothness of tracking.

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#23 bseltzer

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Posted 23 January 2009 - 05:27 PM

Since I have never done astrophotography I probably should not even be commenting but I thought the amount of PE made no difference if you are using a CCD Autoguider. I thought the only problem is when you have a sudden big change in PE that can't be corrected quickly enough by the Autoguider. Isn't that true?


Auto-guiding can only correct an error after the fact. By the time a guider sees an error and responds to it, your data has been, to one degree or another, corrupted. Recording PE and using a PEC to minimize it is an attempt to prevent errors before your data is corrupted. The smaller and more regular, i.e., predictable, the inherent PE of a mount is, the more effective PEC can be in minimizing it's effect.

In other words, no, auto-guiding is most definitely not a substitute for accurate tracking. That's why I asked about it. At least for imaging, a mount's PE is the measure of it's merit, IMHO. Things like poor cables, weak saddles, shaky tripods,gnarly knobs, or even suspect electronics can all be fixed more easily than a PE of > 25". That's not to say bad PE can't be fixed. I've done it myself on an Atlas. But... it took me several months of sometimes frustrating trial and error to get a 50% reduction. That shouldn't come as a surprise when you consider the number of components in a drive system and the huge difference teeny, tiny little imperfections in any single one of them can make.

Short version... 1) PE matters. 2) Auto-guiding doesn't change #1

Regards,
Bert

#24 rmollise

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Posted 23 January 2009 - 05:48 PM

Short version... 1) PE matters. 2) Auto-guiding doesn't change #1

Regards,
Bert


Nevertheless, given good focus and collimation, autoguiding produces good images, just as manual guiding did before there was such a thing as PEC, and when 30-arc seconds was considered "dang good."

:lol:

BUT...I do NOT think you can go wrong buying the best mount you can afford, up to and including AP and Bisque and beyond.

#25 Jared

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Posted 23 January 2009 - 05:59 PM

Since I have never done astrophotography I probably should not even be commenting but I thought the amount of PE made no difference if you are using a CCD Autoguider. I thought the only problem is when you have a sudden big change in PE that can't be corrected quickly enough by the Autoguider. Isn't that true?


Auto-guiding can only correct an error after the fact. By the time a guider sees an error and responds to it, your data has been, to one degree or another, corrupted. Recording PE and using a PEC to minimize it is an attempt to prevent errors before your data is corrupted. The smaller and more regular, i.e., predictable, the inherent PE of a mount is, the more effective PEC can be in minimizing it's effect.

In other words, no, auto-guiding is most definitely not a substitute for accurate tracking. That's why I asked about it. At least for imaging, a mount's PE is the measure of it's merit, IMHO. Things like poor cables, weak saddles, shaky tripods,gnarly knobs, or even suspect electronics can all be fixed more easily than a PE of > 25". That's not to say bad PE can't be fixed. I've done it myself on an Atlas. But... it took me several months of sometimes frustrating trial and error to get a 50% reduction. That shouldn't come as a surprise when you consider the number of components in a drive system and the huge difference teeny, tiny little imperfections in any single one of them can make.

Short version... 1) PE matters. 2) Auto-guiding doesn't change #1

Regards,
Bert


That's interesting, Bert. You and I seem to have had similar experiences but drawn different conclusions. I don't worry about the total amount of periodic error--any more than I worry about absolutely perfect polar alignment--because autoguiders seem to do a nice job of correcting for both periodic error and drift as long as the error is gradual and smooth. Of course you are correct that technically some error has already been introduced before an autoguider can address it, but as long as the error remains low enough to be masked by other sources of error such as seeing conditions, I don't worry about it.

That being said, I agree with you that there is no substitute for a good mount--smoothness, I believe, is of paramount importance--and total periodic error often correlates well with the quality of the mount.






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