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Buying Celestron CG-5 Mount

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#1 Javier

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Posted 04 October 2009 - 03:27 PM

I'm about 90% sure I'm going to order a Celestron CG-5 Advanced Series mount for my telescope. Before I jump in are there any CG-5 owners here that can chime in on the pro's and Cons of the mount?

For now I'm going to mount my Celestron Omni 150MM Refelector on the mount (it's currently for sale on S&S but if I get the mount I'm keeping it).

Have there been any chronic problems with the electronics or hardware such as it's motors?

Thanks,

Javier

#2 Eddgie

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Posted 04 October 2009 - 04:17 PM

These seem to be reliable mounts. The most common problem is that the small internal projection in the power plug on the mount looses contact with the tip of the power cord. A small screwdriver inserted in the slot to spread the pin open solves the problem (well, for a while andway).

Some people report that the power switch fails, but I don't know if this is "Common" (meaning I don't think that the average owner will experience it in normal usage), but it does appear to be an area where problems have occurred.

Othewise, I have owned 2 of these and both have been trouble-free.

A 6" refractor will tax this mount, but if you can live with some wobbling, it should serve ok for visual use.

#3 BlueGrass

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Posted 04 October 2009 - 04:41 PM

My CG5 has been very reliable and with the latest HC / MC firmware updates from Celestron, you get the All Star polar alignment capability. I replaced the Celestron AC/DC converter with an older Dell laptop power supply I found in my companies surplus equipment and the mount runs much smoother. This adapter provides a rock solid 12v @ 2A and the power plug is a right angle. Keeps the power plug from being pulled loose. Also the more recent CG5's with the latest firmware allow you to use PEC tool to load PEC corrections to the mount. All in all, the CG5 is a great entry mount and lots of people have had good success with it visually and for beginning AP.

#4 Doug76

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Posted 04 October 2009 - 04:41 PM

The only problem I've had with mine is I don't get to be at home enough to use it much! :lol:
Seriously, great mount, very accurate tracking and Goto, a bit noisy when slewing but that's not a problem to me. Some have reported problems with the power connector and power switch but I've had no trouble with mine.

#5 Gregk

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Posted 04 October 2009 - 04:59 PM

I use it for imaging Used to have one heavy atlas mount

A little noisy as reported and also the dec cord can be bothersome..for the money it's a best buy....

I guide with it doing 5 minute subs with 15lb capacity just fine Balance is critical

greg

#6 Patrick

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Posted 04 October 2009 - 07:40 PM

Hi Javier,

I've had 2 CG5's and found them to be a great value. The goto's are very accurate when done with a 2+3 alignment routine. The mount can carry a decent payload and I don't think you should have any problems with your 6" f/5 Newtonian (piece of cake...actually :smirk: ). At one time I put my 6" f/8 Newtonian on my CG5 and it worked very nicely even with it's longer physical length.

I use my current CG5 as my primary imaging platform which has a payload of about 24 lbs. You can see my rig HERE. I use physically short scopes which allows the mount to carry that much load when imaging.

As far as problems go, the main ones seem to be the on-off switch and the power connection, as previously mentioned. I will suggest one more thing which I've seen on several Celestron mounts recently. The hand controller buttons seem to take a little more pressure to get them to react than they should, ie, you have to really mash them down to get a response. On the other hand, even though the buttons on my unit were that way at first, it seems like over time the buttons don't require as much force as they used to...so maybe they just need to be 'broken in' (if that's possible...:shrug: )

Regarding periodic error, I've found that my mount is not capable of imaging at longer focal lengths (1000mm +) without throwing out a substantial number of frames...even with autoguiding. Others have had more success than me in that regard, so I don't know if it's my sample or my imaging techniques. I am imaging with good tracking at shorter focal lengths. If you're planning on imaging with the 6" f/5 (750mm focal length) you're probably okay with guiding.

To summarize, for the scope you're considering for the CG5, the mount is quite capable. For the money, it's a very good deal and one of the best mounts going. The hand box software is very mature and the All-Star polar alignment routine is a real time-saver (mainly important if you're imaging). There are a few negatives but they're not insur'mount'able (pun intended :smirk: )

Clear skies!

Patrick

#7 Javier

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Posted 04 October 2009 - 08:06 PM

Thanks to everyone for all the advice. I'll probably have my hands on one by Friday.

Patrick....nice rig man

#8 Chris Rowland

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Posted 05 October 2009 - 02:05 AM

Also the more recent CG5's with the latest firmware allow you to use PEC tool to load PEC corrections to the mount.

I think you may be confusing it with the CGEM, the CG5 doesn't have PEC.

Chris

#9 HaleBopper

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Posted 05 October 2009 - 06:12 AM

I recently upgraded to a Losmandy G11, but I kept my CG5. It has great gotos, and I was able, with autoguiding, to successfully image 5 min subs with a C8 using a 0.63 focal reducer. That would put my focal length at about 1260 mm I believe.

I also taxed the mount a bit on weight. My imaging system weighed just over 20 pounds in total. Not really recommended, but it worked out well enough for me. One advantage I had with the SCT was its length. It was not as susceptible to wind as a longer newt or refractor would be. I also had vibration suppression pads which helped a bit. If you have a lighter load, I think you can do well with this mount. IMO, you can get 5 min subs with autoguiding.

#10 Javier

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Posted 05 October 2009 - 03:18 PM

I took the plunge, it should be here by Friday. That means the it will rain or be cloudy for the next three weeks.

#11 BlueGrass

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Posted 05 October 2009 - 06:54 PM

Chris, you may be right... but I've used PEC tool to run a batch analysis and uploaded it to my CG5. I also was able to download it back to PEC tool. I'm not sure whether the CG5 actually used the corrections I uploaded to the mount but it did allow me to do it.... so it may just be a feature of the new HC / MC software that's enabled but not used by the CG5. I'll have to do some testing to see.... anyone else done this with their CG5s?

#12 mblack

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Posted 05 October 2009 - 07:09 PM

I took the plunge, it should be here by Friday. That means the it will rain or be cloudy for the next three weeks.


Javier- I also took the plunge on one of these babies. Should be arriving, with appropriate clouds, on Friday. The Naples tourists will _not_ be happy. ;)

Good luck to you :waytogo:

#13 Javier

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Posted 06 October 2009 - 04:15 PM

Would anyone happen to know if the 12V cigarett lighter adapter comes wiht the mout as well as the cable that conencts the hand controller to my PC?

Javier

#14 dandabson

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Posted 06 October 2009 - 05:12 PM

Power cable yes, interface cable no.

#15 Javier

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Posted 06 October 2009 - 05:37 PM

Would anyone happen to know the pinouts on the interface cable? I can probably make one.

#16 drksky

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Posted 06 October 2009 - 05:46 PM

The trick is that the connector on the handset is an RG-22.

Nextstar Site has lots of good information as well as pinouts in the firmware update section for the AS-GT mounts.

I made mine from a phone handset cord (RG-22 on both ends). Cut one end of and replace with an RG-6, then use an RG-6 to DB-9 adapter to get the right pinouts. Then a serial to USB adapter to connect to the computer.

Again, there's a very good section for this on the Nexstar site, complete with pinouts.

#17 Luigi

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Posted 07 October 2009 - 06:51 AM

Shop around and you might find the PC/HC interface cable for ~$10. I did. Look/Google for Celestron 93922. The usual price is around $25.

#18 Chris Rowland

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Posted 07 October 2009 - 03:04 PM

Chris, you may be right... but I've used PEC tool to run a batch analysis and uploaded it to my CG5.

I didn't know that!

PECTool runs and you can train PEC.
There's no PEC index detector so it's not clear if PEC can be synchronised after the scope has been restarted.
Maybe it's possible to train PEC, then replay it using PECTool but it may need retraining every time because a new one won't be synchronised to the worm gear.

Chris

#19 BlueGrass

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Posted 07 October 2009 - 07:47 PM

Actually if you use PEC tool on your CG5 it does seek and find the index mark. Once it finds it, you can then start running a batch analysis. I had mine out last night but it was just for some quick 30sec pics of various GCs. Didn't have time to setup the laptop too... but you're probably right. We may be able to use PEC tool to show the worm corrections, but the HC may not be able to apply them during tracking.... when I get time, I'm going to try it out anyway....

#20 anivision

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Posted 09 October 2009 - 02:21 PM

I sent a mail to Celestron:
"Is it possible to use PEC Tools aquired from your website here to record and correct the periodic error of my CG-5 mount? My firmware on the hand controller is the latest (at least I think so) 4.16."

And the answer I got from them:
"yes, it is already programmed into your hand control."

I hope this will help...

#21 BlueGrass

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Posted 09 October 2009 - 05:50 PM

Well now the question is, does the CG5 apply the PEC corrections all the time since there's no way to turn it on and off via the menus? at least that I can remember.... If the latest HC/MC updates enable PEC in the CG5's then Celestron has given us an upgrade... :-) I'd like to hear from other CG5 owners if they're looking at this and what their experiences are.

#22 Chris Rowland

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Posted 10 October 2009 - 04:43 AM

There's nothing controlling PEC for the AS-GT in the 4.18 HC software.
I think all the Celestron mounts need PEC to be turned on each time.

I asked my contact and got much the same reply as anivision, PEC can be done on the CG5 mount using PECTool but it's unofficial and unsupported.

BUT - and it's a big BUT - there is no worm gear index detector so the synchronisation of the PEC with the worm will be different each time. PECTool does a sync move but there's no hardware so nothing to sync to.

It is temporary PEC - TPEC. You will need to do a PEC calibration at the start of every session. However it might survive hibernation with a fixed scope.

But who knows what's possible! Maybe there's some way to determine or set the PEC index position so a previously determined PEC calibration can be used.

PECTool can be used to enable PEC, then disconnected.

Further experiments are needed...

Chris

#23 rmollise

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Posted 10 October 2009 - 08:50 AM

I sent a mail to Celestron:
"Is it possible to use PEC Tools aquired from your website here to record and correct the periodic error of my CG-5 mount? My firmware on the hand controller is the latest (at least I think so) 4.16."

And the answer I got from them:
"yes, it is already programmed into your hand control."

I hope this will help...


I wonder why they are not shouting this to the high heavens? Being able to use PEC with the CG5 would be a plus.

The latter part of the reply, though, "It is already programmed into your hand control" seems a little oddly stated, and makes me wonder if the person who answered you knew what she/he was talking about. Who will be the first to try a PEC playback with a CG5 (it's damned sure cloudy here)?

#24 BlueGrass

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Posted 10 October 2009 - 10:46 AM

We have a star party scheduled for tonight and I'm taking both mounts so I may get a chance... if the weather cooperates that is... what I was going to try was this:
Power and align the mount, start up PEC tool and have it seek the encoder index. Then simply let it run with the corrections I've previously loaded to the mount. I'm thinking this way because there is no way to turn it on or off via the HC so having PEC tool force the mount to seek the index will give it a starting point, i.e. act like a start command... does this make sense?

#25 rmollise

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Posted 10 October 2009 - 02:50 PM

We have a star party scheduled for tonight and I'm taking both mounts so I may get a chance... if the weather cooperates that is... what I was going to try was this:
Power and align the mount, start up PEC tool and have it seek the encoder index. Then simply let it run with the corrections I've previously loaded to the mount. I'm thinking this way because there is no way to turn it on or off via the HC so having PEC tool force the mount to seek the index will give it a starting point, i.e. act like a start command... does this make sense?


I'm not sure. I would guess that since it has no way of establishing the worm index/starting point, you'd have to do a brand new recording.






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