Celestron CGX Mount (Updated 6/27/17)

This tab will deal with the new Equatorial mount from Celestron the CGX.  Any views in here are independent.  The mount was bought by me and my review will be based on what I find out about it both setup and use.  This blog entry will be on going as it will be dependent on the weather.  All photos will be taken by me.

I bought the mount at Skies Unlimited in Pottstown, Pa for full retail price.  This was the first one they received and I did not delay picking it up. The first thing you notice is the handles which make carrying the mount easier.  It is still difficult to get out of the box because of the tight fit, but that means a plus in security in shipping.  

Here my friend and fellow amateur astronomer and Boyertown Planetarium director, Pete Detterline, is holding the mount to show how easy it it to carry with the handles.  It took about 90 minutes to assemble, mount the scope, balance and roughly align all three scopes (main, guide and finder) to be within a reasonable range of each other.  When done it looks like this.

The scope is an Edge 9.25 the guider is an Orion 80 mm and the finder is a stock Celestron finder.  The mount comes with two 11 pound counterweights and I found I needed to add an AVX counterweight to balance this setup.

The tripod is definitely wider for stability and the center post does not go up into the mount like other Celestron mounts.  It's only purpose is for the spreader.  They now use the tray that is used on the Evolution line of scopes.  The legs of the tripod have black lines and in between the lines there are indents to use as a reference for setting up the length you want your tripod legs to be.

One of the first things I noticed was the lack of index lines on the mount.  My friend, Pete Detterline has experience with CGE Pro and told me that the set position is probably built in at the factory like the Pro and would activate when shut down.  When we aligned the three scopes and shut down after slewing around it did go to a previously set position to shut down.  I will be looking at this more since like most people I didn't read the manual yet.

Another thing noted in the random slewing was the quietness of the mount.  If you own a DX or CGEM you know they can sound like a truck sometimes.  This one doesn't.  Also, the slewing is very smooth and you can watch the belts and gears through little windows to check on their operation. (BTW...one of the little things that won't mean much to some, but I find as an excellent touch is that Celestron supplies the wrench that is used to tighten the bolts that secure the mount to the tripod and is used for other bolts if necessary.  They also allow it to be stored under the handle in the back of the mount at the bottom.  No fumbling around looking in the dark in containers or whatever.  Small thing, but very useful.)

At the end of the first day I hope I have clear skies tomorrow night to do the 2+4 and PA and maybe a few images.  I discovered one con tonight.  The software download from Celestron to control the scope is not up yet on their website.  Lets hope they post it soon.

End of Day 1.

Unfortunately other things prevented me from doing anything with the mount last night although it was a clear night (wasted a good night although the dew was heavy).  Now rain is moving in for the weekend and the next clear night might be Sunday, but more likely Monday so I went out and took some random shots of the mount to show more detail.  See Below.

Close up of the where the mount attaches to the tripod.  There are 3 bolts about 120 degrees apart.

More views of where the mount attaches to the tripod.

Outlets available.  HC goes into one AUX.  Other is available for things like Star Sense.  Others are for PC control and autoguider.

Close up of handles in front and back for ease of handling.

Photos showing the windows where you can see the belts and gears and check on their status.

First light 10/7/16

Last night had high clouds moving in because of an approaching front and outflow from Hurricane Matthew so it wasn't in the cards to do any imaging last night.  However it was good enough to do a 2+4 align/cal and a ASPA to prepare for the next clear night.  During the ASPA a problem showed.  While my friend, Pete Detterline, was doing the ASPA the altitude knob quite adjusting the altitude upwards. It was loose.  We had to stop and think this through when I noticed one of the Allen screws in the knob was loose while the other two were definitely tight.  So I put the knob back on and ran it down to the nut and washer and once they met I turned the alt knob a few times to make sure it was flat against the nut and I tightened the set screw as tight as I could.  That fixed it.  So then Pete did another ASPA and got it to all zeroes except for one second of altitude.  Not good enough.  I always want all zeroes.  So Pete graciously did it again and this time "BINGO" all zeroes.  I don't know if the screw came loose in shipping, wasn't tightened good enough at the factory or if we has a flaw in the system.  Afterwards it dawned on me I should have put some clear nail polish or something on it to hold better, but if it comes loose again I will do that.  Considering calling Celestron next week and let them know about this and see what they think.  The picture below shows the knob and the set screws.  If this happens to anyone else please let me know by email or in the comment section.  Miserable day here.  Imaging is next.  Hopefully Sunday or Monday night.


Home grown tracking test.

Last night I did a new 2+4 and ASPA on the mount and made sure that it read all zeroes on the Display Align before continuing (took two tries).  I then inserted a 12mm illuminated reticle eyepiece that has a small box at the center for centering.  I picked Mirfak for the test.  I centered Mirfak in the box and then left it there to track for 15 minutes.  Let me discuss my view of tracking for my personal reasons.  Where I live (about 41 miles NW of Philly and 20 miles south of Allentown and 15 miles east of Reading, Pa) light pollution is a problem.  Personally I wouldn't shoot unguided at all and my exposures on a good night would be no longer than 8 min at the most.  Usually I shoot multiple exposures between 2 and 5 mins and stack them.  Those of you who have it better than me....enjoy the skies.  So I decided to let the mount track for 15 min unguided on Mirfak.  When the time was up I came back and was pleasantly surprised to see that Mirfak was still basically in the center box.  It had drifted left so that the star was slightly over the left line that outlined the box.  I reset it to the center to try another one for collaboration and left.  I got involved in a phone call and didn't come back for 26 min.  Expecting the star to now be noticeably outside the box I was shocked, but ecstatic the the star was still in the box.  This time it was completely in the box , but was off center left slightly after 26 min.  I concluded the difference in star position (better in longer exposure) was do to my setup.  I have my scopes on a deck.  No permanent placement here.  The first time I walked away I walked around the mount and left a different way.  The second time I walked carefully back away from the mount and came inside through a different door.  i believe the give in the deck caused more movement i the first try.  I am very pleased so far with this tracking on such a medium priced mount.  I am planning to do this test again when I bring it out of hibernation the next time to see if it duplicates the result.  Imaging is a no go right now because of the Moon.  I will try an unguided exposure of 1 or 2 min just to see when I do.

Update 10/25/16

I have not been too successful in getting the weather to cooperate.  It's either cloudy, bright moon light and now that the Moon is starting to be absent and the skies are clear the wind has decided to flex its muscles.  Winds have been breezy and gusting anywhere from 20-40 mph the last 3 days.  Hopefully it will get better soon.  Welcome to Pennsylvania weather.  Just wanted to let all watchers of this article know I haven't forgot.  Thanks for your patience.

I have read several postings on Cloudy Nights about mounting a CGX on a pier.  Since I am not in that boat I don't know if this is useful information or not, but below is a link to a PDF file from Celestron showing the schematic of a pier adaptor needed.  

Link to file: Cgx001revb CGX Adapter To Pier

Update  11/11/16

Finally started getting some time to work on imaging with the CGX and my Edge 9.25 when the scope started to have a problem after a very dew laden night.  I had to take it over to my goto guys at Skies Unlimited in Pottstown, Pa (you can google their web sight).  They are very knowledgeable not only in sales, but in helping with the gremlins that seem to show up now and then.  While they have the scope my rig for imaging with the CGX will be a StellarVue 130 mm refractor that Vic Maris has manufactured a reducer for that drops the setup from an f 7 to an f 5.6.  The guidescope is a StellarVue 60mm APO and the camera will be a Canon 60Da.  See the picture below of the setup.

Now if the 20-40 mph winds will just let up I will be in business.

Update 11/17/16

Tonight had a three hour window between sunset and moonrise to do some imaging with the above setup.  Below are the results...

This is a 30 second unguided image of Albireo using the CGX mount.

This is a one minute unguided image of Albireo using the same setup.

This is a one minute unguided image of M27 The Dumbbell Nebula.

This is a 5 minute guided image using the CGX and SV 130 mm at f 7 (I did not use the .8x reducer/flattener), an Orion Starshoot Autoguider and a Canon 60 Da.

As soon as I figure out how to get graphs from PHD2 I will put them up.  I have never done that before, so bear with me while I learn.  If anyone can give me any info on how to do that please email me at dfisherows@gmail.com.  Thanks.


A few more unguided images from tonight.

30 secs  M31

75 secs  M31

90 secs of M31

Pec graphs will have to be done by someone else because of my inexperience with that situation.  I will be adding graph(s) of guided situations as soon as the weather allows(high winds here next two days).



I haven't forgot about this write up.  As the song goes for this season "Oh, the weather outside is frightful".  Clouds on top of clouds and when it is clear, the winds are howling.  Last night it was still and broken clouds so I did a fresh 2+4 and a new ASPA and had a PEC done before it totally clouded over and rain is expected for today. The next time I can image(hopefully before next summer) I can do imaging with the PEC on and off and hopefully some graphs.  Until then...clear skies somewhere.

PoleMaster now mounted on CGX/Edge 9.25

Update 6/27/17

M27 using my StellarVue 130mm f5.6, the CGX and a Canon 60Da.  Four exposures totaling 10 minutes.

Update 7/10/17

M27 (a favorite target when attempting differing techniques) taken with a Canon 60Da multiple exposures of 2 minute duration and stacked.  Scope was an Edge 9.25 on the CGX.  Guider was a ZWO ASI120MM-S.  Skies were very bright due to 1 day past Full Moon.

(More to Come...Check back)


  1. Which adapter did you use for the polemaster mount.

  2. Thanks for this post. I am currently trying to decide between this mount and the Atlas EQ-6 Pro. I currently use an ED80 mounted on a Sirius mount (on a concrete pier) for imaging but eventually I want to upgrade to an ES-127mm Triplet. I probably will not move the new mount to concrete pier anytime soon so I will be setting it up and taking it. Thanks again. - Kurt http://kurt-zeppetello.blogspot.com/

  3. Hi Dave. you have a excellent web site. I have subscribed. Just wanted to know if you are having good luck with the CGX. I am thinking of this one and the CEM60. what would be your choice. They both have great reviews. Thanks Bill Needham Bgalxie@comcast.net

  4. Honestly, I have 2 CGXs and both were early production run including one that was #12 out of the factory. Both have performed well for visual and with guiding. I had 2 CEM60s early production run and neither one worked right. I understand later non-EC versions were corrected, but I still won't buy anything IOptron anymore because of my experience. Do your research and weigh them evenly. Any mount could be a lemon from anybody. Buy through a reputable dealer who will replace or send back to the factory for you. Determine what you will use it for. Visual is more forgiving. Good luck and welcome aboard. Let me know what you decided and why. I'll be curious to hear your response. Clear skies.

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  7. ASPA stands for all star polar align. This is Celestron's hand control program to do a polar align which you need to do for astrophotography. The 2+4 stands for 2 alignment stars and 4 calibration stars which is necessary for the go-to function for finding stars to work good. When you star up pick 2 star align and follow what the HC tells you. When prompted for calibration stars do all 4. Some do 2 or 3, I do all 4.