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CGX Alignments

beginner cassegrain Celestron imaging mount
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#1 sandconp


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Posted 16 January 2020 - 06:22 PM

I will be getting a CGX equatorial Mount this week.  I have always had a ALT AZ Evolution Mount and used Star Sense to perform usually a automatic alignment.  I under stand with an equitorial mount that the first thing I need to do before I start imaging is a polar alignment.


I have a few options like Sharpcap Pro or ASPA built into the CGX Mount or CPWI for Polar Alignment.


Just checking what tool is the best for performing a polar alignment? I do not want to spend $300 on a pole master because I don’t think it’s required with the other options I have.

So I was wondering what would be the chronological steps I would need to take to perform a polar alignment either using Sharpcap Pro or ASPA on the CGX hand controller?  I would also like to use my Star Sense for automatic star alignment after I perform the polar alignment.  So wouldn’t I have to be using my Star Sense Hand controller instead of the one that comes with the CGX?






Edited by sandconp, 16 January 2020 - 06:23 PM.

#2 Stargezzer


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Posted 16 January 2020 - 07:22 PM

I have a CGX and I only use the 2+4+ASPA. After you get the hang of it you can be aligned in just a few minutes. I can get up to 5' exposures unguided....but I usually use 2-3' exposures. I sometimes run a second ASPA to get dialed in.  The SharpCap PA is very popular with a lot of folks on CN as well. I just stick with what works for me. There are a few things you need to remember Always use the up button and then the right button on the HC to center the target in the ep. If you don't have an illuminated reticle ep you need to get one. Check out Uncle Rods blog. He has a lot of good info that helped me refine  my alignment  process. Feel free to PM me if you have questions. 

#3 MikiSJ


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Posted 16 January 2020 - 07:28 PM

Download a copy of the CGX manual. It discusses Celestron's method of alignment.


I am also a new CGX user but my sunny (NOT!) California weather has only allowed me one night of viewing. But I did a two star alignment using CPWI and it was close enough to keep my interest alive in wanting to spend more time with the C11/CGX combo.


Good luck!

#4 aa6ww



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Posted 16 January 2020 - 07:41 PM

Can't you just set your new mount on its index marks, balanced, then do a manual polar alignment using the knobs on the mount, centering Polaris in the telescope eyepiece. That should be more then close to start with. Then from there just turn on the mount and do the full Auto align, then come back and perform the ASPS from the hand controller?


#5 mclewis1


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Posted 17 January 2020 - 09:40 AM



Yes you can but it can be a little frustrating for some folks trying to center Polaris (with the polar offset taken into account) in larger (longer fl) primary scopes without some aids (offset marks in the finder, an external polar pointing camera, etc.).


You don't need to be that accurate starting off to be able to do a good initial alignment and then an ASPA. A better polar alignment before the initial alignment will make the initial alignment a bit faster (better slewing to the alignment stars) but it doesn't affect the final accuracy of the initial alignment, that is totally down to how well you do the initial alignment (good star choices, well centered, any backlash mitigated - using only up/right final movements) so most folks don't spend too much time doing pre initial alignment polar alignments.


Some who have external polar alignment tools like a Polemaster and the like can do a very accurate polar alignment first and then the initial alignment and be done.

Edited by mclewis1, 17 January 2020 - 09:42 AM.

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#6 skaiser


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Posted 17 January 2020 - 01:35 PM

With my cgx, starsense, CPWI setup.

setup mount, using phone app or iPad app to rough in polar alignment.

balance out ra and dec with all equipment mounted, leave mount a little west heavy. 

level mount using built in bubble.

startup mount with starsense connected 

run CPWI and connect to mount via cgx USB port ( this allows you to use hand control for jogging)

(note the cgx has home switches to auto home on during initial startup. No need to worry about alignment of markers on the axis)

run auto align with starsense 

( as you may know, if this is first time of starsense on the scope you will also have to cal starsense)

CPWI will then prompt you if you want to tweak polar alignment.

if yes follow instructions.

will then have to rerun CPWI with starsense to get final alignment.

(note. I have had problems using the DELETE ALIGNMENT function so I always restart CPWI for a new alignment)

Should be good to go.

take care

Edited by skaiser, 17 January 2020 - 01:41 PM.

#7 W7VL


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Posted 17 January 2020 - 02:02 PM

I recently purchased the CGX mount along with the edgeHD 11" SCT.

Since I'm a beginner in this hobby, I had a lot of frustration and a steep learning curve(see my post), but with some advice from CN folks and perseverance here's what I found.

1. Use the StarSense(SS) hand controller. The HC that comes with mount can be put away in a box. SSHC does everything the Nexstar HC does but is required for communication with the SS.

2. Use the HC instead of CPWI for alignment. My success was limited using CPWI or SkyPortal. Works fine for GoTo,mount slewing, and focusing but initial polar and SS align seems much better with hand control.

3. Keep the HC as warm as you can. Below 20 degrees, the scrolling on the LCD display is unreadable and the buttons seem to get "sticky". I keep mine in a wool sock with a hand warmer(advise from CN). Makes a big difference.

4. Check the settings for location, time , mount home position every time you turn mount on. I discovered that I was trying to align several times with incorrect info loaded. Don't know if I did it inadvertently or not, but I always check now. 

5. I have a clear view of Polaris so I don't use ASPA. The times I tried it failed, mostly because suggested stars weren't visible. The Celestron CGX polar scope works ok, but has some design flaws. Very difficult to initially calibrate and you have to remove it to slew mount in the dec axis. Don't know if it would stop before damage but can't be good.

6. Probably stating the obvious, but calibrating the StarSense camera is critical. Close isn't good enough! The more time spent coarse and fine centering the better your plate solving will be. An illuminated reticle helped me a lot. Which reminds me....don't forget to scroll HC up/down during each step. You can miss important instructions if you just hit enter button without reading all. 

7. Someone already said it, but make sure you slew up and right during centering. Need to see the little checkmark on HC screen to proceed.

8. The locking levers for CGX tripod legs need to be really cranked down once you level mount. Hand tight will not work. I've been out of level several times after I installed all equipment. I use a pair of channel locks now.

Hope all this helps

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#8 sandconp


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Posted 17 January 2020 - 05:58 PM

Thanks for all the suggestions.  Wish me luck when the snow and cold are gone.  In the meantime I will try and learn as much as I can indoors with CPWI and Sharpcap Polar alignment.

#9 speedster


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Posted 21 January 2020 - 09:18 PM

You will love the mount.  Easy polar alignment:  Get in the menu, hit "scope" or "utilities" and hit "move to switch".  It will slew to the switch locations.  Then, just use mount adjustment bolts to get Polaris in the finder.  Then get Polaris in the OTA where ever you want it and you're within less than a degree of the pole.  There is a free phone app that shows Polaris location in real time so you can see its offset from the pole.  If you need to get finer, run ASPA.

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#10 Bill G.

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Posted 22 January 2020 - 09:53 PM

I got one of these a few months back. Used it for AP a month ago. Did a rough visual PA with home position and the knobs then did the full alignment and polar alignment using CPWI and ASPA routine. It was a breeze!!! You can get a good PA with nothing else. I was very pleased. Had zero issues with guiding.
Bill G.
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