More about connections

[mhamburg44]

I had no success in posting a reply directly in the old messages so I resorted to posting a "new" message. Forgive me. 

Is the the usb-serial adapted cable the very same one that I have used to update the hand controller? Let me get this right: If I want to use the hand controller via Ascom, the hand controller is connected to the pc via said cable. Then a serial cable connects the mount to the pc? Where?(CGEM. I am using a powered hub right now. Also, there are 2 cables connected to the Lodestar -- a data cable and a mini usb for power. I know this is probably simple but for first time users, it could never be too simple! What would help for insecure people like me would be a simple schematic showing all the connections. Many thanks. Michael

[Bryan]

Michael

You might want to poke around in Mike Swanson's site.  It is fairly up to date; although David Carter's cables (astrogadgets.com) are no longer available.

http://www.nexstarsite.com/

It has info on all the Celestron Nexstar line, including the CGEM.  There is a diagram that may be helpful. The PHD2 folks can't possibly provide diagrams for all the potential configurations.

I used to have a CGE. I hope my experience is helpful.   However, the CGEM is somewhat different in terms of what ports are available and the following is a just a theory on my part.

The CGE has a standard port (PC Port) that allowed me to connect the mount to my PC via the serial-USB adapter that Bruce mentioned.  Using this, the Celestron ASCOM driver, and Cartes du Ciel (or other compatible planetarium programs) in combination with NexRemote, that comes with all Celestron Nexstar mounts, I can control the mount without the need for the Hand Control or HC cable.  This includes both GoTo and guiding.  With the ASCOM driver installed, I eliminated the ST-4 cable from the guide camera to the mount and use PHD2 pulse guiding.

You can get the equivalent of the PC port using the Auxiliary Port Accessory Kit (part number 93965) .  This plugs into the AUX port on the CGEM.  However, Celestron may not make this part anymore.  DIY approach is possible.  

http://www.nexstarsite.com/OddsNEnds/PortsCGEM.htm

The 4-connector RJ-45 on the Hand Control is NOT the same as the 6 connector RJ-12 needed for the PC Port.  Also, do NOT connect a serial port - RJ12 cable directly to the AUX port.  The 93965 kit (hard to find) is needed.

In re-reading the above, I recognize that it is complex and, perhaps, not helpful.  I don't have enough experience with the CGEM  to make it better.  My apologies.  Hopefully someone with CGEM experience will be more helpful.

Bryan

[peter wolsley]

Michael,

I own a CGEM and here is what I do and know.

The usb-serial cable you used to update your hand controller is the only cable you need to use.  Connect this cable in exact same way that you did when you updated your hand controller.  The small four pin connector plugs into the bottom of your hand controller.  Your hand controller then needs to be plugged into your CGEM as you always have been doing.  When you plug in the usb-serial cable into a usb port on your computer it will be assigned a COM port number (COM3, COM4...etc)  Whatever port is assigned is the com port number that the Celestron ASCOM driver will use.

This is the simplest arrangement for getting PHD2 to provide guide pulses to your CGEM using the ASCOM software.  You will no longer need to attach the ST-4 cable between your camera and the AUTO GUIDE port on your CGEM.

I have assumed that, because of how you posed your question, you do not use the Celestron software program called NexRemote on your computer.  You align and calibrate your mount using the handcontroller.  You also use your hand controller to GOTO whatever object you wish to photograph.  If this is true then you are good to go.  There are other features that are now available to you because you have converted over to ASCOM.  Those features can wait while you focus on getting your PHD2 calibrations and pulse guiding back on track.

Peter

[mhamburg44]

Hi Peter,

First let me thank you for the reply. I am not at the site of my equipment so I am at a disadvantage trying to see all these permutations. My pc is in a separate warm room about 10 feet from the mount. Just about everything is routed through a powered USB hub. The HC is connected with a powered  extension cable so I can use it in the warm room. How does the powered hub feature in the new configuration? How is the Lodestar camera powered? And the data cable? Once again thank you and I will be better able to figure this out once I am my observatory. To be continued, I'm sure.

Michael

[peter wolsley]

Michael,

Since we are adding only one additional cable I would say that all of your existing connections stay the way they are.  The Lodestar camera can be powered using your usual method...including it's data cable.  You should only need to connect the usb-to-serial cable between your handcontroller and a spare USB port on your computer.  This would mean that you need to keep your handcontroller in your warm room.   You can always disconnect the usb-to-serial cable if you need to do something with the handcontroller right at the mount...this will cause your pulse guiding to stop because you no longer would have a connection for ASCOM to communicate.  PHD2 will generate an error message but it's relatively easy to get PHD2 going again.  This may seem to be a bit of a pain but remember that you are troubleshooting your pulse guiding.  There are nice improvements that are available to you but you should really get your pulse guiding problem fixed as a priority.

Once you have your pulse guiding figured out you can enjoy trying Celestron's NexRemote program.  NexRemote gives you all the functionality of your handcontroller on your computer screen and allows you to use Celestron's NexTour program.  You can also experiment with Celestron's PECTool program.  My personal opinion is to not spend to much time persuing PEC on your CGEM...it's a can of worms.  I know what I'm talking about.

There are also great programs like Stellarium which will give you an incredibly detailed sky chart displayed on your computer screen.  You can actually pan and zoom in to a galaxy using Stellarium and then have Stellarium send a GOTO command to your CGEM.  Stellarium will also display your CGEM's location graphically in real time which is really fun to watch.

These are advanced topics...your focus must be to get pulse guiding up and running!

Peter

[mhamburg44]

Peter,

Thanks again. Your name sounds very English. Besides cyberspace, are you in the U.K?

Michael

[peter wolsley]

Michael,

My roots are English/Irish. I live in very snowy Canada.

Peter

[mhamburg44]

If you are ever in NYC, let me know. I work at the American Museum of Natural History and  love giving to tours to visitors.