Connecting Celestron CG5 Advanced GT

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Posts: 12
Joined: Fri Feb 22, 2019 12:53 am

Re: Connecting Celestron CG5 Advanced GT

Post by Bonorden » Wed Apr 24, 2019 9:54 pm

The cameras are recognized by the asiair...but the cg5 gets the error message “connection failed”.

I’ve tried all Celestron type mounts in the asiair selection/options. All come back with the same error message.

My CPC connects without issue.

Posts: 17
Joined: Sun May 06, 2018 8:52 pm

Re: Connecting Celestron CG5 Advanced GT

Post by TCampbell » Thu Apr 25, 2019 5:49 pm

Do you have the Celestron #93920 cable?

This cable plugs into the modular jack on your Nexstar hand controller and provides the RS-232 serial DB-9 Female connector which will attach to the DB-9 Male connector supplied with the ASIair.

The RS-232 standard for the 9-pin connector (and earlier DB-25 cables) had many pins that served some function in the days before UARTs (Universal Asynchronous Receiver Transmitter chips) were available. But today the UARTs do most of the heavy lifting and the only pins that are really used anymore are the "transmit", "receive" and "ground" pins ... just 3 of the 9 pins are used.

Pin #5 is ground. On the "male" side pin 3 is transmit and pin 2 is receive. On the "female" side, pin 3 is receive and pin 2 is transmit.

While that part is "standard" ... each vendor does their own proprietary thing when decided how those pins map to the modular jack that plugs into the scope or hand-controller. It's really not possible for ZWO to supply all the possible connectors because there are so many of them.

They supply the interface that gets you to the DB-9 male connector ... and you have to supply the cable that gets you from the DB-9 female connector to whatever it is your scope needs. (Some scopes are supported via direct USB and don't need the RS-232 DB-9 adapters).

Hopefully the correct cable will resolve the issue. If it does not ... you may need to contact Celestron.

I'm not sure about Celestron ... but some scopes don't leave the serial port enabled at all times (some don't enable it until after the star alignment is completed.)

Posts: 12
Joined: Fri Feb 22, 2019 12:53 am

Re: Connecting Celestron CG5 Advanced GT

Post by Bonorden » Thu Apr 25, 2019 10:11 pm

I have that cable but hadn’t tried it.

I just tested without success...however, it is daylight now. I’ll try tonight after an alignment and see if that makes any difference.

Thanks for the suggestion,

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