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Interested in computer control of your CGE?

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#1 jbalsam

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Posted 05 April 2013 - 12:44 PM

To anyone interested in controlling their CGE from a laptop, here's a list of what you'll need.

Buy any USB to male serial adapter ($20, same price as the one that Celestron sells but you can buy them at your local store so it saves you waiting for it) and one of these customizable RJ45-to-serial adapter and wire it up like this. Don't worry, they're super easy to wire and no tools are required. Just be sure you push the little connectors into place firmly. And grab one of those six-foot ethernet patch cables that you have lying around the house (or a longer one if you want to be farther from your scope).

You'll need to install NexRemote also (available free from Celestron page), and install the ASCOM drivers for all Celestron telescopes (get those here).

After that's all done you should be good to go. When you install your USB-to-Serial adapter it will create a COM port and give it a number (that number will change if you move the adapter to a different USB port). When you run NexRemote it will ask you to specify which COM port the scope is connected on (it will be a number, like 10, and if you can't remember which number it is, go to Device Manager in windows and look for something that says COM ports and use the number that's there). NexRemote will also ask you to specify a virtual COM port to use. This is the imaginary port that your telescope control program (maxim or whatever) will use. So when you go to connect to the telescope from Maxim, you tell it to look at that virtual COM port number that you specified.

You don't need to use another program, by the way. You can just use the hand controller on the screen if you want. But it's nice to have a program like Maxim because it has a much better library of items to search for.

Now if you're like me and you want to control your scope from your warm house, you need a few more bits and bobs. If you can pick up your home wifi signal from where your laptop is out there, you're good to go. If you can't, then get yourself a wifi range booster (I got a refurbished one from microcenter for $30 and it works great). Don't use your neighbors wifi; this needs to all be on your network unless you want to beg your neighbor to forward ports from his router. Next, go here and download TightVNC on both inside and outside computers. Set up and remember passwords for the program (done during installation). On your outdoors laptop, you should now see a little 'V' icon next to your clock on the task bar. If you hover over it, you'll see an IP address (something like 192.168.1.##) which you should write down or remember. Go to your warm indoors computer and start a TightVNC viewer (start, programs, TightVNC, TightVNC Viewer). It will ask for an address (type in the one from your laptop). If it sees that address, it will immediately ask you for a password (the one you set up on that machine when you installed TightVNC). Once you enter that, a window will open that shows you the screen on your laptop. When your mouse is inside that window, you can control your laptop from your indoors computer (at this point you should cackle maniacally with your new-found powers).

Before you tell your scope to slew to anything from the comfort of your house, make sure you can spin it in every possible direction without it crashing into anything or ripping out wires.

#2 Raginar

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Posted 05 April 2013 - 01:47 PM

Wow, cool :)

#3 mclewis1

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Posted 05 April 2013 - 05:29 PM

You actually have a few different options when considering how your going to control your CGE. You need to answer a few questions to determine which way to go.

1) Do you want to use the real hand controller for the initial alignment or do you want to run it from NexRemote? Real is easier but NexRemote on a PC means you have the option of remote control.

2) If you want to run from NexRemote do you want to connect to the mount directly or through the hand controller? Choosing directly means you can actually unplug your hand controller. This option works for any Celestron mount with the PC port (CGE, CGEPro, CPC, NexStar GPS). If you have a CG5, AVX, CGEM, etc. you don't have a PC port and therefore don't have this option. A PC port can however be added via a fairly simple hardware add on.

3) If you choose though the hand controller you'll need the Celestron serial HC cable #93920. It's an inexpensive thin short grey cable with a small RJ22 connector on one end. This cable is also used to upgrade the firmware in the hand controller and motor controllers.

4) If you choose direct connection without the HC you'll need the hard to find PC port cable #93922. This is a more complex serial cable. It's an RJ45 Ethernet patch cable with a small DB9 adapter on one end. This cable was once called a programming cable because once upon a time it was the only way to upgrade the firmware in the motor controllers. Since that's no longer the case the smaller #93920 cable is now often referred to as a programming cable (just to confuse things).

You can make your own versions of these cables if you choose - instructions are on www.nexremote.com

For controlling the mount you have many choices of software. You can use NexRemote on it's own. You can run a planetarium/scope control app like Stellarium which doesn't require ASCOM (this would be the absolute simplest setup - USB to serial adapter, serial HC cable, and Stellarium configured to directly control the mount and you're done). Or if you choose to use ASCOM and the Celestron driver you then have access to tons of other apps, some free some pay for (Maxim, Cartes du Ciel, The Sky, etc. etc.).

If you choose to use NexRemote you'll need to be careful of the real hand controller. You can still do your intial alignment at the scope but you start it all from the PC and the ONLY thing you use the real hand controller for is mount movement via the arrow direction buttons. All other interaction MUST be done with NexRemote so you need access to the PC as you perform the initial alignment. One option to make all this easier is to use a Gamepad connected to the PC and enable within NexRemote. The gamepad becomes a remote control unit that you can hold as you look through the eyepiece when doing the initial alignment.

If you setup a remote finder scope and remote viewing through the primary scope you can do all the initial alignment remotely. This is where having a local PC and a remote PC connected via Ethernet (wired or wireless) and controlled via VNC type of software really becomes necessary.

No matter which way you go you need as Josh has laid out, to properly setup your USB to serial adapter and if you want to run everything remotely the dual PC VNC (or similar software) setup.

#4 Tom Andrews

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Posted 06 April 2013 - 10:23 PM

Thanks for posting this. I had everything else handled but hadn't been able to figure out how to work TightVNC. How simple it is once you know how to work it!

#5 jbalsam

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Posted 09 April 2013 - 11:43 AM

Thanks for the added info Mark! And Tom: glad this helped.

#6 mclewis1

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Posted 09 April 2013 - 11:47 AM

There's a bad link in my posting above and it's too late to edit it ... sigh.

It should be www.nexstarsite.com

#7 PhilCo126

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Posted 30 May 2013 - 02:34 PM

Thanks for sharing...

#8 rmollise

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Posted 30 May 2013 - 04:09 PM

Let add most strongly that just "any" USB serial adapter may _not_ work reliably with NexRemote. Save yourself a lot of grief and get a Keyspan.

Also, you do NOT need to install ASCOM if all you are going to use is NexRemote. It does NOT require that. It is only necessary if you are going to use a program _with_ NexRemote that requires ASCOM to communicate with the telescope.

Also, you really don't need to network the PC. Just run a long serial or PC-port cable to the mount. You will control it with a wireless gamepad like the Logitech Wireless Wingman, which is really a requirement for using NexRemote. Much simpler...works better. ;)

#9 orlyandico

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Posted 30 May 2013 - 07:26 PM

.. doesn't have to be a Keyspan. Any FTDI type USB to serial is pretty much foolproof.

#10 rmollise

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Posted 30 May 2013 - 07:55 PM

.. doesn't have to be a Keyspan. Any FTDI type USB to serial is pretty much foolproof.


That's fine, but I know a Keyspan works with NexRemote...been using one with it for years and it's easy to find. ;)

#11 orlyandico

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Posted 30 May 2013 - 10:35 PM

Thing is a Keyspan is $46 list ($27 on amazon) while a cheap ebay FTDI is $8. Not really a crushing price differential.

I use the cheap ebay FTDI's with both my CGEM (with Nexremote and for the usual ASCOM stuff to the handset) and with my Mach1. Surprisingly they work much better than an (expensive) Targus USB to serial adapter that I got before I knew better..

#12 cn register 5

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Posted 31 May 2013 - 02:52 AM

I use FTDI and Edgeport with success. The Prolific one works if connected directly to the laptop and using a short serial cable but isn't reliable otherwise. I can't speak for Keyspan but Rob already has.

BTW the ASCOM driver works just as well with the real HC, NexRemote isn't required. You connect the serial port to the base of the HC and select that one in the ASCOM driver setup. I find this easier for semi-remote operation. I go outside, set up and align the mount using the real HC, then retreat indoors and do the slewing, fine adjustment and synchronising from the PC connected to the mount through u USB extension, hub etc.

#13 corpusse

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Posted 01 June 2013 - 01:46 PM

After reading this thread I have decided finally to do computer control. It may be as simple as being able to adjust the scope from inside during hot solar imaging, or making minor adjustments when making jupiter animations, but within 2 years I plan on remote control at my dark site observatory so I figure I better start learning this stuff now.

I have the celestron hand controller to serial cable. It seems to work fine when connected to the hand controller but not when connected to the PC input. I need a different cable to connect directly to the mount? What if any advantages does this serve? The HC version I have is 4.19 It won't let me upgrade to 4.21. Everytime I try and hit next it just goes back to selecting the com port. The port is working since I can control the scope through it, it just won't let me update to the latest version.

I got it to work with stellarium fine, are there any suggestions or even options out there that will improve go to performance? I typically just use the last alignment and then sync to one star, this brings the go to to a "pretty good" but not great state.

Finally is TightVNC better then teamviewer? I already had that installed so I tried that. Using nexremote I was able to control the CGE inside no problems however I could not get stellarium to work. It would just show a black screen when I opened stellarium. Periodically it would show the screen but I was unable to use stellarium remotely.

Overall getting nexremote installed and working was maybe a 30 minute process and that includes being able to use it remotely. I don't know why I didn't do this earlier! hoping it wont be too much work to use other programs. I have installed ASCOM as well but currently am not using it for anything.

#14 rmollise

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Posted 01 June 2013 - 04:36 PM

The PC port is ONLY for NexRemote, and, yes, requires a different cable. Don't plug a standard serial cable in there. There is the potential for damage.

The advantage is that you can then run NexRemote without the hardware handcontrol being plugged in.

As for your upgrade problems, the difficulty usually lies in the USB - serial converter or the wrong comm port being selected.

Accuracy has to do with centering the correct alignment stars and using up and right only for final centering. If you are using NexRemote, you align with NexRemote and leave the HC alone. You can use its direction keys, but nothing else. DON'T use "last alignment." Do a 2 star plus 4 calibration star alignment with NexRemote or the hardware HC, whichever you are using. Leave sync alone.

To use Stellarium with NexRemote, you must specify a virtual comm port in the NR setup screen and use that with Stellarium.

#15 mclewis1

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Posted 01 June 2013 - 05:39 PM

Andrew,

About the cables - have a look at my points #3 and #4 in my earlier post above. Note the cable model numbers are different.

About the remote PC control. It's almost a religious debate about whether one VNC is better than another vs. Teamviewer vs. Remote Desktop vs. whatever. There are differences and it will depend on your specific requirements to determine which would be "best" for you. Update speed, cpu utilization, RAM usage, cut/paste capabilities, audio transmission, etc. are just some of the differences.

I've tried quite a few of the VNCs and one thing I found was that the choice of software on the server side didn't matter too much but on the viewer side the Chrome VNC viewer was very responsive compared to the other viewers I tried (dramatically better in some cases).

#16 corpusse

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Posted 01 June 2013 - 08:50 PM

Seems kinda silly the cables are different but good to know especially if there is potential for damage. They should have included both then or maybe they did my CGE was bought used.

Anyway I'm sure it's the right port, I upgraded the MC but it wouldn't work with the HC update. Also nexremote worked fine as did stellarium.

I really don't want to have to do the align every night I know it doesn't take that much time but typically I just sync to one star and it's good enough especially if I'm in the same area night after night. For planetary imaging I just use last align and it's close enough, but most DSO's I'd have to take a long exposure to see where it is on the chip if at all due to light pollution.

#17 cn register 5

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Posted 02 June 2013 - 02:33 AM

The PC port is not needed now because everything it was originally intended for (updating motor controllers, NexRemote) can be done through the port on the HC.

Hibernate/Wakeup is a good way to avoid doing the alignment every time. You do need to set the time accurately (to a second or so) every time. Also I think that you will find that a one or two star alignment will use the mount errors (cone etc.) from the previous alignment.

Chris

#18 rmollise

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Posted 02 June 2013 - 08:53 AM

Seems kinda silly the cables are different


They are different because they are for different purposes. Originally, the PC port only had one reason for being: to allow you to update the Motor Control Board firmware, which could not be done through the HC in the early NexStar days.

Then some talented programmers realized that port would allow them to access the board, bypass the HC, and run the scope from a PC with no (hardware) hand control involved. Their program "HcAnywhere" was soon picked up by Celestron and being sold as NexRemote.

NexRemote, e'en in the HcAnywhere days could be run through the HC port...

Alas, when Celestron developed a means for upgrading the MC through the HC, they began to phase out the PC port...

And now...you know...THE REST OF THE STORY. Good day. :lol:

#19 rmollise

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Posted 02 June 2013 - 08:57 AM


I really don't want to have to do the align every night I know it doesn't take that much time but typically I just sync to one star and it's good enough


If that kind of accuracy is good enough for you...well...rock on! :lol:

No idea what is going on with the HC update, but I suspect it is on the you/computer end rather than the telescope end. The HC updater works well, including with 64 bit Win. :shrug:

#20 Tom Andrews

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Posted 02 June 2013 - 01:47 PM


No idea what is going on with the HC update, but I suspect it is on the you/computer end rather than the telescope end. The HC updater works well, including with 64 bit Win. :shrug:


I had this same problem and it ended up being the serial-USB adapter. It worked on one but not the other. I bought THIS ONE and it works just fine.

Of course, the one Rod recommends is proven too.

#21 corpusse

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Posted 03 June 2013 - 12:01 PM

thanks for the history lesson, I still think it is silly they could not have designed one port to do both. I mean I know the CGE is old, but it's not that old that something like this would be unthinkable.

Up until reading this thread I've always just turned my scope off and chose last alignment until it needed to be corrected. Hibernate does seem to make a difference although I only briefly tried it thanks to clouds.

Do I really need to upgrade the hand controller? I mean this USB to serial adapter seems to work for everything else except updating the hand controller so if I don't need to I won't bother getting another.

I briefly tried solar imaging from inside. Very neat to be able to make the minor adjustments to have the sun where I want it on the chip. This is my first time doing everything from inside except rolling off the roof and pointing the scope at the sun originally. I then opened nexremote thats why it still says cge ready, I just needed to use it for minor adjustments.

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#22 rmollise

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Posted 03 June 2013 - 12:03 PM

thanks for the history lesson, I still think it is silly they could not have designed one port to do both.


They did. These days you can update both the motor control board and the hand control with the same port. Just took them a few software revisions to get it working. ;)

#23 PhilCo126

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Posted 13 June 2013 - 08:59 AM

Anyone tried this with the wireless keyspan USB to Serial adapter ?

#24 Mkofski

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Posted 13 June 2013 - 09:16 AM

Anyone tried this with the wireless keyspan USB to Serial adapter ?


I wasn't aware there was a "wireless USB to,serial" adapter. Do yu have a link to one you can post here?

#25 cn register 5

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Posted 13 June 2013 - 11:49 AM

An alternative to NexRemote that will allow you to make minor centering movements remotely is the Celestron ASCOM driver. It has a small window that has HC buttons that work like the real HC buttons.

As for updating the HC what version do you have?

Chris






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