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SkyBt and LX200 EMC

A friend is looking to control his scope from an Android tablet. I am looking for solutions to help him and wonder about this device. I have the following questions:

1. Would this work with an older scope like this?

2. If it does, can any app like Stellarium, etc., be used with it?

3. If Sky Safari Pro were used, would he align with the app, or would he have to align with the hand controller first?

thanks, appreciate any guidance.

5 comments

  • 1
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    Tim Campbell

    1.  Yes

    2.  Yes

    3.  I believe you will have to do the initial alignment with the hand controller (Sky Safari Pro supports some mounts -- particularly some Celestron mounts, but I don't know that it supports others.)  You can always "sync" using Sky Safari (a "sync" is not quite the same as an "alignment").

    Most computers support serial-over-bluetooth.  This means the serial port you select for the software (any software that wants to use a serial port) is really a bluetooth "port" (virtual port).   If the computer doesn't have Bluetooth built in then you'd have to get an adapter for it.  The SkyBT is the remote end of the serial-over-BT connection.  It provides the 9 pin serial connector and you still need a short serial connect to go from the SkyBT to the serial port on the scope.  

    At that point, the SkyBT looks just like any other serial connection (to the computer software it is just the same as having run a physical serial cable between the computer and scope). 

    I have an LX200 ACF (same as the LX200 GPS ... only the optics are different) and have used it with Starry Night Pro Plus to control the LX200 over bluetooth.  

    I still had to perform the basic 2-star alignment using the keypad at the scope (I didn't attempt to use the computer software to perform the alignment.  I don't see much point in that since you really need to be at the scope to refine the centering on the alignment star anyway.

    When you align on a star you align on a star... there's no advantage to asking one device to perform the alignment over another.  This is because ultimately what you align is the scope's notion of the orientation of the celestial sphere of the sky and in the case of your LX200 that computer is the Autostar II located in the base of the scope.  Any other computer (laptop, tablet, phone, etc.) are just communicate with it via serial protocol and will ask the scope to report it's current pointing position or ask it to move to a new pointing position by sending it the coordinates.

     

    There is sometimes some confusion of the notion of an "align" vs. a "sync".  When you perform a 2 star alignment using the LX200's keypad, the scope not only determines a known point in the sky, it can also determine if the mount wasn't perfectly level (and compensate).   When you perform a "sync" it simply shifts the scope's notion of where it was pointed based on the LAST go to command it received.  E.g. if you "go to" Vega, suppose it slightly misses Vega... so you re-center and perform a "sync", the mount assumes it is now pointing at the position of the last go-to command received (in this case it assumes it is now pointed at the coordinates of Vega).  This will improve pointing accuracy for objects near Vega (suppose you then wanted to find the Ring Nebula... it'd probably be bang-on accurate after you "sync" on Vega).  But it will decrease pointing accuracy for objects on the other side of the sky.

    Sky Safari refers to this "sync" as an "align" (that's the label on the interface).  But it's not the same as performing a 2 star alignment during the LX200 setup process (it will not, for example, help the mount compensate for being slightly un-level.)

     

  • 1
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    Bill Tschumy

    I agree with Tim for #1 & #3.  However, with respect to #2, I don't believe the Android version of Stellarium does scope control.  If that is your goal then I think you will need to use SkySafari.

  • 0
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    Tonymanchi

    Thanks a bunch for all the info. Since I don't have a scope like this I'm sorta unfamiliar, but my friend doesn't do a lot of on line hunting like I do. I try to explain there are good folks everywhere that have experience & you can always find answers.

    The reason I asked about aligning is that I own a Celestron Evolution and can align from an iPad and Sky Safari so am just familiar with that. I appreciate the info on align vs. sync since whatever road he goes down I'll probably assist him. I had some Arduino modules for WiFi & BT suggested by another guy, but not sure about going down that road since I am totally ignorant of those. Plus I think my friend would be better off with a solution like Sky BT or even Sky WiFi knowing there are places to get documentation and assistance.

  • 0
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    Tim Campbell

    Apologies... I missed the "from his Android tablet" in the original request and was viewing this as something that might be done via a regular computer.

    Sky Safari Plus & Pro version are certainly more full-featured.  Plus is only $15.  Pro is $39.  That's pretty inexpensive compared to the average astronomy purchase (I don't think I have much in my gear bag that costs less than $39).  

    The software gets regular care & feeding from the developers.  I noticed the new Solar eclipse icon that just showed up in the  Sky Safari interface ... quick access to all the eclipse event times based on your viewing location.

     

     

     

     

  • 0
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    Tonymanchi

    I agree Tim, Sky Safari Pro is what I use on my Evolution.

     

    Also, my friend just called me and seems he has changed direction a bit. Seems he has enrolled in a Physics course and is buying a laptop for use there. So now, all he needs is cables which will be quite a bit cheaper, and simpler. The only thing I see as near negative, is the idea of making sure your cable doesn't get tangled up in anything or anyone, and he will need a table when he goes out. But, I see his point that if he is putting out for a laptop, why spend any more money on other devices when a cable will do the job. He also likes Stellarium and is very familiar with it so, in the long run he is doing what is most comfortable to him.

     

    Thanks for all the responses, there is nothing wrong with acquiring new knowledge and I appreciate knowing a little more about this type of scope & control of it.

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