FREQUENTLY ASKED QUESTIONS (FAQ)

Q: I have a ServoCAT installed on my telescope. Do I need any additional devices/cables?

A: You only need two extra cables to connect Nexus to ServoCAT for a full wireless control of ServoCAT. In case of using non-USB version of ServoCAT you need two serial cables. In case of using USB version of ServoCAT you need one serial cable and one USB cable. You do not need any additional DSC. You will also need a laptop or a tablet to perform a two star alignment.

Q: How long does the battery last?

A: That depends on a number of different factors – type of encoders used, operating temperature, the type of the battery. It also depends on the mode Nexus is running in. For example, the 9V Duracell Coppertop battery will last 4-5 hours with Nexus operating as a Serial to WiFi adapter. However the same battery will last only two hours when Nexus is used as a wireless DSC with S2 optical encoders (each encoder draws up to 57mA from 5V source!).

Q: Can I use a rechargeable battery?
A: Yes, Nexus will operate with rechargeable 9V batteries (the actual voltage for them is usually 8.4V).

Q: What type of batteries is recommended for operating in cold conditions?
A: The most economical type of batteries is 12V SLA (sealed lead acid). Lithium batteries have very good performance in cold conditions but they are quite expensive. Rechargeable Lithium batteries (Li-Poly) without over discharge protection are not recommended as Nexus does not have a low voltage cut-out level and they can be discharged below the recommended level.

Q: Can I use non-optical encoders?
A: Yes, the firmware processes pulses from standard quadrature encoders. They can be optical, capacitive or magnetic encoders. Any of them can be used as long as they provide TTL level quadrature output.

Q: I currently have encoders installed on my telescope and use SkyCommander / Argo Navis... Can I re-use the same cable and encoders for Nexus?
A: Yes, Nexus uses the same type of the connector as used by SkyCommander/Argo Navis / JMI NGCMax / Celestron Advanced Astro Master/ Lumicon Sky Vector / Orion Sky Wizard / Micro Guider 5. There is no need for a new cable or new encoders. The same cable can be re-used to connect to Nexus.

Q: Does Nexus use external power when both external power and the battery are inserted?
A: Nexus uses only external power source if the 2.1mm DC plug is inserted into the external power connector.

Q: Does Nexus have a built-in charger for the installed battery?
A: No, Nexus does not charge the battery when the external power is connected to it.

Q: How can I determine the resolution of my encoder?
A: Just multiply the CPR (counts per revolution) of your encoder by four and then multiply the result by the ratio of the gears it is connected to your telescope (if you have any).

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