Getting power to Astroberry

If you are using Astroberry or Stellarmate as your system image on a RPi then make sure the power supply to the RPi is adequate – do not share power unless you are sure that it is a good 5v supply with around 3a is getting to you RPi. Strange behavior has been seen when power is inadequate and even crashes can occur.

You can provide power in many different ways but I always try to ensure the minimum of trailing wires with everything on the mount and just one decent power supply cable. Note: I use an IOptron CEM60 as my primary mount, great payload and it has convenient 12v dc power sockets located in the mount head making this quite easy – no cable drag when slewing / guiding.

Your needs will depend on:

1. Portable imaging or if it is (semi) permanent at home?
2. Your Mount payload – remember the 50% load rule for the best guiding.
3. Your Tolerance of trailing cables!

Some suggested options include:

• Power the RPi from a powered USB hub on the mount (with sufficient power) via a USB to C-type socket cable;
• Build yourself a “Power box” that takes input of 12v but gives an output of 5.1v (with enough juice). You can either use a car USB C socket like this one or buy an inexpensive $/£5 board to smooth and convert the power and stick it in a plastic hobby case. I use both dependent on which rig I am using.
• Some Battery tanks (like the Celestron / skywatcher ones) have USB power sockets built in.
• Run the RPi off a decent lithium power bank – I have a 22k amp hour one that will last all night, and more so best to get a big one – they are quite cheap online these days and great when out in the field away from plug sockets.

Communication

How you communicate with your Astroberry can have a big bearing on the experience you ultimately have. Through trial and error, I have experimented with a fixed IP cable and variants of Wi-fi, both of which have pros and cons and which changed how I use Astroberry depending on my circumstances.

Using a Network Cable

There are lots of decent cables around but I suggest a good quality one like this UGreen cat 7 one as the connectors are decent, the cable is light and its fast.

Pros

• This will always give you the best performance and eliminate many problems caused by slow and poor Wi-fi connections.
• Kstars/Ekos (or other software) can be run on a laptop – no speed issues for connections to your RPi INDI server.
• Images can be downloaded and plate solving done on the laptop improving performance (unless its an old slow one )

Cons

• A decent cable of the right length can be expensive;
• Fragile connectors – they break if you tread on them or yank them too hard;
• Trailing cables in the dark usually mean trouble;
• Cable drag on your mount when slewing/tracking;
• If you plug it into a PC outside – most times that means you will be outside with it and you may have to manage for condensation over night on the laptop.

My current favourite is to connect the Ethernet cable using the outside main power cable to my router inside the house – TP-Link do some cheap ethernet to mains converters – see AV100 Gigabit Powerline as a good example.  Just make sure you share the same fuse box circuit to get connectivity. These work really well with great speeds.

Wi-Fi

There are constraints using a Wi-fi only solution but I still prefer this as I hate cables and love being inside with a glass of wine on a cold winters night. It also makes one of my rigs very portable for taking out into the field.

My best approach to Wi-Fi is to have the RPi run Kstars / Ekos / INDI itself and manage the whole process – I use VNC viewer to remote into the RPi and control the whole session as if it were local. All images are stored to a removable USB / SD Card on the RPi to make their later transfer easy. I have also added a Wi-fi dongle to my setup because the RPi on-board Wi-fi can sometimes have poor signal.

Pros

• No cables, love it!
• Kstars/Ekos or other software runs exclusively on the RPi – poor WiFi connection does not affect your imaging even if the connection drops out. Great if using Ekos Scheduler to automate a session.
• No expensive laptop getting damp outside;
• When offsite, control the whole session using a tablet (Apple or Android)  – just install the VNC client and configure Astroberry as a hotspot and away you go – less battery life issues than with laptop battery;
• You can sit inside, snug and warm being sociable with the family (if you want too, of course ).

Cons

• You need a decent garden Wi-Fi router, preferably 5G;
• Kstars/Ekos or other software cannot be run on a laptop in client mode as if the connection drops (which it can do often when slewing with ) it ruins your imaging session – you can experience wifi drop outs from your Rpi – this can be due to power supply or wifi interference from neighbours.
• Images cannot be easily downloaded to your computer so all plate solving, guiding, focusing etc. has to be done on the RPi and Astrometry (or similar) index files have to be installed on the RPi’s SD Card (lucky its a 64gb one then!).
• Tricky for EEA…

Onboard router Wi-Fi connected to RPi with ethernet

The constraints using a Wi-fi only solution largely seem to disappear if you use the combination method. Because the RPi is connected via a short ethernet cable to your onboard router, drop outs of signal seem to disppear and performance inproves.

I use VNC viewer to remote into the RPi and control the whole session as if it were local as per the Wifi only option.

The router I currently use is a USB C type powered TP-Link TL-WR902AC Nano Router AC750  – its tiny, light, comes with all the required leads (and a power supply), is low power and seems very stable taking power from my USB powered hub – see rig 1.

Pros

• No trailing cables again, love it!
• Kstars/Ekos or other software runs exclusively on the RPi – great if using Ekos Scheduler to automate a session.
• No expensive laptop getting damp outside;
• When offsite, control the whole session using a tablet (Apple or Android)  – just install the VNC client and configure the router as a hotspot (external switch) and away you go – less battery life issues than with laptop battery;

Cons

• You will still need a decent garden Wi-Fi router, preferably 5G;
• Images are still slow to download to your computer so all plate solving, guiding, focusing etc. has to be done on the RPi and Astrometry (or similar) index files have to be installed on the RPi’s SD Card (lucky its a 64gb one then!)
• A bit more cost but only about £30 but you won’t need an additional wifi usb dongle so cost neutral.

Conclusions

If you can hard wire ethernet cable then it is the best option with the most flexibility of Ekos connection and usage but the onboard router Wifi comes a close second and removes the unreliability of the RPi built in Wifi and opens up your choice of RPi cases to stronger metal ones for those where this is not possible (like me!)

Static IP Address

Having your RPi use the same IP address each time it connects can be really helpful when using your Astroberry server especially when you use VNC viewer to connect to it over Wi-Fi – it doesn’t lose it and your local DNS knows where to find “astroberry.local”.

Every connection has an IP address, whether its an ethernet cable or a Wi-Fi connection, its like a mailing address, post can’t get there without one! Normally your router (using dhcp) assigns a temporary IP address (in a given set range) for a specific time period (2 hours upwards) to the connections it talks to.

If you Google setting a static IP address on a Raspberry Pi you will find lots of articles, many of which don’t work in my experience (out of date?) to set a static IP for your LAN and/or Wi-Fi connections. Its very fiddly and requires knowledge of how to edit configuration files which some might not enjoy…

I have a much easier trick – configure your router’s dhcp with reserved addresses! Yup, tell your router to always give your Astroberry the same addresses…

To find the mac address on the RPi,  open terminal and type “IP A” at the command prompt and hit enter and you will see the following – I have two wi-fi connections (wlan0 and wlan1) as I also use a wi-fi dongle – eth0 is usually the first network cable (when plugged in). I have highlighted a mac address in the picture for you.

Although all routers can look a bit different, most will have an otion to reserve allocated IP addresses based on the hardware mac address. Log into your router admin interface and under Wi-Fi DHCP somewhere you should find the ability to do this.

Using the mac addresses found above, associate them with an IP address (in the allowed range your router gives out) and thats it – update the router (reboot it too) and in future after the existing addresses have expired, it will always allocate the IP addresses you reserved to the mac addresses on your RPi – its a sort of psuedo static IP address but it works just as well – they don’t change! Better still when you are out in the field using the hotspot or need to connect to someone elses router, all will still function as before.

Router Address reservation

Router address reserved in action 

I am sure there are many other bits I have missed so please do leave me your comments and views at the bottom and I will update as required. As always I appreciate the feedback.