Freezing to death is probably the number one unnatural cause of death for astrophotographers. If not physically, then at the very least mentally. Every mobile astrophotographer who has been out imaging during the cooler days knows the pain of either sticking outside by their gear and carefully monitoring it – or having to leave the warm cozy car periodically to check on how things are running. Assuming one does not have the luxury of having a garden, where one could image from home, or a hut one can sit in, this is the kind of situation many people find themselves at.

This harsh reality does not need to be that way. “How” you say? “Help me darkarchon, the 1.5m USB cable is limiting me” you say? Well read on and find out about the most luxurious type of imaging one can do while staying a mobile astrophotographer: Mobile Remote Imaging – stop hanging on a leash and detach yourself from the ungrateful wires that tether you to your equipment.

Signals through the air
(The Setup)

So you are still here and curious about the dark ways that will let you avoid your death by freezing? Good, then let’s go. This whole article is based on the assumption that you are already controlling your gear with a Laptop running Windows and want to stick to this principle because your gear is either not supported on other Operating Systems or you don’t feel like leaving your cozy comfort zone running a different OS – and that is totally fine. That is why I’m here.

But first things first, it will cost money. Yes. It is unavoidable. Well, for the most part – unless you actually already own all the hardware that will be necessary to run all of this. But then you probably already know the way I am going to describe here. Anyway, back to the hot topic nobody likes to talk about: money. This whole setup, even without properly describing it yet, will cost you a few hundred dollars, euros or whatever else your local currency equivalent is. Not scared yet? Still want to avoid freezing? Excellent.

So, assuming you are currently controlling your gear with a USB-tethered Laptop, let me warn you, this whole setup will increase the complexity of connectivity. Ultimately, the USB cord is what is holding you back; it’s what tethers you and the one thing we need to get rid off to be able stay in the cozy car and avoid the frozen landscape outside. The problem? Wires. The solution? As easy as it sounds – going wireless.

Now there are multiple ways to achieve that goal but I will focus on one specific setup by replacing the Laptop with an equivalent Mini-PC. Basically that’s all there is to it. Get a Mini-PC. But this might be daunting, you don’t know what to buy or what to look for, don’t know how to set everything up and other potential pitfalls that could be included. Don’t worry, I’ll try to help you getting through this.

Anyway – the gist of this whole setup is really just a Mini-PC, a small WiFi Access Point/Router and the magic of Remote Desktop Protocol in Windows. With two small hardware and one software component you too could be controlling your whole rig from your car without having to step outside once you have set it up. In the end it is not much more difficult, or could even be easier to use than a tethered connection. Let’s get through the necessary hardware to get you started.

But before that let’s take a brief look at the Pros and Cons of a mobile remote imaging setup by starting with the pros:

• You don’t have to freeze anymore
• You can move freely with the device that is remotely controlling your hardware
• The whole gear set is a single unit running off one battery, no chance that your imaging laptop might run out of battery, if anything, everything runs out of juice together
• No need for inverters or step-up converters since everything ideally runs off 12V
• You can connect from your phone, tablet or laptop to control the imaging device
• You don’t have to freeze anymore
• Easier cable management (only one cable to mount the for battery is possible)
• Potentially easier to waterproof a Mini-PC than a Laptop

And for the cons:

• Battery consumption goes up since the Mini-PC needs power too
• More potential points of failure (WiFi not connecting, Mini-PC breaking)
• More complex to set up
• Costs extra money

We need more stuff
(Hardware and Software)

There is a lot of different hardware out there, especially in the way of Mini-PCs and WiFi Access Points so it will be hard to give concrete advice on what to exactly get – you will have to excuse me for that. However I will try to describe what you should be on the lookout for as best as I can, and if you have concrete questions to some specific piece of hardware just ask me on Discord (darkarchon#4313).

The beating heart
(Mini-PC)

Too much to choose from
(Specifications)

Let me try to outline the specifications for the Mini-PC you should be looking for, based on the current hardware availability as of 2020-06-12. Try to find a Mini-PC that suits those needs in a price range of about 150-250 EUR/USD. The list is not really sorted by priority, just by the way I thought about those things.

• Some kind of dual- or quadcore CPU with at least 4 threads, avoid Celeron N-series and Atom CPUs; those are painfully slow
• Preferably fanless cooled
• At the very least 4GB of RAM, better 8GB or possibility to upgrade
• At the very least a 64GB SSD, more is not really necessary but doesn’t hurt (except the price)
• Graphics don’t matter
• At the very least 2 USB3 ports, more is better but you can always use USB hubs
• WiFi is a must – external WiFi antennae are a plus because the mount can interfere with radio signals
• 12V DC connection – this is important unless you want to somehow step up your battery to 19V or whatever the PC will need. You can find this out by looking at the output voltage of the power brick, this is usually stated
• Powers on on power connection – not a must but a plus, can’t really test this without owning it however
• 2.5″ internal HDD bay is a plus but not a must, you can use an USB stick to save your captured images to
• Weight matters, especially if you want to mount the Mini-PC on the RA of the mount which typically has a lot of space, 500-600g is good
• Installed Operating System doesn’t really matter

Shut up and take my money ?
(Where to buy)

You will probably find a wide range of Mini-PCs on eBay, Amazon or whatever your local computer retailer is. They are abundant and most often described as living room PCs or something for hotels or whatever. The descriptions and purposes don’t really matter as long as they fulfill the specifications. Also look at AliExpress, our Chinese friends produce a lot of them and many Mini-PCs available in western countries are really just rebrands of Chinese Mini-PCs. Just be wary that shipping could take a few weeks.

If your Mini-PC doesn’t come with a Windows license try to buy one from eBay or other key reseller sites. You can typically get a digital Windows 10 Pro (recommended) license for about 20-25 EUR/USD. Downloading and installing the Operating System with an USB stick is trivial nowadays and Microsoft offers tools to do so.

I need to buy even more???
(Further Considerations)

The Radio Operator
(WiFi Access Point / Router)

Okay once you have chosen a Mini-PC you already have spent most of the money necessary for this remote mobile imaging setup. The WiFI AP/Router in comparison is stupidly cheap but you still need a somewhat decent device that sends out a strong signal so it can reach both your mount and your controlling device (Laptop, Tablet, Phone… more on that later).

The choice is yours
(Specifications)

As before with the Mini-PC, I cannot give proper recommendations so here’s a list of things you should look out for when buying a WiFI AP.

• Antennae preferred, but should also work without
• Can do 802.11n (5Ghz) but realistically 802.11g (2.4Ghz) is what you’re mostly be using – the signal should still be strong, read reviews. Since you’re mostly going to cover open ground however the distance from where you will be able to have signal will be higher
• 5V or 12V connection, that’s up to you. 5V can be run off USB easily and for example attached on your Mini-PC
• LAN ports are irrelevant, except if you attach it to your Mini-PC and connect to it via LAN
• USB port on the WiFi AP and Router connectivity is a plus, you could for example use your phone to tether and give internet connection to both your imaging and controlling device; make sure that if you want to do that, the device supports it
• Check the devices manufacturer page to see whether they are still supporting the device with firmware upgrades, something like an OpenWRT firmware is a plus

Okay that seems easy enough
(Where to buy)

Personally I just got the first best cheap WiFi AP off Amazon and surprisingly it basically did everything I needed to (and described above). Just search on Amazon for USB WiFi Router or Access Point and you should find plenty of results. Other retailers or AliExpress also works, but those devices are so cheap (about 15-25eur/usd) that it’s not worth buying it from China. USB is the easiest way to power such a device, which is why I would recommend it over 12V hardware.

The All Seeing Eye
(Remote Control)

However there is a small crux in using RDP: While you can connect from any version of the Operating System, Windows, from version 8 upwards, requires at least the Professional version to being able to have an RDP server running on the machine, so you can connect to it. Only having Windows 10 Home Edition? Don’t fret – there is an unofficial way to avoid the requirements of Windows Pro by using RDPWrapper. I will explain how this works later.

y tho
(Benefits of RDP)

With this caveat you might think “Why should I use RDP? There is plenty of other software around. And you are not wrong in that, there is TeamViewer, VNC and many other free alternatives to using RDP when you don’t have it available. Why should you bother installing RDPWrapper if you have Windows 10 Home instead of using another solution? Well, there are a few key points that make RDP worthwhile using compared to other software. Most importantly is this: with RDP you are actually logging into the machine while other software just streams images to you.

First of all: it feels right at home. When you connect using RDP to a remote machine and open it in full screen you will feel like you are sitting in front of it. There’s little to no compression artifacts, little lag or delay between inputs and the performance impact of using RDP on either machine is minimal. In addition, the sound is also streamed so you’re not missing out. In fact, overall it feels so native to the device that connects to the RDP host that you might forget that you are connected to a remote session from time to time.

How could this be? The reason is simple: RDP does not send screenshots. Unlike other software like VNC or TeamViewer, RDP is built for Windows into Windows. That means it can utilize technologies other software cannot. And the major one is that it does not send images and delta of the images (unless it actually is an image), but information on how to render the windows it displays. That’s right: RDP tells your client PC how to render the software it displays and sends only the actual information about that instead of an image of the window it displays on the host.

This leads to another benefit: native resolution. With TeamViewer or VNC you are limited to the resolution the Mini-PC runs at. If you have only a tiny or no screen attached, neither of those will give you the full resolution of the device you use to connect to the Mini-PC with. RDP, since it renders most of the things on the client, is resolution independent and can run at the native resolution of your, for example, Laptop that you use to control the Mini-PC. So even if you have a screen of 800×480 resolution attached to the Mini-PC and your Laptop is 1080p, RDP will give you a crystal clear 1080p image.

With that, the last thing I want to note here is native copy paste. Copying files or things into the clipboard works seamlessly between your client and RDP connected Mini-PC. As with other things it feels right at home. Taking screenshots of windows inside the RDP connection will also copy them to the client clipboard so you can just paste them, copying files over or text, none of that is a problem when using RDP. With other solutions it most often feels more clunky. Also: all keyboard shortcuts work well when connected to the RDP session without major issues.

A note worth mention at this point is also that there are RDP clients for every Operating System. You are not limited in using Windows to connect to your Mini-PC with but can use an Android or iOS Tablet or Phone, MacOSX or Linux device – it doesn’t matter. It will all work irregardless, but the full benefit will be most prevalent when connecting to the system with a Windows client.

Here is a tl;dr summary:

• Feels right at home: no compression artifacts, little lag and delay, low performance impact, sound transfer too
• Renders instead of streams: RDP doesn’t send images (unless the content is an image), it actually renders the window content on your client machine
• Native resolution: RDPs resolution can be as high as of your client machine instead of the RDP host
• Native copy paste: the clipboard is shared between the client and the RDP host, allowing you to use it like it you are running it locally
• Native keyboard shortcuts: use all the keyboard shortcuts you’re used to from your local machine on the host
• Great Connectivity: RDP clients exist for basically every Operating System, allowing every type of devices to connect to the host

Using RDP also has a few downsides, but they are not major and mostly shared with other remote applications. You will need to know the name of the PC you are connecting to (TeamViewer shows you a connection ID). Actual displayed images could still be compressed (also an issue, if not worse, with all other software). Connecting to RDP through the internet requires more configuration – although this is less significant for a mobile remote imaging setup.

I was too cheap and now I regret
(Installing RDPWrapper for Windows 10 Home)

This chapter is solely for you if you are running a Windows 10 Home version and can’t or don’t want to upgrade to Windows 10 Professional. As I said, there is a solution to get RDP running on Windows 10 Home, it’s called RDPWrapper and you can download it here:

https://github.com/stascorp/rdpwrap/releases

Those steps need to be executed on the Mini-PC!

Download the RDPWrap-v1.6.2.zip file, or whatever is the latest version currently available, and ignore all AntiVirus complaints that it gives you. Yes, AntiVirus will complain, this will modify System libraries so RDP can run, but trust me, this is safe.

The carrier has arrived
(Setting up)

Assuming you now have all the fancy new hardware and are eager to start your journey into mobile remote imaging we first have to set up the environment. Ideally you do this at home where you have a proper display and mouse and keyboard available.

First, if you haven’t, install Windows 10 on the Mini-PC. You can use older Windows versions (why) but this guide will assume you have a Windows 10 Pro installed and ready on the device and the PC is connected to some display and has input devices that allow to control it locally. Because to become mobile, we first need to be static. You might want to temporarily connect it to an internet source to get all the drivers and software that you need for your imaging.

Next up would be actually installing drivers and software of all of your devices and making sure that everything connects well and runs. This step I will leave to you – you managed to set up your imaging Laptop, so I’m pretty confident you will be able to manage to set up your mobile remote imaging PC too. There is nothing special to this, just go ahead and make sure everything works like it would be on the imaging Laptop.

Tethering through the air
(Connecting through remote)

Now this part is kind of difficult to describe because I can’t know what kind of WiFi router you got but the gist is always the same.

The small device that could
(WiFi setup)

Connect your new WiFi router and turn it on, be it over USB or a direct power connection, it doesn’t matter. Then you want to connect to that WiFi network over your new Mini-PC. For that you need to figure out what the network name is and ideally the IP of the router. Normally you can refer to the backside of the router which should have all necessary information, including the default password.

Either way you want to customize the SSID to give it a proper name and also change the password for the router and for the WiFi network. Make sure the router is in Access Point or Router mode, there might be a switch on the device – consider the manual for your specific model.

Once you change both it is very likely the device has to restart and you have to connect to the network with the new name afterwards providing the password you have set in the last step. Should you somehow bork it, consider the manual how to reset the router to factory settings.

Establishing the Matrix
(RDP Setup)

This step is only for Windows 10 Pro, for Windows 10 Home look at the Installing RDPWrapper section

Riding the hyperlanes
(Testing RDP Connectivity)

And that is pretty much it. You will be greeted with the desktop of the Mini-PC on your local screen. Just maximize the RDP window and you’re good to go! We can now finalize the setup by finding a place to mount your new mobile remote imaging PC on the mount or scope.

Attach the Detacher
(Mounting the Mini-PC)

Finally we got to a point where your setup is ready to go and all that is needed is to mount your MIni-PC on your rig and call it a day. There are a few options that you have here, so let’s go through them.

Generally, those Mini-PCs aren’t really made to be attached to anything Astronomical per se. That doesn’t mean you can’t easily do so. Personally my way of attaching the device is velcro. It works well, the Mini-PC isn’t particularly heavy and two small strips of velcro hold down the device firmly on the mount.

For positioning the WiFi router it really doesn’t matter too much. You can velcro it on the Mini-PC, on the mount or put it near the battery if you have USB connections there. It shouldn’t matter too much in either case. However the Mini-PC positioning requires a bit more thought and will depend on your system. Here are my suggestions.

Let’s go through the pros and cons for each of the 3 positions for the Mini-PC that I deem reasonable. You are not limited to using those but this should give you a rough guideline where you could put the Mini-PC.

Position 1/2/3: On the Mount Base/Leg/Ground

Position 4: On the RA

Position 5: On the Scope

Time to be free
(Wrap Up)

Well, I’m not gonna lie, this article turned out way longer than I expected it to turn out to be honest. We went through a lot here together, you and I. From the basic explanation of how this setup works to a fully realized and set up system for yourself, we covered a lot of ground.

I am fully aware that lots of the recommendations I did here are very situational and highly depend on your personal preferences, your gear setup and lots of other things. Especially the choice of Mini-PC will probably still be hard – there’s a lot to choose from. But it should not be a big deal with the recommendations I put in here. As always in case of questions or concrete suggestions contact me on Discord (darkarchon#4313).

I sincerely hope this will make your imaging life easier. I know it did for me. In fact I am writing this wrap up right now connected to my WiFI router that tethers from my smartphone. All while sitting in my car and my imaging rig doing its thing outside. What luxury this is!

In any case I don’t want to waste more of your precious time, thank you for reading this article. If you liked it and found it informative share it to your friends and astrophotography groups, maybe someone else will find it interesting too.

I wish you clear skies and happy imaging.

(also not freezing to death, keep those death rates down!)