A wireless RaspberryPi Prime Focus Astrophotogaphy Camera

Webcams and planetary cameras are compact and take great images, but they require a laptop computer to control the camera and capture image data. The Astro Raspberry Pi camera uses the Raspberry Pi deck of cards sized computer and its camera module to create a camera that can be wirelessly controlled by a cell phone and saves data on a local memory card.

The slides and a PDF download from my 2015 talk at the Texas Star Party are on Slide Share:

With a long focal length telescope like the Questar (about 1350mm to the camera), the narrow field of view can make finding your target difficult. With my setup there was also a couple of seconds delay in viewing an image via the wireless connection to the iPhone. The delay make focusing a difficult process. A software focusing aid that could provide a visual focus quality indication would be very helpful. Good results are possible with the setup I used. A full Moon mosaic took 72 images:

The image below shows Jupiter's great red spot and its moons Io and Europa:

Overall I found the small sensor size of the Raspberry Pi camera very limiting for astrophotography. I'd like to be able to find a sensor with a much larger size to use with the Pi.

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Good news on the RaspberryPi astrophotography front. The Instrument Neutral Distributed Interface (INDI) is a cross platform software library to control astronomical instruments. It is available for the Raspberry Pi. I'm hoping that it will provide a way to capture data from and control high functionality astronomical cameras from the Raspberry Pi. The RaspberryPi could be headless running the INDI service and providing capture storage for a USB connected camera.

An app like the CloudMakers INDI Control Panel could provide the user interface. This would be a more capable version of the ultra-portable astrophotography platform that I'd wanted when I began the RPiCam work. I have a ZWO ASI120MC planetary camera and will be trying it out with the Raspberry Pi and report back on the results.

The image below was taken with the ZWO camera (captured using a MacBook rather than the Raspberry Pi). Compare the results to the image of Jupiter above. It would be great the have this quality of result using a RaspberryPi and phone without needing a laptop.

New RaspberryPi HQ Camera

I have the new High Quality Raspberry Pi Camera and the adapters needed to mount it on the William Optics Redcat f/4.9 250mm! The HQ camera module has a 12.3 MP back illuminated Sony IMX477 sensor with 1.55x1.55 micrometer pixels. In addition to higher resolution and lower noise, it is capable of longer exposure times than the previous RPi cams. I've made some proof of concept images with a 250 mm telescope the William Optics RedCat 51 f/4.9. The small pixel size of the HQ cam gives good detail on the moon with only 250mm of focal length.

For more about this image see my blog post. Next I plan to figure out how to package the Raspberry Pi and HQ camera module for convenient use and control it from my iPad.

New commercial products based on the Pi

While I've been busy with other projects two commercial astrophotography controller products have come on the market:

• StellarMate’s Next Generation Internet of Things (IoT) astrophotography gadget. The software is available separately for installation on your own Raspberry Pi.
• ZWO's ASIAir and ZWO's ASIair Pro allows you to control all ASI USB 3.0 cameras, ASI Mini series guiding cameras, and an equatorial mount to polar align, target, and image with your phone or tablet/iPad when connected to ASIAIR via WiFi.

These Raspberry Pi based astronomy appliances include capabilities to control and automate many telescope related tasks in addition to camera control. This includes mount control and aiming, polar alignment focusing, control of other accessories. Real time plate solving can definitively tell you exactly where your telescope is pointed within seconds. These products provide support for cooled astronomical cameras with performance far beyond what is possible with the Raspberry Pi camera modules.

Response to both the StellarMate and the ZWO ASIAir has been very positive. The ASIAir is focused on the ZWO suite of products and a few additional DSLR cameras. The 2nd generation ASIAir Pro has added control of 12V powered accessories like cooled cameras, focuses, filter wheels, focuser, and dew heater strips. I decided to try the ASIAir Pro because I’ve been pleased with the ZWO cameras I already owned and its wireless user interface via the iPad (also iPhone and Android devices). The ease of use that this can provide was the motive behind my initial work with the Raspberry Pi years ago.

From my earlier work with the Pi, I know that making the best of the limited and variable wireless bandwidth is a key to success. The faster Pi 4 and upgraded networking make a big difference, but the real beauty of the ASIAir is the clever design of it’s software interfaces. For example during polar alignment a synthetic for where you are pointing and where you want to move to for polar alignment avoids any communications bandwidth problems. Plate solving is local on the ASIAir and often takes just a fraction of a second. The interface is robust and reliable as you connect and disconnect to the Pi. The regular updates adding new functions and refining existing ones, show that they have a top notch software team.

Polar alignment used to be a frustrating chore; now I look forward to a precise alignment in just a few minutes. I don’t use the ASIAir with a Go-To mount. With just a small portable star tracker (Vixen Polarie), the fast plate solving capability allows me to find invisible targets with bright urban light pollution. The display of real time images stacking confirms my view of the target and lets me share it with a group while imaging.

With a ZWO ASI533 Pro low noise cooled color camera, I was able to capture the Pelican Nebula with a full moon and city lights:

You can read my first light story about imaging with the ASIAir for more details. I hope to try out the StellarMate someday and to see other Raspberry Pi based astrophotography appliances. The ASIAir is a compelling demonstration that you can have great functionality in a tiny package that will run all night on a small lithium-ion batter.