A prime focus planetary astrophotography camera is built using the Raspberry Pi camera module with wireless camera control and image display via a table or smartphone. A simple construction architecture allows the camera to be implemented with other processors and sensors with a reliable rigid connection to most telescopes. Presented at the 2015 Texas Star Party. High resolution example images are available from http://astronomy.robpettengill.org/

1. Rob Pettengill - TSP 2015
The Astro Raspberry Pi Camera System 4
Rob Pettengill (rcp@alumni.stanford.edu)Rob PettengillRob Pettengill
Texas Star PartyTexas Star Party
16 May 2015
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Pie image from http://www.flickr.com/photos/rexroof/3802694376/
Creative Commons Attribution 3.0 Unported

2. Rob Pettengill - TSP 2015
AGENDA
• Why Build Your OwnWhy Build Your Own
Camera?
• How I Built Mine
• What I Learned
• What’s Next?
• Build Your Camera Not Mine
Christos Vasilas of Dash One
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1st afocal RPi Cam astro images

3. Rob Pettengill - TSP 2015
Internet Of Things And Astronomy
• Remote Observing downsized & updated.
• GoTo telescope control
• PushTo instrumentation and link to
planetarium software
• Automatic focusing.
• Guiding
• Camera control and enhancement.
• Plate solving.
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http://vaticanobservatory.org
http://simonbox.info/index.php/astronomy
http://www.recantha.co.uk/blog/?p=3615
http://astrobeano.blogspot.com/2014/01/instrumented-telescope-with-raspberry.html

4. Rob Pettengill - AASRob Pettengill - AAS 4
http://www.raspberrypi.org
http://beagleboard.org/Products/BeagleBone+Black
http://www.intel.com/content/www/us/en/do-it-yourself/edison.html

5. Rob Pettengill - AAS
W h a t Wa s I m p o r t a n t To M e ?
I wanted to combine my interests in small
electronics & Astronomy in a project.
• Saw potential in credit card sized
computers.
• Replace the laptop with a small low
power wireless computer. ARM based
IOT computers are powerful yet small
and low power.
• Replace the laptop display with a
wirelessly connected cell phone or iPad.
Better displays than many laptops and
far better than camera displays.
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Terry BeliaTerry Belia astrotex.com

6. Rob Pettengill - AAS
Why Build Your Own Camera?
• Sensor
• Customize to your scope and
target
• Functions
• Enhanced Focusing
• Region of Interest Crop
• Packaging
• Size & Weight
• Cooling
• Cost
• Fun
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7. Rob Pettengill - TSP 2015
R P i + C a m e r a M o d u l e +
Q u e s t a r C a m e r a A d a p t e r
C a n I t Wo r k ?
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https://www.flickr.com/photos/robpettengill/sets/72157635483690850/

8. Rob Pettengill - TSP 2015
Hang Me ’Til I’m Done
Astro RPi 2.0
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9. Rob Pettengill - TSP 2015
Screw Me Up Tight
Astro RPi 3.0
Uses a T-ring as a nut to bolt mounting plate for camera to theUses a T-ring as a nut to bolt mounting plate for
extension tubes
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10. Rob Pettengill - TSP 2015
A System Platform
Astro RPi 4.0
Uses simple metal cage for sensor board with a T-ring as a nut toUses simple metal cage for sensor board with a T-ring as a nut to
bolt
Uses simple metal cage for sensor board with a T-ring as a nut to
mounting plate to the telescope adapter.
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11. Rob Pettengill - TSP 2015
Sensor Board Mount Parts
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12. Rob Pettengill - TSP 2015
Assembled Sensor Cage & Telescope Adapter
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13. Rob Pettengill - TSP 2015
Assembled Sensor Cage & Telescope Adapter
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14. Rob Pettengill - TSP 2015
Acquisition Software Stack
IOT based model - smart devices, using web based
interfaces on the network, to talk to personal devices.
• On the Raspberry Pi
• Camera Interface (raspicam)
• Web Server - translate camera control from Web
requests to raspicam, serve up images for aiming and
focusing
• Image storage on local SD card
• Wireless ad hoc WiFi network for communication
• On a smartphone or tablet
• Web browser / Berrycam with camera control interface
• Last still image
• Streaming video
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15. Rob Pettengill - TSP 2015 15
72 image Astro Raspberry Pi Lunar Panorama made with Hugin
Rob Pettengill - TSP 2015Rob Pettengill - TSP 2015

16. Rob Pettengill - TSP 2015 16
BerryCam ready for Jupiter
imaging

17. Rob Pettengill - TSP 2015 17
Jupiter Io & Europa 240 of 500 images stacked & sharpened

18. Rob Pettengill - TSP 2015
Lessons Learned
• To ease switching from visual to sensor views, Prime focus sensor
should be located as close to parfocal with the eyepiece as possible.
• Wireless connection speeds limit ease of aiming and focussing.
Important features include:
• high speed wireless networks
• focus peaking
• region of interest cropping
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19. Rob Pettengill - TSP 2015
What's Next?
• Investigate larger sensors - Lack of Linux ARM drivers for high
quality imaging chips is a barrier for now. A few already provide
Intel Linux drivers and some ARM Linux (Point Grey).
• Improve ad hoc network speeds via faster wireless adapter or
feathered operation.
• Add region of interest cropping to focussing mode and image
capture mode.
• Add adjustable focus peaking display fo focussing mode.
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20. Rob Pettengill - TSP 2015
Extra Slides On ImageExtra Slides On Image
Evaluation
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21. Rob Pettengill - TSP 2015
Quick Resolution Check
• Calculate angular
pixel size
• Down-sample image
to reference
resolutions
• Up-sample reference
images to original
size
• Compare original to
reference images
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22. Rob Pettengill - TSP 2015
• Down-sample a reference image to the desired resolution
• Up-sample reference images match your own image
• Compare your original to reference images
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Comparative Resolution
Check
• Find HQ Reference
• Calculate angular pixel
resolution sizes