Raspberry Pi HQ camera, a work in progress in AstroDMx Capture for the Raspberry Pi, with some astronomical results.

 Nicola has been working with the low level API for the HQ PiCamera.

AstroDMx Capture now has 8-bit support for the HQ camera with exposures of up to 1s. The documentation for the API is surprisingly incomplete, a consequence of which is that implementation takes much longer than for a USB astronomical camera. Such cameras have an SDK with a public interface that allows the camera to be implemented in capture software. Not so with the HQ PiCamera. This is not a USB camera, so the usual techniques won't work. Part of the job of the camera is carried out by the GPU part of the SOC, so the whole process of implementing the camera is different from a USB camera. The camera module constantly streams data to the GPU via a ribbon cable and the task is to capture the buffer and put it into the environment of AstroDMx Capture.

I have reported some bench tests on the camera, but can now report some lunar capture results on the 58% waxing Moon.

The HQ PiCamera was placed at the Cassegrain focus of a Skymax127 Maksutov that was mounted on a Celestron AVx GOTO mount. The HQ PiCamera was attached to a Raspberry Pi 4B with 4GB RAM and data were captured, using AstroDMx Capture, to an SSD that was attached to the Pi by USB3.0.

Click on an image to get a closer view

The equipment setup

Using AstroDMx Capture for the Raspberry Pi, 1000-frame SER files were captured of overlapping regions of the terminator.

Screenshots of AstroDMx Capture for the Raspberry Pi capturing Lunar data with the HQ PiCamera

The best 90% of the frames in the individual SER files were stacked in Autostakkert!, wavelet processed in Registax 6 and post processed in the Gimp 2.10

Individual overlapping panes comprising stacks of 900 frames each

The panes were stitched in Microsoft ICE to make a mosaic of the terminator

It is clear that the HQ PiCamera is a viable Lunar imaging camera with AstroDMx Capture for the Raspberry Pi. The camera is, for the moment, limited to 8-bits with a maximum exposure of 1000 ms. It is likely that Nicola will release this version as a work in progress some time in the near future. Further implementation will not have a high priority as work on this camera is very time-consuming, and other projects require attention.

AstroDMx Capture for Windows, macOS or Linux (Including Raspberry Pi) can be downloaded freely here:

https://www.astrodmx-capture.org.uk

Progress in implementing the HQ Raspberry Pi Camera in AstroDMx Capture for the Raspberry Pi

I have previously mentioned that Nicola was researching the possibility of implementing the Raspberry Pi Camera (In this case the HQ PiCamera) in AstroDMx Capure for the Raspberry Pi. In that post I showed that she has had the camera streaming in the software.

Now she has implemented most of the camera controls and AstroDMx Capture for the Raspberry Pi can capture data at some resolutions.

Screenshot showing the camera streaming data from the camera looking at an aquarium

Some aquatic snail eggs were placed on a cavity slide and imaged with the HQ PiCam and AstroDMx Capture. The eggs were then returned to an aquarium in which there are no fish.

The HQ PiCamera mounted on a trinocular research grade microscope

Cropped snapshot of a snail egg captured with AstroDMx Capture

Screenshot showing a SER movie file captured by AstroDMx Capture playing in SER player

Animation of a snail egg captured by AstroDMx Capture as a SER file

We are now waiting for a clear night with the Moon visible, to capture some lunar data.

The implementation is so far a partial implementation. The data captured are 8-bit and the maximum exposure so far is 1 second. It is possible that when one or two small issues are sorted out that this version may be released with the partial camera functionality that it has, but that will not happen until we have done a lot more testing. In the future, Nicola will return to this camera after she has completed some other aspects of her astronomical imaging work.

AstroDMx Capture for Windows, macOS or Linux (Including Raspberry Pi) can be downloaded freely here:

https://www.astrodmx-capture.org.uk

Testing a rebuilt William Optics ZenithStar 66 SD Apochromatic refractor with AstroDMx Capture for macOS and a ZWO ASI178MC

A William Optics ZenithStar 66 SD Apochromatic refractor was mounted on a Celestron AVXGOTO mount and a ZWO ASI178MC 14-bit camera was placed at the focus.

The refractor was one that I rebuilt after it was left partly disassembled by a late colleague. Having been rebuilt and cleaned, the scope seemed to be good optically. Holes that had been drilled in the tube were covered with black insulating tape and a Red-dot finder was attached using black Surgu.

Rebuilt William Optics ZenithStar 66 SD Apochromatic refractor 

The scope was aimed at the Orion nebula and AstroDMx Capture for macOS was used to capture data from the ZWO ASI178MC.

The imaging setup

An occultation board can be seen on a photographic tripod, shielding the scope from a nearby street light.

Screenshot of AstroDMx Capture for macOS capturing data on the Orion nebula

A total of 150 x 15s exposures were captured with matching dark-frames, and although there were some passing clouds Deep Sky Stacker was used to register and stack the best 135 frames, giving a total exposure time of 33.75 min. More frames would have been captured but thickening clouds prevented further captures.

The final Autosaved 32-bit floating point image was post processed in the Gimp 2.10, Affinity Photo, Topaz sharpen and Neat image..

Final image of M42/M43

Closer view

The scope performed well, giving good colour performance, and AstroDMx Capture for macOS displayed the image nicely using the non-destructive 32-bit visualisation controls.

AstroDMx Capture for Windows, macOS or Linux (Including Raspberry Pi) can be downloaded freely here:

https://www.astrodmx-capture.org.uk

Bench-testing cameras in AstroDMx Capture; testing new functions in the software; and a sneak preview of current research with the HQ Raspberry Pi Pi-Camera

A cold and starry night is not the time to be testing new functions, new cameras or new SDKs in AstroDMx Capture. The starry night is reserved for doing serious field testing of the software to try to obtain worthwhile astronomical images. Bench-testing is where the first line of testing takes place.

There are two modes in which the capture software needs to be bench-tested on whatever cameras are required, and on all available cameras when major changes to the software have been made. These modes are mainly:

• 8-bit fast exposures such as would be used for imaging planets, the Moon or the Sun (through suitable solar filters).
• 16-bit long exposures such as would be used for imaging deep-sky objects.

These tests need to be done at any time of day and have to be realistic.

For 8-bit fast exposures we use a clamp-stand on which are mounted the cameras currently involved in the testing, with lenses mounted on the cameras. (with cameras that cannot take a lens, they are mounted on a small scope and structures across the valley are imaged)

A well-lit aquarium gives a good subject for fast imaging.

For some 8-bit testing the camera is mounted on a trinocular research-grade microscope.

However, if the light source is turned very low and white neutral density filters are placed on the light source, it is possible to set the illumination levels arbitrarily low.

Then, a lights-out canopy completes the darkening procedure

Using this set of equipment it is possible to simulate any imaging situation and to perform meaningful tests of cameras, SDKs and AstroDMx Capture.

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A sneak preview of current AstroDMx Capture research with the Raspberry Pi HQ Pi-Camera.

These bench-testing systems are currently being used by Nicola to test the feasibility of controlling the Raspberry Pi High Quality camera and capturing data via AstroDMx Capture for the Raspberry Pi. This post is a preview of some current research.

I did some preliminary tests with python programs to determine whether the Raspberry PI HQ camera might be suitable for astronomical imaging, and these tests can be seen HERE

In general it appeared that acceptable astronomical images could be obtained from the camera, and this made it worthwhile looking further into the possibilities.

Every camera that has been implemented in AstroDMx Capture to date, including DSLRs has been connected to the computer via USB2.0 or USB3.0. 

The Raspberry Pi Pi-Camera is quite different. In a sense, the camera is not an independent device from the computer. The camera module streams data continually to the Raspberry Pi GPU part of the SOC. So, in a sense, we can regard the GPU as performing some of the key functions of the camera. The data have to be sent to the GPU from the camera module, via a special Ribbon cable that connects to a port on the Pi circuit board. These are the things that make the Pi-Camera different from a USB camera.

The first point that was noticed is that the V4L kernel driver for the Pi-Camera is not a fully developed and stable implementation and Nicola rejected it as the first line of approach to controlling the camera.

There are a number of libraries available to control the Raspberry Pi cameras but the documentation is incomplete and the libraries contain very complex routines, few if any are of any relevance to astronomical imaging.

These libraries themselves depend on lower level abstraction layers that form library dependencies for the higher level libraries.

The whole API system is like a Russian doll with lower and lower level APIs that can possibly be used to do the sort of things that an astronomical imaging program needs to do.

Nicola is working with a low level API to try to understand its capabilities and, if possible to use it as an SDK for AstroDMx Capture for the Raspberry Pi.

She first was able to stream video from the HQ PiCamera as this screenshot shows

The reason that the stream is monochrome is simply that for initial tests the Y, luminance component of a YUV stream was used.

The next stage was to incorporate the calls to the API into AstroDMx Capture for the Raspberry Pi, to work with a full colour YUV stream, and to begin the implementation of the camera controls in the AstroDMx Capture GUI.

First in monochrome

Then in colour

Although there is a lot of work to be done on the HQ Pi-Camera part of the AstroDMx Capture project, it looks at this moment in time as though the camera will be controllable by AstroDMx Capture for the Raspberry Pi, and we look forward to testing it on astronomical objects and to discovering the limits of the camera

AstroDMx Capture for Windows, macOS or Linux (Including Raspberry Pi) can be downloaded freely here:

https://www.astrodmx-capture.org.uk

Maintenance Release of AstroDMx Capture and how to install and run on macOS and Windows

Nicola has released version 0.84.9 as a maintenance release of AstroDMx Capture on Windows, macOS and Linux, including the Raspberry Pi OS.

The latest version of AstroDMx Capture can be downloaded here:

 https://www.astrodmx-capture.org.uk

This release addresses some issues that have come to light since the last release and increases the stability of the system overall.

The AstroDMx Capture project has now grown to 56,670 lines of code plus 9,594 lines of internal documentation that enables the programmer to understand what exactly the code is doing if it is revisited in the future. This is a total of 66,264 lines. This is a minimum because some of the lines of code span several physical lines.

To get a feel for how much this actually is: If a book contained 50 lines per page, then it would require two volumes, each of at least 663 pages to contain the whole of AstroDMx Capture. This is a considerable amount and requires a commensurate effort to maintain and advance the software.

We have noticed that some people are unsure about how to install AstroDMx Capture in macOS or Windows. Both operating system place obstacles in the way of software that has not been downloaded from their respective stores, or has not had expensive and recurrent certification. These obstacles go away when sufficient numbers of downloads of a given piece of software have been made.

In both operating systems it is only necessary to give permission for the software to run. In both operating systems, these obstacles are put there to protect a user from inadvertently running a program that they had downloaded from a source that they don't trust. 

macOS

When the install file has been downloaded to the desktop it should be double clicked and a window will appear the the AstroDMx Capture icon in it. Then a separate window of Finder should be opened and the AstroDMx Capture icon should be dragged over into the Applications folder at the left of Finder.

Then, if you try to run the software this will appear.

Simply open System Preferences

And then select Security and Privacy

Click on Cancel in the small window with the Exclamation mark in a yellow triangle.

Then click on Open Anyway in the Security a Privacy window.

Another small window with a yellow triangle with an exclamation mark will appear.

Click on Open in this window.

You will then be able to run AstroDMx Capture

Windows 10

AstroDMx Capure for Windows is now downloaded as an MSI file, and similar to macOS, Windows places obstacles to make you think about what you are installing and intending to run.

When you double click on the MSI installer file a Window appears.

Just click on More info.

Just Click on Run anyway and your program will install and be able to run.

We hope that you enjoy using AstroDMx Capture on your operating system of choice.

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A recent result:

The Flame nebula captured by AstroDMx Capture for macOS

Screenshot

The Flame nebula

Stack of 20 x 30s exposures

The camera used was the full spectrum version of the SVBONY SV305 camera and a Skywatcher Explorer 130 PDS 130mm, f/5 Newtonian mounted on a Celestron AVX mount.

Testing the SV305 full spectrum camera with AstroDMx Capture for macOS

AstroDMx Capture for macOS now supports the SV305 family of cameras. The camera used in these tests is the SV305-F (my designation for minus Filter, or it could represent Full spectrum. The camera has an optical glass filter that does not block UV/IR, rather than the usual UV/IR cut filter. It is, therefore, a full spectrum camera).

The first test was done with the Moon, using a Skymax 127 Maksutov on a Celestron AVX EQ, GOTO mount. The SV305 was placed at the Cassegrain focus of the scope and focused on the Moon.

The first thing that was noticed was, as expected, the Moon showed a reddish hue.

Click on an image to get a closer view.

Screenshot of AstroDMx Capture for macOS streaming data of the Moon.

This is not a problem because AstroDMx Capture's One-Touch white balance button instantly corrects the white balance.

Screenshot showing the effect of clicking on the One Touch white balance button

2000-frame SER files were collected of various regions of the Moon and the best 50% of the frames in the SER files were stacked in Autostakkert!

The resulting images were wavelet processed in Registax 6 and post processed in the Gimp 2.10.

Microsoft ICE was used to stitch the overlapping panes into a mosaic.

The Maksutov SV305-F combination was then aimed at the Trapezium region of the Orion nebula and 93 x 15s, 16-bit exposures were captured with matching dark-frames: all under a full Moon.

Screenshot of AstroDMx Capture for macOS capturing data on the Trapezium

Autostakkert was used to stack the best 90% of the frames and the final image was post processed in the Gimp 2.10 and Affinity Photo.

The Trapezium region

The six stars of the Trapezium are resolved

The following night a Skywatcher Explorer 130 PDS 130mm, f/5 Newtonian was placed on the AVX mount and the SV305-F was put at the Newtonian focus. 100 x 20s, 16-bit exposures of M42/M43 were captured with matching dark-frames.

Screenshot of AstroDMx Capture for macOS capturing data on the M42/M43 region of the Orion nebula.

The best 90% of the frames were stacked in Deep Sky Stacker and post processed in the Gimp 2.10 and Affinity Photo.

The M42/M43 region of the Orion nebula

The SV305 full spectrum camera is proving to be a capable lunar imager as well as performing well on the brighter deep-sky objects. I am looking forward to testing its capabilities further.

It is working well in AstroDMx Capture for macOS and its Full HD aspect ratio allows it to capture wide fields of view, whilst also being able to use more usual dimensions common in other cameras.

Among the low-cost USB astronomy cameras, the SV305 family of cameras are among my favourites. They are stable and work very well with AstroDMx Capture for macOS, Windows and Linux, including Raspberry Pi OS.

AstroDMx Capture for Windows, macOS or Linux (Including Raspberry Pi) can be downloaded freely here:

https://www.astrodmx-capture.org.uk

Feature release of AstroDMx Capture for All platforms Version 0.84.7

Feature release of AstroDMx Capture for All platforms

Version 0.84.7

The new version can be downloaded from https://www.astrodmx-capture.org.uk

We are pleased to say that AstroDMx Capture for macOS now supports the SVBONY SV305 and SV305 Pro cameras.

Nicola has made a feature release of AstroDMx Capture on all platforms.

It features a new, non-destructive, incremental 16-bit brightness control that can be used either on its own in Linear mode, or in association with the other visualisation transforms as well as the Transform coefficient. This control is to facilitate the visualisation of 16-bit image data as they are captured, but being non-destructive, does not affect the data that are saved.

It also features an optional exposure delay function.

Various bug fixes have been implemented.

The Windows version of AstroDMx Capture is now installed into a location that does not require administrator rights to launch.

The debug mode now launches from a toggle in the Options drop-down menu. This means that there is now just one launch icon rather than two as in the past.

A considerable amount of work has gone into the coding of new installers and launchers

Experience has shown that many people don’t read the instructions before downloading and installing the appropriate version for their computer. 

If you install a version intended for an advanced CPU and your computers CPU doesn’t have the correct instruction sets, the software will not work. Also, if you install a version for an older CPU, and your computer has a modern CPU, you may not get the performance that your computer is capable of. 

Nicola has put an inordinate amount of work into coding smart launchers to prevent these things from happening. 

AstroDMx Capture launchers now make sure that the correct version runs on the user’s computer depending on the computer’s CPU and its instruction set.

Beginners are often confused about exactly what debayering is… A colour camera has a monochrome sensor with red, green or blue filters over each of the pixels. The exact pattern of the order of the colours of the filters varies from camera model to camera model. This is called the Bayer pattern. 

Bayer pattern of colour filters over the monochrome sensor

The signal produced by a given pixel has come through one of the R, G or B filters. The process of decoding the information coming from the pixels and combining it into a colour image is called debayering. 

In AstroDMx Capture debayering can be switched on or off both for display and for saving. The default is for the display to be debayered (full colour) but for the saved data to remain undebayered. It should be remembered that undebayered data contain all of the colour information, but if they are displayed, the result is a monochrome image with a small-scale pattern in it. Many beginners are confused as to why their captured data looks like this.

Some stacking software such as Autostakkert! Is able to detect the Bayer pattern and to debayer the data, so that the final result is a colour image. Other stacking software may not be able to do this.

 

So, what is the advantage of saving undebayered image/video data? The main advantage of saving undebayered data is that, depending on your computer, you may get faster frame rates when saving undebayered data. For long exposures however, there is no advantage.

AstroDMx Capture now has an automatic warning that you are about to save undebayered data when you start to capture. You are given the option to save debayered, full colour data before the capturing starts. This reminder can be turned off for the remainder of the session if required.

Another reminder is given when you are choosing the format, that RGB24 is, in fact an 8-bit format. It is called RGB24 because there are three colour channels and each channel is 8-bits, hence the 24. If you choose RGB24 then you are forcing the camera to use an 8-bit format, and to debayer the data on camera, which could slow things down a little. If you are capturing deep sky images, then RAW16 should always be used. Whether your camera has a 12-bit, 14-bit or 16-bit ADC, the data will be saved into a 16-bit image container, TIFF or FIT. Never use RGB24 for capturing Deep sky objects otherwise you will be saving you data with only 2⁸ levels of brightness, that is, 256 levels. If you save as RAW16 you will be saving data with 2¹²(4096) levels if your camera has a 12-bit ADC; 2¹⁴(16384) levels if your camera has a 14-bit ADC; or 2¹⁶(65536) levels of brightness if your camera has a 16-bit ADC. 

Windows 7

Nicola intends to release a version of AstroDMx Capture for Windows 7 almost immediately. This version will work with all of the supported astronomy cameras and DSLRs but will have no support for UVC cameras (webcams and USB capture cards). The reason that UVC devices will not work in the Win 7 version is that the technology used for the UVC implementation is Win 10 technology that does not work with Win 7. There are no plans to implement UVC devices on the Win7 version of AstroDMx Capture.