Tuesday, 24 April 2018

FITs files, AstroDMx Capture for Linux and a Bresser Messier AR-102XS ED, f/4.5 refractor,

Nicola has implemented FITs files in AstroDMx Capture for Linux. These are the first tests of this implementation.

A Bresser Messier AR-102XS ED, f/4.5 refractor, was mounted on a Celestron AVX, EQ, GOTO mount. A  QHY5L-ll-M camera was mounted at the prime focus and AstroDMx Capture for Linux, running on a Fedora laptop was used to capture Fits files with matching dark-frames. The FITs files were stacked in Deep Sky Stacker 4.1 running in Wine 3.5 and post processed in the Gimp 2.9.

Click on an image to get a closer view.

M65 and M66 in Leo, M51 in Ursa Major and M3 in Bootes were the objects imaged. 16 bit FITs images were captured throughout (12 bit images in a 16 bit FITs container).

20 x 30s exposures were captured of M65 and M66. 


30 x 45s exposures were captured of M51 


50 x 5s exposures were captured of M3.

A new release will be made when Nicola has added more functionality to the filter-wheel controls.

Monday, 23 April 2018

Experiments with a low cost SVBONY SV105 camera and AstroDMx Capture for Linux

The SVBONY SV105 camera is very sensitive and a ND13 filter was attached to an extender tube attached to the camera. In all experiments, unsaturated data were collected.


This allowed the diagonal to be removed, and the camera directly attached to the focusing tube of a Bresser Messier AR-102XS, f/4.5, 102mm, ED refractor.

AstroDMx Capture for Linux was used to capture an unsaturated, 2000 frame SER file of the 9.4% crescent Moon. All of the data were collected unsaturated in the following tests.

Screenshot of AsroDMx Capture for Linux capturing the SER file


The best 75% of the frames in the SER file were stacked in Emil Kraaikamp's Autostakkert! 3.1.0 currently under beta testing. Running in Wine 3.5 on a Fedora Linux laptop.

The resulting image was wavelet processed in Registax 5.1 also running in Wine and post processed in the Gimp 2.9.



Another test was made using a Skymax 127 Maksutov

The SVBONY SV105 camera was fitted with an extension tube with a ND13 filter. (the extension tube was needed because the camera nose-piece is not threaded to take a filter.) The camera assembly was attached to a Skymax 127 Maxutov mounted on a Celestron AVX, EQ, GOTO mount. AstroDMx Capture for Linux was used to capture a 2000 frame SER file of the Mare Crisium region of the 17.2%, waxing, crescent Moon. The best 75% of the frames in the SER file were stacked in the beta version of Autostakkert! 3.1.0 running in Wine 3.5. The resulting image was wavelet processed in Registax 5.1 also running in Wine and post processed in the Gimp 2.9.




A third test was made using a Newtonian modified to hold a filter in the focuser tube.
A Celestron Omni SLT 150mm, f/5 Newtonian was mounted on a Celestron AVX, EQ, GOTO mount. An SVBONY £35 SV105 camera was placed at the Newtonian focus and a ND13 filter was used. AstroDMx Capture for Linux was used to capture 1500 frame SER files of three overlapping panes of the Moon, with real-time flatfield correction. The best 80% of frames of each SER file were stacked in the beta version of Autostakkert! 3.1.0. running in Wine. The images were stitched together in Microsoft ICE running in Wine and the final image was wavelet processed in Registax 5.1 also running in Wine. The final image was post processed in the Gimp 2.9.

Screenshot of AstroDMx Capture for Linux capturing a SER file of part of the Moon

Final mosaic



A fourth test was done with the Bresser Messier AR-102XS ED, f/4.5 refractor
The Bresser Messier AR-102XS ED, f/4.5 refractor, was mounted on a Star Discovery AZ GOTO mount. An SVBONY SV105 camera was attached to an extension tube with a Baader green continuum filter fitted, and it was placed at the prime focus of the refractor.
AstroDMx Capture for Linux was used to capture a 1000 frame SER file of the Moon using real-time Flat-field correction.

Screenshot of AstroDMx Capture for Linux capturing the SER file

The best 90% of the frames in the SER file were stacked inthe beta version of Astrostakkert! 3.1.0 running in Wine 3.5. The resulting image was wavelet processed in Registax 5.1 also running in Wine and the final image was post processed in the Gimp 2.9.


The use of the Baader 1.25" Solar Continuum Filter, 10nm bandpass, centred on 540nm, served to reduce the amount of light (because the camera is very light sensitive and requires filtration in order not to saturate the sensor). Moreover, because the light is almost monochromatic, there are no dispersion effects in a refractor, notwithstanding the fact that an ED refractor was used in this experiment.

Wednesday, 11 April 2018

Testing the low cost SVBONY SV105 camera with AstroDMx Capture for Linux

The SVBONY SV105 camera was purchased from the SVBONY store on AliExpress for £36. Delivery was fast, taking about a week and the tracking information was first rate.
The camera comes well boxed


The camera is supplied with a USB cable and a dust cap for the front of the built in telescope adapter.
The camera is very well built with a metal housing.


The inside of the camera is sealed by a built in optical window and it is recommended not to unscrew the adapter and allow air inside.

The sensor is a 1/3" 2Mpixel (1920 x 1080) colour CMOS OV2710 sensor with 3µm x 3µm pixels. The camera consumes 150mA at 5volts.

Initial tests have been done in daylight. and the first thing to notice is that the camera suffers from the reverse pixel vignetting that we have discussed in relation to other cameras, but which can be rectified by flat-field correction.

An average flat field was produced using AstroDMx Capture for Linux.

The reverse vignetting is clearly evident, with the lighter regions being around the periphery of the image.
This is the log file for the production of the average flat field frame by AstroDMx Capture for Linux

 AstroDMx Capture for Linux was used with real-time flat-field correction and this demonstrates that the flat-field correction rectifies the reverse pixel-vignetting.

Animation showing the correction of the reverse vignetting
The image is of an area on the other side of the valley, taken through an 80mm ED refractor.

The camera only produces output in Motion Jpeg format, but AstroDMx Capture for Linux extracts data from the video stream at the highest possible quality, so any possible problems are minimised. We have discussed Motion Jpeg in a previous post, and it is possibly the best mode of compression if any compression is imposed on the video stream. This is because each frame is separately compressed, with no reference to the contents of other frames. In an image with lots of detail, the Jpeg compression should be minimal. It is best to have no compression for astronomical imaging.

This is how the SVBONY SV105 camera presents itself with the Terminal command
 v4l2-ctl --all -d /dev/video1

...
As a separate bit of news: Nicola has now implemented FITs file capture in AstroDMx Capture for Linux. The software can now capture:

  • Greyscale FITs
  • Separate FITs files for each colour channel
  • Genuine colour FITs images with all of the colour channels in a single FITs file
Nicola will shortly be releasing another version of AstroDMx Capture for Linux incorporating the FITs capture.

Monday, 26 March 2018

A new release of AstroDMx Capture for Linux

Nicola has released a new version of AstroDMx Capture for Linux.




Changelog (version 0.10.2.0)


Full support for the QHY-5L-II MONO
Full support for the QHY-5L-II COLOUR
Other QHY cameras should work but have not been tested
Histogram Added. The histogram supports both Linear and Logarithmic scales and shows channels in RGB combined, Luminance, RGB Average, Red, Green, Blue or Greyscale.
Histogram image saved as a TIFF file
Automatic Exposure, Automatic Gain and Automatic White Balance improvements (If supported by camera)
Frame integration now works for all cameras operating in 8-bit modes
Improvements to the camera log file
Improvements to the over-exposure markers
Over-exposure markers now have a sensitivity control
Improvements to the Reticle
Custom colours not allowed for the over-exposure markers and the reticle
Right-click to reset controls now works for the exposure control
Reset all controls implemented
Long exposure countdown indicator improvements
Long exposures are now cancelled before the new exposure is set
Installers now create menus to launch the software
Detailed debugging mode added - which can be invoked from the menus or manually by passing -D to the astrodmx binary
Bug fixes and other improvements

Release 0.10.2.0 has full support for:

Astronomy cameras
QHY 5L-II-M (USB2.0, 12 bit ADC)
QHY 5L-II-C  (USB2.0, 12 bit ADC)
DMK 21AU04.AS (8 bit ADC)
DFK 21AU04.AS (8 bit ADC)
DBK 21AU04.AS (8 bit ADC)
ZWO ASI120MC (USB2.0, 12 bit ADC)
ZWO ASI120MC-S (USB3.0, 12 bit ADC)
ZWO ASI120MM-S (USB3.0, 12 bit ADC)
Bresser MicrOcular Full HD Digital Camera (8 bit ADC)
USB cameras
ELP 1.3Mp CMOS board-level HD USB camera (8 bit ADC)
Lucky Zoom 5Mp microscope USB CMOS camera (8 bit ADC)
Vimicro USB2.0 UVC PC camera (e.g. Maplin USB2.0 Microscope) (8 bit ADC)
USB Capture cards
KWORLD DVD MAKER 2 (8 bit ADC)
UVC capture card (Motion-JPEG only) (8 bit ADC)
EasyCAP (Motion-JPEG only) (8 bit ADC)
USB webcams
Sweex WC066 HD webcam (8 bit ADC)
Sweex WC070 ViewPlus (8 bit ADC)
Sweex WC035V2 VGA webcam (8 bit ADC)
Philips SPC900NC including SPC800 and Philips 740 flashed to SPC900NC (8 bit ADC)
Philips 690 Vesta Pro Webcam (8 bit ADC)
Logitech HD C525 (8 bit ADC)
Microsoft LIFECAM 2 (8 bit ADC)
Creative Webcam Live (8 bit ADC) Bayer output only.
All Video 4 Linux cameras.
ZWO filter wheel

Nicola is now working on implementing FITs files and the Atik CCD cameras

Watch this space!

More tests with the low cost Sweex WC035V2 webcam

A Sweex WC035V2  VGA CMOS webcam costing less than £8 on Amazon UK was fitted with an IR/UV cut filter and placed at the Cassegrain focus of a Skymax 127 Maksutov. The scope was mounted on a Celestron AVX, EQ, GOTO mount. AstroDMx Capture for Linux, running on a Fedora laptop was used to capture 2000 frame SER files of various regions of the 63.4% waxing, gibbous Moon. The best 90% of frames in the SER files were stacked in Autostakkert! 3 and the resulting images were wavelet processed in Registax 5.1, both running in Wine. Microsoft ICE was used to stitch together two overlapping images in the Tycho, Clavius region.

Sweex WC035V2 camera


Screenshot of AstroDMx Capture for Linux, capturing a SER file

Composite of two overlapping panes showing craters Clavius, Gruemberger, Morteus, Maginus and Tycho

Eratosthenes, Mons Wolff and Montes Apenninus

Archimedes, Autolycus and Aristillus

There were some slight compression artifacts, but not enough to spoil the results from this very low cost webcam. The camera also gave very pleasing live views that would be very suitable for outreach work.

It is likely that Nicola will release the next version of AstroDMx Capture for Linux later today.

Tuesday, 27 February 2018

The Moon with a Sweex Viewplus WC070 webcam testing with AstroDMx Capture for Linux

A Sweex Viewplus WC070 webcam was placed at the Newtonian focus of an f/5 Sky-Watcher 130PDS Newtonian.

Sweex Viewplus WC070 webcam
Remounted WC070 webcams
The camera on the left is mounted in a project box and that on the right is in its original case with a C/CS ring glued to the front of the case.

AstroDMx Capture for Linux was used to capture 1000 tiff files at 1600 x 1200 resolution with real-time flatfield correction, using flatfield captured earlier, on a laptop running Debian Linux with the XFCE desktop environment. The capture was set to mapping YUYV to greyscale to avoid the chrominance, pixel vignetting problems with this camera. The images were registered and stacked in Autostakkert! 3 running in wine and the resulting stacked image was wavelet processed in Registax 5.1 also running in Wine. The final image was processed and re-scaled in the Gimp 2.9.
Clicking on an image will give a closer view.
Screenshot showing AstroDMx Capture for Linux capturing data. Note the histogram showing details of the exposure
The movable capture dialogue has been moved to show the histogram

Animation of alternation between applying realtime flatfield application and not applying it
The realtime flatfield correction can be seen clearly in this animation

Chrominance problems with the pixel vignetting make it more difficult to correct if YUYV mode is used. However, mapping YUYV to greyscale is prefectly satisfactory for lunar imaging.

Images produced by the above system




As long as flatfield correction is used, this low cost webcam produces images with very little compression, and is a good starter lunar imaging camera. At the time of writing, the WC070 camera can be purchased on Amazon for about GBP 15. More experiments will be done at a later date using the camera as a planetary imager.

Tuesday, 13 February 2018

Astrocrop for Linux final testing

Nicola has compiled deb and rpm install files for Astrocrop for Linux, a native Linux rendering of her Windows software. She will shortly be releasing the Linux version.
A static tripod mounted Panasonic Lumix DMC-FZ72 bridge camera at 60x optical zoom, fitted with a Baader solar filter, was used to image the Sun. The camera was set to burst mode, ISO-100 and 1/500s exposure at f/5.9. Images were captured in bursts of three. 104 images were precisely cropped and registered in Nicola Mackin's AstroCrop for Linux running on a Debian Linux laptop, stacked in lxnstack, wavelet processed in Registax 5.1 running in Wine and post-processed in the Gimp 2.9.
Click on the image to get a closer view.

AR2699 is clearly visible.

Wednesday, 7 February 2018

Testing the Sweex WC035V2 webcam as a starter imaging device

Sweex WC035V2 webcam only has a VGA resolution and costs, at the time of writing, less than £8 on Amazon. The camera is very easy to modify for attachment to a telescope using a standard webcam Mogg adapter. It has a number of controls that make it potentially suitable as a lunar imager: Exposure, gamma, brightness, contrast and white balance.
The silver coloured focusing ring can be popped out with the aid of a screwdriver or blade.

The lens can then be unscrewed from its 12mm thread holder
The IR cut filter is mounted on the lens rather than in front of the sensor.

A standard webcam adapter simply screws into place.

The bottom clip intended for holding the webcam on a computer screen can be removed by removing the single screw that holds it to the camera body.


The camera was fitted with a UV/IR cut filter and was placed at the Newtonian focus of an f/5, 130mm Newtonian and AstroDMx Capture for Linux was used to capture 1500 frames of each of three overlapping regions of the lunar terminator. The camera exhibits very little pixel vignetting and gives pleasant live views of the Moon making it suitable for use as an electronic eyepiece and for outreach.

Screenshot of AstroDMx Capture for Linux capturing with the Sweex WC035V2 webcam


The frames were stacked and flat-field corrected in lxnstack, wavelet processed in Registax 5.1 and the 3 panes were stitched together with Microsoft ICE, both running in Wine and post processed in the Gimp 2.9.

The camera does show some compression, but not as badly as in many cheap webcams. As a beginner's solar system camera it would be a suitable starting point.

Tuesday, 6 February 2018

Sample code to capture .bmp images from the Raspberry Pi Module

Here is a short sample Python 3 program to control a Raspberry Pi camera module and capture a specified number of named .bmp images to a folder. It also allows the camera to be set to capture mono or colour images.
It makes use of the PiCamera Class which provides a pure Python interface to the Raspberry Pi camera modules.

The program (Could be saved as 'Capture.py' for exmple.)

# Pi Camera Capture Demo Program
# by Steve Wainwright
import picamera
camera = picamera.PiCamera()
camera.resolution = (800, 600)
i=0
count = 30
num = 0
# Start preview overlay top left of screen, of size 800 x 600
camera.start_preview(alpha=255,fullscreen=False, window=(0, 0,800, 600))
# Bring the output below the overlay by printing empty lines
while i < count:
    i=i+1
    print ("")
    continue
print (" ")
print ("Commands MENU")
print ("mono = Unsaturated images")
print ("col = Colour images")
print ("cap = capture images")
print ("q = quit")
while True:
    command = input('Enter a command: ')
    if command == "mono":
        camera.saturation=-100
    elif command == "col":
        camera.saturation=0
    elif command == "cap":
        print ("Enter filename")
        fnam = input()
        print ("Enter number of images to be captured for  ",fnam)
        picno = input()
        picno = int(picno)
        print ("Capturing   ", fnam)
        for i in range(picno):
            # The path for saving must be set something like the next line
            # where images are saved to a folder on the desktop called PiImage
            camera.capture('/home/steve/Desktop/PiImage/%s_%s.bmp' % (fnam, num))
            num = num + 1
# Close camera and quit
    elif command == "q":
        camera.close()
        break

When loaded into IDLE 3 or the Thonny IDE, The code should look like this:

The program can be run from this IDLE 3 window by clicking Run and selecting Run Module as below:

Or from Thonny, the program can be run by clicking on the standard Run icon.
This will open the Python Shell and run the program.

Documentation for PiCamera can be found HERE.

Sunday, 4 February 2018

Flat-field correction of Pixel vignetting in CMOS webcams

A similar experiment was performed to the one with the Pi Camera in the previous post, imaging distant buildings across the valley to obtain test data. Two CMOS webcams were used: the Sweex ViewPlus WC070 and the Logitech HD C525. Both of these cameras were placed in turn at the Newtonian focus of an f/5, 130mm Newtonian. The data were captured with AstroDMx Capture for Linux.Stacking was done with lxnstack.
Both cameras showed Pixel vignetting when attached to the scope. However, unlike the Raspberry Pi camera module, the vignetting was not a reverse vignetting, as can be seen in the two flat-fields made by stacking 50 flat-field frames.
Sweex camera
Sweex colour flatfield

Sweex mono flatfield obtained by mapping YUV to greyscale
It can be seen that the vignetting is classical in that the centre of the image is bright whilst the outer regions are darker; unlike the Raspberry Pi camera module which showed reversed vignetting.

Uncorrected colour image (stack of 50 frames)

Corrected colour image

Uncorrected monochrome image

Corrected monochrome image

Logitech camera
Logitech colour flatfield

Uncorrected image

Corrected image

Tests of lunar and planetary images will be carried out when data can be collected. Meanwhile, simple flat-field correction looks very promising for the use of these CMOS, HD web cameras with small sensors, as solar system imagers.
The difference between the nature of the vignetting produced by a Raspberry Pi camera module and a different webcam such as the Sweex and Logitech devices tested here, when placed at the focus of a telescope is interesting. It can be speculated that in addition to microlens displacement, the Pi camera module has a processing correction in firmware. Either way, the flat-field correction makes these cameras usable for Lunar imaging, and possibly planetary and solar imaging.
AstroDMx Capture for Linux has real-time flat-field correction, which makes viewing and outreach use of these cameras a possibility.