Monday, 17 September 2018

58% waxing, gibbous Moon with AstroDMx Capture for Linux and a DMK 37AUX273 (USB3.0, 12 bit ADC) camera

A DMK 37AUX273 (USB3.0, 12 bit ADC) camera, fitted with an 850nm IR pass filter was placed at the prime focus of a Bresser Messier-AR-102-AS ED refractor, mounted on a Skywatcher Star Discovery AZ, GOTO mount, and AstroDMx Capture for Linux was used to capture 2 overlapping, 5,000 frame SER files of the 58% waxing, gibbous Moon at full resolution 1440 x 1080, in a twilight sky. The best 25% of the frames in the SER files were stacked in Autostakkert! 3.10 and wavelet processed in Registax 5.1 running in Wine. The two resulting images were combined in Microsoft ICE running in Wine and post processed in the Gimp 2.10.


58% waxing, gibbous Moon

Full Size


Screenshot of AstroDMx Capture for Linux capturing data from the 
DMK 37AUX273



The DMK 37AUX273 again proving that it is a very capable Lunar imager.

Sunday, 16 September 2018

Comet 21P/Giacobini-Zinner

Comet 21P/Giacobini-Zinner was imaged using AstroDMx Capture for Linux with a ZWO ASI178MC camera at the prime focus of a Bresser Messier-AR-102-AS ED refractor, mounted on an iOptron Cube Pro AZ, GOTO mount. 10s, 16 bit TIFFs were collected with matching dark frames. The images were stacked and dark frame corrected in Deep Sky Stacker running in Wine. The image was post processed in the Gimp 2.10.


Comet 21P/Giacobini-Zinner






Alignment was difficult from the site chosen, and tracking was not perfect. However, about a third of the images captured were good enough to stack. The exposures were of limited duration due to tracking issues. Nevertheless, the comet tail and star colours showed up quite well. Focus was a little soft and is not as easy to achieve as with a dual speed focuser.


The ZWO ASI178MC camera

This camera has a 14 bit ADC so it is much less likely to saturate. AstroDMx Capture for Linux auto detects the ADC bit depth and so correctly places the data into either the bottom or the top bits (User defined) of a 16 bit container.






Thursday, 13 September 2018

11.6% waxing, crescent Moon with a DMK 37AUX273 and AstroDMx Capture for Linux

The 11.6% waxing, crescent Moon was imaged in broad daylight with a DMK 37AUX273 camera fitted with a 850nm IR pass filter attached to a Skywatcher Explorer 130 PDS 130mm, f/5 Newtonian, mounted on a Celestron AVX EQ, GOTO mount. A 5,000 frame SER file was captured using AstroDMx Capture for Linux running on a Fedora machine. The SER file was stacked and wavelet processed in Registax 5.1 running in Wine and the final image was post processed in the Gimp 2.10.


At full resolution, the camera maintained a frame rate of 52 fps, which allows the acquisition of large numbers of frames in a short period of time.

Wednesday, 5 September 2018

A solar prominence in H-alpha light with a DMK 37AUX273 and AstroDMx Capture for Linux

A Solarmax ll, 60, BF15 H-alpha scope was mounted on a Celestron AVX mount. A DMK 37AUX273 camera was fitted with the lens from a 2x Barlow and was placed at the focus of the scope. AstroDMx Capture for Linux was used to capture a 10,000 frame SER file exposed for a prominence at 160 fps with a ROI of 640 x 480. A 3000 frame SER file was captured, exposed for the disk. Autostakkert! 3.1 running in Wine was used to stack the best 15% of the prominence frames and 50% of the disk frames. Registax 5.1, running in Wine was used to wavelet process the resulting images. The two images were combined and post processed in the Gimp 2.10.


Again, the DMK 37AUX273 proved its worth as a high speed capture device for H-alpha solar imaging with a ROI.

Sunday, 2 September 2018

Protecting a Newtonian primary mirror from dew and extraneous light.

The telescope featured here is a Skywatcher Explorer 130 PDS 130mm, f/5 imaging Newtonian. The back end of the primary mirror is protected by a black, rubberised sheet.

The bottom of the Newtonian reflector 



A problem with Newtonian reflectors is that in very cold weather, the back of the primary mirror can cooled by being exposed almost directly to the cold, ambient air. This can result in the front of the primary mirror dewing up even though it is at the bottom of a long telescope tube.
One way to ameliorate this problem is to use foam packing material, cut to size and attached to the sheet at the back of the primary mirror. Two layers of this material can be used (depending on thickness) and they can be attached using double sided sticky tape.

The foam insulation in place



This insulating foam protects the back of the primary mirror from the cold, ambient air. However, if  any stray light should happen to fall on the bottom of the scope, the white, semi-translucent foam will direct some of it outwards towards the edge of the telescope tube. This presents the danger that some unwanted light might make its way from the back of the scope onto the edge of the primary mirror. Sources of such light could be street lights, light from windows, street light reflected off building walls etc.
What is required is to cut a disk of matt black, 1mm styrene Plasicard and attach at least one sheet to the foam insulation and with a slightly greater diameter than the foam insulation. This serves to prevent extraneous light from falling onto the foam insulation, as well as adding another thin layer between the ambient air and the back of the primary mirror.

The black styrene Plasticard on top of the insulation foam


A finishing touch could be to attach a black shower cap to the bottom of the scope. In addition to extra darkening, this would trap another layer of air at the bottom of the scope to act as extra insulation. 1mm black Plasticard, A4 styrene sheets can be obtained from Amazon. 

Friday, 31 August 2018

M27 with AstroDMx Capture for Linux and a ZWO ASI178MC (USB3.0, 14 bit ADC) camera


A Skywatcher Explorer 130 PDS 130mm, f/5 Newtonian was mounted on a Celestron AVX EQ, GOTO mount. A ZWO ASI178MC (USB3.0, 14 bit ADC) camera was placed at the Newtonian focus.

ZWO ASI178MC


AstroDMx Capture for Linux was used to capture 45 x 55s Tiff files in RAW, undebayered format of M27. The best 40 images were stacked and debayered in Autostakkert! 3.10 running in Wine. The final image was post processed and scaled in the Gimp 2.10 and Neat image.

Having a 14 bit ADC means that this camera can yield 16,384 levels of brightness, compared with 4,096 levels with a 12 bit ADC camera. The data can either be saved to the lower bits of a 16 bit container, or to the upper bits, when captured by AstroDMx Capture for Linux.


M27


Larger view


Thursday, 30 August 2018

High resolution 88% waning Moon images with AstroDMx Capture for Linux and a DMK 37AUX273 camera

A Skymax 127 Maksutov was mounted on a Celestron AVX, EQ, GOTO mount. An Imaging Source DMK 37AUX271 machine vision camera was placed at the prime focus. AstroDMx Capture for Linux was used to capture 8 overlapping, 2000 frame SER files of the 88% waning, gibbous Moon in High contrast and terminator areas, as well as the Copernicus/Kepler region.
(All running in Wine), Autostakkert! 3.10 was used to stack the best 80% of the SER file frames, Microsoft ICE was used to stitch the resulting images together and Registax 5.1 was used to wavelet process the resulting Mosaic. The resulting high resolution mosaic was post processed in the Gimp 2.10.
The scope was protected from the intrusive light from a nearby garden lamp by means of an occultation board which cast a shadow across the scope.
Occultation board


Copernicus and Kepler

Full size

High resolution Mosaic

Closer view


Full size pane of the Aristotelese, Eudoxus, Lacus Mortis, Hercules, Atlas, Posidonius region


Full size pane of the Theophilus, Cyrillus, Catharina, Fracastorius, Mare nectaris, Piccolomini region

Full size pane of the Tycho region


The DMK 37AUX273 can be considered to be an excellent Lunar and Solar imaging device. Seeing was too poor to gather worthwhile planetary images as Mars and Saturn were far too low in the sky. However, a test showed that high frame rates could be achieved capturing monochrome planetary data through this modest 5" Maksutov. Larger, planetary imaging scopes would cope even better.

Saturday, 25 August 2018

H-alpha Sun with a DMK 37AUX273 and AstroDMx Capture for Linux

A DMK 37AUX273 camera was mounted at the prime focus of a Solarmax ll, 60, BF15 H-alpha scope, mounted on an iOptron Cube Pro, AZ GOTO mount.


AstroDMx Capture for Linux was used to capture two overlapping 1000 frame 8 bit SER files, which were Stacked in Autostakkert! 3.1, stitched in Microsoft ICE and wavelet processed in Registax 5.1, all running in Wine. The final image was post processed and colourised in the Gimp 2.10.


The Sun in H-alpha light


Active regions 2719 and 2720 are clearly visible as is a large filament.

Full size



The camera had sufficient dynamic range to be able to capture both disk and prominence details. The stitched image was duplicated and one image processed for the disk and the other processed for the prominences. The two images were then combined in the Gimp 2.1 to give the image presented here.

It is clear that this is a good camera for H-alpha solar imaging and was able to deliver over 60 fps whilst imaging at maximum resolution.

Friday, 24 August 2018

94% waxing Moon and the Ring nebula with AstroDMx Capture for Linux and a ZWO ASI178MC 14 bit camera

We are on the home straight towards the next release of AstroDMx Capture for Linux. These images were produced as part of the pre-release testing program.
The  ZWO ASI178MC is a camera with a 14 bit ADC and a back illuminated 6.4 MP Sony IMX178 CMOS sensor with 7.4 x 5 micro metre pixels which use STARVIS and EXMOR R technologies.

These technologies produce higher sensitivity and lower noise as well as reducing rolling shutter distortion. The back illumination avoids the internal circuitry in the sensor obstructing some of the light falling on the sensor before it reaches the photodiode. This allows for the reduction in size of the pixels and higher pixel counts on the sensor without increasingly the proportion of the light that is attenuated before it reaches the photodiode. The global shutter reset reduces the rolling shutter distortions that can occur if the subject moves (In astronomical imaging, the only movement should be due to seeing. However, some people image while the object drifts across the field of view or manually nudge the scope to keep the object in the field of view).

This test was done on a night with a low, 94% waxing Moon in the sky. This produced relatively poor seeing and a sky filled with Moon glow.

The ZWO ASI178MC camera was placed at the Newtonian focus of a Skywatcher, f/5, 130PDS Newtonian mounted on a Celestron AVX EQ, GOTO mount. Two overlapping 500 frame SER files were captured at full resolution (3096 x 2080). The best 95% of the frames were stacked in Autostakkert! 3.1 running in Wine. The resulting images were wavelet processed in Registax 5.1, and stitched into a single image using Microsoft ICE, both running in Wine. The final image was post processed in the Gimp 2.10.




Deep sky on a moonlit night

The ZWO ASI178 has a 14 bit ADC unlike many of the CMOS astronomical cameras which have 12 bit ADCs. This means that it can capture images with 16384 levels of brightness, compared with a 12 bit ADC which produces 4096 levels of brightness.
AstroDMx Capture for Linux saves the 14 bit data, mapped to the lower or the upper bits of a 16 bit container. This is still not up to the 16 bit ADCs of traditional CCD based astronomical cameras, but it is a substantial improvement on 12 bit devices.

With the bright Moon illuminating the sky, the ZWO ASI178MC in the same configuration was used to capture 40 x 40s exposures of the Ring nebula.

Screenshot of AstroDMx Capture for Linux capturing images of M57.

The display was using Gammalog, but could be changed to show more contrast if required, but as all that is usually required is to correctly position the object of interest, no further adjustments were made. It should be remembered that the display controls are non destructive, so do not affect the data being captured.

The best 90% of the images were stacked in Deep Sky Stacker running in Wine, and post processed in the Gimp 2.10.



Performance and real-time display are still being improved, but a release will not be far away.

Saturday, 18 August 2018

More about the soon to be released version of AstroDMx Capture for Linux


The next release of AstroDMx Capture for Linux will support the following cameras and run on the following Linux distros.

List of cameras implemented for AstroDMx Capture for Linux
USB Astronomy Cameras
DMK 21AU04.AS (CCD,USB2.0, 8 bit ADC)
DMK 37AUX273 (CMOS, USB3.0, 12 bit ADC)
DFK 21AU04.AS (CCD, USB2.0,8 bit ADC)
DBK 21AU04.AS (CCD,USB2.0, 8 bit ADC)
ZWO ASI120MC (CMOS, USB2.0, 12 bit ADC)
ZWO ASI120MC-S (CMOS, USB3.0, 12 bit ADC)
ZWO ASI120MM-S (CMOS, USB3.0, 12 bit ADC)
ZWO ASI178MC (CMOS, USB3.0, 14 bit ADC)
SVBONY T7 W2568A (CMOS, USB2.0, 12 bit ADC)
QHY 5M-IIM (CMOS, USB2.0, 12 bit ADC)
QHY 5M-IIC (CMOS, USB2.0, 12 bit ADC)
Bresser MicrOcular Full HD Digital Camera (CMOS, USB2.0, 8 bit ADC) (Motion-JPEG only)
SVBONY SV105 Full HD Digital Camera (CMOS, USB2.0, 8 bit ADC), (Motion-JPEG only)
Atik 314L mono (CCD, USB2.0, 16 bit ADC)
Atik 320E colour (CCD, USB2.0, 16 bit ADC)
USB cameras
ELP-USB130W01MT-SFV HD camera (CMOS, USB2.0,8 bit ADC)
ELP 1.3Mp CMOS board-level HD camera (CMOS, USB2.0, 8 bit ADC)
Lucky Zoom 5Mp microscope camera (CMOS, USB2.0, 8 bit ADC)
Vimicro PC camera (e.g. Maplin USB2.0 Microscope) (CMOS, USB2.0, 8 bit ADC)
USB Capture cards
KWORLD DVD MAKER 2 (8 bit ADC)
UVC capture card (8 bit ADC),(Motion-JPEG only)
EasyCAP (8 bit ADC) (Motion-JPEG only)
USB webcams
Sweex WC066 HD webcam (CMOS, USB2.0, 8 bit ADC)
Sweex WC070 ViewPlus (CMOS, USB2.0, 8 bit ADC)
Philips SPC900NC including SPC800 and Philips 740 flashed to SPC900NC (CCD, USB2.0, 8 bit ADC)
Philips 740 ToUCam Pro (mono feed only) map YUYV to greyscale for true mono. (CCD, USB2.0, 8 bit ADC)
Philips 690 Vesta Pro Webcam (CCD, USB2.0, 8 bit ADC)
Logitech HD C525 (CMOS, USB2.0, 8 bit ADC)
Microsoft LIFE-CAM 2 (CMOS, USB2.0, 8 bit ADC)
Creative Webcam Live (CMOS, USB2.0, 8 bit ADC) Bayer output only.
Creative Webcam Live (CMOS, USB2.0, 8 bit ADC) JFIF/JPEG output only.
All Video 4 Linux, UVC cameras.

List of Linux Operating systems and desktop environments tested to date with AstroDMx Capture for Linux
Debian 9, xfce, LXDE, Cinnamon, GNOME 3, MATE, Plasma
Fedora 24, 25, 26 Gnome 3
Fedora 26, 27, Cinnamon
Fedora 28, xfce, Cinnamon, Gnome 3 
Linux Mint 18.2 Cinnamon, MATE, xfce
Kubuntu 16.04 LTS
Kubuntu 17.04
Xubuntu 17.04
Lubuntu 17.04
Ubuntu Gnome, Gnome 3 or classic
Ubuntu 16.04 with Unity (with the additional download package)
Ubuntu 17.04 with Unity (with the additional download package)
Peppermint OS
Antergos Linux
PC Linux Mate
Mageia Linux
Elementary OS. Runs from the command line only at the moment


Nicola has already implemented these cameras and a release is imminent. She is just finalising the improved display of 16 bit images as they are being captured and checking for memory leaks.

Shortly after this release it is intended to release a version for the Raspberry Pi. This needs a little more work and so is unlikely to be released simultaneously.

The current release and all subsequent releases can be downloaded here:    http://www.linux-astro-imaging.uk/

The latest version will be released very soon.

As this is not a full time enterprise and generates no funds, delays are inevitable. The aim is to keep the software as stable as possible, so, as testing reveals issues, they are systematically solved. Sometimes this takes more time than anticipated. 

Nicola works on DMxCapture for Linux most days. The program is now huge and contains more than 30,000 lines of active code (many of which extend over a number of physical lines) and more than 7000 additional lines of internal documentation comments, and this excludes all dependencies. 

To put this in perspective, if the source code was to be printed in a typical book, the book would run to many more than 1000 pages in length. That is a lot of code to maintain, test and extend.

Saturday, 11 August 2018

Testing the new DMK 37AUX273 USB3.1 Machine-vision camera in AstroDMx Capture for Linux


Following an invitation to make proposals to The Imaging Source to test their new cameras, we have received a DMK 37AUX273 that we selected because it has a number of possible desirable characteristics for astronomical imaging:

Dynamic range 8/12 bit
Video output format 8-Bit Monochrome, 16-Bit Monochrome

Sensor type: CMOS Pregius
Sensor: Sony IMX273LLR
Shutter global
Format 1 / 2.9
Resolution 1,440×1,080 (1.6 MP)
or 640 x 48 ROI
Frame rate 270 fps
Pixel size H: 3.45 μm, V: 3.45 μm
Lens mount C/CS

The DMK 37AUX273 USB3.1 is a very diminutive camera compared with the familiar DMK 21AU04 AS camera. Its dimensions are 36×36×25 mm not including the nosepiece. It currently retails at 286.8 Euro including VAT.




The initial tests were with AstroDMx Capture for Linux before 16 bit output and ROI are implemented for this camera.

Solar and Lunar imaging

DMK 37AUX273 attached to a SolarMax ll 60 BF15 H-alpha scope




The first test was on the Sun using a Coronado Solarmax ll, 60, BF15 H-alpha scope. Two overlapping, 2000 frame SER files were captured at prime focus with AstroDMx Capture for Linux, exposed for the disk and two more exposed for the prominences. The best 80% of the frames were stacked in Autostakkert! 3 and stitched in Microsoft ICE, and wavelet processed in Registax 5.1 all running in Wine. The overexposed prominence images were stitched in Jon Grove’s iMerge running in Wine. The images were post processed and combined in the Gimp 2.10.



Full Size



Another test involved using a 2x Barlow lens screwed on the front of the nosepiece and imaging a region with a prominence. With this arrangement no Newton’s rings could be seen, but they were present if the Barlow lens was mounted normally in the Barlow housing. A 2500 frame SER file was captured exposed for the disk and a second SER file was captured exposed for the prominence. The SER files were stacked and wavelet processed in Registax 5.1 running in Wine. The two images were combined and post processed in the Gimp 2.10.


The camera showed good dynamic range in these experiments.

The best 80% of frames captured of the Palus Somni region of the waxing, crescent Moon were stacked in Autostakkert!3 and wavelet processed in Registax 5.1, both running in Wine. The image was post processed in the Gimp 2.10.


There is no doubt that for lunar and solar imaging, this camera performs well.

Deep sky imaging.

The DMK 37AUX273 was placed at the Newtonian focus of a Skywatcher Explorer 130 PDS 130mm, f/5 Newtonian mounted on a Celestron AVX EQ, GOTO mount.
The DMK 37AUX273 camera had not yet been implemented in AstroDMx Capture for Linux, so the deep-sky imaging had to be done in 8 bits. The software was set up to integrate 10 x 2s, 8 bit exposures into a 16 bit Tiff file. 50 such files were captured of the Swan nebula. 10 matching, 16 bit dark frames were captured. The images were stacked in Deep Sky Stacker running in Wine and the final image processed in the Gimp 2.10

Screenshot of AstroDMx Capture for Linux


The Swan nebula



The eagle nebula was imaged using integrations of 10 x 6s exposures. 15 such exposures were captured along with 5 matching dark frames. The images were stacked in Deep Sky Stacker running in Wine. The resulting image was post processed and cropped in the Gimp 2.10 to show the Pillars of Creation.

The Pillars of Creation in the Eagle nebula



So, first impressions of the camera using AstroDMx Capture for Linux that had not yet had the camera implemented for 16 bits and ROI, are favourable. However, until the camera is fully implemented, no more information is available.

After 16 bit capture was implemented, A stack of 45, 30s exposures yielded the following image which is cropped from the middle of the frame to avoid currently intractable amp glow regions.

ROI has now been implemented.

Wednesday, 8 August 2018

A replacement nosepiece for the SVBONY SV105 low cost camera

SVBONY have released a replacement nosepiece with filter threads for the SV105 low cost astronomy camera. This is one of the suggestions that I made to the company about this low cost, well built, USB astronomy camera. The camera is too sensitive to use with a fast scope on a bright object such as the Moon. If an extender tube was used to attach a neutral density filter, it became impossible to bring the camera to focus on some scopes due to lack of back focus. This simple solution allows a ND filter to be attached directly to the nosepiece, so that focus can be achieved.

Replacement nosepiece
The old nosepiece simply unscrews without disturbing the IR cut filter, and the replacement nosepiece screws into place. There is thus, no danger of introducing dirt onto the sensor during the process.

Replacement nosepiece in place
The filter threads can be seen.

A Double polarising filter is attached to the nosepiece in this instance, to allow exactly the right attenuation to be achieved for optimal exposure and frame rate.

The SV105 with a double polarising filter attached.


This is a significant improvement to the camera.
It should be remembered that for best results, flat fields should be employed to correct for pixel vignetting.

Monday, 6 August 2018

AstroDMx Capture for Linux and the Raspberry Pi 3

In May 2017 I wrote here about using AstroDMx Capture for Linux to capture long exposure images with the Raspberry Pi 
However, Nicola did not make a release as she was busy implementing more cameras in the 64 bit RPM and DEB versions of the software.
Nicola has now been working again on a 32 bit version of AstroDMx Capture for Linux for the Raspberry Pi 3 running the latest Rasbian with Desktop (Based on Debian), but this time, implementing all of the cameras implemented in the 64 bit version. It is her hope to release both versions very soon, after a small number of known bugs are fixed and a new way of visualising the incoming data from a 16 bit (or 12 bit data in a 16 bit container) has been completed.
The Raspberry Pi version was tested using two cameras; the QHY 5M-II-C 12 bit colour camera and the Atik 314L 16 bit mono camera. At this stage, the data were transferred to another computer for processing, although subsequent experiment will be done to determine how much can be done on the Pi itself.
QHY 5M-II-C testing with the Raspberry Pi 3
A Celestron Nextstar 8 OTA was mounted on a Celestron AVX EQ, GOTO mount. A QHY 5M-II-C camera fitted with a 2x Barlow was used to capture a 1500 frame SER file of Saturn.

The Raspberry Pi capturing data on Saturn with AstroDMx Capture for Linux

The best 80% of the frames were stacked in Autostakkert! 3 running in Wine and wavelet processed in Registax 5.1 also running in Wine. The image was post processed in the Gimp 2.10 and Neat Image.
Saturn with the QHY 5M-II-C and AstroDMx Capture for Linux

The QHY 5M-II-C was kindly loaned by Derek Francis of the Swansea Astronomical Society to help with the development of the software.
Atik 314L testing with the Raspberry Pi 3
A Skywatcher Explorer 130 PDS 130mm, f/5 Newtonian was mounted on a Celestron AVX EQ, GOTO mount. An Atik 314L mono camera fitted with a narrowband H-alpha filter was placed at the Newtonian focus and AstroDMx Capture for Linux was used to capture 50 x 60s exposures of M16, the Eagle nebula with the Pillars of creation. 10 matching darkframes were also captured. The best 90% of the frames were registered and stacked in Deep Sky Stacker running in Wine and the resulting  FITs image was processed in ESO, ESA, NASAs Fits Liberator software running in Wine.

M16 H-alpha data on M16 being captured by the Paspberry Pi 3 and AstroDMx Capture for Linux

Closeup of the screen showing the real time display of the captured data

Final image of M16 in H-alpha light

Full size

The new versions of AstroDMx Capture for Linux will soon be released, including the version for the Raspberry Pi 3.
One thing that is abundantly clear is that the Raspberry Pi 3 is a viable astro-imaging device.
Watch this space for further developments and more news on releases.