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.
