| The GSTAR-EX
CLR is a highly affordable deep sky and planetary imaging camera that
can be operated in either colour or black and white modes.
Q. Is the GSTAR-EX CLR as
sensitive as the classic monochrome model?
A. No - This colour camera comes with a
built in IR blocking filter which, like all other CCD cameras will cut
the image sensor sensitivity at infrared wavelengths that normally
produce brighter images like those of the GSTAR-EX (unfiltered).
Furthermore, having a colour filter matrix across the image sensor
further reduces low light sensitivity and spatial resolution. However,
if you were using the classic GSTAR-EX mono camera with IR blocking with
RGB filtering, the light loss is similar overall.
Q. Can I see colours
live on the monitor?
A. Yes however some consideration to
the overall surface brightness of deep sky objects like galaxies and
nebula must be taken into consideration. Aperture and focal length will
rule how much colour is possible to see live and record. In our tests
from a semi dark sky location using a 10-inch telescope we could see the
magenta / red hues of the Trifid Nebula at only 20 degrees above the
horizon without difficulty along with its blue reflection nebula. M57
(Ring Nebula) and M27 (Dumbbell Nebula) also produced live colours in
near real-time on the computer CRT monitor.
Q. How many frames do I
need to capture to get the best results?
A. This is up to your own personal
preference however we have found that using only the 128X frame
accumulation mode, at least 600 captured video images will produce a
smooth result. But given the additional noise of a single colour CCD,
the more frames stacked, the better.
Q. Does this camera
produce good planetary images?
A. Yes - in our tests so far (see
Jupiter image above) colours are reproduced quite well and resolved
detail matches many low cost USB type cameras being used today.
Q. Is the 256X sense up
better than 128X ?
A. The images seen in real time are
deeper however if your telescope is poorly aligned or strong breezes are
causing havoc, it is always best to decrease the frame accumulation
setting. From our testing, very nice images in colour are produced from
the 128X mode (see sample image below).
Q. Can I use the colour
camera as the colour instead of filters with my GSTAR-EX monochrome?
A. Yes. The GSTAR-EX CLR can be used to
take colour images of a nebula or galaxy then applied to a
luminance exposure taken with the classic GSTAR-EX mono to create a
colour image. In fact the cost compared to filter wheels
and filters is just about equal but taking only one third the time in
imaging and post processing to achieve a nice result.
See image below
Q. Does the GSTAR
colour camera have more hot pixels?
A. No - In fact it has less obvious hot
pixels than the super sensitive monochrome version, however it is also
not a thermally cooled camera and thus is susceptible to background
noise. With 14 bit internal
super digital noise reduction circuitry, you can almost avoid taking
dark frames altogether. However test are ongoing. Even the classic dark
rings often appearing around bright stars are greatly minimised however
the internal colour rendering algorithms do produce a green and blue
smear to the nearby right and left of very bright stars which are easily
brushed out in post processing.
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