About Me:
I am an amateur astronomer located in northern Jefferson County near Eureka, MO. Most of my imaging is done from my front yard.
My primary astronomical interest is in taking astrophotos of the Moon.
Equipment:
Telescope:
Currently
I use a Stellarvue SV102ED refractor for lunar imaging. It is 102mm
(4in) and has a focal length of 709mm. It has excellent optics. It is
light weight, and easy to carry out to the mount and install. Its not a
true APO, but I don't see any color fringing.
Tracking Mount:
Celestron
CG-5. It is semi-permanently installed in the front yard. Its rated for
20 lbs, so the 10 lb Stellarvue is easy. Lunar tracking is excellent
for a least 1-3 minutes. Polar alignment controls are pretty rough. Its
been sitting outside since Fall of 2009 and still works fine. I cover
the upper part with a couple of heavy plastic bags and an inverted
plastic trashcan ("Dome by Rubbermaid").
CCD Camera:
I
am using an Imaging Sources DMK31AU03. Image is 1024x768 and
monochrome. Good lunar images are taken these days by stacking many
(100s-1000s) short exposure video frames. Short exposures will "freeze
the seeing" normally present due to atmosphere distortions. This camera
has good sensitivity (0.05 lux) which permits short exposure frame
captures of the Moon even near the terminator. The DMK31AU03 is capable
of 30fps at full resolution through the USB port. At that rate 1800
frames can be captured in 1 minute. Some of the top imagers take
3000-4000 frames per video. That many frames should insure quite a few
good frames are captured. Also, stacking frames reduces the noise in the
final image. Image sharpening techniques yield better results when
there is lower noise in the image.
This
camera's pixels are 4.65um x 4.65um which is smaller than most cameras.
Smaller pixels give better resolution all else being equal. High
resolution images is what I am after.
I
decided on monochrome primarily to eliminate any possibility of codec
problems some people reported with color cameras. With B&W it is
Y800. With monochrome I can experiment with filters and maybe improve
resolution under certain condition. (Also, my instincts say that
deBayering a color video might reduce resolution. I don't have any proof
of that statement, but that bias was a part of my decision.)
The DMK31AU03 isn't as cheap as a webcam, but it has done a great job for me and I am completely happy with it.
Accessories:
Televue
PowerMates - 2.5x and 5x. With these I can get focal lengths of 1772mm
and 3545mm in addition to 709mm straight from the SV102ED.
Electric
Focuser - I bought a motor and hand control from Orion and built an
adapter to attach the motor to the tube of the SV102ED. Its probably
impossible to take high resolution lunar images without an electric
focuser. At best it is extremely frustrating.
Software:
Image Capture: Either Craterlet or IC Capture.
Image Stacking: AviStack.
Post-Processing: AstraImage for deconvolution and wavelets.
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