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First Light: March 25, 2005
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This first light image from the RC-16 was
shot on a hazy moonlit night. This is M82 in Ursula Major, a favorite of many astrophotographers because of the unusual characteristics eminating
from the center of this edge on spiral galaxy. This was imaged with an SBIG ST-10XME and A0-7 at prime (f/9).
An LLRGB image (6x10 minute exposures of L, R. G and B). Images aquired with CCDAutopilot II and CCDSoft.
Processed with Maxim DL, Adobe CS and deconvoluted with AIP. Deconvolution significantly improved the "relative"
seeing to approximately 2 arc-sec/pixel (FWHM of 6.00 pixels, image scale of 0.38 arc-sec and 'rough' conversion factor of
80% gives 6 x .38 x .8 = 1.84 arc-sec). Of note, this image was taken before the RC-16 was properly collimated.
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This comes from NOAA, and is just my way of
saying that, from an amateur astronomy perspective, our New England weather is, lets just say, less than optimal this month
(May of 2005). We've essentually had rain for a week and we're expecting another weeks worth. Notice the weather
in the Southwest. Some things just aren't "fair".......
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After looking closely at the previous image I suspected
that the collimation might be off. In fact, a check with the Takahashi Collimating Scope showed this to be the case,
as can be seen above. The primary mirror required a slight tip/tilt for correction. Details on how to perform
this is in the users guide at the RCOS users website. The primary is adjusted after centering the secondary, which was
also out of allignment.
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M51
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This image was dissapointing,
and I have posted it for just that reason. This was imaged with an SBIG ST-10XME and A0-7 at f/6.
Although the original image was performed with 8 separate 10 minute images (LRGB), only 3-4 images were usable due to technical
errors, clouds obscuring some images and a series being shot after dawn. It was assembled as an LLRGB image (only 3-4
x10 minute exposures of L, R. G and B). Images aquired with CCDAutopilot II and CCDSoft. Processed with Maxim
DL, Adobe CS and deconvoluted with AIP. Lesson Learned: You can only push the limits of processing
when you have the data to support it. On the other hand, I was amazed to get even this much from the poor data available.
I saved what I could by being careful NOT to overprocess, as evidenced by the lack of any "burn-out" of the core (though
some overprocessing was necessary with color saturation and unsharp masking towards the end, as is unfortunately evident).
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This was an attempt during a full moon with
a great deal of humidity. The green gradient, most pronounced on the right, and the green halo around the stars, resulted
from these conditions. The "seeing" was 3.51 arc-seconds (AIP calculated FWHM of non-saturated stars was 6.89 pixels
and the image scale, at f/9, was 0.51 arc-seconds/pixel). With Richard-Lucy deconvolution the FWHM improved to
2.7 arc-seconds, for an adjusted "seeing" of 1.37 arc-seconds/pixel. Nonetheless there is a horrible greene cast which
I was only partially able to remove with Maxim's gradient removal tool, the New CCD Astronomies dradient tool removal and
the use of Adobe Photoshop CS (others are much more expert at doing this, and it will be a new goal of mine to learn).
This is an H-alpha/Clear-RGB image of 18 separate 2 minute guided exposures. Images captured with an SBIG STL-6303
and guided with the internal autoguider. Image aquiition with CCD AutoPilot II. Processed with Maxim DL AIP and
Adobe Photoshop (KBQ, June 21, 2005). The "Luminescence" image was a 60%-40% layering of the Ha and Clear
filtered images (assembled in Adobe Photoshop). Combining the H-alpha and Clear images seemed to cause less color distortion
than combining the Ha and Red images.
Lesson Learned:
Imaging during a full moon in a hazy/humid sky is going to result in a significant gradient. Trying to remove this gradient
will diminish the signal to noise ratio, resulting in what is shown here. Others have found more effective ways to deal
with these gradients and it's worth the time to learn their techniques. As an example, I doublt anyone can see any gradients
in Dr. Robert Gendler's images, most of which were shot over lighted suburban skies.
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The primary mirror error is corrected, with the baffles
now looking like concentric rings. These images were taken by simply aiming my Sony CCD camera down the barrel of the
Takahashi Collimating Scope.
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Another image which just couldn't be worked any further.
Thisnis NGC 4565, a stunning edge-on spiral galaxy in the constellation of Coma Berenices, some 31 million light years
distant, with a length of 125,000 light years. Theres a beautiful "dust" lane which covers about two thirds of its'
length. This is an LLRGB image of 6 separate 10 minute guided exposures using the AP 0.67 FLR. Images captured
with an SBIG ST-10 XME and guided with the internal autoguider. Image aquiition with CCD AutoPilot II. Processed
with Maxim DL and Adobe Photoshop (KBQ, April 2005).
Lesson Learned: On
a positive note, the stars are beautifully round. On the other hand, this is a composit of an too few images under
less than ideal cky conditions. Although the detail surpasses any previous attempts, on my part, at this galaxy,
there is a stunning lack of faint background galaxies and the image is somewhat grainy. The cause is due to a number
of issues including poor flats and the need for more images (ie, increase the signal to noise ratio).
The REAL lesson here is to spend
more time on fewer images. This is VERY difficult for anyone, such as myself, who still is in the early stages of this
"hobbie" (or is that "obsession"). It is very tempting to image new objects. Despite the technical flaws which
arise from this approach, the delight in imaging many galaxies sometimes overwhelms the desire to image a few well.
Now that I've got some of this "out of my system" with this remarkable telescope, I plan to collect more data PRIOR to processing.
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A revisit with M51. This
time around the image was taken with a Class I SBIG STL-6303XME. There were approximately 16 separate 15 minute
images taken with the L, R, G and B filters; for a total expoure time of 16 hours. The image was assembled as
an LRGB image. Images aquired with CCDAutopilot II and CCDSoft. Processed with Maxim DL, Adobe
CS and deconvoluted with AIP. Lesson Learned: The increased amount of data and improvements in
data processing "helped" improve this image. The telescope was not properly collimated when this image was taken, and
it is hoped that the next series will show even greater detail. Prior to deconvolution the seeing was about 3.5 arc-seconds
with a 'percieved' post-deconvolution improvement to about 2.3 arc-seconds.
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Secondary Mirror Poorly Collimated
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Prior to correcting the primary mirror the secondary
has to be allligned. This image shows that the center of the secondary mirror is NOT centered in the Takahashi Collimating
Telescope. The central irregular mark with the circle around it is the felt tiped marker region (made in the exact center
of the secondary mirror) This image was taken BEFORE the primary mirrors were collimated, and therefore the primary
collimation error is still visable.
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