Astrophotos Taken Through A Meade ETX 90
Cosmology 101 Items',
The survey results shown below, obtained from over 250 amateur astronomer
participants, shows that over half amateur astronomers surveyed at one time or
another have taken their own moon pics, and nearly as many have taken planetary
pics. Another survey result showed that while film cameras are still used some
by amateur astronomers, digital photography is now by far the most popular
choice for astrophotography. In addition to showing pics of the moon that I've
taken, this web page gives some hints on how to take photographs of the moon
The collection of lunar and planetary images on this web page were taken
with my Meade ETX90, an older version of the Meade
Instruments ETX90 Observer Maksutov-Cassegrain Telescope. I used a modified Quickcam Express Webcam and a 2x
Edmund Barlow for some
images. I've recently added some additional images taken using a Celestron NexImage
web cam conversion. Most of the images are movie captures (avi files) whose
frames have been combined with a Yorick imaging stacking program I created. If
you can still find a Celestron NexImage, I can recommend it, but it has been
replaced with the even better Orion
StarShoot Solar System Color Imaging Camera IV.
In 2011 Meade apparently dropped their popular ETX 125 Maksutov telescope,
though they kept making a version of the ETX 90. In 2017 Meade re-introduced
a new version of the
Meade Instruments ETX125 Observer Telescope.
similar telescope to the ETX 90 from the Celestron lineup is the Celestron
NexStar 90SLT Mak Computerized Telescope. If you want to do some solar system photography on
a budget, then the Orion camera and Celestron MCT would give comparable
instruments to what I used to get these images.
Some Photo Hints
These moon pics and planet pics give some illustration of what can be
accomplished with the compact Maksutov and SCT telescope designs. With their
short tube and built in tracking motors and computers, setting up for solar
system photography is relatively easy. Not all of the moon images are
representative of the best the telescope can do, but some are very
close to that.
First Problem, Getting the Target in CCD FOV
The Jupiter photographs are not as good as I hoped, but again,
near the best this scope can do, at least with a digital camera of
web cam design. I think to get better Jupiter photos I need to move to a
3X Barlow to magnify the planet to a greater extent. That may sound
simple enough, but it turns out to be a significant challenge to get
a planet to show up on the very small field of view of a CCD using
Barlow lens projection. The higher the magnifaction factor, the more
difficult to get the target to show up on the CCD.
These images were obtained by first aligning the equatorial mounted
telescope with Polaris. This helped the clock drive do a better job, keeping
image drift to a minimum. I found that with the digital web cam camera, the
moon was an easy target. Even if considerably out of focus initially, when
the moon swept through the camera field of view it was noticeable. I could then
adjust the focus to get the best image to show on my laptop, which was running
the web cam program and presenting the real-time display.
For the Jupiter pics, Mars pics, and Saturn pics, I found that it was best
to focus the telescope-camera combination first on something before trying to
get the planets into view. I used the moon if it was up, otherwise a
streetlamp or something similar at least a block or two away. In this way, when
I swept across a planet, it would be at least be noticeable on the computer
screen, letting me complete fine focus and take my photographs. If I didn't
pre-focus on anything, I found I could sweep past a planet and not even tell
that it had passed through the field of view.
Next, Adjust Camera for Best Image
After finding a target, I adjusted the parameters of the web cam to give an
optimal image in terms of brightness and contrast. If I had the contrast or
brightness too high, some parts of the images would be saturated, and nothing I
could do in post processing would recover that. So be sure if you do this you
set your camera parameters for an image that has good contrast, but nothing
besides the empty space is totally black, and nothing is completely white.
Next, and perhaps most difficult, I'd try to get the finest focus. This is
difficult when looking at an image on a computer screen. The camera display
update rate is a bit slow, and touching a focus knob can cause motion. When the
motion subsided, often I couldn't tell if I'd improved the focus or not. Don't
rush this step. Unfocused images, like poorly exposed ones, can't be recovered
in post processing.
Best to Take Movies and Stack Frames
Best results were obtained by taking
movies through the web cam,
rather than taking individual pictures. This allowed image stacking, which
gives far superior results. But on some of my earlier outings I didn't get
enough images to do that. Try for a minimum of 20 images for stacking,
more is better. With a 10 frame per second web cam, that means take
at least a few seconds per intended final image.
I now typically take 20 to 30 second exposures, yielding 200 to 300 frames.
The Yorick program I use allows me to set a correlation factor used to dispose
of frames below some selected limit. I usually end up with around 60 frames
that meet selected conditions.
Saturn makes a difficult target for smaller telescopes. Not because it is
so small, but that it is so far away that it is not that bright. My first
Saturn photo was taken at prime focus because of this dimness. The
result after processing was then enlarged. To learn more about how stacking
images can give better results, check out the Celestron NexImage
Some of these photos turned out very well, including Copernicus, Tycho, and
Eratosthenes as examples. I've compared these to about every similar photograph
on the web, and have concluded that for the size instrument used, they are top
notch. The only images I've managed to find that put some of these to shame are
a few taken by 8 inch and larger instruments, and sometimes even these don't
seriously shame the ETX 90 efforts. It just shows what a remarkable instrument
the ETX 90 is.
Click On Any Of The Following Images For A Larger View
| ||The Equipment: Meade ETX 90 Maksutov
telescope on pipe tripod with wedge. Attached to the fork mount base with
Velcro is a hand controller for the RA motor. It is a simple modification to
the controller circuit card, and is indispensable for doing digital photography
of solar system targets. The newer computer controlled ETX 90 models
already have the necessary controls.
||Moon, Aristarchus region. Meade ETX 90 with Celestron NexImage camera and
2x Barlow. Stack of 76 frames. The brightness of the floor of Aristarchus hides
details of the crater floor, but Schroter's Valley shows up well.
||Moon Image, Copernicus, Meade ETX90 With Celestron
NexImage Webcam, 2x Barlow, stack of 50 frames. The mountain peaks are well resolved, and some of the roughness of the crater floor to the upper left of the peaks is discernible.
||Moon Image, Alpine
Valley, Meade ETX90 with Celestron NexImage, 2x Barlow, stack of about 60
frames. The fascinating Alpine Valley, near the crater Plato, was well displayed by the position of the
terminator in this view.
||Moon Image, Plato
region, Meade ETX90 With Celestron NexImage Webcam, using 2x Barlow, stack
of 60 frames. This is one of my favorite lunar regions, and the terminator was
just about perfect for a nice view of Plato. Just above Plato is the pitchfork
||Moon Image, Straight Range,
Meade ETX90 With Celestron NexImage Webcam, using 2x Barlow, stack
of about 50 frames. Near Plato, this enigmatic small mountain range is unusually linear.
||Moon Image, Clavius, Meade ETX90 With
Celestron NexImage Webcam and 2x Barlow, stack of 50 frames. This big majestic feature is always a treat, with many smaller craters on the floor of the big crater.
||Moon Image, Tycho, Meade ETX90 with Celestron
NexImage Webcam, 2x Barlow. In this closeup view, the resolution of the amazing ETX 90 is evident. Too close for the magnificent system of rays to be seen, this image shows clearly the crater floor and rim, as well as the heavily cratered region surrounding Tycho.
||Moon Image, Albategnius region, Meade ETX90 with
Celestron NexImage, 2x Barlow, stack of about 60 frames. The nearby large crater of Ptolemaeus is also well displayed.
||Moon Image, Eratosthenes,
Meade ETX90 With Celestron NexImage Webcam, 2x Barlow. I've
oft strained to see the three mountain peaks on the floor of Eratosthenes, and
this image shows them well.
||Moon Image, Purbach
region, Meade ETX90 With Celestron NexImage, 2x Barlow, stack of about 60
frames. Purbach is the large crater at the bottom of the image.
Bay Of Rainbows, Meade ETX90 With Quickcam
Express Webcam, 2x Barlow, stack of 50 Images. This large feature, near the Plato region, gives testimony to a large impact in a distant past, largely filled in with lava.
||Moon Image, Pallas region,
ETX90 With Celestron NexImage, 2x Barlow, stack of about 60 frames. Pallas is the crater near the upper left of the image. It overlays the rim of the larger crater Murchison
||Moon Image, Apennine Mountains Region, ETX90 With
Celestron NexImage, 2x Barlow, stack of about 60 frames. This mountain range forms the southeastern border of Mare Imbrium
||Moon, Gassendi Crater. ETX90 With Celestron NexImage and 2x Barlow. While not a region I view often, Gassendi presented itself well on this evening. Seeing, however, was only moderate, allowing me only a so-so image.
||Moon Image, Hyginus Region, ETX90 With
Celestron NexImage, 2x Barlow, stack of about 60 frames. In this view, the small crater is seen split by the Hyginus rill.
||Moon, Stofler Region. ETX90 With Celestron NexImage and 2x Barlow,
stack of about 60 frames. Stofler is the large crater to the lower left, with part of its rim destroyed by a series of later impacts.
||Jupiter Image, Nov 4, 2010, ETX90 With
Celestron NexImage, 2x Barlow, stack of 22 frames. In 2010, the SEB did its famous but infrequent disappearing act. This image shows clearly that the SEB is missing.
||Jupiter Image, Nov 5, 2010, ETX90 With Celestron
NexImage Webcam, 2x Barlow, stack of 82 frames. The Great Red Spot shows up
well in this image. Normally the GRS is seen on the border of the SEB, which happened to temporally disappear in 2010.
||Jupiter Image, Nov
03, 2001. ETX90 With Quickcam Express Webcam, 2x Barlow. Above Center And Left
of each image is Io's Shadow, Shown Moving In The Successive Images. Note in these older,
non-stacked images the SEB is clearly visible.
||Saturn Image, Oct 14, 2001, ETX90 With
QuickCam Express Webcam. This was an early attempt, and with the limited gain of the QuickCam Express, I was forced to shoot Saturn at prime focus. This left me with a small image, and only limited detail was thus available.
||Saturn Image, Apr 4, 2012, ETX90 With Celestron NexImage Webcam, 2.5x
Barlow, stack of 141 frames. With the added sensitivity and resolution of the
Celestron NexImage camera, I was able to use a Barlow to boost up the image
size for this image. Note that between the 2001 and 2012 images, Saturn had gone through a ring transition.
||Mars Image, 2003 Opposition. ETX90 with Quickcam Express Webcam and 2x Barlow, stack of 48 frames. This image turned out better than I ever expected, aided in large part with an opposition that presented Mars at its closest approach in decades. Mars was at an apparent size of 25 arc-seconds.
||Mars Image, 2003 Opposition, colorized to Mars typical photograph color.
||Mars Image, 2012 Opposition, ETX90 with Celestron NexImage and 2.5x Barlow, stack of about 60 frames. In 2012, the Mars opposition wasn't nearly as favorable as in 2003. In this image, Mars was only at an apparent size of about 12.5 arc-seconds.
||Mars Image, 2012 Opposition, colorized to Mars typical photograph color.
||Mars Image, 2016 Opposition, ETX90 with Celestron NexImage and 3x Barlow, stack of about 80 frames. In 2016, the Mars opposition presented an image with an apparent size of about 18 arc-seconds.
Though the pictures on this web page were taken with a modified web cam, they
could have also been obtained with a digital camera mounted behind the
eyepiece. With a digital camera, you don't need to haul a computer out to the
telescope to control the camera. I've constructed a simple mount to hold my
Fuji behind the eyepiece, and will soon be adding photographs taken with that