Climbing the Learning Curve .
by Paul Rix 02/12/2007
The purpose of this article
is to illustrate the climb up the learning curve that everyone has to face when
they start out in this immensely satisfying, challenging, enjoyable and yet, often
rather frustrating pursuit. I have been imaging now for two years and would
rate myself as being at the intermediate level, using average equipment under
rather light polluted skies. Over
the course of this two part article I will look back at how my images and
technique have progressed from the first over exposed shots up to where I am at
now (still learning but at the point where I am not embarrassed to put my best
work in a frame and hung on the wall).
I feel extremely fortunate
in that Erika and I started out in Amateur Astronomy together. It has been a wonderful shared interest
that has turned into a passion for both of us even though our specific areas of
interest are different. Through
Astronomy we have come to know a lot of very interesting, helpful people and
made some great friends.
It started for us in
2004. We had casually talked about
getting a telescope to try our hand at Astronomy as it was a subject that
interested us both. In November 2004
Meade sold off some factory refurbished ETX70AT refractors for the bargain
price of $130. It seemed like a
deal not to be missed, and so we bought one as a Christmas present to
ourselves. It was at this
time that we joined the Cloudy Night's forums (and what a great decision that
We spent a lot of time
looking at the Moon, Saturn and Jupiter (which required getting up very early)
. It was an exciting time. I wanted to see more detail though. One of my early goals was to see
Jupiter's Great Red Spot, but even with a 3X Barlow Lens I couldn't make it out
(although I could easily see the cloud belts).
Having seen what could be
done with webcam imagers by CN members and in the mainstream astronomy
magazines, I decided to give it a try myself. Celestron had just released their $100 NexImage Solar System
imager onto the market. It seemed
to be the perfect way to start out as it required no modification and came with
all the required software. The
NexImage uses the same CCD sensor as the popular ToUcam Pro webcam that many
were having great success with. Of
course, when the NexImage was delivered the clouds rolled in for several days
which was rather frustrating. It
did give me some time to learn some basic techniques and get a feel for the
operation of the camera. I took
some test video AVI's to practice
with and became familiar with the Registax software and how to use it for
stacking individual frames. My
first image taken with the ETX70 and the NexImage was of a car parked about
3×4 of a mile away.
I almost fell off my chair when I saw the
difference between the raw frames and the final stacked version. This was exciting stuff and it is fair
to say I was hooked even before I took my first Astro-Image.
On the 2nd
January 2005, our dogs woke me up at something like 6am wanting to be let
out. I stepped outside and the sky
was crystal clear. The Moon was up
to the South West, and there, to the South was Jupiter shining brightly. Once the Dogs were back inside I
hurried out with the telescope, Laptop PC and NexImage camera for my first
Astro-Imaging session. I shot
AVI's of both the Moon and Jupiter.
Within half an hour I was back inside working on the video files. They were over exposed but I was
proverbially 'Over the Moon'. The
resulting images showed Lunar craters and Jupiter with it's four Galilean
As with many things, initial
progress can be made quickly. By
the middle of January I started to get a handle on the exposure settings which
allowed me to image the Rings of Saturn, and the equatorial cloud belts on
Saturn January 28th
I was really encouraged by
the results. Each new image seemed
to take me a step forward. By
March I was getting quite ambitious.
I discovered that it was quite possible to stack Barlow lenses (ie use
more than one at the same time).
We had 2X and 3X Barlows by
this time. Focusing was quite a
challenge at this magnification. I
found that the best method was to increase the frame rate of the NexImage to
about 20 frames per second which smoothed out the live preview a lot. Once in focus I went back to 10 frames
per second to record the AVI file.
In early March I was able to
image Saturn and capture the Cassini Division in the rings.
I finally achieved my goal
of capturing the Great Red Spot on March 18th
2005 using the stacked
It was certainly not the prettiest image, but
the GRS was clearly visible! I was
By this time both Erika and
I had developed a strong case of 'Aperture Fever'. We started looking around for a larger telescope and I
bought a used Meade Deep Sky Imager so that I could try my hand at DSO's. Within a week or two of the DSI
arriving, we found a great deal on a used Meade 10in LX200 'Classic'. I drove to North East of Cleveland in a
bad snowstorm to pick it up (quite an adventure, but that is another story).
The LX200 and
ETX70AT (and one very happy novice imager).
The LX200 was a huge upgrade
for us. It allowed Erika to
advance with her visual observing and sketching while opening up a whole new
area of imaging for me. The improvement
was immediately apparent when I took images of Jupiter and Saturn through the new
Imaging planets with the
LX200 was not all that different from using the ETX70. The operation of the telescope was
similar (they are both Meade products after all), so all that I had learned up
to this point was directly transferable.
The extra aperture provided
by the new telescope meant that Deep Space Objects would be within my grasp
using the DSI camera. I learned
very quickly that DSO Imaging was an entirely different ball game. I had to learn about dark frames, field
rotation (I was using the LX200 in Alt/Az mode), histogram stretching, colour
saturation and balance. It was mind boggling to say the least. Even so, the
idea of taking a picture of a distant Galaxy or Nebula from my light polluted
back yard seemed like an interesting and exciting challenge.
The first Galaxy I attempted
was M64 (the Black Eye Galaxy). It
was the first time I had tried to image an object that didn't show up on my
preview screen so I had to trust the Telescope's GoTo ability.
As you can see, the
alignment was good enough to get the target on the sensor chip but not
I was using 15 second exposures as a starting point. It was amazing to see the shape of the Galaxy start to show
as the individual exposures were automatically stacked in real time. Looking at the image now I almost
cringe, but at the time I was extremely pleased with it.
I found that imaging DSO's
was far more time consuming than using the NexImage for planets. Even so, at this point I was knocking
out images of several targets each time I went out.
The following were taken in
April and May of 2005.
M88 which for some reason
showed more detail in the blue channel, so I set the colour balance to
lean that way. At the time I was more interested in
seeing the spiral arms than what the picture looked like aesthetically.
soft in focus but I was pleased to capture the dustlane.
M51 which was too large to fit completely in the frame.
You can see that there was
significant field rotation and tracking error showing up. It took me a while
to learn that Meade's AutoStar Image Processing software (supplied with the DSI)
the individual frames using two stars as reference points. This dealt with field
rotation quite effectively as long as the exposure times are short enough that
did not show in the individual frames.
Tracking errors were another matter though. I found the longest exposure length
I could use was 30 seconds and even then, I would end up discarding about half
of my frames before
stacking the good ones.
Mostly I stuck with 15 seconds which was much more consistent.
International Space Station
In early May I diverted my
efforts to another interesting challenge.
I had seen a number of images taken by amateurs of the International
Space Station (most notably Wes Higgins stunning images and also one featured
in the Meade Catalog). I wondered
if I could do something like that with the equipment I had at my disposal. I asked the question in the Cloudy
Night's Solar System imaging forum and the replies were encouraging. There were a couple of favorable ISS
passes predicted within a few days so I gave it a try. My NexImage was the best camera for the
task. I used Jupiter as a focusing
and exposure aid (because it has detail and similar brightness to the
ISS). After achieving focus and my
best guess at a suitable exposure setting, I powered off the LX200 and loosened
the locks. The ISS appeared on
is a great resource) . I tracked it manually, letting the ISS pass through the
center of the inner ring on the Telrad Reflex Finder before repositioning my
aim to let the Station fly through the Telrad again, and again, until it
disappeared from sight. The first
attempt was a success although a little over exposed. My second try turned out better, showing the gold coloured solar array and main structure of the
I have tried a number of times
since then and until very recently I ended up with very disappointing
results. I think beginner's luck
must have played a part.
Eagle and Dumbell
Over the next couple of
months I imaged several of the well known Deep Space Objects
on my 'hit list'. I was particularly interested in
capturing an image of the giant gas and dust columns in M16. The image I took
at the time was pretty rough around the edges, but it did show the famous 'Pillars
of Creation'. Planetary Nebulae are also
fascinating and dramatic objects.
M27 gave great results even with short exposures. I was surprised at it's size
Even though I obviously I
still had a lot to learn, I was
managing to capture images that were at least recognizable.
The showpiece for Amateur
Astronomers in 2005 has to be the Mars Opposition. I spent most of my imaging sessions during the last half of
the year concentrating on the Red Planet.
The more I read about Mars, the more excited I was about imaging
it. To start with I thought I
would be satisfied if I could capture the Southern Polar Ice Cap which proved
to be easier than I thought. I got
my first Mars Image at the Sky Tour 2005 star party held at Bellevue, Ohio on
My first image of Mars
showing the Southern Polar Ice Cap.
Seeing as I had managed to get the Ice Cap, the next
challenge I set myself was to take an image where the giant volcano Olympus
Mons could be identified. That was
tougher and would have to wait until Mars was much closer. Each time I went out over the next few
months, Mars was getting closer and larger.
By September Mars was close
enough for me to achieve my goal of capturing Olympus Mons. Far from Damien Peach quality, but the
volcano was there if you look closely.
On October 2nd
captured my best Mars image of the season by stacking the 2X and 3X
barlows. It must have been a
night of very good seeing.
into Deep Space
With Mars rapidly becoming
more distant, it was time to focus once again on deep space imaging.
One of the Deep Space
Objects that I wanted to capture was the Horsehead Nebula. It is a fascinating dark nebula in a
stunning region of the night sky.
I didn't think it would be an easy target though, and I was right. I was just hoping to get something
recognizable to show for my efforts.
It was just as well that I did not have high expectations as my first
image was not up to much. Still,
the basic shape was there, so it was a good start.
My first image of Horsehead Nebula
This pretty much brought to
an end my first year of imaging. I
still had a lot to learn but real progress had been made in a number of
areas. My planetary images were of
higher quality than their deep space counterparts, but that is to be
expected. My setup was more suited
to long focal length, short exposure imaging which is great for the bright
planets. Deep space imaging required
much better tracking than I was able to achieve consistently in Alt/Az mode (if
I wanted to use anything greater than 15 seconds of exposure). One thing was for sure though, I was 12
months in and completely hooked.
Up to this point all my
images were taken in Alt/Azimuth 'mode', but it was becoming increasingly clear
to me that I would need to get the telescope polar aligned if I wanted to
extend exposure times and achieve better tracking (as I had been told many
times on CN). In January 2006 I
was browsing Meade's 'Factory Outlet' web page. They were selling off a version
of their Standard Wedge that used to be shipped with an earlier
10inch SCT. I had been unable to
justify spending several hundred dollars for a 'Super Wedge' at that time, but
here was one that would at least get me started for under $100. The internet is a wonderful thing but
it does make spending seem all too easy.
About a week later I had the new wedge installed on the LX200
tripod. I was so excited I even
set it up in the basement to see what it looked like all assembled.
I was a little concerned
about attaching the heavy scope on the wedge when alone (I was worried about
the scope being held in place by just one bolt during the time it took me to
get the other two bolts in place), so I made sure Erika was there to help in
case I got into trouble. It proved to no real problem though and now I am
perfectly happy setting it up unassisted.
& Drift Alignment
I now had a whole new skill
to learn ? Polar Alignment. It was
a little intimidating at first as there were several new concepts to get my
head around. Right Ascension,
Declination, Meridian, Reticle Eyepieces, Drift Alignment! I did a lot of reading before heading
out for the first time. Getting
the telescope polar aligned well enough for visual observing was not all that
hard. Accurate Drift
Alignment for imaging purposes
proved to be rather frustrating though.
It took me a long time each session to get the alignment right. A lot of experienced imagers can get a
good drift alignment completed within 20 minutes to half an hour. It was taking
me an hour and a half to two hours, by which time I was cold and frustrated (it
was January after all).
I am one of those people who
believes that technology can solve most problems like this. I started looking for a better solution. I found it in a program called WCS
which was very reasonably priced.
I use it every time I go out now.
The program allows me to be accurately aligned in about 15 minutes,
sometimes less. It uses a
webcam to track a star and analyzes the drift over a given period of time. When you click on the 'Correction'
button you are given all the information you need to quickly adjust the
mount. It takes all the guesswork away. If you are interested in finding out
more about this program you can run a search on the Cloudy Nights imaging
forums or head over to http://wcs.ruthner.at/index-en.htm
are several other programs out there that can help with drift alignment such as
K3CCDTools, but I have stuck with WCS mainly because I am now familiar with it.
Once I was able to get a good drift alignment I
immediately saw better results. I
was able to take 30 second exposures with acceptable tracking. This really helped to add detail to my
images. I should also point out that I was now using an F3.3 focal reducer,
which made a big difference too.
I revisited the Horsehead Nebula and also tried for M1 The Crab Nebula
for the first time.
I think you will agree that this version of the Horsehead
Nebula was a significant step forward from the previous attempt taken in
Alt/Azimuth mode. The Crab Nebula
image was very encouraging too, but required some work in Photoshop to remove
some star trailing.
I decided that to push the
exposure time out further I would need to work on guiding. I have seen some amazing images on
Cloudy Nights that were manually guided by the photographer while looking
through a reticule eyepiece. That
takes a lot of patience and skill.
Once again, I turned to technology as an answer in the form of
Auto-guiding. At about this time I
bought Erika a Coronado PST for her birthday and we needed a mount for it. Meade were selling off some cheap 70mm
refractors that came with Alt/Az mounts.
We bought one so that Erika could attach the PST to the mount and I had
the 70mm scope for guiding.
Initially I used the Neximage as the guide camera but it was rather hit
or miss finding a suitable star to guide on. It was rather frustrating at times as I had thought this
would be an easy step forward (compared to moving up to the wedge). Even so, I did manage to get an image
of M51 that was, up to that point, my best image of a galaxy. I was very pleased with this one.
I also added a new galaxy to
my tally in the form of NCG2903
This proved to be the last
image I took using the Meade DSI camera.
In early March 2006 I took
the plunge and bought a used Meade DSI Pro monochrome CCD camera. I chose the DSI Pro for two main
reasons. Firstly the cost. It was expensive for me at the time but
I found a good deal on a lightly used one. For the price I don't think there was a better camera out
there. The second reason being
that I was already familiar with the basic operation of the DSI camera. The new challenge would mainly be with
image processing after the 'data' after the imaging session at the scope.
To test the new camera I
decided to shoot NGC2903 once again to see what kind of improvement I would
have over the older Colour DSI.
The weather was not fully co-operating that night and so I was only able
to get the Luminance set of data (imaged through an IR-cut filter).
I was pleased to see that the image seemed much
sharper than the Colour DSI version.
A few nights later I was able to go back and get the red, green and blue
data needed for the final colour image.
That was a new concept for me too.
The thought of taking the colour elements of an image on different
nights seemed pretty strange at first, but I now find it is something I have to
do quite often if, for example, the clouds roll in or the object is only in a
favorable position to image for a short time.
The image that really showed
me that I was moving in the right direction with the new camera, polar
alignment and autoguiding (now using the old DSI as the
guide camera) was of M16 . It
was taken on April 27th
I think that the first four
months of 2006 was the period where my images improved the most rapidly. I can't put my finger on one particular
change that made the biggest difference, mainly because I changed both the
method of mounting the telescope
and the change from using a one shot colour camera to using filters and
a monochrome CCD. I can say though
that moving up to a polar aligned mount, and learning how to get it accurately
set up, was the biggest challenge.
It was all worth the effort though.
During the next few months I
gained experience using the new camera and also image processing. I revisited M51 and M27 using the new
techniques I had learned.
Junior and Discovery
I also took a few images of
Jupiter towards the end of May. I
wanted to capture 'Red Junior' which was discovered by Chris Go (who is a well
known CN member). The NexImage was
still hanging in there and I managed to take this shot with it.
In July there was a lot of
excitement due to the 'Return to Flight' Space Shuttle mission. I was eager to get an image of the
Shuttle to compliment my ISS image taken in May 2005. I was lucky to have a good pass a day or two before
Discovery was due to land. Unfortunately
the NexImage was on it's last legs and performed badly with lots of 'bleeding'
around bright objects. The image
below is the best I managed. I was
rather disappointed with this shot as I think it would have come out quite well
if the camera had behaved. Of
course, only a bad workman blames his tools, but in this case it was a
The camera problem was not
all bad though, because it prompted me to find a replacement. I settled with the Philips SPC900NC
webcam which has proved to be very capable.
In September 2006 I added
some significant upgrades to my imaging arsenal. These came in the form of a DSI Pro II camera and an Orion
The DSI Pro II is now my
main imaging camera while the DSI
Pro has been relegated to guide camera duty. The new camera has a bigger CCD sensor with a greater
pixel count. It has greater
sensitivity while providing a cleaner image than it's predecessor. Another neat
feature is that the CCD has a temperature sensor attached which allows the
Meade Envisage software to automatically select a matched Dark frame. This negates the need to take dark
frames each imaging session ( long as you have a suitable dark frame already in
your 'darks library'). That
saves a lot of time and results in
very clean 'subs'.
The ED80 was picked up
second hand in immaculate condition as a birthday present from Erika. I wanted this telescope because it
would open up a whole new set of targets to me that the SCT was not suited for. These included M31 The Andromeda Galaxy
and the Veil Network Nebula. With the use of a 0.5X focal reducer the ED80 lets
me image a fairly wide area. The
refractor gives me pin sharp images too.
The shorter focal length also has the added benefit of being much more tolerant
of guiding and tracking errors. I
use the ED80 'piggybacked' on top of the LX200 but I have a set of rings that
allow it to be attached to our LXD75 mount when Erika wants to use it for
visual observing (it is a very nice telescope for visual work too). I have been extremely pleased
with both the new DSI Pro II and the ED80.
Below are some of the images
I have taken so far with the ED80 and DSI Pro II.
The Horsehead and Flame Nebulae. The very bright star is Alnitak (the
left star in Orion's Belt). As you
can see, Alnitak has produced a large halo effect. I am hoping that as I progress further I can learn how to
eliminate that. One of the most
enjoyable things about this hobby is that there is always something else to
The Eastern Veil Nebula (NGC-6992).
M33 The Triangulum Galaxy.
and the ISS
The last image I took in
2006 was of the ISS and the Space Shuttle Discovery (STS-116) as it passed high
overhead on the 19th
of December. It was a very lucky shot as a lot of things came together
that were not under my control.
The video file contained about 3900 frames. The ISS and Discovery were on quite a few of those, but for
the most part they were blurred and unrecognizable. Just a few came out
well, and of those the image below was definitely the best. At the time I took this, ISS and
Discovery were approximately 220 miles above my head traveling at roughly 17000
miles per hour. As I said, it was a lucky shot but it more
than made up for the poor results I had back in July.
That brings us up to where I
stand presently. Looking to the
future, there are a number of things I would like to add to my equipment list
that would help advance my climb further up the learning curve. Number one on that list has to be a 'roll off roof' observatory. This would allow me to spend more time
imaging rather than setting up and tearing down. Hopefully in the next year that will come to be a
reality. As for goals, I would
like to get a handle on imaging the Sun in Ha. I have tried to do this a few times now but found it to be
frustratingly difficult and my results were rather poor. I know it can be done though, as the
stunning images in the CN forums prove time and again.
I hope that this overview of
my imaging experience so far has
illustrated that, although the learning curve may seem impossibly steep at the
beginning, good progress can be made over a fairly short space of time if you
keep at it and take things one step at a time. For me it has been a very enjoyable and rewarding journey so
far. The great thing is that I
still have so much to learn and there are many unique and awe inspiring objects
left up there that I have yet to image (a lifetime's worth I am sure)..