| In the past couple
of years I
have been experimenting with afocal digital astrophotography. Using
a digital camera with a variety of setups to attach the camera to
the eyepiece. The results can be quite satisfying, but it can try
one's patience as well!
My start into this hobby was
like the cart before the horse. I had purchased a digital camera
first. I was taking
pictures of everything at the time, but one night at my brother-in-law's home, he had his 4.5"
reflector out and was viewing the lunar landscape. I decided to point the camera
at the eyepiece. The entrance pupil to the camera was quite small,
so it made it difficult to aim the scope and the camera at the same
time to have a image show up on the camera's display . Once
the image appeared, the other trick was to hit the shutter release
without jerking the camera and losing the image. It proved to be a
task, but the first results were inspiring. As I look back on these
first images, I can honestly say, they are less than desirable, but
it helped nurture a new hobby.
There are a number of ways to
attach the camera to the scope. My first was the EZ-Pix digital
camera adapter from Scopetronix.
The folks at Scopetronix have a wide variety of attachments for all
types of digital cameras and if you are interested in pursuing this
hobby, I can't recommend viewing their site enough, it is loaded
with help and ideas on digital imaging. Orion
has a few themselves that are along the same lines as Scopetronix.
The initial setup using one of
these adapters can be quite a chore. The camera adapters attach
directly to the eyepiece by using a 1 1/4" clamp. Attaching the camera adapter to a small plossl is tedious, but can
be done, but changing eyepieces during the middle of
a image session is difficult. I did manage to attach the adapter to
the diagonal of the scope using the 2" clamp that normally is provided with
the adapter, but I had to pad the inside of the clamp for a tighter
grip. It still proved to be a touchy arrangement .... no pun
Then comes the alignment of the adapter. Adjusting the camera
to the eyepiece to minimize vignetting, it is a process of trial and error.
Raising or lowering the camera from the eyepiece while viewing the
camera display is the best way to rid yourself of this "hole
effect" to your images.
Turn off the flash! Don't know how many times
that I have done this, but it comes as quite the surprise when that
flash of light goes off!
Use either your timer or a remote to trigger
the shutter. Any movement to the camera or scope during the time the shutter
is open can and will ruin your image. Using the timer function on
the camera can be a bit tricky. Depending on zoom settings, you may
have to place the object at the outer range of the camera display so
that the object will be centered when the shutter releases.
Use rechargeable batteries or a DC power adapter.
One can pay a small fortune in batteries with the way digital
cameras eat them! Refer to the camera manual for compatible rechargeable
batteries or DC adapters. This purchase will pay for itself in no
Don't use the digital zoom. The digital zoom
degrades the image quality. Use the optical zoom only.
The setup I currently use is a
Olympus C-4000z with a plumbing coupler that I purchased for $5 at a
local hardware store.
This coupler fits nicely over the entire camera lens and holds a
lanthanum eyepiece at the other end. The coupler has one side at an
inner diameter of 2" while the other side has an inner diameter
of 1 1/4". Hose clamps are used to just snuggly clamp down the
arrangement. I normally use a Lanthanum
eyepiece. It's outer diameter is the perfect size for the coupler.
Some digital cameras will come with a video cable. I use this
to cable to output the LCD display to the TV. The TV is used instead of the small LCD viewer on the back of the camera to adjust
the focus. This is a great setup for the backyard, but is not
recommended at Star parties! Any outside light source at a star
party is considered a nuisance.
Most digital cameras have a variety
of settings one can choose from. Digital cameras can have four
different shooting modes: Program (automatic), Aperture Priority,
Shutter Priority and Manual. The Program mode will use the factory
settings which will most likely be designated to the most basic, or
Automatic modes. Using the Program mode is not recommended.
setup so far is to use the Manual Mode to adjust the Aperture and
Shutter speeds manually. These are some of the settings one can try.
||F2.8 or F3.2
||1/100 - 1/400
||100 or 200
||16 seconds or more
One can experiment with these
settings to try and achieve the best image. If your image shows up
as a white blob, it's a good indication that the shutter speed is
too slow and it needs to be quicker.
Example: A full moon image with 1/100 of a second shutter
speed turns out to be a white orb, increase the shutter speed to
1/150 of a second to not allow as much light through the shutter.
The process is reversed if an image of an object is dim.
The Elusive Focus:
Focusing is the hardest part of digital
imaging. Using the auto focus works with lunar images, because the object is bigger and will
remain in the LCD display, but by
using the timer, there may not be any object to focus on till it
comes into view. Some cameras will allow manual focus. By setting
the manual focus to infinity, one must use the scope's focuser to
properly focus the image. This is where the TV hook up can allow one
to see a larger image than what is on the LCD display on the camera
to allow for a finer focus. I can't tell you how many images I have
sent to the recycling bin that have been out of focus. This is
probably the most frustrating part of imaging. The elusive focus.
Another setting is to set your camera for sequential
shooting. This setting will rattle off four images at one time. This
is nice when it comes to stacking your images. One can have four
images in a row, with barely any time between shots. This is
especially nice for planets like Jupiter where the planet surface is
in a constant state of motion.
Doing deepsky images for obvious reasons, one needs a scope
that can track the object. If your camera
has a Noise Reduction feature, it's recommended to use this
feature especially for the longer exposures images. As the
camera stays on, the camera's CCD chip heats up producing millions
of tiny red and green dots in an image and ruining the shot. These
dots will increase as the camera stays on. Plus with the LCD display
on, all it does is add to the heat within the camera. Again, this is
where the TV hook up can allow for more images before the
"Dot's of Death" will be produced in every image. The
only downside to using noise reduction is that you cannot set your
camera for sequential
One of the tricks of producing a
better image is by stacking your images. This process will take
multiple images and practically pile them one on top of the other
making a composite image.
There are some freeware programs available on the WWW and they
are quite nice for the price!
is a very nice piece of freeware that can process these file
extensions; jpg, jpeg, bmp
is another nice piece of freeware that can stack images as well.
Astrostack works with bmp's and avi file extensions.
These freeware programs can not work with large image sizes though.
From a 3 megapixel camera, a raw image can be somewhere in the
neighborhood of 2200x1700 pixels in size. The
image must be cropped down to a minimum of 800x600 pixels.
digital cameras come with an imaging program to help with the
processing of your images. So one can use their imaging software to
crop or resize their image prior to introducing it to a stacking
I don't claim to be an expert on
this! I have made plenty of mistakes, trying different setups, but
hopefully this will help someone to avoid the same mistakes I have
made. I am continually trying new ways and settings to achieve digital
nirvana and that path is not always straight and narrow, but that's the beauty of
digital imagery, if
you don't like the image, send it to the recycling bin and try
Bottom line is to have fun and enjoy
And a few pictures of the experience is a bonus!
Try here Scopetronix
"How to" with digital cameras
Or drop me a line.
Remove nogarbage ;-)
I can't say thank you enough
to the folks on the OO Board!
(too many to thank but TD
Carls has been an inspiration)
Thank you for sharing the wisdom
and the passion to reach for the Stars.