As You may have read on the home page I
started this hobby with a Meade DS114 AHA Newtonian
Telescope Computer controlled with a 494 hand box in
December of 2006.
After perusing the web and various Yahoo groups I
decided to purchase a Phillips SPC900NC web cam to use for
imaging. I applied the
exposure (SC1) mod to the camera, removed it from it's housing
and placed it and the new circuitry into a plastic project box. I added
a small fan for cooling in the summer. That was my starter
Since I was new to astrophotography I started out with
easy things to practice with, the sun and the moon were some of my
first targets. You can see some of the images in my
image the sun I needed a solar
filter to limit the amount of light that enters the telescope.
I found the right material on the web and made one to fit the
This combination worked OK. The only issue I had
was with the Meade focuser that came stock on the telescope.
It is real sloppy. Ok for viewing but almost useless when you are
trying to adjust the focus while using a camera. Just
touching the scope would cause the image to wiggle so bad that
it was almost impossible to get a fine focus.
solution to this problem was a JMI motorized reverse
Crayford focuser. This unit is extremely smooth in operation and because
it has a motor drive there is no need to touch the scope in
order to focus.
When using the telescope and camera combination at
prime focus the field of view (FOV) is very narrow. In
order to take some wide angle shots I purchased an adapter from
web caddy to
allow me to use my Canon SLR camera lens with
the web cam. .
My setup with the 114mm scope looks
something like this.
I use a laptop running Windows XP to control the
scope and the camera and capture the images. When I'm done I transfer
the images to my desktop and process them with a
variety of programs.
This setup served me well through most of the
year but I was looking for something that would be a bit more
stable and have better tracking. Again off to the web I went to
see what was available for a reasonable price. After consulting
with my friends in the QCUIAG group and other sources I figured
that an equatorial mount is the thing to get with something
around an 8" telescope. The budget was around $1000.
As luck would have it, someone was selling a
Meade LXD75 equatorial mount with a SN8 telescope which was
fitted with a motorized Moonlight focuser. I checked into it and
found the deal too good to pass up and purchased the setup.
As you can see in the picture at right the telescope is a
8" Schmidt-Newtonian with a focal ratio of f4 which is very fast
optically. The scope is controlled by a 497 hand box. However, most of
the controlling and imaging is done thru the laptop computer.
the need to sit out with the scope during imaging sessions on the
cold winter nights. I connected the laptop to my local area
network at home via a Cat5e cable (don't have enough ports on the laptop
for wireless, besides the 100' of cat5 was cheaper than a wireless
card for the PC). I loaded VNC on
both the laptop and the desktop in the house and control the laptop that
way. Work like a dream. Now I can stay relatively warm while
pursuing my hobby in the winter time.
At about the same time as acquiring the LXD75, Meade
decided to discontinue their first
generation Deep Space imaging camera and the various dealers were
selling the color DSI, which normally goes for almost $400 for a mere
$99. How can I ignore such a sale? So now I'm the owner of a DSI
camera and use primarily when imaging deep space objects. The
software which Meade provides with is makes it real easy to take
Which ever camera I use to image with, I
attach a Baader IR/UV cut filter. This reduces the infrared and
ultraviolet exposure of the cameras. Unlike our eyes the CCD chips in
the camera are sensitive to UV and IR which can degrade the
January '08 [LXD75]
Well I've been using the LXD75/SN8 combination for about
4 months and it does a decent job at allowing me to image some
deep space objects. ( see some on my gallery page).
A new wrinkle that came about using then
equatorial mount for imaging is that you must have good
polar alignment. Setting up the Az/El mount on the DS114 is
straight forward. Point the scope to the magnetic North and make
sure that its level. That's pretty much it.
Polar alignment is another animal all together. The LXD75 comes with
a polar scope which you use align the mount to point the north
pole. If you don't have a Polar scope you can use the
drift method. The drift method, though very accurate, is tedious and
time consuming when done right( can take 30 minutes or more).
In learning about polar alignment I came across a method
the uses two stars, POLARIS and KOCHAB, along which you align the counter
weight bar and then shift the mount until Polaris is in the circle of
the polar alignment scope. This is called the
Kochab Clock method . Using this process I've been able to image
within the PEC (Periodic Error Correction) limitations of the mount.
The main issue that I have is that there is
enough error in the RA worm gear which causes the image to
swing east and west slightly that exposures longer than 15 seconds
become problematic. In trying to correct for this problem I
have PEC trained the controller which helped a little. Another thing
that I found which had a great affect on how well the scope
tracked was the balance on the RA axis.
When setting up for imaging I shift the weights so that the
scope weight is slightly biased to the east. This helps keep the load
on one side of the RA worm gear since it always turns to the west.
Using this balancing act, on a good night, I may even be able to
run some 30 second exposures.
Unfortunately for many DSO's 30
second exposures just don't cut it. To get enough photons
into the camera to pick up the fine detail for some targets
2 or 3 minute exposures sometimes even longer are need. The only
way this is possible is by using a guide scope, camera and
software that will keep the setup locked on a target
allowing for such long exposures.
I have finally chosen to go that
route and purchased a used 80mm f11 guide scope made by Orion. At this
time I have not yet had the opportunity to try it out.
My plan is to use the Philips SP900Nc web cam as the guide
camera and guiding with PHD created by
Stark Labs. I'll use the Meade DSI for imaging, as I have been, on
the SN8. My hopes are that I can get at least two minutes exposure
time if not better.
While waiting to try out my guide setup, we had a beautiful day
and there were some interesting sun spots available for imaging so I put
my DS114 on my LXD75 mount and took a few
To mount the DS114 on the LXD75 I made a dovetail bar out of
oak to match the profile of the dovetail on my SN8, I picked
up a set of tube rings from ORION and screwed them to
the dovetail plate. The setup works like a dream.
Finally got my guiding set up and started playing with it.
As I mentioned above I'm using a Orion 80MM f11 refractor as the guide
scope and the Phillips SPC900NC SC1 as the camera. The guiding software
is PHD by Stark-Labs. I had to make my own mounting for the Orion
scope using a T-Slot rail (Light blue on top of the SN8) which is
screwed into the Meade scope rings. Using two Stainless steel carriage
bots If fastened the rings for the Orion scope to the rail.
So far it's holding up. Nice and solid. Because of the extra weight of
the 80mm, I needed to add some counter weight. Here I'm using some
5Lb ankle weights temporarily.
Now to get the guiding set
up and working correctly.
To maximize my imaging time I leave the the scope set up in
my back yard all ready to go. It's safe under a
cover . It's almost as good an observatory ( That's next (-: )
(stay tuned for updates )