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 My Equipment

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 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 Long 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 outfit.

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 Gallery page.

To  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 telescope.

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.

My 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.
     To reduce 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 decent pictures

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 picture quality

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.

3-30-08[DS114 on LXD75]
 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 pictures.

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.

4-19-08 [Guide equipment]

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 Telegizmo 360 cover . It's almost as good an observatory ( That's next (-: )

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(stay  tuned for updates )

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