Meade #777 Off-Axis Guider
Last updated: 1 December 2011
The report below was originally posted 27 March 2007 and discusses using the Meade Off-Axis Guider (OAG) on my LXD75-8"SC. The telescope and OAG were stolen, along with most of my astronony equipment in December 2007, as I was moving to Arizona from California. The telescope was eventually replaced with a Meade 8" LX200-ACF, which is installed in my SkyShed POD at Cassiopeia Observatory. I also replaced the OAG and use it frequently for long duration DSO astrophotography on the wedge mounted 8" telescope using my Nikon D7000 DSLR. You can see many of my astrophotos on the Cassiopeia Observatory web site. Here is a photo of the OAG and D7000 DSLR on the 8" LX200-ACF:
[27 March 2007]
In February 2007 I received a Meade #777 Off-Axis Guider I had ordered from OPT for use with my LXD75-8"SC and Nikon D70 DSLR. Meade's marketing material for the Off-Axis Guider (OAG) is rather out of date; it states that the OAG is only for 35mm film cameras. However, it also works fine with Digital SLRs. I took it with me on my next trip to Oracle Observatory. Here is what it looks like attached to the telescope and camera:
I had one initial problem with it; the screw that holds a reticle eyepiece would not stayed screwed in with the eyepiece inserted and so would not hold the eyepiece firmly. On a whim I decided to try the screw from my Meade #126 Barlow Lens. It worked perfectly in the Off-Axis Guider. And surprisingly the screw from the Off-Axis Guider worked fine in the Barlow Lens!
My first target was M42, the Great Nebula in Orion. This approximately 1 minute exposure was done with the D70 set at ISO 1250. I like the results!
It was tremendously gratifying to watch a guidestar in the illuminated reticle eyepiece and know that tracking was pretty accurate during the exposure. For this one, no manual corrections were made.
M51, the Whirlpool Galaxy, was my second target with the OAG. This photograph was approximately 5 minutes at ISO 1250 with some manual guiding corrections. (Image cropped from original fullframe version.)
Overall I'm pleased with the Off-Axis Guider. The only challenge is finding a bright star near the target that can be used to guide on through my 12.5mm guiding eyepiece. But once a star is located it is fairly easy to keep it in nearly the same location on the illuminated reticle, yielding long exposures with no or minimal tracking errors. I did discover that when the image in the camera was in focus, the eyepiece was not. I had to slide the eyepiece outward about 5mm to get a focus. I needed to attach a "parfocal ring" to the eyepiece to compensate for this difference.
A month later I again went to Oracle Observatory. I still found achieving a precise focus a challenge, even with the parfocal ring attached to the eyepiece. I plan to hopefully resolve that by focusing both the camera and the reticle eyepiece using the Moon. But I was still able to get some interesting shots:
M1 - The Crab Nebula - 5 minute exposure, ISO 1250, Noise Reduction ON, cropped from original Raw image. Some trailing is evident as there was a slight breeze affecting the telescope during guiding.
M51 - The Whirlpool Galaxy - 10 minute exposure, ISO 1250, Noise Reduction ON, cropped from original Raw image. Focus is slightly off.
M101 - The Pinwheel Galaxy - 10 minute exposure, ISO 1250, Noise Reduction ON, cropped from original Raw image.
On 16 March 2007 I set up the LXD75-8"SC and did some focusing tests with my reticle eyepiece and the D70 using the OAG. I was able to find an infocus position for both and set the parfocal ring on the eyepiece so that I could consistently achieve focus in the D70. Here is the result of the focusing test on the Moon.
I look forward to getting more Deep Sky Objects (and in focus) with the D70 and LXD75-8"SC on my next trip to Oracle Observatory. Stay tuned!
Go to my LXD55/LXD75 web site.
Go to my Cassiopeia Observatory web site.