In August 2011, I decided to upgrade my optical train. The initial upgrade was to be the FW8-STL, an 8-position computer-controlled filter wheel which replaces the internal 5-position filter wheel in the STL-11000M camera; this would allow me to move to full narrowband images - Ha, OIII, SII as well as the normal L, R, G, and B (so 7 filters are required in total). The FW8 filter wheel is quite heavy, and I was unsure of whether the 2" TCF-S focuser I was using would handle the additional weight. In addition, with narrowband filters (very narrow at 3nm bandwidth), not much light from stars gets through the filters, so guiding with the normal guidechip (a second, smaller CCD in the SBIG cameras) is usually not practical - it is nearly impossible to find a bright enough guide star ... and then the framing of the image may become non-optimum. So, an off-axis guider and remote guide head is needed, which can pick off some light from the scope before the light passes through the narrowband filters - such light being focused (by a Borg helical focuser) onto the chip of a small CCD guide camera - in my case, the "remote guide head" (RGH) which is an accessory to the STL-series SBIG cameras. In addition, my Pyxis 2" rotator would not be able to handle the additional weight of the large filter wheel and the off-axis guider and remote guide head ... so a larger rotator would also be required (!). Altogether, it was estimated that my upgraded optical train would weigh about 17-18lbx, so each component needed to be able to support the weight of downstream components. I could have started at the telescope with either the Pyxis 3" rotator or a larger focuser (so the focuser weight doesn't need to rotate, easing the strain on the Pyxis). I chose the Bellerophon 3" RoboFocus-driven focuser made by Don Clement.

The Pyxis 3" (clear diameter) camera rotator enables precise rotation of the camera package (CCD camera, filter wheel, off-axis guider, remote guide head) in order to frame images and/or to position a guidestar on the guide CCD chip. The Pyxis 3" rotator can handle a maximum of 20 lbs of load, and uses a 6" gear driven by a stepper motor to rotate the camera package 0.0078125 degrees per step. This is approximately 0.47 arcminutes of rotation per step. The 3" Pyxis rotator is quite large - about 2.4" thick, and weighing 4.5 lbs ... so is mainly suitable for larger telescopes. I wasn't sure that the back casting of the Meade 12" LX200R scope would actually handle a 20-lb load (extending nearly 12" from the back of the scope, and therefore putting significant torque on the back of the scope, depending on the position of the mount/scope). It also wasn't clear whether I should mount the Pyxis 3" directly to the scope, and then rotate the focuser, or connect the focuser to the scope and then the rotator; I settled on the latter - with the Bellerophon focuser attached to the scope, and the rotator attached to the Bellerophon using a custom-made adapter from PreciseParts.com.

I should note that the bright blue Pyxis 3" shown in the photos here was only a loaner, while my Pyxis was being manufactured (part of the great customer service from Optec, Inc.). My Pyxis is actually a black anodize, as are most of the other components of the optical train.

At right is a photo of the Pyxis 3" rotator holding the camera package. The camera package includes the AO-L adaptive optics unit, the Astrodon MOAG off-axis guider - which has a prism that picks off some of the field and reflects it through the Borg helical focuser to the SBIG remote guide head (RGH). The RGH provides the guiding for the scope, as would the internal chip in the STL camera; but the RGH is placed ahead of the filter wheel (large light-gray box connected to the camera), so that the guidestars are bright, and not 100X dimmer due to narrowband filters. Attached to the MOAG at right is the FW8 filter wheel, which holds 8 2-inch diameter filters, and the STL camera. It is this entire package that must be held - and moved - by the Bellerophon 3" focuser.

Again, please note the 'improper' positioning of the AO-L/MOAG/RGH - as the RGH should be pointing up (in this image), away from the camera connectors; AND, the RGH connector (barely seen at left of the RGH) should be positioned closest to the camera. I had thought that the position shown would work, as this should be equivalent, as far as the RGH image is concerned ... but I neglected to realize that the AO-L is also then positioned "upside-down". So I will be re-mounting the AO-L/MOAG/RGH package 180 degrees from that seen in the photo at right.