With Jupiter still near opposition and Mars opposition approaching I would like to do a little high resolution planetary imaging. For planetary I use our Nexstar 11″ telescope, with 2800mm of focal length is has the high magnification needed.
One lesson in high resolution imaging is that collimation matters. Having the optics in your telescope precisely aligned makes all the difference in the results. A small misalignment will result in mushy images that will not quite focus properly. No amount of fancy image processing will salvage the image.
The Nexstar has not been giving me the results I know it is capable of. I shot Venus just before inferior conjunction and noted that there was probably some issues in collimation that were not addressed in the quick star collimation I had performed.
Thus I borrowed a Hotech CT Laser Collimatior from a friend. The collimator is an interesting piece of kit, enabling the user to check more than simple the tip-tilt of the secondary.
The original NexStar telescopes are great instruments. Ours has seen many uses, from dark skies to not so dark skies as it has been set up in the Arizona Desert, the summit of Mauna Kea, or various school yards and resorts for public viewing. It has been used as a visual instrument, a photographic ‘scope, even done a little real work.
For the most part the scope has worked well, and has been well maintained, even updated with the latest hand pad controller. But on occasion there is a problem… connection issues would crop up. The dreaded “No Response 16” or “No Response 17” errors would appear, indicating that the motor control board is not talking. This would result in having to power cycle and realign the telescope.
Lately the errors have become more problematic. The last straw was a public event I recently used the telescope for, setting up the telescope for Halloween. Continual errors plagued the evening, a constant struggle. While the scope usually tracked, I could not use GOTO as each alignment was quickly off by just enough to be useless.
I have had the telescope apart too often in attempts to fix this, inspecting and re-seating the cables. This usually works, the problem will go away, for a while.
In general I like what I see inside the telescope. A well designed piece of kit with good components. Decades of taking gear apart have provided me so many examples of poor or good design. Inside the NexStar I just like what I see. The telescope is easy to get apart, just a few screws to remove each cover, exposing everything you might need to work on. The designers of this telescope obviously took pride in their work, it shows.
The exception to this is the wiring. There are a number of issues that can create trouble. Or rather there were a few issues, I just took care of that…