I recently bought a used Celestron CG-5 mount and decided that after verifying basic operation, the next thing to do was to take it apart and do some basic maintenance.
It’s well known that the Celestron mounts made overseas need some rework to get full performance out of them. They frequently contain “lube” that is more like glue, the gears need polishing to remove burrs and many of the plastic rings look they’ve been cut from milk bottles.
I’d done the same maintenance job on my Super Polaris mount which is almost identical to the CG-5 except that the CG-5 has brass gears and ball bearings rather than just sliding plastic rings.
Armed with information from Astroboy I set about disassembling my CG-5. Full pictures of the dis and re-assembly are in the gallery, selected pictures will be included here. I also won’t cover every single step since it’s already been covered by Astroboy.
As some of you have no doubt read, the audio quality coming out of the built-in Fujitsu T4215 microphone is bad at best. There is frequently a lot of noise even at low recording levels and the "Intellisonic speech enhancement" is completely useless, turning all speech into something that sounds like it’s been recorded underwater. I finally gave up trying to make it work and bought an inexpensive external mic and was still getting too much distortion and the mic sensitivity was too low so I decided to give the SP-USB-MIC-1 microphone from The Sound Professionals a try. I’d seen one recommendation for it on the web but it appeared that people weren’t gushing about it. It actually seemed like not many people were using what some people call "external sound cards". Either that, or they just weren’t talking about it. Continue reading “SP-USB-MIC-1 Microphone”
I spent some time on Thursday night finishing up the platform for the new laser.
I’ve got a Kee-Klamp scaffold over my table that holds the big red laser and nothing else. I had planned to hang optics off the scaffold but that didn’t quite work out. Fortunately it made a great place to put the SP-907 laser box.
Now it’s got another rider in the green laser, telescope and shutter.
For several weeks I had a functionally dead Spectra Physics 907 laser. This was especially bad because this laser is the one I use for mastering my holograms which meant I couldn’t make anything new until it was fixed.
During those weeks I picked brains and websites far and wide and managed to get the laser lasing again (several times in fact) but couldn’t get the beam quality back the way it was before I screwed it up. I ended up enlisting the help of a local laser expert and was able to get beam power and quality back where it needed to be.
What follows is a tutorial on how to re-align an external mirror laser. Most specifically the Spectra Physics 907. I also include some tips on cleaning the mirrors and removing stuck boots.
Before I go any further I want to thank the following people:
The guys at the Holography Forum who provided suggestions for getting the beast aligned. Tony, BobH, Wler, Colin, Ron Michael, Martin, JohnFP, dcgman.
Sam Goldwasser for making public such a treasure-trove of information about lasers.
Tom Ehrichs for spending time cleaning and aligning the laser. I gained as much by watching him work as I did by him working.