Inside the ETX-70

I got my ETX-70 on February 1st. 2003. Of course the skies were NOT clear, so I decided to take a look inside and do some modifications. On this page are the results. It was a very nice little telescope with surprisingly good views. Also the GOTO worked very fine. Eventually I sold it, because I did not use it enough.

	First I removed the lens. To do this, carefully unscrew the plastic ring at the front of the OTA. Also, it is a good idea make the inside of this ring flat. In my case, there were quite some sharp leftovers from the casting process. I used a piece of sandpaper to make everything smooth. Another good idea is to make the edges of the lenses black: this will cause less reflections in the glass. Do this with a permanent felt tipped pen, not paint, because the lenses are very tight inside the OTA. Paint will produce a thick layer, preventing the lenses to be inserted again. Remember which lens has to go first inside the OTA, and which side will be the front and backside!
	This is the inside view of the OTA. Very shiny plastic. The treaded rod is the focuser. With this rod, you move the front part of the OTA back and forth. To remove this front part, unscrew the small hex-nut inside the focuser knob. Then you can pull off the front.
	Another view of the inside of the OTA. After painting everything flat black, all the reflections are gone.
	The RA-gear. I redistributed the grease, as it was not spread out correctly.
	The RA-drive motor and gearbox. I carefully removed all the debris between the gears. Every small particle will make the telescope jump as it comes into contact with another gear. I also redistributed some grease on the worm.
	The DEC-drive gear with the main circuit board. After removing the OTA from the fork arms, I cleaned the clutch disk, because it was quite greasy. I could hardly tighten the DEC-knob tight enough to lock the OTA before cleaning.
	Almost all the parts of the ETX-70. Not shown is the RA-base. The front part of the OTA is still assembled, because of the fragility of the lenses. To loosen the RA-base, first remove the RA clutch lever. Then you can unscrew the bolt. Next, turn the ETX over and remove the white 'crowned' nut. Be VERY careful, it will easily break and the fine thread is quickly damaged.