Excelsis - Display Vote

Celestron G-8N Newtonian

I bought from a retailer ($959) and still consider it a good value. You MUST let the mirror reach working temperature or the images double. It's easy to tell when it's right (you hear a curious little "pop" if you happen to be there when this happens) and -- if you're watching at the time -- the images just magically resolve all at once. Collimation is spot on, but recollimating might be a problem if needed because both the primary and secondary adjustments are potted with silicone adhesive. I have trucked this thing all over Texas and never had to tweak it, though. Very bright views due to fast f/ratio. Jupiter and Saturn are remarkably good, even at higher powers. Best when limited to about 200mm (probably due to the large central obstruction). Very good optics, with sharply defined diffraction rings on bright stars. Sirius is so bright it actually hurts to look at it. Venus has a discernible disk but the heavy secondary spider provides distracting "star points" and a visible diffraction pattern ... curious. Star clusters (especially M13) are absolutely amazing. Weak point is the mount. It comes with 2 11-lb counterweights and you MUST carefully balance this scope. You should fill the tripod legs with something (sand or spray foam insulation) and put c-clamps on each leg between the spreader and the top of the mount. Otherwise, it takes almost 20 seconds to stop vibrating if you tap the tube. Wind is a problem because the mount is just not steady. With the above improvements (which are "dirt" cheap) you can get the vibration down to under 5 seconds. I purchased encoders and a JMI MicroMax, as well as the Celestron dual-axis drive with PEC, and this mount tracks like a demon. I can visually observe Jupiter or Saturn for a full 15 minutes without pulsing the drive. Celestron recently upgraded the bearings in the CG-5 mount and it's a big help. I like this scope. However, at about $1,500 with the drives and MicroMax there are a number of mail-order and Internet alternatives in the 8" SCT range that offer better mounts and larger computer databases. This is my "big" scope (I have a 5" Mak, a 3" Short-tube refractor, and a 4.5" Meade Newt) and I agonized over the purchase. I feel I got good value for the dollar given the excellent optics, but if I don't move up to a 12" SCT in the near future I will have to invest in a CI-700 or Vixen GP mount to be happy.

Overall Rating: 7
Optics:9 Mount:7 Ease of Use:8 Value:7
Weight: 6 (Veritable Vote)
Date: 05/01/2002 11:34:55 pm PST
By: Anonymous (xxx.xxx.66.160)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=87361

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