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ETX-90/LX-90 Comparison

The Selection Process

Well, it didn't take long for me to get the itch to upgrade. The candidates under consideration were the ETX-125, the LX-90 and the Nexstar 8.

The things I didn't like about the ETX-90 were:

  1. Unstable Plastic mount.
  2. Large backlash, even after tweaking with training and alt/az percentages.
  3. Autostar inaccuracy think mine was worse than most, as I seldom had things even near the center of the viewer, even after extensive training, leveling and in both alt/az and polar mounts.
  4. Small aperture, although it's tack sharpness made up for some of that.

The ETX-125 fixed most of (4), but left (1)-(3) to be desired. The cost would be: $1100; $900 for the ETX-125 itself and $200 for the Deluxe field tripod...My Tilt-All tripod was fine for the 90, but the bulk of the 125 at polar alignment would just not work. I could reuse my ETX-90 Autostar, as I was able to only return the Scope itself to Natural Wonders.

The Nexstar-8 was a great consideration. It pretty much took care of (1)-(4). It was $1700 with everything (scope/tripod/computer). But I've seen mixed reviews on it's goto system and I had some concerns on stability and backlash. I also had a Nexstar80 for a few days, and didn't care for their computer compared to the Autostar.

The LX-90, similar to the Nexstar 8, took care of my needs. It was also $1700 (by no coincidence). From everything I read on the LX-90 egroup , it seemed to have everything going for it. The tripod was super-stable as compared to the Nexstar. The Autostar seemed to be dead-on.

I took a look at my local Dealer and was amazed at the LX-90's stability and quality, so I went for it.

The Comparison

The LX-90 was remarkably easy to set up. I just have to make one more trip between the house and yard over the ETX-90 (Tripod then Scope, rather than both in one shot). Screwed the scope to the massive tripod, did a sight level, a rough North align and fired it up. Did easy align and some goto's. Better than my ETX, but not great...Oh shoot, the drives didn't calibrate (factory???) and I didn't train. Did the calibration, lined up with Polaris and did the training. Put in in the home position, did another easy align and voila...perfection!!! Everything I went to was virtually dead center. Went on the whole tour and everything was great. (3) above was taken care of. Plus, everything was nice and bright in comparison to the ETX. (4) was taken care of.

Looked at Jupiter. Was noticeably more detailed, but lacked that sharpness. I decided to check collimation and low and behold it was a little off. Did the collimation (was wishing for a Mak rather than a SC at this point) and went back to Jupiter...much better. I could really visually make out some great details and it was sharp, limited by seeing, not the optics.

Fired up the Webcam, removed the diagonal, attached my mount and centered on Jupiter through the finder (and what a great finder it is!). I just saw the out-of-focus white patch in the corner. Centered the secondary dark spot of the out-of-focus patch in the middle of the view and then focused in on Jupiter. The focuser is every bit as stiff as everyone says. I'll have to try that de-stiffener method described in the e-groups. Image was bright and clear...very nice. Added the 2x teleconverter in front of the Webcam. On the ETX, I usually had to readjust the whole rig due to the extra weight. Much to my delight, there Jupiter was smack in the middle...no searching!!! It tracked beautifully. I left for 15 minutes to do something and when I got back, Jupiter was still there! With the ETX, the image was less magnified but I still had troubles keeping it in view. In fact, I totally gave up on using the Autostar for taking pics with the ETX, as chasing the backlash was a lesson in frustration.

With the LX-90, the tracking was fantastic and the backlash was negligible, or at least well compensated for. When I pushed a button, it went. It didn't pause/jerk/fly off...it simply moved linearly...pure happiness. And when I change accessories, this thing remains dead solid. No having to compensate constantly for added weight. And when I bump the tripod or scope, it doesn't throw everything way off. (1) and (2) are fixed!!!

I did have an issue that the diagonal is not collimated. It seems I can either collimate for using the diagonal, or using straight out the back...not both! For now, I'm using the Webcam through the diagonal.

As far as convenience, I find that I can be up-and-running in about the same or less time with the LX-90 vs. the ETX-90. I have one more trip to make, but the alignment process goes much quicker. And the Webcam process is probably 3 times as efficient. I spend FAR less time getting and keeping objects centered than with the ETX.

End result??? I'm VERY happy. My sessions are far less frustrating and the views are wonderful!


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