USER OBSERVATIONS Last updated: 16 October 2009

Subject:	Why I'm Keeping My ETX-90M
Sent:	Wednesday, October 7, 2009 21:48:26
From:	chris brown (chrisbrown4@cox.net)
Please cancel my ETX-90 ad in your "For Sale" section.

I decided to keep the ETX-90M, and heres' why...

A few months back, I got a used Celestron/Vixen 80mm f/11.3 Achromatic
refractor (Japan), mounted to a Meade LXD-55 manual mount, and I have
been using it as my backyard instrument instead of my ETX-90.

The Vixen has truly wonderful optics, and the capability of 200x powers.

I thought it was time to retire the ETX.

Tonight, I finally had a side-by-side comparison of the two telescopes,
here's what I found out...

On Jupiter, about 100x (9mm circle-T Ortho for the Vixen, Chinese 12.5mm
Plossl for the ETX), the ETX shows a brighter image, and definitely
higher contrast then the Vixen! Details in the main bands took on a
greyish tone in the vixen, and came in and out. Through the ETX, the
details were bolder and steady. I thought the non-CO telescope would
have a contrast advantage, not so, but it did have a wider FOV...

Next, I pointed at WZ Cassiopia, a nice little red/blue double, and the
ETX showed a slight color advantage.

The same dim stars were averted vision in both telescopes but again, the
Vixen had a wider FOV. Apparently, the extra 10MM of aperture makes a
difference, even with a central obstruction! Also, the ETX has no false
color, which seems to affect the Vixen at times.

Both telescopes have excellent optics, but I have decided to keep the
ETX because not only does it do everything the Vixen does, it's half the
size!

Next week, Im doing a Moon shoot-out! I have yet to see a craterlet in
Plato with the Vixen, I've seen 5 with the ETX on one great night!

I'll keep you posted!
Good to be back!
Regards,
Chris Brown

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