Last updated: 18 October 2003
Subject:	high-power views of mars with the etx-90
Sent:	Wednesday, October 15, 2003 20:59:51
From: (chrisbrown4)
I must report that I have had considerable success with my ETX-90 RA
using powers in excess of 200x durring this year's opposition of the
planet Mars. Typically, I use a Teleview 8mm Plossl (156.2x) or a 7mm
Meade Research Grade Ortho (178.5x) when viewing the gas giants, with
very good results (see Mike's Eyepiece Reviews, Meade RG Orthos),
However, three weeks before the opposition of Mars, I was able to use
208.3x (6mm Optica b/c Ortho) in the city, on a very steady night! The
ball appeared a vivid orange color, with a broad "X" shape in blue
(Syrtis Major) across the face. The south polar ice cap was very clear,
and a bright white color! The view was sharp and clear, with virtually
no image breakdown.

I was able to recreate this feat on the weekend of 10-11 at a semi-dark
sight in Southern California, using a slightly different method. I am
usually a fan of low-glass count eyepieces for the ETX-90, (I currently
have in my possession, 8 Ortho's, just for use in the ETX!) to preserve
image brightness when using high power on planets. On this clear night,
I used an Ultima barlow in conjunction with a 10.5mm Meade RG Ortho to
give a wonderful view at 238x! (I usually save the barlow for my 8-inch
Dob, which I find to be an effective filter to reduce the glare of
bright objects and restore surface details; For example, my 12.5 ultima
with barlow shows more surface detail on Jupiter than my 6mm Ortho, yet
the situation is reversed with the ETX! ) The colors were a little dull,
and the sharpness was starting to soften, but the view was still
spectacular! I must note that the clock drive wasn't designed for this,
the object would leave the field of view after about 5 minutes! I
attribute this exceptional performance to a wonderfully clear night, and
a very steady atmosphere, not to mention a mighty good telescope!

       Chris Brown

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