Last updated: 20 February 2004

Subject: go 105, go!!!
Date: 2/20/04, 20:15
From: Tomas Hekkers (
here is my firstlight experience with my new ETX 105. Together with a
small comparison of my experiences with the ETX 90.

Finally at 20 February we had a clear sky in Holland, so we packed our
stuff and headed for Otterlo. First serious light for my new ETX 105.  I
switched over to the 105 begin February, owning an ETX 90 before. I was
very satified with the 90, but I decided to pick the larger 105, because
I had the bucks for it. In the 8 months that I had the 90, I have been
observing a lot with it. I did a lot of DSO and followed Mars in the
summer of 2003. I'm not a photographer, but a drawer; I think you gain a
lot of experience in carefully observing and sketching skyobjects.

Setup and alignment went smoothly that night and with Jupiter and Saturn
high in the sky I had a serious change of taking the ETX to its limits
the first time. The 105 is a much more serious instrument than the 90.
It's almost twice as heavy, has better bearings and it seems to run more
accurate than the 90. Slewing takes a little more time than the 90 I
owned, but that is not annoying. The planetary views are crisp and more
3D, so it seems. I can see the depth in Saturn now, I couldn't see with
90. There are also more moons of this queen visible. Jupiter has much
more details in its belts and the polar regions. With a reasonable
seeing and a clean sky I made two fine sketches. The difference in DSO
between the 90 and the 105 is also very clear. Autostar didn't hestitate
placing the requested objects almost deadcenter in the FOV during the
whole session. I made a flight through the Virgocluster seeing galaxies
I hadn't seen before, and visited some old regulars as M1, M3, M13, M42,
M43, M51, M65 and 66, M92, M97 (Owl) and lots more, including some faint
NGC objects. With a UHC-filter the owl even showed a glimpse of its

Filters become more interesting now, since they show more effect when
you apply them on a larger aperture. The Lumicon Ultra High
Contrast-filter is a very handy gadget for your 105. It improves the
contrast of many objects, as I have seen it on M42 (Orion) and M97 (Owl)
and much more deep sky objects. I also recommend the Baader Contrast
Booster, using it on Jupiter and Saturn. I reduces the glare and
sharpens the details on these two giants. I didn't see much difference
on Mars with it last summer with the 90, I preferred an orange Wratten
filter which worked fine.

I can conclude that I made a good step in switching the 90 for an 105.
It is worth the money, your improved views of the treasures of the sky
and the pleasure of your hobby, in other words,

Go 105, go!!!
Tomas, happy-ETX-user.
Greetings from Arnhem, Netherlands to all the ETX-user on our small globe.

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