Posts Made By: Stanley Yen

July 15, 2003 09:01 PM Forum: Deep Sky Observing

Finally!

Posted By Stanley Yen

Darren,
By all means try M22 in Sagittarius; it's
about 50% bigger and easier to resolve than
M13. Even from latitude 49.5 N (Vancouver BC)
it's an easy, impressive object on a dark clear
night. Also try M5 in Serpens, M92 in Hercules
as globulars that are nearly as easy to resolve
as M13.

September 19, 2003 01:10 AM Forum: Solar System Observing

Blue Color on Mars Northern Limb

Posted By Stanley Yen

I have also seen a blue fringe around the
northern limb, accompanied by reddish fringe
around the southern limb, in my Mak-Cass.
I thought it was atmospheric dispersion.
Mars is only about 24 degrees above my horizon
at best.

January 2, 2004 08:39 PM Forum: Equipment Talk

Some advice on an astro-makeover

Posted By Stanley Yen

Anthony,
I recently acquired a Ranger and found myself observing more than I ever did with my bigger scopes. The wide
field of view, sharp optics, fast cool-down and
easy portability make it such a pleasure to use.
It allows me to be spontaneous about astronomy.
What's the phase of Venus tonight? What are the
moons of Jupiter doing? Are there any sunspots?
I can see for myself in about 1 minute.
Instead of setting up and cooling down for a lengthy
observing session, I can just spend 10 minutes whenever
I feel like it to look at whatever strikes my fancy or
just revisit some of the old friends in the sky.
A smaller, high quality scope could indeed be what
you need.

August 9, 2007 02:27 AM Forum: Refractors

Vixen NA 120 - First Night Out

Posted By Stanley Yen

Yes, I have one too. I just love it -- nice
resolution and contrast, a robust package
with minimal adjustment, and light enough
for grab and go. With a 32mm Erfle, I get
a 2.6 deg field of view. This scope does
everything from rich field to high resolution,
at a fraction the cost of an APO.

March 18, 2008 05:10 PM Forum: Refractors

Vixen NA140 Neo Achromat

Posted By Stanley Yen

The blue halo is reduced compared to a achromatic doublet
of the same focal ratio, but the blue halo is still
visible (to visual
observers) on bright objects like Jupiter and 1st mag stars.
The blue will likely be even more apparent in DSLR imaging.
See the review section of the website for the report of
a visual observer, also google 'vxreview' for the report
on the Orion VX-120 (aka Vixen NA120), which is the
120mm version of the NA140. The reviewer there complained
about photographing "bloated stars" on the 120, and the
140 version will be worse. It's not an APO by any means.
The Petzval element does flatten the field so that you get
sharp images across the whole field. Probably a mild minus
violet filter like the Lumicon MV will take care of most of the blue halo.

August 16, 2008 02:38 PM Forum: Eyepieces

Meade 4000 Super Plossl "Japan" 4 or 5 element

Posted By Stanley Yen

I browsed through my collection of Astronomy magazines.
The May 1993 Meade ad still lists the Series 4000 eyepieces as having 5 elements. The September 1994 ad describes the Series
4000 as having 4 elements, "updated and redesigned to utilize
the lastest in optical glass types for 1994".

I've heard that the 5-element ones were actually made by
Masuyama in Japan. I can't comment on which type performs
better.