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Main
Date: 03 Sep 2007 00:21:32
From:
Subject: Obs: Jupiter & Lambda Oph.
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After a month or more of smokey and/or cloudy skies I decided to
attempt an observation and sketch of Jupiter earlier this evening.
Ripples were always present around the limb of the planet due to poor
seeing conditions. Nevertheless I was able to complete a rough sketch
and upload it to my blog.
At 138x Jupiter's North Equatorial Belt appeared to have a reddish
brown color. That was the only noticeable color seen with the 13cm
refractor. Io was near the planet's north-following limb. A little
later in the evening Io was seen in transit. The planet's following
limb appeared shaded a bit more than its preceding limb -- a phase
effect. A Moon-SkyGlow filter improved the view a little for this
twilight observation.
After the Jupiter observation I did some "sight seeing" and eventually
landed on Lambda Ophiuchi. The A & B pair were split at 218x with a
narrow gap between the two stars. A #82A Light Blue filter improved
the view a bit under the relatively poor seeing conditions. The "A"
star appeared yellow or yellow-orange while the "B" star appeared
bluish in color.
Bill Greer
To sketch is to see.
http://cejour.blogspot.com
http://www.rangeweb.net/~sketcher/index.html
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Date: 05 Sep 2007 19:58:58
From:
Subject: Re: Obs: Jupiter & Lambda Oph.
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On Sep 5, 5:03 pm, "jonisa...@aol.com" <jonisa...@aol.com > wrote:
>
> I discovered Lambda Ophiuchi this summer and have enjoyed viewing it
> in a 130mm Newtonian. ON a good night at 300x is quite a stunner,
> nice round airy disks with shared diffraction rings. I have spread
> sheet based on the WDS that does up to date calculations, it says
> Lambda Ophiuchi (Marfik) is at 1.45 arc-seconds right now. I have
> tried it in an 80mm, it should be right at the limit, no separation so
> far, just elongation... No sketch either.
>
Hi Jon,
Thanks for the added info. Your comment on diffraction rings reminds
me why I like my free (door prize at a starparty:-) four-inch SCT for
double stars. The huge central obstruction sends a noticeably larger
percentage of the starlight into the diffraction rings. In addition,
the surprisingly good optics and small aperture make for a good
performer under conditions where a larger telescope would be swamped
by worse seeing-related effects.
My 13cm refractor is a very sharp scope; but doubles don't look quite
so beautiful (asthetically) due to the significantly reduced amount of
light in the diffraction rings.
I've not tried Marfik (so far) with the 102mm SCT nor with my ST-80.
Bill Greer
To sketch is to see.
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Date: 05 Sep 2007 16:03:58
From: jonisaacs@aol.com
Subject: Re: Obs: Jupiter & Lambda Oph.
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Bill:
I discovered Lambda Ophiuchi this summer and have enjoyed viewing it
in a 130mm Newtonian. ON a good night at 300x is quite a stunner,
nice round airy disks with shared diffraction rings. I have spread
sheet based on the WDS that does up to date calculations, it says
Lambda Ophiuchi (Marfik) is at 1.45 arc-seconds right now. I have
tried it in an 80mm, it should be right at the limit, no separation so
far, just elongation... No sketch either.
Jon
On Sep 3, 12:21?am, AstroSketc...@gmail.com wrote:
> After a month or more of smokey and/or cloudy skies I decided to
> attempt an observation and sketch of Jupiter earlier this evening.
> Ripples were always present around the limb of the planet due to poor
> seeing conditions. Nevertheless I was able to complete a rough sketch
> and upload it to my blog.
>
> At 138x Jupiter's North Equatorial Belt appeared to have a reddish
> brown color. That was the only noticeable color seen with the 13cm
> refractor. Io was near the planet's north-following limb. A little
> later in the evening Io was seen in transit. The planet's following
> limb appeared shaded a bit more than its preceding limb -- a phase
> effect. A Moon-SkyGlow filter improved the view a little for this
> twilight observation.
>
> After the Jupiter observation I did some "sight seeing" and eventually
> landed on Lambda Ophiuchi. The A & B pair were split at 218x with a
> narrow gap between the two stars. A #82A Light Blue filter improved
> the view a bit under the relatively poor seeing conditions. The "A"
> star appeared yellow or yellow-orange while the "B" star appeared
> bluish in color.
>
> Bill Greer
> To sketch is to see.http://cejour.blogspot.comhttp://www.rangeweb.net/~sketcher/index.html
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