Anthony Ayiomamitis wrote:
Dear Group,

With very good seeing last night (FWHM ~ 1.9") and equally impressive transparency, I decided to pursue the most impressive of the three open clusters in the constellation of Auriga which is nicely overhead a couple of hours after the end of astronomical twilight.

For those interested, please see

http://www.astrovox.gr/forum/album_pic.php?pic_id=3079 (1200 x 900)
http://www.perseus.gr/Astro-DSO-NGC-1960.htm (image details)

The LRGB image is based on two-hours total exposure.

Clear skies!

Anthony.

I normally leave astrophotographers to their own devices but as you
specialise in the 17th century celestial sphere fudge known as the
analemma,let me educate you briefly in what the Equation of Time is
and what it does.

"A seemingly contradictory condition in the time of sunrise is often
noted by critical observers. In the northern hemisphere the shortest
day of the year is the first day of winter, December 21. Yet the time
of sunrise continues to grow later into early January when the duration
of the daylight period is actually lengthening. The reason is that this
is the time of the year when the equation of time still dominates the
seasonal effect, causing both sunrise and sunset to occur later each
day. "

http://www.cso.caltech.edu/outreach/...Y/twilight.htm

Would anyone like to know why this geocentric event occurs from a
heliocentric standpoint ?.

The answer is of course the Equation of Time and the Total length of
the day which effectively ignores daylight/darkness asymmetry or at
least keeps it seperate from the observed phenomena.As an
astrophotographer who chains the Sun's apparent motion and position
within the 24 hour day through promoting a barren analemma concept you
are unlikely to approach the matter correctly from the point of view of
the Total length of the natural day and what causes it and how
brilliant men overlayed the system on terrestrial geography to create
the clock system and its correlation with axial rotation.

You couch your terms 'astronomical twilight',constellations and
analemmas without the slightest trace of using your ability to promote
the heliocentric reasoning and that is the real shame.