Astrophotography by Anthony Ayiomamitis

Solar Image Gallery - Scenic Phenomenon

A common misconception is that the sun is larger when it is near the horizon than when it is high overhead. However, this optical illusion is not true, for the apparent size of the sun is virtually the same when it is rising or setting near the horizon or when viewed overhead (in fact, it is very slightly smaller when viewed near the horizon due to refraction as well as the greater added distance in observing across the earth's radius). This illusion has been wrongly attributed to landmarks near the horizon, such as homes and trees, supposedly giving a sense of perspective and whereas the same perspective is lost when looking at the overhead sun bathed in an empty sky. As noted by Donald E. Simanek and Carl J. Wenning, the real reason behind this trick by our brain is the perception of the sun (or moon) being against a "close" or "distant" foreground and which is lucidly described by the above two references.

However, if we were approach the apparent size of the sun methodically by studying it during perihelion and aphelion, we can detect a small change using photographic equipment thanks to the elliptical orbit of our planet around the sun which leads to variations in distance (and apparent size) of the order of about 3.4%. More specifically, at perihelion each January, earth is approximately 147 million km away from sun whose apparent diameter is about 32.53' whereas, at aphelion each July, earth is approximately 152 million km away and the sun is characterized with an apparent diameter of about 31.46'. This difference of 5 million km between perihelion and aphelion leads to the slight change in the apparent diameter of the sun as illustrated by two images of the sun captured six months apart when the sun was near its minimum possible perihelion (Jan 2/2005) and maximum possible aphelion (Jul 5/2005) and while crossing the local meridian and which are presented here.

Note: With aphelion for the sun being a few days away, the opportunity was used to travel to the greek island of Naxos so as to catch the setting (aphelion) sun against the Portara and which is the primary remnant of the unfinished Temple of Apollo. The photo below as well as two other photos from the same session (click here and here) were taken from a distance of 439 meters to the southeast of the Portara and which provided the ideal location for these photos with respect to aspect ratio, azimuth and altitude.

Note: My excursion to Naxos for this particular opportunity included the presence of four other personal friends and fellow astrophotographers. For a stunning animation of the sunset at the Portara using simple DSLR images, see this impressive result by John Doukoumopoulos here.

Note: For additional photos of the sun and/or full moon against other well-known Greek archaeological grounds and sites, please click here and/or here.


Image Details
Aphelion Sun and the Portara: III
Imaging Details
Body:
Sun

Mass:
332,900 x Earth

Mean Eq Diameter:
109.1 x Earth

R.A / Dec:
06h 32m 07s /
+23 14' 01"


Distance:
Aph 152,102,363 km
Peri147,099,182 km

Diameter:
Aphelion 31.46 '
Perihelion32.53 '

Magnitude:
-26.8
Date:
June 28, 2008
20:27:43 UT+3


Location:
Isle of Naxos, Greece
(38.1083 N, 25.3767 E)


Equipment:
Canon EOS 350D XT
Canon EOS 100-300 USM II
    @ 300 mm/f14


Exposure(s):
1 x 1/4000 sec
ISO 100
RAW Image Format
3456x2304 Image Size
Manual Mode


Software:
Digital Photo Pro V1.6.1.0
Photoshop CS2


Processing:
RAW to TIFF (16-bit) conv
White Balance
Contrast/Brightness
Resampling (25%)
JPG Compression