Hope One Dyson Sphere is an ancient construction enclosing a white dwarf star at the Delta Quadrant terminus of the Geroch Wormhole. Based on Talaxian historical records, the star Saepio (a name of Johvan origin) disappeared from the sky approximately 2,500 years ago. A species known as the Builders consumed all of the planetary matter within the star system to build the sphere. It is a technological wonder and an ancient cultural artifact.
It was first explored by USS Andromeda in 2389 with First Contact initiated by it's senior scientist, Dr. Shun'de Gor'Vosh II.
At the centre of the sphere is a white dwarf star with a radius of 14,000 kilometres (ie. 2% the radius of Sol). It is the smallest white dwarf star mapped by the UFP to date.
The sphere is inhabited by three distinct species: Johvan, Kharian and Lacosian. All were species native to planets now lost to time and utilized in the construction of the sphere. The name 'Hope One' was given by Dr. Gor'Vosh. The original Builders departed the sphere 2,500 years ago with no clear explanation in the historial record.
The spheres interior is partially terraformed to M-class conditions. Nature has shaped the surface into lakes and hills with climate ranging from semi-arid to semi-tropical. Several animal species have thrived as well. The ground is, on average, 10 kilometres thick of soil and silicate and aluminum stone.
The artificial troposphere is 17 kilometres thick. It is the habitable portion of the sphere's interior.
The 1.5-kilometre-thick magnetosphere separates the haibatable troposphere from the airless interior of the sphere. It also keeps the surface protected from solar wind and hard radiation from the star. The magnetosphere also disperses directed energy weapons.
The day-night cycle is simulated by variation in the opacity of the magnetosphere. The visible and near-visible light spectrum dims during the night. Night occurs simultaneously across the entire interior surface of the sphere.
Gravity is artificially generated within the shell of the sphere with a scale height of 38.5 kilometres (ie. the strength of gravity is weaker by a factor of e per unit of scale height). Only ships capable to maintaining low orbit or planetary landing can safely approach the sphere's interior surface.
Seasonal variation is a result of Saepio wobbling on it's axis. The minute change in distance from the star's surface to the sphere's interior surface is sufficient to distinguish summer and winter.
The shell of the sphere is a largely nickel-iron-carbon superstructure . In general, it is a geodesic sphere containing all of the systems that maintain the sphere's habitability.
The exterior radius of the sphere is 108 million kilometres . The spheres interior surface area is 150 quintillion square kilometres (ie. the surface area of 300 million Earth-sized planets). Even after 20 years of continuous mapping the sphere's interior is still largely unexplored.
No planets, asteroids nor meteors remain in what was once the Saepio system. It is reasonable that extra-solar material was used in construction of the sphere. Whether the material was collected via the Geroch wormhole or another method is arguable.
Multiple apertures in the sphere's surface provide access to the interior. There is no order to their placement. They appear as bright circles on the otherwise unlit surface of the sphere.
Because the typical light source in astrophotography is within the Hope One Dyson Sphere itself (ie. it's own star), the image presented is generated from long-exposure, multi-sprectrum radiation sources. It's appearance is distinctly that of a K-class planet (eg. Sol I, Beta Eridani I). It's outer surface is a thick layer of regolith pockmarked by impacts by rogue asteroids drawn by the sphere's gravity.
Image of Mercury courtesy of NASA.