Personal dome

Illustration of the personal dome concept in Walter Bilsin's Flat Earth Dome Model

The personal dome, dome of vision, or azimuthal grid of vision is a nonsensical and ad hoc concept used by flerfs to "explain" observations of the celestial sphere that are incompatible with flat Earth.

The concept is approximately as follows: encompassing each observer is an equidistant dome, onto which all celestial phenomena are "projected" in exact accordance with what the globe predicts from their location. Flerfs generally agree that the personal dome is only a conceptual model to illustrate apparent celestial positions, rather than a physical object that follows each individual around.

To at least some degree, it is an extension of the concept of flerfspective, but adherents usually believe that light-bending is involved too.

The personal dome is essentially a desperate rescuing device, because flerfs realise how radically incompatible observations of the sky are with their models.

Types of personal dome concepts

The personal dome concept can be separated into two main subconcepts depending on what is mechanistically causing it. Not all flerfs will agree on the same mechanism(s), but most will agree the mechanism(s) result in the following:

• the personal dome displays half of the celestial sphere;
• the altitude of the nearest celestial pole exactly matches the observer's latitude.

Perspective only

On flat Earth, the altitude angle to the North Celestial Pole (NCP) would decrease asymptotically as a function of the distance from the North Geographic Pole (NGP). This would make far northern stars like Polaris visible far below the equator. The actual relationship is linear, as predicted by the globe, and the NCP becomes obstructed below the equator due to the negative angle.

This view holds that the two criteria above are created solely as a result of linear perspective. Anyone who can work with basic trigonometry (or even common sense) will realise obvious flaws with this hypothesis.

Regarding the first criterion, there is no reason half of the celestial sphere should be seen in a given location, because the altitude angle to something (like a star) will never reach zero if it is physically higher than the observer (see diagram to the right). All stars would remain above the horizon from an observers perspective, and the proportion of the celestial sphere visible would entirely depend on visibility conditions (i.e., fog, clouds etc.). Some flerfs however do lie about the proportions we see.

Regarding the second criterion, the altitude of the celestial pole would not match the observer's latitude, given the fact that latitude lines are equidistant (even the AE map agrees this is the case). The angle would decrease asymptotically, not linearly as is observed (see the diagram to the right).

There is also the issue that the perspective hypothesis cannot account for the existence of the south celestial pole.

If flerfs still hold onto the perspective hypothesis after having these flaws explained to them, they are practicing flerfspective. Austin Witsit is one such example: he claims that perspective is responsible for creating the south celestial pole while looking at Walter Bislin's model showing the light rays bending.

Perspective + light bending

When pressed on the perspective only view, many flerfs will concede that the personal dome can only account for the two criteria above and a south celestial pole if light bending is involved.

This then leads to questioning the mechanism behind the light-bending.

Problems

Lets recap the two key criteria the personal dome model must explain:

• an observer sees half of the celestial sphere in clear conditions,
• the altitude of the nearest celestial pole exactly matches the observer's latitude.

Far-fetched

The perspective hypothesis objectively fails to explain both criteria. The light-bending hypothesis is the only one that can at least work in theory (as shown by Walter Bislin's model). Which ever way the light bending occurs in the personal dome model, it results in the appearance of a globe Earth by sheer coincidence. The light from stars just so happens to bend in precisely the correct way for all observers. We can create a list of coincidences to illustrate just how absurd this is:

• Polaris is never visible in the southern hemisphere (despite the lies).
• Sigma Octantis is always seen due south
• Stars lower in elevation by one degree every ~111km from their ground position
• There appears to be a celestial sphere that rotates at 15 degrees per hour
• Star trails always trace perfect circles for all observers.
• Equatorial mounts track stars perfectly (within mechanical limits)
• The sun and moon set and rise at precisely the times predicted by the globe
• Solar eclipse paths precisely match the globe prediction
• All observers see the same side of the sun, moon and planets simultaneously
• The light-bending changes throughout the year to perfectly simulate stellar parallax and stellar aberration
• many, many more

The fact that all of these coincidences simultaneously occur for all observers at all times is so incredibly far-fetched, the hypothesis is almost certainly wrong. Its ironic that flat Earthers continue to bring up Occam's razor, when the personal dome model needs to make an insanely large number of assumptions just to kind of sort of work.

Unfalsifiable

The personal dome is, by its own nature, unfalsifiable (and therefore pseudoscience). There is presently no observation which could disprove the idea, because the required light-bending lacks any coherent mechanism that can be tested.

The concept technically cannot be falsified until every conceivable mechanism is falsified, of which there are virtually infinite. Even if countless mechanisms are disproven, flerfs will still go to enormous lengths to find a new one, no matter how absurd, even if it means asserting "the personal dome is created by unicorn farts".

The unfalsifiablility also means the personal dome is not exclusive to flat Earth models; it could be used in exactly the same way to rescue the theory of a banana-shaped Earth.

See also

• Plagiarism of Walter Bislin's model
• Shane St. Pierre
• Curved visual space
• Flerfspective
• Flerfraction