# `Sidereon.GNSS.Staleness.StalenessMetadata`
[🔗](https://github.com/neilberkman/sidereon-ex/blob/main/lib/sidereon/gnss/staleness.ex#L76)

Structured description of the product staleness behind a selection result.

Attached to every selection; a degraded result is never produced without it.
Epoch fields are seconds since the J2000 epoch (2000-01-01 12:00:00 in the
product's time scale). `staleness_s` is `requested - source` and is never
negative. `kind` is the degradation path (`:exact`, `:nearest_prior`, or
`:diurnal_shift`); `staleness_days` is `staleness_s / 86400` (the whole-day
offset for a diurnal shift).

# `kind`

```elixir
@type kind() :: :exact | :nearest_prior | :diurnal_shift
```

# `t`

```elixir
@type t() :: %Sidereon.GNSS.Staleness.StalenessMetadata{
  kind: kind(),
  requested_epoch_j2000_s: float(),
  source_epoch_j2000_s: float(),
  staleness_days: float(),
  staleness_s: float()
}
```

---

*Consult [api-reference.md](api-reference.md) for complete listing*