• Pixel-art Siderelle, the Four-Minute Ghost, on a black mug with the slogan "THE STARS RETURN 4 MINUTES EARLIER. I DON'T."

IndexCatalogueMug

Siderelle, the Four-Minute Ghost Mug

\[\frac{1}{T_{\text{sid}}} = \frac{1}{T_{\text{sol}}} + \frac{1}{T_{\text{yr}}}\]
$21.99 USD
$21.99 USD
Promotion Épuisé
Size

A sidereal day is about 23 h 56 min 4.09 s, so stars rise about 4 minutes earlier each solar day.

The joke: Observers' schedules drift with LST. The slogan on the mug reads THE STARS RETURN 4 MINUTES EARLIER. I DON'T.

Source: IERS Conventions (2010), Tech. Note 36; Astronomical Almanac (USNO).

Shipping calculated at checkout by destinationMade to order, ships in ~10 days

Details

Size & material11oz · 15oz

Black glossy ceramic mug with a C-handle. Lead- and BPA-free.

  • 11oz: 0.33 l
  • 15oz: 0.44 l
CareDishwasher & microwave safe

Dishwasher safe (top rack) or hand wash. Microwave safe.

ShippingBy destination

Shipping calculated at checkout by destination.

Made to order: about 10 days of production and handling before it ships.

Delivery times & where we ship

Returns & replacements21 days

Every item is printed to order, so we can’t accept returns or exchanges for change of mind, or if you ordered the wrong size or colour.

Print defect, misprint, damage or the wrong item? We’ll send a free replacement, or a refund if you prefer. Report it within 21 days of delivery with a photo; no need to send it back.

Full refund & replacement policy

The physics

A sidereal day is about 23 h 56 min 4.09 s, so stars rise about 4 minutes earlier each solar day.

The joke: Observers' schedules drift with LST. The slogan on the mug reads THE STARS RETURN 4 MINUTES EARLIER. I DON'T.

Source: IERS Conventions (2010), Tech. Note 36; Astronomical Almanac (USNO).

Equations

\[\frac{1}{T_{\text{sid}}} = \frac{1}{T_{\text{sol}}} + \frac{1}{T_{\text{yr}}}\]
\[T_{\text{sid}} \approx 23\ \text{h}\ 56\ \text{min}\ 4.09\ \text{s}\]
SymbolMeaningUnit
\(T_{\text{sid}}\) sidereal day \(\mathrm{s}\)
\(T_{\text{sol}}\) mean solar day \(\mathrm{s}\)
\(T_{\text{yr}}\) year \(\mathrm{s}\)

Sources

  1. IERS Conventions (2010), Tech. Note 36
  2. Astronomical Almanac (USNO)

Field notes

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