Backglowen, the Sky-Limited Lantern Mug
CCD equation: in the sky-limited regime, sky background noise dominates read noise and SNR ∝ √t.
The joke: Noise from the sky, not the detector: the observer's existential crisis. The slogan on the mug reads SKY-LIMITED. EVEN MY NOISE ISN'T MINE.
Source: S. B. Howell, Handbook of CCD Astronomy, 2nd ed. (Cambridge, 2006), §4.4.
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.
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.
The physics
Equations
| Symbol | Meaning | Unit |
|---|---|---|
| \(\text{SNR}\) | signal-to-noise ratio | — |
| \(t\) | exposure time | \(\mathrm{s}\) |
Sources
- S. B. Howell, Handbook of CCD Astronomy, 2nd ed. (Cambridge, 2006), §4.4
Field notes
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