Blinkit — SPHEREx

Scientist view: raw pixels and flags

Every detector pixel of one exposure behind the flipbook frame, exactly as NASA IRSA delivers it, coloured by what its FLAGS value says. Point at a pixel (or use the arrow keys) to see its position, value, wavelength and every flag bit.

Exposure

Pixel grid

Flag bits defined in this file

Each pixel's FLAGS value is one 32-bit integer: the sum of 2^bit for every bit that is set. Names and meanings come from the file's own header. Click a name to highlight its pixels.

Bit	Value	Name	Meaning (file header)	In the add-up	Pixels here

How to read this

One square = one detector pixel of one exposure, before anything is lined up, rotated or added. The flipbook frame of this visit is made from these exposures.
FLAGS is one whole number per pixel. Written in binary, each of its 32 bits is a yes/no answer, for example bit 21 (2²¹ = 2097152) = SOURCE. A value of 2097153 = 2097152 + 1 means SOURCE and TRANSIENT (bit 0).
Kept or left out: the add-up keeps a pixel only if it has a value and none of the flags on the official bad list (SPHEREx Explanatory Supplement v2.0, section 3.4.3). SOURCE, OVERFLOW, OUTLIER and FULLSAMPLE never remove a pixel.
Why so much blue? SOURCE marks pixels that a catalogued star or galaxy covers. In these files it is set on most pixels, so blue is normal: it is a label, not a problem.
Position: x counts columns to the right and y counts rows upwards, as in the FITS file. The detector numbers come from the file's own coordinate system "A" (0-based active pixels), so the same pixel can be found in the full IRSA file. North and east are drawn in the corner: the detector is not north-up.
Wavelength: SPHEREx's filter passes a different wavelength at every place on the detector, so neighbouring pixels see slightly different colours of light.

Inside one visit: single exposures

The flipbook frame adds up several exposures that SPHEREx took hours to days apart. Here they are one by one, lined up on the same grid: an asteroid moves visibly within a visit, a star does not. Squares mark the known asteroids and comets NASA JPL puts in the frame at each exposure time.

Proof

Before / After / Difference

Before (A)

After (B)

−5σ fainter in B+5σ brighter in B flagged or no value in either visit

How good is the spot finder on these two visits?

Fake moving stars of known brightness were added to copies of these two real frames, and the same difference and 5σ spot search were run again. This says how faint a mover can be and still be found here.

Fake's peak	Found	Both ends	Lost: no value / blended / too faint	mJy	AB mag

How it was measured, and its limits

Both photo panels use the flipbook's one brightness scale. The difference is (B − A − sky change) / √(σ_A² + σ_B²), with σ from the SPHEREx VARIANCE maps, made by backend/app/diff.py. Blink (above) is the honest animation; there is no fade between the visits.

The sky is never the same twice.

SPHEREx flipbook

Six Eyes

Coarse spectrum

When SPHEREx looked here

Scientist view: raw pixels and flags

Flag bits defined in this file

Inside one visit: single exposures

Proof

Motion against Gaia DR3

What it rests on

Before / After / Difference

Spots above 5σ

How good is the spot finder on these two visits?

Light curve

Spectrum

Go to a position

SPHEREx flipbook

Six Eyes

Coarse spectrum

When SPHEREx looked here

Scientist view: raw pixels and flags

Flag bits defined in this file

Inside one visit: single exposures

Proof

Motion against Gaia DR3

What it rests on

Before / After / Difference

Spots above 5σ

How good is the spot finder on these two visits?

Light curve

Spectrum