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NASA's Roman telescope can hold steady on a dime 150 miles away
Fine-guidance tests wrapped Sept 21, and the coronagraph, the part built to blot out starlight, saw first light.
A telescope is only as good as its grip. Take a photo with a shaky hand and the picture smears. Point a telescope that drifts by a hair at a faint galaxy and you get the same smear, just billions of miles wide. So before a space telescope does any science, engineers test how still it can hold.
NASA's Nancy Grace Roman Space Telescope just passed those tests, called fine guidance, between Sept 15 and 21. NASA's comparison: its pointing is steady enough to aim a laser at a dime about 150 miles away, and more tuning is expected to stretch that to about 230 miles. Fine guidance works a bit like keeping a camera level by watching the horizon: the telescope locks onto reference stars and makes tiny, constant corrections.
The second milestone is the Coronagraph Instrument. A coronagraph is a mask that blocks a star's glare so fainter things right next to it, like planets, can show up, the same trick as holding your thumb over the sun to spot a bird beside it. On Sept 22 and 27 it got first light, imaging stars in the Large Magellanic Cloud, a small neighbor galaxy, and confirming it can make a focused image.
The caveat: these are engineering checks, not discoveries. First light means the instrument works; it has not imaged a planet yet. That work comes later. This week was about proving the hands are steady, and they are.
Read the original at NASA via ScienceDaily →