3 ms·
Those exposure times (weeks / 140 hours) are for these images [0,1], Hubble's deep fields. Hubble's photo of this galaxy cluster, the one our root comment shows
by perihelions 4y ago
Those exposure times (weeks / 140 hours) are for these images [0,1], Hubble's deep fields. Hubble's photo of this galaxy cluster, the one our root comment shows superimposed over JWST's, took 5 Hubble orbits [2]. I think that's around 2-3 hours of exposure time.
[0] https://en.wikipedia.org/wiki/Hubble_Deep_Field https://en.wikipedia.org/wiki/Hubble_Deep_Field
[1] https://en.wikipedia.org/wiki/Hubble_Ultra-Deep_Field https://en.wikipedia.org/wiki/Hubble_Ultra-Deep_Field
[2] https://archive.stsci.edu/prepds/relics/ https://archive.stsci.edu/prepds/relics/ ("For each cluster, the team observed to 5-orbit depth with ACS and WFC3/IR")
(If you want to verify [2] is talking about the same photo, you can retrieve it from the "SMACS J0723.3-7327" row, from the "Color Images" column/field).
- lamontcg 4y agoLEO should be >= 80 mins so 5 hubble orbits should be >= 400 mins / 6.6 hrs? EDIT: nasa.gov says 95 mins, so ~8 hrs.
- perihelions 4y agoYes, but Earth obstructs the field of view for about half that time. The way HST refers to an "orbit" for scheduling, only part of the elapsed time is usable observational time, for a single target. https://hst-docs.stsci.edu/hsp/the-hubble-space-telescope-primer-for-cycle-30/hst-primer-orbit-calculation-overview https://hst-docs.stsci.edu/hsp/the-hubble-space-telescope-pr... - "HST GO observing time is counted in terms of orbits. Each 96-minute orbit contains a certain amount of useful time when the target can be observed, called the orbital visibility period..."
- lamontcg 4y agoAh right, because it is basically in LEO so the Earth is enormous.