Hubble's 30-Year Anniversary PIC in its best imaging format

Post #433,759 by Ashton 4/24/20 5:54:41 PM 4/24/20 5:54:41 PM Reply	Hubble's 30-Year Anniversary PIC in its best imaging format BBC (Have not yet looked-up just HOW? the platform is stabilized to nanometers) say, to width of ~One Pixel? I. Mean. W.t.f. Can the assemblage use for feedback? of its Absolute-position within that old space-time continuum, aka nano-trembles from Solar effects on all the construction materials within !?
Post #433,765 by a6l6e6x 4/24/20 10:04:11 PM 4/24/20 10:04:11 PM Reply	Nice! Thanks. Alex "There is a cult of ignorance in the United States, and there has always been. The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that "my ignorance is just as good as your knowledge." -- Isaac Asimov
Post #433,774 by scoenye 4/25/20 9:11:46 PM 4/25/20 9:11:46 PM Reply	Gyroscopes It has 6. Three were originally needed to keep Hubble on target.They can now do it with just 2. Unfortunately, they have a limited lifespan. All gyros were replaced during the servicing mission in 2008. 3 have since failed.
Post #433,776 by Ashton 4/25/20 11:18:38 PM 4/25/20 11:18:38 PM Reply	Feared that.. 'MTBF' KIlls. But how else to do the physics? if there's no mass-in-motion :-/
Post #433,777 by Andrew Grygus 4/25/20 11:31:23 PM 4/25/20 11:31:23 PM Reply	Re: Feared that.. I seem to recall our ballistic missile submarines are using atomic gyros.
Post #433,795 by Ashton 4/27/20 4:47:56 PM 4/27/20 4:47:56 PM Reply	Thanks! ... I n t e r e s t i n g . . . PIco-gyros!
Post #433,796 by scoenye 4/27/20 5:30:05 PM 4/27/20 5:30:05 PM Reply	Likely solid state accelerometers I don't know what shape those were in when Hubble was in the design stage. Some of earlier reference to their application in missiles dates to the early '80's but that may have been too late/too classified* for use on the Hubble. Recall the NSA (NRO ?) had a couple of spare Hubble performance class never used spy sats hiding in the basement. It would surprise me one bit that sharing of guidance tech with mostly-civilians was off the table too.
Post #433,797 by scoenye 4/27/20 5:36:44 PM 4/27/20 5:36:44 PM Reply	DIY guide https://asd.gsfc.nasa.gov/archive/hubble/a_pdf/news/SM2-MediaGuide.pdf I forgot the guidance cameras. The gyros keep Hubble on-track during slewing and while not observing. During observations, the telescope is kept on target by two guidance cameras. Those lock on to a star in the general direction of the main tube and direct the telescope's motion controls to keep the star centered in the field of view.
Post #433,822 by Ashton 4/29/20 4:03:08 PM 4/29/20 4:08:45 PM Reply	Ah.. thanks, clear. (Why didn't I think of that? ..must be low in DaVinci genes). Still: those little Maksutov-Cassegrain spotter cameras, looking a far---distance: One Pixel precision in thoso tiny hunks of quartz?? (Think the exponential-cost for "Ten-Nines purity" (in chemical reagents /or Anywhere ya nees a 17-place log-table). Edited by Ashton April 29, 2020, 04:08:45 PM EDT Expand All History

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