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Author Topic: And another one...  (Read 876 times)

martin

  • Join date: May 2009
  • Location: EFTO
  • Posts: 693
And another one...
« on: Sat, 30 Apr 2022 17:59 »
..bites the dust, -- well, at least leaves the stratosphere...
 :'(

(Ch|T)e(e|a)rs,
martin

Markus Vitzethum

  • Join date: May 2009
  • Location: Reutlingen, Germany (near EDDS)
  • Posts: 467
Re: And another one...
« Reply #1 on: Sun, 1 May 2022 08:07 »
... and the end of the SOFIA mission really makes me sad. It had pleasure of visiting the interior of SOFIA when she was visiting EDDS for a scientific conference in 2019 and it was quite impressive to see the telescope (at least the accessible parts inside the hull) from nearby. Also, you are rarely able to see a 747SP from nearby these days and even be able to board that unique aircraft. (The upgraded flight deck was off-limits, unfortunately.)

martin

  • Join date: May 2009
  • Location: EFTO
  • Posts: 693

Markus Vitzethum

  • Join date: May 2009
  • Location: Reutlingen, Germany (near EDDS)
  • Posts: 467
Re: And another one...
« Reply #3 on: Wed, 22 Jun 2022 09:26 »
Here are the final flight plans for the last Christchurch mission:

https://www.sofia.usra.edu/science/proposing-and-observing/flights/series/oc9r

Markus

Hardy Heinlin

  • Moderator
  • Join date: May 2009
  • Posts: 13155
    • Aerowinx
Re: And another one...
« Reply #4 on: Wed, 22 Jun 2022 10:31 »
It seems almost all of their route legs are arcs rather than great-circle distances. Do they aim at a constant non-zero bank angle along each leg?


)-)ardy

Markus Vitzethum

  • Join date: May 2009
  • Location: Reutlingen, Germany (near EDDS)
  • Posts: 467
Re: And another one...
« Reply #5 on: Wed, 22 Jun 2022 11:08 »
Maybe it helps to think with an analogy - if you are looking at the path of the shadow of the moon during a total solar eclipse, it will be typically some sort of arc.

The point is - SOFIA doesn't want to go from point A to point B but wants to do astronomical observations enroute, observing astronomical objects at which the telescope in the back is pointed. The telescope can be rotated (along the bank axis of the airplane) but if I'm not totally wrong it only has little compensation for deviations on the forward/backward axis so the telescope will be kept pointed at the correct object by changing the course of the airplane - constantly, because the airplane flies on the curved surface of the earth while the earth rotates so it follows the resulting arc.

Markus

p.s.

Here is a nice video from SOFIA pilot's point of view, approx. 1h (the "practical" view)
https://www.youtube.com/watch?v=of2TU9SCdKg

Hardy Heinlin

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    • Aerowinx
Re: And another one...
« Reply #6 on: Wed, 22 Jun 2022 11:28 »
I thought so that it's due to a certain observation technique. I'm just curious whether the bank angle is really constant, i.e. whether there is really just one FMC leg between such a pair of points illustrated on those Internet maps -- or whether there are multiple direct legs that are just not displayed.

I'm asking because I don't see a way to maintain bank angles smaller than 5° with regular 744 AFDS/LNAV equipment, not to mention the programming of such long continuous route arcs in the FMC.

I think it makes sense that they made the telescope's bank angle freedom greater than its pitch angle freedom -- as the aircraft's bank may vary much more than its pitch.


|-|


Thanks for the video link. Here at 20:52 they discuss the Pluto shadow under a certain star; they could stay within this shadow for about 10 seconds, if I got it right:

https://youtu.be/of2TU9SCdKg?t=1252

A minute later in the video he seems to talk about HDG SEL :-) Sounds like they click the HDG SEL one degree further in certain time intervals ...
« Last edit: Wed, 22 Jun 2022 11:45 by Hardy Heinlin »

Markus Vitzethum

  • Join date: May 2009
  • Location: Reutlingen, Germany (near EDDS)
  • Posts: 467
Re: And another one... SOFIA cockpit video
« Reply #7 on: Mon, 11 Jul 2022 07:00 »
Hi Hardy, Martin et.al.,

another nice SOFIA cockpit video became available this weekend, this time by airclips.com.

They have a 35 min preview video which is already quite nice. It includes some extended flight deck coverage (rarely seen in other SOFIA videos) but also interviews with the captain, crew, science staff and science operators plus some description of the equipment and the pre-departure briefing.

https://www.youtube.com/watch?v=Yi9KkgfdejY

The full video is 3 hours, split in two parts and available for (payware) subscribers of the (commerical parts
 of the ) airclips.com Youtube channel.

https://www.youtube.com/playlist?list=PL8alvu1oEpsy5Jna6yW4nCX0xkpZ2J_t2

Markus



martin

  • Join date: May 2009
  • Location: EFTO
  • Posts: 693
Re: And another one...
« Reply #8 on: Tue, 12 Jul 2022 19:06 »
Thanks for the pointer, Markus!

Cheers,
Martin