New Horizons Pluto System Final Approach, 28 Jun-13 Jul 15 |
New Horizons Pluto System Final Approach, 28 Jun-13 Jul 15 |
Jun 28 2015, 08:08 AM
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Merciless Robot Group: Admin Posts: 8784 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
More than nine years in flight, many more years before that in the making--this is the time. Please post all comments related to New Horizon's passage through the Pluto system here.
What to expect Reminder that despite the rather brief duration of the actual encounter, it will be literally months before all acquired data is returned so this thread will be active for an equivalent time. Intrepid TPS space journalist and UMSF admin Emily Lakdawalla has written an excellent guide to planned imagery activities. EDIT: Updated version of guide. Emily has also produced a simulation of the kinds of images that are anticipated. FAQs Most Forum members are advanced spaceflight enthusiasts; many are in fact professionals in space-related disciplines. Accordingly, there are no plans to post answers to questions that can be easily answered via a Google search, and we ask that everyone please attempt to do so before posting a question. EDIT (4 Jul 15): Admin Astro0 has produced an extensive New Horizons FAQ thread. EDIT: Review rule 1.9 and keep it firmly in mind before posting. Posts violating that rule will be deleted without notice. ____ With all that said, the most important thing by far is to witness the marvel of discovery, of exploration, of New Horizons on worlds never before seen. This is the best seat in the house for doing so, right in the comfort of our own homes. As with previous major events in planetary exploration over the past decade it is likely that not only professionals but also the press may be watching the Forum during the coming days due to its hard-earned reputation as a place for noise-free commentary and stunning contributions by amateur image processors, so please bear this in mind... ...and I can't stop smiling with anticipation and excitement. What marvelous things we will soon see. Enjoy the ride!!! -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Jun 29 2015, 05:53 AM
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Junior Member Group: Members Posts: 47 Joined: 21-June 15 Member No.: 7518 |
It is much easier to use these formulae to determine the size in pixels of the objects :
Pluto : 392/N px Charon : 205/N px Styx : ~3.5/N px Nix : ~7/N px Kerberos : ~5/N px Hydra : ~8/N px resolution = 5.9*N km/px where N is the number of days (decimal number) before NH goes through the planetary system. [i]For example, right now the number of days remaining is 15 days 5 hours, this gives 15.2 days. The diameters are : Pluto : 26 px Charon : 14 px Styx : < 1 px Nix : < 1 px Kerberos : < 1 px Hydra : < 1 px resolution = 90 km/px A view of sizes, with the Moon as a model, full size : -------------------- Astronopithecus normandimensis nephophobis
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Jun 29 2015, 05:42 PM
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
Thanks, fred_76. This is a good way to convey the progression.
It's particularly poignant to see that 3-days-out image, because that's the best view we'll get of the anti-encounter hemisphere (AEH). However, I'll point out that the Moon is about 1.5x the size of Pluto, so while Pluto will appear that *size*, we'll see Pluto at 1.5x the resolution that those Moon photos show. Consequently, we'll see the AEHs of Pluto and Charon at the same resolution as your left 2-days-out image of the Moon. It's quite evident there that Tycho is a crater and one could surmise that Copernicus is. Otherwise, one could interpret the features in comparison to the better imagery of the other hemisphere, but on its own, it's still quite murky. The spectral imaging will add a lot, so that units on the AEH can be identified as likely similar to corresponding features on the encounter hemisphere. The Charon-shine imagery may fill that in wonderfully, though, and even more important, give us a look at the winter pole that won't otherwise be seen at all. The data set will basically be a tale of three Plutos: The encounter hemisphere, the anti-encounter daylight "hemi"sphere, and the winter pole. Similar for Charon, but we will only see its winter pole in Plutoshine from 3 days out, so we'll only get albedo/spectral information at very low resolution. On the other hand, Plutoshine is 4x brighter than Charonshine. As a reminder of "shine" imagery, here's Iapetus in Saturnshine. http://www.nasa.gov/mission_pages/cassini/...a/pia06168.html Saturn is, of course, a hell of a lot bigger and brighter than Pluto or Charon, but it's also 200 times farther from Iapetus than Charon is from Pluto, so Charon occupies ~2x the area in Pluto's sky that Saturn occupies in Iapetus'. So Charonshine on Pluto is only a few times dimmer than Saturnshine on Iapetus. |
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