New Horizons Jupiter Encounter Options

[helvick]

Jols ( Jovian Sols???)

Jovials?

[Alan Stern]

Yes, we'll slow after Jupiter. See the Press Kit on the JHUAPL web site front page for the numbers.
As to V1 and V2 comparisons to NH, you'll have to scare those numbers up for yourself, I think.

-Alan

[elakdawalla]

I just asked Mark Showalter at the PDS Rings Node if they were going to incorporate New Horizons into their Jupiter viewer. Turns out they already have a separate New Horizons Jupiter Viewer and Ephemeris Generator, which I hadn't noticed before. The Viewer is very handy to get a prediction of how the planet, satellites, and rings will look to the ORS instruments at different times during the encounter. To get the field of view you want using the viewer:

LORRI's FOV is square at 1044 arcsec
The slit of the Alice spectrometer is 14438 arcsec long (it's only 350 arcsec wide)
MVIC panoramas are 20626 arcsec wide and whatever number they want long
LEISA's FOV is square at 3280 arcsec.

...I think. I calculated these based on the FOV numbers given at http://pluto.jhuapl.edu/spacecraft/instruments.html.

Have fun.

--Emily

[ElkGroveDan]

If someone would please invent a multicycle engine that can morph from turbofan to ramjet to scramjet to rocket then SSTO (and back)

Well I'm real busy with the concrete walk and back patio these days, but I promise I'll have a look as soon as I'm done (probably May if we don't have too much rain this winter) ....unless of course Doug finishes the UMSF shed first, then maybe he'll have time.

[john_s]

Here's a simplified and slightly updated version of the Jupiter observation timeline...
 jupiter_timeline_static.xls ( 114.5K ) Number of downloads: 847


John.

[djellison]

And new images added to the SOC gallery up to the 21st.

Doug

[peter59]

Two satellites and two shadows !
First details visible on Ganimedes (or Callisto)

[volcanopele]

Here is a rotation movie for January 21:

http://pirlwww.lpl.arizona.edu/~perry/New_...Jan21_movie.gif

The moon that crosses that transits during the first half of the movie (and casts a shadow on Jupiter) is Europa, while Io makes a brief, one frame appearance.

[J.J.]

Based on the approximate orbital velocity of Pluto at encounter, and the total relative velocity of NH and Pluto at encounter, I (awhile back) derived a velocity of ~12.7 km/s for NH at Pluto. Assuming that's correct, that puts NH well above the velocities of P10 and P11 (at 12.1 and 11.5 km/s, respectively), but far below either of the Voyagers (at 15.6 km/s for V2 and 17.1 km/s for V1).

For those a little more bored than I, one can calculate the "loss distance" of NH from P10 and P11, based on the difference in velocities. Lessee...NH will be moving at about 2.7 AU/yr. once she passes Pluto. That means she'll be gaining 1.2 AU/yr. relative to P11, and 0.6 AU/yr. relative to P10. That isn't as much as it sounds; if my numbers are right, NH won't catch up with P11 until ~2066 (at 138 AU), and not to P10 until ~2151 (at 367 AU).

For the record, in 2066, the Voyagers will be at:

V2: 250 AU
V1: 286 AU

In 2151:

V2: 531 AU
V1: 592 AU

Feel free to check my figures, all.

[ugordan]

Why do these NH images look somewhat blurrier than Cassini's comparable NAC frames? Does LORRI have a greater PSF? I'm judging by the sharpness of the moons' discs to be clear.

[djellison]

Got some side by side comparisons?

Doug

[ugordan]

Not at the moment, I'm at work, but I'll try to dig up some Cassini PDS ones for comparison later. It might be subjective, but I do get the feeling LORRI has a slightly wider PSF.

[djellison]

It may be true of course, and I think LORRI is a narrower FOV than either of the CICLOPS pair - but of course comparing JPGs with PDS IMG's isn't a true comparison.

Hopefully John or Alan will comment.

Doug

[john_s]

It's true, LORRI is a much smaller and simpler camera than the Cassini NAC, and the PSF isn't quite so sharp. The high-frequency information is there, however, and the images can be sharpened nicely (though with increased noise).

[elakdawalla]

I read in "Calibration of the New Horizons Long-Range Reconnaissance Imager" by Morgan et al. that LORRI has "a PSF FWHM of 1.5 pixels with little variation across the FOV..."

PSF = Point Spread Function; FMHM = Full width at half maximum.

And from the instrument info on the Cassini PDS disks: "The NAC point spread function (PSF) was designed to be approximately the same physical size as a pixel in the near-IR. The full width at half maximum (FWHM) of the PSFs of the NAC through the clear filters is 1.3 pixels."

Why would the FWHM be wider through the clear filters than the IR?

To compare the masses, the mass of both Cassini cameras is about 57.83 kg. Anyone have a guess as to what fraction of that the NAC makes up? LORRI is only 5.5 kg!

--Emily