Sunday May 17th 2009. Day 3.
Things continue
to be quiet. Check-out is still going on. Mission Control has now got a really
accurate orbit determination for Herschel and has decided to make one more, tiny
correction to the trajectory of 0.9m/s (compare this with the approximately
11km/s that Herschel had initially). Last night Herschel passed the Moon just
before 00UT. At 00UT tonight Herschel will be well
beyond the Moon, now 484 000km from Earth and receding at 0.99km/s. Signals
will take 1.6s to reach Herschel from Earth. Herschel right now is in the
constellation of Serpens.
There is great confusion as to the identification the different
objects in telescopic images. The Minor Planet Center (MPC) has identified the
brightest object in the field as definitely Planck. This however disagrees with
the fact that Herschel is much bigger and thus presumably brighter than Planck
and that the object that they identify as Planck has lower radial velocity,
despite the fact that Planck has a higher energy orbit. Mission Control now has
a high-quality orbit determination for both Herschel and Planck that apparently
confirms that the brightest object in the field is, as we thought, Herschel and
that the MPC identification seems to be wrong. It is still difficult to work
out of the pair of fainter objects, close together, is Planck and which is the
Sylda. I am also getting reports that three other objects, two of them much
fainter, are being seen, further away from Herschel, Planck and the Sylda.
With the new orbit of Herschel and Planck that should be available tomorrow I hope that the definitive identifications can be confirmed.
Amateur astronomers continue to get amazing sequences of images. You can check out some of the best ones in the unofficial Herschel Image of the Day archive, here:
http://www.observadores-cometas.com/Herschel/Image_of_the_day/image_of_the_day.htm
Frequent updates are provided during the day on the Herschel Twitter (ESAHerschel) here: