Monday 24 September 2012

Imaging a near-zenith pass of the new NOSS 3-6 pair (NROL-36)

As I wrote earlier, the NRO launched a new pair of NOSS satellites, NOSS 3-6,  on September 13th, as NROL-36. Two days after the launch, I got my first look at these objects, albeit under very poor conditions (see my post here).

Sunday morning, 10 days after the launch, the cloud cover broke and I finally got a renewed and much better view of the two NOSS objects and the Centaur r/b from the launch, during a near-zenith pass. Some very thin cirrus clouds (dispersed aircraft contrails in part) were in the sky. These eerie pictures, taken shortly after 5 am local time on the 23rd, are the result (click them to appreciate them in full glory):

(click images to enlarge)
the NOSS 3-6 duo

the NOSS 3-6 Centaur r/b

The top image shows the payloads, 2012-048A and 2012-048P, traversing Perseus (alpha Persei star association in top). The P-object is leading over the A-object: movement is from lower right to upper left. I could see both payloads naked-eye, at about mag. +4.

Currently, the two satellites are still notably further apart than operational NOSS-es are, as they are still in the process of active manoeuvering. Ted Molczan believes that eventually, the A-object will probably overtake the P-object and become the leading object once the final operational configuration is reached.

The second image shows the Centaur r/b (2012-048N) traversing the Cassiopeia-Perseus border (h and chi Persei in top, stars of Cassiopeia near the bottom). It was very bright, initially +1 just after shadow exit, then +2. I could see no clear periodic brightness variation: the slow tumbling that was apparent in the days right after lauch and which might have been due to remnant fuel outgassing according to Ted Molczan, apparently has subdued.

The USA 237 r/b

On the 16th, I imaged the geostationary satellite USA 237, which is perhaps a 6th Mentor (see the bottom part of my previous post here).

On the 19th, I used the 37-cm Rigel Cassegrain of Winer Observatory (MPC 857) in Arizona to image the USA 237 r/b of this launch (2012-034B) :

(click image to enlarge)

In addition to the USA 237 r/b, I also did one of my periodic observations on Prowler (90-097E) that same night using the same telescope.

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