Friday, October 21, 2011

Gearing up for ROSAT's re-entry, and an older observation of a Breeze-M tank near M31

Shortly after UARS, another satellite about to reenter is in the news: ROSAT. I last observed and photographed it about a week ago (see here and here) - since then, passes have become unfavourable for the Netherlands.

In an interesting twist, Sky & Telescope's J. Kelly Beatty reports that DLR and ESA sources confirmed to him that they expect the entire telescope mirror array - which weights 1.6 tons! - to survive reentry, impacting intact!

Various modellers now project the reentry to occur on October 23rd. Here is a short list of what various sources currently predict [editted 12:10 UTC, Oct 21, with latest Molczan update):

Space-Track (SSC):  23 Oct, 05:49 UTC (+/- 24 hrs)
Harro Zimmer: 23 Oct, 05:03 UTC (+/- 48 hrs)
Ted Molczan (using SatEvo): 23 Oct, 05:00 UTC (+/- 10 hrs) [editted]
Aerospace Corp.: 23 Oct, 13:24 UTC (+/- 16 hrs)

Since Ted uses the same software I used for my UARS predictions, and hence our results will be similar, I will not put forward my own predictions here but refer to Ted's.

A Breeze-M near M31, the Andromeda nebula

In my post of October 2nd, I featured an image I took on 29 September of a Russian Proton upper stage Breeze-M tank near the trail of USA 129. I wrote that:
These pieces of Russian space debris pop up more often on my images lately. They are the jettisonable torroidal (doughnut-shaped) fuel tanks of a Breeze-M, the upper stage of a Proton M. There are now over 40 of these spent empty tanks in space, often in highly elliptic orbits representative of a geostationary transfer.
Just a few days later, on October 2nd, I took advantage of clear skies to image M31, the Andromeda galaxy. The camera (Canon EOS 450D) with the Samyang 1.4/85mm lens was piggybacked on a Meade ETX-70 in order to use the telescope drive to follow the stars. A long series of 10 second images was taken.

Several satellites showed up on the image series, including a Breeze-M tank again, this time 2006-056B:

click image to enlarge

Here is the final image of M31, a stack of 105 individual 10 second images:

click image to enlarge

Given that this image was taken from a town center with modest equipment, I am quite happy with it! If you compare it to a single frame image (above) it shows the strong improvement in signal-to-noise ratio that comes from stacking images.The two satellite galaxies come out much better, and so does a glimpse of the spiral structure and dust bands in the Andromeda galaxy.

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