On 3 Sep, 18:18, jeff wrote:
Donal wrote:

I'm astonished at how little light pollution
you have. I thought that you lived near NY????

Here is a photo of the same object that I took recently.
http://www.astroimaging.org.uk/tener.../donal/M31.htm

It isn't great, but it is only 36m exposure. I'll try to get
more on it if the sky ever clears.

Very impressive. I never get a sky like that near Boston. However,
here's a picture of the same object I took from a higher perspective.

http://mix.msfc.nasa.gov/IMAGES/MEDIUM/8000105.jpg

OK, I was not the lead scientist, but almost all of the data processing
software, from decoding the telemetry to putting the picture on the
display was written by me, and I was at the keyboard when the NASA
photographer took this picture of the screen. In '78 color displays
were so uncommon that we didn't pass around picture files, we
photographed the screen, usually with Polaroids, but 35mm for
publication. Each little red dot is actually one x-ray photon, focused
by a "grazing incidence mirror system." Magic! This picture was one of
the first we got of a nearby galaxy showing individual x-ray sources,
so it caused quite a stir.

More on the pic:http://mix.msfc.nasa.gov/abstracts.php?p=1560

and instrument:http://heasarc.gsfc.nasa.gov/docs/ei...ao2_about.html

I wasn't aware that x-ray imaging had been done so long ago. I
knew that the US x-ray imagers were very narrow field and high
resolution.

It must have been wonderful to see those images coming
in live. I really envy you.


Regards

Donal

--

wrote:
On 3 Sep, 18:18, jeff wrote:
Donal wrote:

I'm astonished at how little light pollution
you have. I thought that you lived near NY????
Here is a photo of the same object that I took recently.
http://www.astroimaging.org.uk/tener.../donal/M31.htm
It isn't great, but it is only 36m exposure. I'll try to get
more on it if the sky ever clears.
Very impressive. I never get a sky like that near Boston. However,
here's a picture of the same object I took from a higher perspective.

http://mix.msfc.nasa.gov/IMAGES/MEDIUM/8000105.jpg

OK, I was not the lead scientist, but almost all of the data processing
software, from decoding the telemetry to putting the picture on the
display was written by me, and I was at the keyboard when the NASA
photographer took this picture of the screen. In '78 color displays
were so uncommon that we didn't pass around picture files, we
photographed the screen, usually with Polaroids, but 35mm for
publication. Each little red dot is actually one x-ray photon, focused
by a "grazing incidence mirror system." Magic! This picture was one of
the first we got of a nearby galaxy showing individual x-ray sources,
so it caused quite a stir.

More on the pic:http://mix.msfc.nasa.gov/abstracts.php?p=1560

and instrument:http://heasarc.gsfc.nasa.gov/docs/ei...ao2_about.html

I wasn't aware that x-ray imaging had been done so long ago. I
knew that the US x-ray imagers were very narrow field and high
resolution.

It must have been wonderful to see those images coming
in live. I really envy you.

It was a real rush, starting with being about 3 miles from the midnight
launch of the spacecraft! I didn't quite get to see data in real time,
although the control center did. With the exception of a few very
strong sources, the raw data didn't yield much of an image - each photon
had to be adjusted for the pointing of the spacecraft based on star
trackers (the aspect solution) and then accumulated over time. We did
get "quicklook" data flown in overnight, and since the scope was 100
times more powerful than the early crude instruments, almost every
observation produced a major result. I was fascinated by the "photon
counting" nature of the instrument, so my strongest memory was a Deep
Survey of an empty field for several weeks. As the photons were put on
the screen, 2 and then 3 fell at the same point. A scientist punched
his HP-45 for a minute and said, "That's going to be the furthest object
ever observed." My boss, Dr. Riccardo Giacconi, received the Nobel
Prize for the work.
http://nobelprize.org/nobel_prizes/p...ni-lecture.pdf

Dr. Giacconni, and many others from the team, went on to be the early
team on Hubble. I did some consulting for Hubble in the '80s before
launch, but with the delay after the Challenger disaster, I ended up at
Lotus/IBM.

This thread reminds me of a reunion party in August '87. The Perseids
were active so after midnight about 30 astronomers were out on the lawn
looking up. I had a couple of 7x50's and started pointing people
towards various objects in view. It turned out that of the entire
crowd, only one grad student and myself knew anything of the visible
sky. In fact, I don't think any of the famous astronomers could find
Polaris!