Wilbur Hubbard wrote:
Jeff's photo showed data acquired in x-rays. There is *NO* lens
involved in x-ray photography. Please do not feel stupid
because you did not know this. I'm sure that you are not
alone.

When my dentist points that lens-looking think at my mouth and it buzzes it
directs the x-rays just where they need to go. It might not be a GLASS lense
but there's got to be a lense of some sort in there.


No, that type of x-ray picture doesn't use a lens. Think about it.
Here's a hint: if the thing the dentist points at you bounces around
during the exposure, it doesn't affect the picture.

wrote:
On 3 Sep, 18:42, "Wilbur Hubbard"
wrote:
"jeff" wrote in message

. ..

and instrument:
http://heasarc.gsfc.nasa.gov/docs/ei...ao2_about.html
I just don't get it.

Hi Wilbur,
I like you. So, I will help you to avoid the extreme embarrassement
that you must feel after displaying the enormous ignorance
which your post exposed.

Why would anybody waste their time and money futzing
around with tiny little amateur lenses taking tiny little amateur deep space
photographs when there are millions of REAL large and detailed photos
available from Hubble alone?

Jeff's photo showed data acquired in x-rays. There is *NO* lens
involved in x-ray photography. Please do not feel stupid
because you did not know this. I'm sure that you are not
alone.


No lens, but like most telescopes it had a mirror, actually I think it
was two sets of three mirrors. They were concentric rings of quartz,
and the x-rays reflected at a very shallow angle to achieve a resolution
of about 1 arc-second.

The first x-ray telescopes I worked on ('75) used bizarre arrangements
of wire or slats that rotated to form an image. Lo res and not very
sensitive, but they were able to locate a few hundred sources. The
research that went into them was use to build the early CT Scanners,
proving that astrophysics does have direct benefits.

Actually, you are missing the point that amateurs are using the
very latest technology. You do not understand that technology
in optics has made enormous advances in recent years. My
4" refractor can outperform a 20 year old 10" reflector.

I hope that you have found my post useful. I don't want
you to look so stupid again.

Regards

Donal


No, Donal, they are not. I can assure you that even the most expensive
optical systems geared to the high end amateur does not represent
state of the art in optical design or execution. True, a new high end
refractor will be better than older models, but again they are still
amateur instruments.

The most expensive scope I've owned was a Celestron 14 on a custom
built pier, but it was still a toy.



R.

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!

My
4" refractor can outperform a 20 year old 10" reflector.



Uh, Donal....a Cave Astrola reflector from the early 80's will easily
top the highest end 4" refractor. It's simply going to collect too
much light over the 4 and transmission coatings don't equal raw
aperture. They've been making VERY good mirrors for even longer than
20 years.
I thought you knew something about this, but it sounds more like
you've read a lot of Vixen and Tak ads.


R.

On Sep 3, 6:11 pm, "jlrogers±³©" wrote:
http://ghostlight.zenfolio.com/img/v1/p61487401-5.jpg



But if you love shooting the stars then by all means go at it!
Now that's impressive! Who's the bug?




Jumping spider shot with a Nikon D300 and a reversed 24mm lens. The
spider is about the size of a rice grain.

Here's a bit more of my work....

http://ghostlight.zenfolio.com/img/v0/p954096487-5.jpg
http://ghostlight.zenfolio.com/img/v2/p597837560-5.jpg
http://ghostlight.zenfolio.com/img/v2/p52643971-5.jpg

I like this shot of the moon as I pulled it off with a Nikon D80 and a
fairly average 70-300mm zoom lens...

http://ghostlight.zenfolio.com/img/v3/p1072386785-4.jpg



R.

"Capt. Rob" wrote in message
...
On Sep 3, 6:11 pm, "jlrogers±³©" wrote:
http://ghostlight.zenfolio.com/img/v1/p61487401-5.jpg



But if you love shooting the stars then by all means go at it!
Now that's impressive! Who's the bug?




Jumping spider shot with a Nikon D300 and a reversed 24mm lens. The
spider is about the size of a rice grain.

Here's a bit more of my work....

http://ghostlight.zenfolio.com/img/v0/p954096487-5.jpg
http://ghostlight.zenfolio.com/img/v2/p597837560-5.jpg
http://ghostlight.zenfolio.com/img/v2/p52643971-5.jpg

I like this shot of the moon as I pulled it off with a Nikon D80 and a
fairly average 70-300mm zoom lens...

http://ghostlight.zenfolio.com/img/v3/p1072386785-4.jpg



R.

You do have eyes.

On Thu, 4 Sep 2008 07:11:26 -0500, "jlrogers±³©"
wrote:


"Capt. Rob" wrote in message
...
On Sep 3, 6:11 pm, "jlrogers±³©" wrote:
http://ghostlight.zenfolio.com/img/v1/p61487401-5.jpg



But if you love shooting the stars then by all means go at it!
Now that's impressive! Who's the bug?




Jumping spider shot with a Nikon D300 and a reversed 24mm lens. The
spider is about the size of a rice grain.

Here's a bit more of my work....

http://ghostlight.zenfolio.com/img/v0/p954096487-5.jpg
http://ghostlight.zenfolio.com/img/v2/p597837560-5.jpg
http://ghostlight.zenfolio.com/img/v2/p52643971-5.jpg


Not impressed!
The lighting on the poor child dramatically distorts her face
The woman has multiple highlights in her eyes....and blackheads on her
nose .... ughhhh
And the leaf...well the leaf is just an uninspiring leaf.

I've seen very much better from you!!




OzOne of the three twins

I welcome you to Crackerbox Palace.
** Posted from http://www.teranews.com **

On Thu, 4 Sep 2008 07:11:26 -0500, "jlrogers±³©"
wrote:


"Capt. Rob" wrote in message
...
On Sep 3, 6:11 pm, "jlrogers±³©" wrote:
http://ghostlight.zenfolio.com/img/v1/p61487401-5.jpg



But if you love shooting the stars then by all means go at it!
Now that's impressive! Who's the bug?




Jumping spider shot with a Nikon D300 and a reversed 24mm lens. The
spider is about the size of a rice grain.

Here's a bit more of my work....

http://ghostlight.zenfolio.com/img/v0/p954096487-5.jpg
http://ghostlight.zenfolio.com/img/v2/p597837560-5.jpg
http://ghostlight.zenfolio.com/img/v2/p52643971-5.jpg

Not impressed!
The lighting on the poor child dramatically distorts her face
The woman has multiple highlights in her eyes....and blackheads on her
nose .... ughhhh
And the leaf...well the leaf is just an uninspiring leaf.




OzOne of the three twins

I welcome you to Crackerbox Palace.
** Posted from http://www.teranews.com **

"jeff" wrote in message
...
Wilbur Hubbard wrote:
Jeff's photo showed data acquired in x-rays. There is *NO* lens
involved in x-ray photography. Please do not feel stupid
because you did not know this. I'm sure that you are not
alone.

Tell these guys:

http://www.iop.org/EJ/abstract/0022-3727/38/10A/042

http://www.patentstorm.us/patents/7289597/claims.html

http://query.nytimes.com/gst/fullpag...C0A9679582 60

http://tu-dresden.de/die_tu_dresden/...ch/xray_lenses

http://www.ifg-adlershof.de/linsen.htm


When my dentist points that lens-looking think at my mouth and it buzzes
it directs the x-rays just where they need to go. It might not be a GLASS
lense but there's got to be a lense of some sort in there.


No, that type of x-ray picture doesn't use a lens. Think about it. Here's
a hint: if the thing the dentist points at you bounces around during the
exposure, it doesn't affect the picture.

Not so. The xray machine is the source of illumination and the xray plate is
a stationary receiver and not attached to the machine. IIf the plate moves
during the exposure, the picture is fuzzy, just like a camera.

Once again, Wilbur is correct.

If the x-ray did not have a "lens", why is it aimed at all?

Here's a lens part number for a GE dental xray machine:

http://answers.yahoo.com/question/in...4063732AATtXgz