- Note - The following emails have been slightly edited
for reading clarity only. Email addresses and phone numbers have been
saved to file to protect the immediate privacy of the persons involved.
- ed
-
-
- From: xxxx
- To: John Lenard
- Subject: Re: ISS photo
- Date: Wed, 17 Jan 2007 17:57:34 +0000 (GMT)
-
- ********************************************************
xxxx FInstP ScD
- Professor of Experimental Philosophy
- Institute of Astronomy
- Cambridge University PA: Suzanne Howard
- Madingley Road
- Cambridge CB3 0HA UK
- *******************************************************
-
- Hi John,
-
- many thanks for sending your remarkable images: you are
clearly an exceptionally talented astro-photographer.
-
- there are of course very many communication, spy and
earth-observation satellites in orbit. The best information source I know
to identify such things is a distinguished astrophysicist, who used to
work here in Cambridge and now works at Harvard, Jonathan McDowell.
-
- his (relevant) web page is
- http://www.planet4589.org/space/jsr/jsr.html
-
- and I've taken the liberty of cc'ing him on this reply.
-
- best regards, and good luck in the hunt.
- xxxx
-
-
- On Wed, 17 Jan 2007, John Lenard wrote:
-
- Dear xxxx
-
- I think Jonathan McDowell is the perfect person, along
with you, to solve the films
- of mine. I would love to show you the real objects
on the moon. when jpl/nasa saw my moon video, they did not know what
I had gotten on my tape.
-
- look at file moon walk jpg file
-
- thank you. I am looking forward to speaking to Jonathan
McDowell
-
- regards,
John
-
-
- From xxxx
- Sent: Thu 1/18/07 3:37 AM
- To: John Lenard
-
- ********************************************************
- xxxx FInstP ScD
- Professor of Experimental Philosophy
- Institute of Astronomy
- Cambridge University
- Madingley Road
- Cambridge CB3 0HA UK
- *******************************************************
-
- Hello again,
-
- And again my congratulations on your superb astrophotography.
-
- You are clearly getting some images at almost the diffraction
limit of your telescope. In the very sharpest images there are hints of
diffraction rings visible on the edges of the satellites. That is of course
the absolute limit of optical performance, and is only rarely attained.
-
- Interestingly, the process you have, of using a high-quality
imaging system, with fast read-out, and then selecting the rare `perfect'
images is something which has been developed and applied somewhat by one
of my colleagues here. You might like to look at our local web page presenting
some of this:
-
- http://www.ast.cam.ac.uk/~optics/Lucky_Web_Site/
-
- You might also be interested in a journal produced by
the MIT Lincoln Laboratory - which is the group which has built some of
the things you are seeing. Much of what they do is what used to be the
Star wars project, which no doubt involves some of your objects. They don't
talk about the military satellites, of course, but there are many
dicussions of earth surveillance, and related issues. It is distributed
only to academic organisations, so you may need to get your local
library to borrow it, but you may be able to get this (for free) from
-
- Subscription Coordinator
- Room L-054
- Lincoln Laboratory
- MIT
- 244 Wood Street
- Lexington
- MA 0240-9185
- USA
-
- best regards
- xxxx
-
-
- From xxxx
- Sent: Thu 1/21/07
- To: John Lenard
-
- ********************************************************
- xxxx FInstP ScD
- Professor of Experimental Philosophy
- Institute of Astronomy
- Cambridge University
- Madingley Road
- Cambridge CB3 0HA UK
- *******************************************************
-
- Hi John,
-
- my work address is perfectly safe, thanks.
-
- I wouldn't worry too much about Nasa restricting you
or your information. They are a civilian agency, and astronomers work with
them all the time. Many of my colleagues are indeed nasa staff.
-
- There is of course nothing like posting stuff on the
internet if you do feel restricted.
-
- But perhaps more useful might be for you to get the coordinate
information to Jonathan so he can identify some of these for you.
-
- ciao
- xxxx
-
-
- From: xxxx
- Sent: Sat 2/10/07 2:37 AM
- To: john lenard
-
-
- Hi John,
-
- Thank you for the images: once again they show that you
are an excellent photographer.
-
- There are of course many satellites in orbit, only a
few of which are anything to do with JPL, but these are readily seen by
astro-photographers like yourself all over the world.
-
- You should just enjoy the excellence of your images,
and make them available as widely as is possible, through the public web-sites,
magazines, etc, so you can get the credit you deserve for your skills.
-
- best regards
- xxxx
-
-
-
- John Lenard wrote:
-
- Dear Jerry
-
- One more important point...
- what should a five and an 8 inch scope see?
-
-
- From: xxxx
- Sent: Fri 4/06/07 8:34 AM
- To: John Lenard
-
-
- ********************************************************
- xxxx FInstP ScD
- Professor of Experimental Philosophy
- Institute of Astronomy
- Cambridge University
- Madingley Road
- Cambridge CB3 0HA UK
- *******************************************************
-
- Hi John,
-
- A telescope does two things: it collects more light than
an eye, so allows one to see fainter (sensitivity), and it increases the
amount of detail (resolution) that one can see.
-
- Sensitivity is simple: it gets better the bigger you
are, so you will always see fainter objects with a bigger telescope: that
is why astronomers like to build big things,
-
- Resolution is more complicated: the finest detail you
will see with a telescope depends mostly on the local atmosphere where
you are. This `seeing' is caused by turbulence in the air, usually at low
levels. There is a typical size to these air-parcels, which is a few inches.
At a site with very good seeing the parcels are up to about 10-12 inches,
more typically they are 5-6 inches at a good site, 1-3 inches are a poor
site, or in bad weather. The air-patches, bubbles, are blown by the wind,
so keep changing as seen by one person/telescope, which is why some frames
have a lot more detail than do others. most of Southern California - in
fact all west-facing ocean coasts - are very good sites, with Mt Wilson
and Palomar being famous examples.
-
- The effect of this turbulence is that telescopes only
see more and more detail until the telescope is larger than the air bubbles.
When several bubbles are seen by the telescope at the same time the image
no longer improves. When it is windy the bubbles move past quickly, so
that the image is changing a lot, and seems fuzzy. That means that larger
telescopes do not see more detail. In fact, a good back-yard telescope,
well-adjusted, like yours, see just as much detail as a very large professional
telescope, like the Palomar 200-inch. Palomar see fainter of course, but
no `better'.
-
- You will get the best possible image quality with a telescope
about the same size as the bubbles, with a magnification which is just
large enough so that exactly one air bubble is between the telescope aperture
and the target image, and with an integration (frame-rate) time such that
the bubble doesn't move by more than one-half its size during one film
frame.
-
- Your technique of `lucky imaging' seems to have identified
exactly the correct combination of telescope size, magnification and frame
rate to match your local atmosphere and wind.
-
- You can do a bit better by having a larger telescope
- maybe twice as big - and using a shorter frame rate, but only when the
conditions are very stable, so less often.
-
- Of course, by far the biggest limitation most systems
have is poor focus and wobble - poor mounts. Most systems don't work anywhere
near their potential simply because they are not setup properly.
-
- You can do better by trying to `correct' the image for
its distortions: that is called adaptive optics, and there are some quite
good systems available. Hand-held video cameras already have them built-in,
to correct for focus and hand-shake.
-
- So, bigger doesn't always mean better. It depends what
you want - to see faint, or to see detail. You can't have both, unless
you get above all the air - which is why we build our telescopes on the
top of very high mountains, or put them in space. That, however, is expensive.
-
- regards
- xxxx
-
-
- From: "xxxx II" jpl.nasa.gov
- To: "John Lenard"
- Subject: other good film
- Date: Sat, 10 Mar 2007
-
- Hi John.
-
- Wow! I'm impressed. It's either enormously huge
(so you can see it as being larger than the bright stars in Orion) or closer
than space.
-
- And the movie is the best ever.
-
- How do you know when to set up your camera? Or where
to point it? I hope you don't mind all my questions.
-
- Have a good weekend.
-
- --xxxx
-
-
- From: John Lenard
- To: xxxx.
- Subject: other good film
- Date: Sun, 11 Mar 2007 09:42:09 -0800
-
- Dear xxxx
-
- This film is very good. I hope you like it.
-
- yours,
- John
-
-
- From: xxxx
- To: John Lenard
- Subject: other good film
- Date: Wed, 21 Mar 2007 10:12:02 -0700
-
- Hi.
-
- Yes. It appears to have symmetrical rectangular appendages,
which are probably solar panels.
-
- It also appears to be rotating on its X-axis a little
-- Thanks for remembering to show me your stuff.
-
- j--xxxx
|
