best of Hubble images

On Feb 28, 5:14 pm, "William Graham" <w....DeleteThis@comcast.net> wrote:

> I have heard of software that removes anything that changes from shot to
> shot, but keeps whatever remains in each shot.....Under the theory that the
> noise will move from place to place, but the real data doesn't change in
> position. Is this what they do?- Hide quoted text -

Actually, more often you would want to do the opposite, i.e., remove
everything that stays the same and leave what changes. That's how you
find comets and asteroids, since they move relative to the background
stars.
 >> Stay informed about: best of Hubble images 

On Thu, 28 Feb 2008 22:13:47 -0800, Paul Furman wrote:

> Craig wrote:
>> On Tue, 26 Feb 2008 20:47:52 -0500, Pudentame wrote:
>>
>>> Nicholas O. Lindan wrote:
>>>> "Troy Piggins" <usenet-0802.RemoveThis@piggo.com> wrote
>>>>> http://photography-on-the.net/forum/showthread.php?t=450144
>>>>> http://photography-on-the.net/forum/showthread.php?t=450156
>>>>> http://photography-on-the.net/forum/showthread.php?t=419180
>>>>> http://photography-on-the.net/forum/showthread.php?t=451640
>>>> Not bad. All taken with a 500mm f8 Apo-doublet:
>>>> http://www.adorama.com/TKTSK9001.html?sid=12039901721249430
>>>>
>>> Why would it be f/8 instead of f/5.6?
>>
>> It looks like Tak sells an F/8 and F/5.6. Based on other images he posted
>> It looks like he as the F/8 and a 1.6 focal reducer-corrector bringing the
>> effective F/ratio to 4.5.
>
> Is that used with a smaller format digital? I never heard of such a
> thing to make lenses faster. Hmm, so it must turn that into a 250mm lens?
> http://www.scopetronics.com/cel_reducer.htm
>
>>>> When used for birds ...
>>>> http://www.anacortestelescope.com/gallery/photos/14316.jpg
>>>>
>>>> In full regalia:
>>>> http://www.anacortestelescope.com/product.asp?pid=1980
>>>>
>>

It has nothing to do with the camera. It is used with a telescope. It works
with CCD/CMOS/Film cameras as well as your eye.

The Takahashi Sky 90II is a 90mm apochromatic Refractor (telescope). Adding
an extension tube changes the location of the focal plane thereby
increasing Focal length.

Some information on how Focal reducers work.

http://www.mailbag.com/users/ragreiner/opticlens.html

http://webcaddy.com.au/astro/F-066FR-pics.htm
http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/21881...Main/21
 >> Stay informed about: best of Hubble images 

In message
<effc8de1-b804-4c4d-ae1c-d49c8b6c12a9.DeleteThis@p43g2000hsc.googlegroups.com>,
Mark Sieving <mark_sieving.DeleteThis@yahoo.com> writes

>The main purpose of adaptive optics is to cancel out atmospheric
>disturbances. Since Hubble is outside the atmosphere to begin with,
>adaptive optics wouldn't help much.

Hubble's real job is to do the sort of astronomical observations
land-based scopes have trouble with, like UV and infra-red spectrum
work. It can also do tricks like very long exposures -- there was a
project a few years ago where the observers pointed the Hubble at a
patch of sky that looked "empty" to normal scopes and left it running
for over 80 hours continuous. At the end of it they found the "blank"
space was filled with very faint galaxies. Even stacking images from
regular multi-hour observations by land-based telescopes won't recover
that sort of detail.
--
To reply, my gmail address is nojay1 Robert Sneddon
 >> Stay informed about: best of Hubble images 

In message <47c6052a$0$24081$4c368faf@roadrunner.com>, Pudentame
<no.one.DeleteThis@no.were.invalid> writes

>I don't know why they can't just grab Hubble on one of their missions
>and move it over near the space station where the station crew could do
>EVAs over to Hubble. Any required repair parts could be sent up in the
>Russian Soyuz supply capsules.

The ISS is in quite a low orbit compared to the Hubble, and requires
boosting every few months to prevent it from deorbiting and then burning
up in the atmosphere. The Hubble has no motors on board to allow it to
do this kind of station-keeping operation. It also has a different drag
coefficient to the ISS so even if it was positioned close to the station
they would separate again over a period of months.

The Hubble can't be fitted back into the Shuttle's cargo bay as its
solar panel array won't fold back into its body and the extra solar
panel unit added after the first set partially failed definitely won't
fit.

The Hubble is obsolete really (it was designed in the 1970s after all)
but it is still producing good research data and will continue to do so
up until it just stops working or is deliberately decommissioned. The
last Shuttle service mission will upgrade some parts to extend its
lifespan a bit more but the concentration of the space astronomy people
is now on the James Webb telescope which will be deployed at the
Lagrange 1 point and is not serviceable by any sort of manned craft
because of its remote location, over 500,000 miles from Earth.
--
To reply, my gmail address is nojay1 Robert Sneddon
 >> Stay informed about: best of Hubble images 

"Don Stauffer in Minnesota" <stauffer.TakeThisOut@usfamily.net> wrote in message
news:955a9892-ea25-4a71-b3b6-e79593375b95@e6g2000prf.googlegroups.com...
> On Feb 28, 5:24 pm, "William Graham" <w....TakeThisOut@comcast.net> wrote:
>> "Martin Brown" <|||newspam...@nezumi.demon.co.uk> wrote in message
>>
>> news:RcPK1>
>>
>>
>>
>> Also you need an immense amount of training and practice to get bulky>
>> parts in and out of a confined space without damaging the instruments
>> > whilst wearing a pressure suit and heavy gloves.
>>
>> I should think that they would design an instrument that was modular, so
>> they could just swap modules in their space suits, and then do the
>> repairs
>> without a vacuum, back inside a normal atmosphere. We did that without
>> being
>> in space, when tunnel time was expensive inside a high energy physics
>> collider....We would just go in and swap out a defective part, and then
>> do
>> the actual repairs somewhere else while the machine continued to operate.
>
> The Hubble is indeed pretty modular. Still, the precise alignment and
> pointing they require for anything in the high res experiments or in
> the control and stabilization system requires those modules to fit
> with EXTREME angular precision, so replacing a module is still not the
> easiest job.

Yes. - Even while I was writing that, I knew that it was being penned by
someone who didn't know what he was really talking about.......Sometimes I
just can't help myself.....:^)
 >> Stay informed about: best of Hubble images 

"Mark Sieving" <mark_sieving RemoveThis @yahoo.com> wrote in message
news:b0d87832-ce30-437d-b528-70ea75dca254@i7g2000prf.googlegroups.com...
On Feb 28, 5:14 pm, "William Graham" <w... RemoveThis @comcast.net> wrote:

> I have heard of software that removes anything that changes from shot to
> shot, but keeps whatever remains in each shot.....Under the theory that
> the
> noise will move from place to place, but the real data doesn't change in
> position. Is this what they do?- Hide quoted text -

Actually, more often you would want to do the opposite, i.e., remove
everything that stays the same and leave what changes. That's how you
find comets and asteroids, since they move relative to the background
stars.

Sounds reasonable.....I guess you really need a more complex, second order
effect program, that is capable of tracking data over several consecutive
frames, and looking for objects that follow a linear path, but not just a
random one. A program than can selectively throw out lots of different
stuff, but save the stuff that it " decides" is part of the data you are
interested in.
 >> Stay informed about: best of Hubble images 

Robert Sneddon wrote:
> In message <47c6052a$0$24081$4c368faf@roadrunner.com>, Pudentame
> <no.one RemoveThis @no.were.invalid> writes
>
>> I don't know why they can't just grab Hubble on one of their missions
>> and move it over near the space station where the station crew could do
>> EVAs over to Hubble. Any required repair parts could be sent up in the
>> Russian Soyuz supply capsules.
>
> The ISS is in quite a low orbit compared to the Hubble, and requires
> boosting every few months to prevent it from deorbiting and then burning
> up in the atmosphere. The Hubble has no motors on board to allow it to
> do this kind of station-keeping operation. It also has a different drag
> coefficient to the ISS so even if it was positioned close to the station
> they would separate again over a period of months.
>

Ok, some blue-sky brainstorming here ... if you can't move Hubble down,
how about draggin' the ISS *UP* to where Hubble is?

And all you'd really need for station keeping is a high-tech ball of
"kite string".


> The Hubble can't be fitted back into the Shuttle's cargo bay as its
> solar panel array won't fold back into its body and the extra solar
> panel unit added after the first set partially failed definitely won't
> fit.
>

OTOH, you could design and build a tug that would fit into the Shuttle's
cargo bay and could latch on to the Hubble to move it around wherever
you needed to take it. I realize it'd have to move pretty damn slow not
to break stuff off, but it could be done.


> The Hubble is obsolete really (it was designed in the 1970s after all)
> but it is still producing good research data and will continue to do so
> up until it just stops working or is deliberately decommissioned. The
> last Shuttle service mission will upgrade some parts to extend its
> lifespan a bit more but the concentration of the space astronomy people
> is now on the James Webb telescope which will be deployed at the
> Lagrange 1 point and is not serviceable by any sort of manned craft
> because of its remote location, over 500,000 miles from Earth.

What you got here is a failure of imagination.

All the rest is just engineering, and this country's got engineers out
the wazoo just begging for interesting work.

Seems kind of dumb to put a multi-million dollar project half-a-million
miles from earth and have no way to get there and fix it when it
inevitably blows a $.50 fuse.

I suspect deploying it to Lagrange 1 works best for the science, but to
me, common sense says if that's where it needs to go, you better be
figurin' how you're gonna' get out there to fix it when it breaks.
 >> Stay informed about: best of Hubble images 

Craig wrote:
> On Thu, 28 Feb 2008 22:13:47 -0800, Paul Furman wrote:
>
>> Craig wrote:
>>> On Tue, 26 Feb 2008 20:47:52 -0500, Pudentame wrote:
>>>
>>>> Nicholas O. Lindan wrote:
>>>>> "Troy Piggins" <usenet-0802.RemoveThis@piggo.com> wrote
>>>>>> http://photography-on-the.net/forum/showthread.php?t=450144
>>>>>> http://photography-on-the.net/forum/showthread.php?t=450156
>>>>>> http://photography-on-the.net/forum/showthread.php?t=419180
>>>>>> http://photography-on-the.net/forum/showthread.php?t=451640
>>>>> Not bad. All taken with a 500mm f8 Apo-doublet:
>>>>> http://www.adorama.com/TKTSK9001.html?sid=12039901721249430
>>>>>
>>>> Why would it be f/8 instead of f/5.6?
>>> It looks like Tak sells an F/8 and F/5.6. Based on other images he posted
>>> It looks like he as the F/8 and a 1.6 focal reducer-corrector bringing the
>>> effective F/ratio to 4.5.
>> Is that used with a smaller format digital? I never heard of such a
>> thing to make lenses faster. Hmm, so it must turn that into a 250mm lens?
>> http://www.scopetronics.com/cel_reducer.htm
>>
>>>>> When used for birds ...
>>>>> http://www.anacortestelescope.com/gallery/photos/14316.jpg
>>>>>
>>>>> In full regalia:
>>>>> http://www.anacortestelescope.com/product.asp?pid=1980
>>>>>
>
> It has nothing to do with the camera. It is used with a telescope. It works
> with CCD/CMOS/Film cameras as well as your eye.
>
> The Takahashi Sky 90II is a 90mm apochromatic Refractor (telescope). Adding
> an extension tube changes the location of the focal plane thereby
> increasing Focal length.
>
> Some information on how Focal reducers work.
>
> http://www.mailbag.com/users/ragreiner/opticlens.html

I'm not familiar with telescope terminology so it's hard to read but
this makes some sense to me:

"Focal reducers are positive lenses which do two things to the real
image. They move the focal point forward (toward the back plate)
considerably and they reduce the image size. It is the reduced image
that is desired since it is both smaller and brighter. Thus more image
fits on the film or CCD imager, which has the effect of decreasing the
effective focal length of the telescope. It also increases the surface
brightness of the real image thus decreasing the effective f number of
the telescope."

Alright, so it's like the opposite of a teleconverter. I see it does
also convert it to a smaller image format and that's how the increased
f/stop is accomplished.

The only similar thing I've heard of is a frazier lens for
cinematography which uses a 'relay lens'. The frazier lens loses
considerable f/stops and gives a slightly wider field of view (17mm ->
12mm) maybe because it does other things and goes through all sorts of
periscope mirrors.

The other similar adapter I've heard of is a converter for old Canon FD
lenses to the new Canon mount which has a longer flange distance. This
uses a 'relay lens' simply to change the flange distance but not the
image size and it's supposed to have a considerable negative impact on
image quality.

The reason this is interesting is most DSLRs are a little smaller
cropped format and the old 'full frame' lenses could be turned into
wider faster lenses with such a focal reducer. Medium format lenses
could be used as well, and I can imagine the increased f/stop could be
useful for various 35mm uses.

One thing I read in there is about the flange distance becoming shorter
which generally means it's going to be useless for 35mm lenses but then
they talk about extension tubes also & I can't sort it all out.

> http://webcaddy.com.au/astro/F-066FR-pics.htm

"This is new. Something I wanted and thought you might also. I couldn't
stand paying US$130 for a focal reducer lens for my LX-90. After all
they are designed for 35mm film guys who want a large flat field. I only
have a 1/3" CCD chip. I don't need a large flat field, I just want to
get more sky on my chip."

Ah, this is interesting, they talk about 35mm uses for focal reducers
but I don't really understand why & they don't say exactly what the
hardware is. Hmm flat field ...maybe this is the same thing you see in
macro lenses where the focal length shortens/widens when getting close
to 1:1 but that situation involves losing f/stops so probably not.

> http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/21881...Main/21

More details in this link but nothing that explains the possible
relevance for 35mm work.
 >> Stay informed about: best of Hubble images 

In message <47c885c0$0$24097$4c368faf@roadrunner.com>, Pudentame
<no.one DeleteThis @no.were.invalid> writes
>Robert Sneddon wrote:
>> In message <47c6052a$0$24081$4c368faf@roadrunner.com>, Pudentame
>> <no.one DeleteThis @no.were.invalid> writes
>>
>>> I don't know why they can't just grab Hubble on one of their
>>>missions
>>> and move it over near the space station where the station crew could do
>>> EVAs over to Hubble.

>> The ISS is in quite a low orbit compared to the Hubble, and
>>requires
>> boosting every few months

>Ok, some blue-sky brainstorming here ... if you can't move Hubble down,
>how about draggin' the ISS *UP* to where Hubble is?

Then the Russian Soyuz manned capsules and the Progress unmanned cargo
vessels wouldn't be able to reach the ISS. They've got a lot less lift
capability than the US Shuttle fleet has. This problem first reared its
head during the Apollo/Soyuz meetup back in the 70s when the Apollo had
to fly lower and slower than it ever had and the Soyuz had to go faster
and higher than it was designed to for the two capsules to actually dock
with each other.

>And all you'd really need for station keeping is a high-tech ball of
>"kite string".

Strings work funny in orbit. There was a "tethered satellite"
experiment done from the Shuttle's cargo bay. It had to be abandoned
after oscillations in the cable started and there was no way of damping
them out.
>
>
>> The Hubble can't be fitted back into the Shuttle's cargo bay as its
>> solar panel array won't fold back into its body and the extra solar
>> panel unit added after the first set partially failed definitely won't
>> fit.
>>
>
>OTOH, you could design and build a tug that would fit into the
>Shuttle's cargo bay and could latch on to the Hubble to move it around
>wherever you needed to take it. I realize it'd have to move pretty damn
>slow not to break stuff off, but it could be done.

There's no trailer hitch on the Hubble telescope that can allow a
pusher tug to move it. If you tried tractoring it the exhaust from the
rocket motors would wreck the solar cell panels and probably trash the
very sensitive instruments inside.

>> The Hubble is obsolete really (it was designed in the 1970s after all)
>
>What you got here is a failure of imagination.
>
>All the rest is just engineering, and this country's got engineers out
>the wazoo just begging for interesting work.

It would be easier and cheaper to design a Hubble MkII and launch that
than try and extend the lifespan of the Hubble Mk I. The computers on
board the existing Hubble are monstrous in size compared to what we can
build today and are unbelievably puny, with a lot less computing power
than your mobile phone or digital camera, never mind your laptop. The
main mirror is known to be defective and it was only made operational
with corrective optics fitted in one of the first service missions.
Those defects bite into its light grasp and resolution. A new Hubble
would have a perfect mirror day one resulting in better science day two.
The problems with the solar cells are known and would be fixed in the
new design etc. etc.

>
>Seems kind of dumb to put a multi-million dollar project half-a-million
>miles from earth and have no way to get there and fix it when it
>inevitably blows a $.50 fuse.
>
>I suspect deploying it to Lagrange 1 works best for the science, but to
>me, common sense says if that's where it needs to go, you better be
>figurin' how you're gonna' get out there to fix it when it breaks.

The James Webb Space Telescope (JWST) is an infra-red telescope, cooled
to 50K (about -220 deg C). It's so sensitive that if it was in a
Hubble-type orbit the radiated heat from the Earth's surface and
atmosphere would swamp the instruments. At Lagrange 2 its heatshield
blocks infrared from the Sun, the Moon and the Earth all at the same
time since they're all in the same direction, mostly. Unfortunately that
puts the JWST over a million km from Earth and well out of reach of
manned repair and maintenance missions. As for unmanned support
missions, maybe but they're not in the budget or ops plan. The JWST is
designed to be fire-and-forget.
--
To reply, my gmail address is nojay1 Robert Sneddon
 >> Stay informed about: best of Hubble images 

"Paul Furman" <paul- RemoveThis @-edgehill.net>

> "Focal reducers are positive lenses which do two things ..."
> The only similar thing I've heard of is

A close-up lens.

It reduces the lens focal length, but the lens stays in the
same spot so the new reduced focal length lens is now focused
pretty close.

It increases the aperture - the new lens is faster - but as
it is extended for close up the bellows correction (close-up
correction) compensates and the effective f-stop is the original
lens f-stop.

If you put a close-up lens on a view camera, where you can
rack the lens closer to the film, you get a usable shorter
lens.

There are negative "anti-close-up lenses(?)" used with
view cameras to increase focal length. Not used much anymore.

==
Nicholas O. Lindan
Cleveland Engineering Design, LLC
Cleveland, Ohio 44121
 >> Stay informed about: best of Hubble images 

Robert Sneddon wrote:
> In message <47c885c0$0$24097$4c368faf@roadrunner.com>, Pudentame
> <no.one.RemoveThis@no.were.invalid> writes
>> Robert Sneddon wrote:
>>> In message <47c6052a$0$24081$4c368faf@roadrunner.com>, Pudentame
>>> <no.one.RemoveThis@no.were.invalid> writes
>>>
>>>> I don't know why they can't just grab Hubble on one of their
>>>> missions
>>>> and move it over near the space station where the station crew could do
>>>> EVAs over to Hubble.
>
>>> The ISS is in quite a low orbit compared to the Hubble, and
>>> requires
>>> boosting every few months
>
>> Ok, some blue-sky brainstorming here ... if you can't move Hubble down,
>> how about draggin' the ISS *UP* to where Hubble is?
>
> Then the Russian Soyuz manned capsules and the Progress unmanned cargo
> vessels wouldn't be able to reach the ISS. They've got a lot less lift
> capability than the US Shuttle fleet has. This problem first reared its
> head during the Apollo/Soyuz meetup back in the 70s when the Apollo had
> to fly lower and slower than it ever had and the Soyuz had to go faster
> and higher than it was designed to for the two capsules to actually dock
> with each other.
>
>> And all you'd really need for station keeping is a high-tech ball of
>> "kite string".
>
> Strings work funny in orbit. There was a "tethered satellite"
> experiment done from the Shuttle's cargo bay. It had to be abandoned
> after oscillations in the cable started and there was no way of damping
> them out.
>>
>>> The Hubble can't be fitted back into the Shuttle's cargo bay as its
>>> solar panel array won't fold back into its body and the extra solar
>>> panel unit added after the first set partially failed definitely won't
>>> fit.
>>>
>> OTOH, you could design and build a tug that would fit into the
>> Shuttle's cargo bay and could latch on to the Hubble to move it around
>> wherever you needed to take it. I realize it'd have to move pretty damn
>> slow not to break stuff off, but it could be done.
>
> There's no trailer hitch on the Hubble telescope that can allow a
> pusher tug to move it. If you tried tractoring it the exhaust from the
> rocket motors would wreck the solar cell panels and probably trash the
> very sensitive instruments inside.
>
>>> The Hubble is obsolete really (it was designed in the 1970s after all)
>> What you got here is a failure of imagination.
>>
>> All the rest is just engineering, and this country's got engineers out
>> the wazoo just begging for interesting work.
>
> It would be easier and cheaper to design a Hubble MkII and launch that
> than try and extend the lifespan of the Hubble Mk I. The computers on
> board the existing Hubble are monstrous in size compared to what we can
> build today and are unbelievably puny, with a lot less computing power
> than your mobile phone or digital camera, never mind your laptop. The
> main mirror is known to be defective and it was only made operational
> with corrective optics fitted in one of the first service missions.
> Those defects bite into its light grasp and resolution. A new Hubble
> would have a perfect mirror day one resulting in better science day two.
> The problems with the solar cells are known and would be fixed in the
> new design etc. etc.
>
>> Seems kind of dumb to put a multi-million dollar project half-a-million
>> miles from earth and have no way to get there and fix it when it
>> inevitably blows a $.50 fuse.
>>
>> I suspect deploying it to Lagrange 1 works best for the science, but to
>> me, common sense says if that's where it needs to go, you better be
>> figurin' how you're gonna' get out there to fix it when it breaks.
>
> The James Webb Space Telescope (JWST) is an infra-red telescope, cooled
> to 50K (about -220 deg C). It's so sensitive that if it was in a
> Hubble-type orbit the radiated heat from the Earth's surface and
> atmosphere would swamp the instruments. At Lagrange 2 its heatshield
> blocks infrared from the Sun, the Moon and the Earth all at the same
> time since they're all in the same direction, mostly. Unfortunately that
> puts the JWST over a million km from Earth and well out of reach of
> manned repair and maintenance missions. As for unmanned support
> missions, maybe but they're not in the budget or ops plan. The JWST is
> designed to be fire-and-forget.

"designed to be fire-and-forget."

Based on previous experience, I expect they'd better have their emphasis
on the latter, 'cause that's what's gonna happen.

Well, like I said, it's really all just engineering and the only thing
standing in the way is the failure of imagination.
 >> Stay informed about: best of Hubble images 

Nicholas O. Lindan wrote:
> "Paul Furman" <paul-.TakeThisOut@-edgehill.net>
>
>> "Focal reducers are positive lenses which do two things ..."
>> The only similar thing I've heard of is
>
> A close-up lens.
>
> It reduces the lens focal length, but the lens stays in the
> same spot

Does it reduce the focal length? If I focus a 'bare' lens at closest
distance, then put a closeup lens on the end I have to crank it to
infinity to get back in focus (and move in closer). For a simple lens
design, cranking to infinity actually *increases* the focal length.

> so the new reduced focal length lens is now focused
> pretty close.
>
> It increases the aperture - the new lens is faster - but as
> it is extended for close up the bellows correction (close-up
> correction) compensates and the effective f-stop is the original
> lens f-stop.
>
> If you put a close-up lens on a view camera, where you can
> rack the lens closer to the film, you get a usable shorter
> lens.
>
> There are negative "anti-close-up lenses(?)" used with
> view cameras to increase focal length. Not used much anymore.
 >> Stay informed about: best of Hubble images 

Paul Furman wrote:
> Nicholas O. Lindan wrote:
>> "Paul Furman" <paul- DeleteThis @-edgehill.net>
>>
>>> "Focal reducers are positive lenses which do two things ..."
>>> The only similar thing I've heard of is
>>
>> A close-up lens.
>>
>> It reduces the lens focal length, but the lens stays in the
>> same spot
>
> Does it reduce the focal length? If I focus a 'bare' lens at closest
> distance, then put a closeup lens on the end I have to crank it to
> infinity to get back in focus (and move in closer). For a simple lens
> design, cranking to infinity actually *increases* the focal length.

Oh, sorry, I had that backwards. You are right.

>> so the new reduced focal length lens is now focused
>> pretty close.
>>
>> It increases the aperture - the new lens is faster - but as
>> it is extended for close up the bellows correction (close-up
>> correction) compensates and the effective f-stop is the original
>> lens f-stop.
>>
>> If you put a close-up lens on a view camera, where you can
>> rack the lens closer to the film, you get a usable shorter
>> lens.
>>
>> There are negative "anti-close-up lenses(?)" used with
>> view cameras to increase focal length. Not used much anymore.
 >> Stay informed about: best of Hubble images