On Wed, 16 Mar 2022 19:47:50 -0700 (PDT), RichA <rander3128@gmail.com>
wrote:

>https://phys.org/news/2022-03-space-telescope-image-star-photobombed.html
>
>Not sure.

2MASS J17554042+6551277

V mag is 11.95. Somewhat brighter in the IR.

http://simbad.cds.unistra.fr/simbad/sim-id?Ident=2MASS+J17554042%2B6551277&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id

That's 100 times dimmer than a mag 7 star.

On Friday, March 18, 2022 at 1:05:49 AM UTC, RichA wrote:
> On Thursday, 17 March 2022 at 01:12:43 UTC-4, Chris L Peterson wrote:
> > On Wed, 16 Mar 2022 19:47:50 -0700 (PDT), RichA <rande...@gmail.com>
> > wrote:
> >
> > >https://phys.org/news/2022-03-space-telescope-image-star-photobombed.html
> > >
> > >Not sure.
> > 2MASS J17554042+6551277
> >
> > V mag is 11.95. Somewhat brighter in the IR.
> >
> > http://simbad.cds.unistra.fr/simbad/sim-id?Ident=2MASS+J17554042%2B6551277&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id
> >
> > That's 100 times dimmer than a mag 7 star.
> Impressive! I wonder why they used a red filter? The mentioned something about it but didn't go into detail.

Really wonderful image and look forward to all the future ones.

On 18/03/2022 01:05, RichA wrote:
> On Thursday, 17 March 2022 at 01:12:43 UTC-4, Chris L Peterson wrote:
>> On Wed, 16 Mar 2022 19:47:50 -0700 (PDT), RichA <rande...@gmail.com>
>> wrote:
>>
>>> https://phys.org/news/2022-03-space-telescope-image-star-photobombed.html
>>>
>>> Not sure.
>> 2MASS J17554042+6551277
>>
>> V mag is 11.95. Somewhat brighter in the IR.
>>
>> http://simbad.cds.unistra.fr/simbad/sim-id?Ident=2MASS+J17554042%2B6551277&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id
>>
>> That's 100 times dimmer than a mag 7 star.
>
> Impressive! I wonder why they used a red filter? The mentioned something about it but didn't go into detail.

It is just one of many possible false colour palettes they could have
mapped the greyscale intensity image onto usually called "thermal" or
something like that. It preserves (or should preserve) luminosity so
that it will look OK on a monochrome display.

It is essentially dim red-red-dim orange-orange-yellow-white. Better
than greyscale for showing up faint details but by no means the best!

The other common one that preserves monochrome luminosity goes something
like this (with carefully chosen RBG coefficients).

dim blue-blue-purple-cyan-green-magenta-pink-white

This one:

https://www.mrao.cam.ac.uk/~dag/CUBEHELIX/

I prefer ones that make better use of the full 3D RGB space. There are a
couple of others that preserve luminosity and use more of the colour
cube. Rainbow is currently popular at the VLA eg. Figs 1&2 here

https://arxiv.org/pdf/1107.2511.pdf

Peano-Koch twisted is my favourite brutal false colour palette for high
dynamic range images. It goes through all of the single colours and
pairwise combinations tracing along the edges of the colour cube in
sequence. Starting at black along the blue edge and ending at white.
(it doesn't preserve monotonic luminosity)

ie
black-blue-cyan-green-yellow-red-magenta-white

It is very good for seeing faint detail provided that there isn't too
much noise (even then it often works OK but looks very messy).

A series of colour coded ramps is also useful for visualising incredibly
high dynamic range almost noise free data.

I have a selection of common false colour palettes online here:

https://nezumidemon.co.uk/consult/excel/image.html

The only common ones missing is the more recent IronBow and Arctic which
has been popularised by thermal imaging cameras.

https://www.flir.co.uk/discover/industrial/picking-a-thermal-color-palette/

--
Regards,
Martin Brown

On Fri, 18 Mar 2022 09:37:41 +0000, Martin Brown
<'''newspam'''@nonad.co.uk> wrote:

>On 18/03/2022 01:05, RichA wrote:
>> On Thursday, 17 March 2022 at 01:12:43 UTC-4, Chris L Peterson wrote:
>>> On Wed, 16 Mar 2022 19:47:50 -0700 (PDT), RichA <rande...@gmail.com>
>>> wrote:
>>>
>>>> https://phys.org/news/2022-03-space-telescope-image-star-photobombed.html
>>>>
>>>> Not sure.
>>> 2MASS J17554042+6551277
>>>
>>> V mag is 11.95. Somewhat brighter in the IR.
>>>
>>> http://simbad.cds.unistra.fr/simbad/sim-id?Ident=2MASS+J17554042%2B6551277&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id
>>>
>>> That's 100 times dimmer than a mag 7 star.
>>
>> Impressive! I wonder why they used a red filter? The mentioned something about it but didn't go into detail.
>
>It is just one of many possible false colour palettes they could have
>mapped the greyscale intensity image onto usually called "thermal" or
>something like that. It preserves (or should preserve) luminosity so
>that it will look OK on a monochrome display.
>
>It is essentially dim red-red-dim orange-orange-yellow-white. Better
>than greyscale for showing up faint details but by no means the best!
>
>The other common one that preserves monochrome luminosity goes something
>like this (with carefully chosen RBG coefficients).
>
>dim blue-blue-purple-cyan-green-magenta-pink-white
>
>This one:
>
>https://www.mrao.cam.ac.uk/~dag/CUBEHELIX/
>
>I prefer ones that make better use of the full 3D RGB space. There are a
>couple of others that preserve luminosity and use more of the colour
>cube. Rainbow is currently popular at the VLA eg. Figs 1&2 here
>
>https://arxiv.org/pdf/1107.2511.pdf
>
>Peano-Koch twisted is my favourite brutal false colour palette for high
>dynamic range images. It goes through all of the single colours and
>pairwise combinations tracing along the edges of the colour cube in
>sequence. Starting at black along the blue edge and ending at white.
>(it doesn't preserve monotonic luminosity)
>
>ie
>black-blue-cyan-green-yellow-red-magenta-white
>
>It is very good for seeing faint detail provided that there isn't too
>much noise (even then it often works OK but looks very messy).
>
>A series of colour coded ramps is also useful for visualising incredibly
>high dynamic range almost noise free data.
>
>I have a selection of common false colour palettes online here:
>
>https://nezumidemon.co.uk/consult/excel/image.html
>
>The only common ones missing is the more recent IronBow and Arctic which
>has been popularised by thermal imaging cameras.
>
>https://www.flir.co.uk/discover/industrial/picking-a-thermal-color-palette/

Yes, but... the details of the image say that it was actually imaged
through a red filter to improve contrast, which is entirely separate
from the color mapping used to display it.

BTW, this is not a "false color palette", it is a "pseudocolor
palette". False color mapping applies to multiple channel images. This
is a single channel, where a grayscale is mapped to some color
palette. That's pseudocolor mapping.

On Fri, 18 Mar 2022 15:53:04 -0700 (PDT), RichA <rander3128@gmail.com>
wrote:

>On Friday, 18 March 2022 at 09:53:15 UTC-4, Chris L Peterson wrote:
>> On Fri, 18 Mar 2022 09:37:41 +0000, Martin Brown
>> <'''newspam'''@nonad.co.uk> wrote:
>>
>> >On 18/03/2022 01:05, RichA wrote:
>> >> On Thursday, 17 March 2022 at 01:12:43 UTC-4, Chris L Peterson wrote:
>> >>> On Wed, 16 Mar 2022 19:47:50 -0700 (PDT), RichA <rande...@gmail.com>
>> >>> wrote:
>> >>>
>> >>>> https://phys.org/news/2022-03-space-telescope-image-star-photobombed.html
>> >>>>
>> >>>> Not sure.
>> >>> 2MASS J17554042+6551277
>> >>>
>> >>> V mag is 11.95. Somewhat brighter in the IR.
>> >>>
>> >>> http://simbad.cds.unistra.fr/simbad/sim-id?Ident=2MASS+J17554042%2B6551277&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id
>> >>>
>> >>> That's 100 times dimmer than a mag 7 star.
>> >>
>> >> Impressive! I wonder why they used a red filter? The mentioned something about it but didn't go into detail.
>> >
>> >It is just one of many possible false colour palettes they could have
>> >mapped the greyscale intensity image onto usually called "thermal" or
>> >something like that. It preserves (or should preserve) luminosity so
>> >that it will look OK on a monochrome display.
>> >
>> >It is essentially dim red-red-dim orange-orange-yellow-white. Better
>> >than greyscale for showing up faint details but by no means the best!
>> >
>> >The other common one that preserves monochrome luminosity goes something
>> >like this (with carefully chosen RBG coefficients).
>> >
>> >dim blue-blue-purple-cyan-green-magenta-pink-white
>> >
>> >This one:
>> >
>> >https://www.mrao.cam.ac.uk/~dag/CUBEHELIX/
>> >
>> >I prefer ones that make better use of the full 3D RGB space. There are a
>> >couple of others that preserve luminosity and use more of the colour
>> >cube. Rainbow is currently popular at the VLA eg. Figs 1&2 here
>> >
>> >https://arxiv.org/pdf/1107.2511.pdf
>> >
>> >Peano-Koch twisted is my favourite brutal false colour palette for high
>> >dynamic range images. It goes through all of the single colours and
>> >pairwise combinations tracing along the edges of the colour cube in
>> >sequence. Starting at black along the blue edge and ending at white.
>> >(it doesn't preserve monotonic luminosity)
>> >
>> >ie
>> >black-blue-cyan-green-yellow-red-magenta-white
>> >
>> >It is very good for seeing faint detail provided that there isn't too
>> >much noise (even then it often works OK but looks very messy).
>> >
>> >A series of colour coded ramps is also useful for visualising incredibly
>> >high dynamic range almost noise free data.
>> >
>> >I have a selection of common false colour palettes online here:
>> >
>> >https://nezumidemon.co.uk/consult/excel/image.html
>> >
>> >The only common ones missing is the more recent IronBow and Arctic which
>> >has been popularised by thermal imaging cameras.
>> >
>> >https://www.flir.co.uk/discover/industrial/picking-a-thermal-color-palette/
>> Yes, but... the details of the image say that it was actually imaged
>> through a red filter to improve contrast, which is entirely separate
>> from the color mapping used to display it.
>>
>> BTW, this is not a "false color palette", it is a "pseudocolor
>> palette". False color mapping applies to multiple channel images. This
>> is a single channel, where a grayscale is mapped to some color
>> palette. That's pseudocolor mapping.
>
>Likely all you will see coming from that scope as the public won't understand shades of grey. The Hubble it ain't.

The JWST images through multiple filters, so the majority of its data,
like the HST, will be multiple channel and displayed using a false
color palette.

On Sun, 20 Mar 2022 18:06:24 -0700 (PDT), RichA <rander3128@gmail.com>
wrote:

>On Saturday, 19 March 2022 at 08:59:05 UTC-4, Chris L Peterson wrote:
>> On Fri, 18 Mar 2022 15:53:04 -0700 (PDT), RichA <rande...@gmail.com>
>> wrote:
>>
>> >On Friday, 18 March 2022 at 09:53:15 UTC-4, Chris L Peterson wrote:
>> >> On Fri, 18 Mar 2022 09:37:41 +0000, Martin Brown
>> >> <'''newspam'''@nonad.co.uk> wrote:
>> >>
>> >> >On 18/03/2022 01:05, RichA wrote:
>> >> >> On Thursday, 17 March 2022 at 01:12:43 UTC-4, Chris L Peterson wrote:
>> >> >>> On Wed, 16 Mar 2022 19:47:50 -0700 (PDT), RichA <rande...@gmail.com>
>> >> >>> wrote:
>> >> >>>
>> >> >>>> https://phys.org/news/2022-03-space-telescope-image-star-photobombed.html
>> >> >>>>
>> >> >>>> Not sure.
>> >> >>> 2MASS J17554042+6551277
>> >> >>>
>> >> >>> V mag is 11.95. Somewhat brighter in the IR.
>> >> >>>
>> >> >>> http://simbad.cds.unistra.fr/simbad/sim-id?Ident=2MASS+J17554042%2B6551277&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id
>> >> >>>
>> >> >>> That's 100 times dimmer than a mag 7 star.
>> >> >>
>> >> >> Impressive! I wonder why they used a red filter? The mentioned something about it but didn't go into detail.
>> >> >
>> >> >It is just one of many possible false colour palettes they could have
>> >> >mapped the greyscale intensity image onto usually called "thermal" or
>> >> >something like that. It preserves (or should preserve) luminosity so
>> >> >that it will look OK on a monochrome display.
>> >> >
>> >> >It is essentially dim red-red-dim orange-orange-yellow-white. Better
>> >> >than greyscale for showing up faint details but by no means the best!
>> >> >
>> >> >The other common one that preserves monochrome luminosity goes something
>> >> >like this (with carefully chosen RBG coefficients).
>> >> >
>> >> >dim blue-blue-purple-cyan-green-magenta-pink-white
>> >> >
>> >> >This one:
>> >> >
>> >> >https://www.mrao.cam.ac.uk/~dag/CUBEHELIX/
>> >> >
>> >> >I prefer ones that make better use of the full 3D RGB space. There are a
>> >> >couple of others that preserve luminosity and use more of the colour
>> >> >cube. Rainbow is currently popular at the VLA eg. Figs 1&2 here
>> >> >
>> >> >https://arxiv.org/pdf/1107.2511.pdf
>> >> >
>> >> >Peano-Koch twisted is my favourite brutal false colour palette for high
>> >> >dynamic range images. It goes through all of the single colours and
>> >> >pairwise combinations tracing along the edges of the colour cube in
>> >> >sequence. Starting at black along the blue edge and ending at white.
>> >> >(it doesn't preserve monotonic luminosity)
>> >> >
>> >> >ie
>> >> >black-blue-cyan-green-yellow-red-magenta-white
>> >> >
>> >> >It is very good for seeing faint detail provided that there isn't too
>> >> >much noise (even then it often works OK but looks very messy).
>> >> >
>> >> >A series of colour coded ramps is also useful for visualising incredibly
>> >> >high dynamic range almost noise free data.
>> >> >
>> >> >I have a selection of common false colour palettes online here:
>> >> >
>> >> >https://nezumidemon.co.uk/consult/excel/image.html
>> >> >
>> >> >The only common ones missing is the more recent IronBow and Arctic which
>> >> >has been popularised by thermal imaging cameras.
>> >> >
>> >> >https://www.flir.co.uk/discover/industrial/picking-a-thermal-color-palette/
>> >> Yes, but... the details of the image say that it was actually imaged
>> >> through a red filter to improve contrast, which is entirely separate
>> >> from the color mapping used to display it.
>> >>
>> >> BTW, this is not a "false color palette", it is a "pseudocolor
>> >> palette". False color mapping applies to multiple channel images. This
>> >> is a single channel, where a grayscale is mapped to some color
>> >> palette. That's pseudocolor mapping.
>> >
>> >Likely all you will see coming from that scope as the public won't understand shades of grey. The Hubble it ain't.
>> The JWST images through multiple filters, so the majority of its data,
>> like the HST, will be multiple channel and displayed using a false
>> color palette.
>
>Hubble colours aren't completely faked. They may be enhanced. They even use them in amateur photography now.
>However, since we don't see any colour distinctions in the IR, the images from Webb will be colourized.

"Faked"?

The majority of HST image are shot through a combination of narrowband
and broadband filters and then have a false-color palette applied.
They do not have their colors enhanced, they have them changed. Some
HST images, of course, are presented in a way intended to capture some
semblance of the actual colors we would see were our eyes sensitive
enough.

My point is that we will not see many pseudocolor images from JWST
(like the one under discussion here). Most will be false-color images,
just like we get from most HST images.