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The Crab Nebula in 1844



 
 
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  #1  
Old December 23rd 05, 10:07 PM posted to sci.astro,sci.astro.amateur
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Default The Crab Nebula in 1844


http://www.seds.org/messier/more/m001_rosse.html

This begs the question of why the drawing so poorly represents the
familiar, modern image of the Crab. Has anybody ever managed to recreate
the conditions leading to this particular image, and if so, are there
photos?

  #2  
Old December 23rd 05, 10:55 PM posted to sci.astro,sci.astro.amateur
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Default The Crab Nebula in 1844

John Schutkeker wrote:
http://www.seds.org/messier/more/m001_rosse.html

This begs the question of why the drawing so poorly represents the
familiar, modern image of the Crab. Has anybody ever managed to recreate
the conditions leading to this particular image, and if so, are there
photos?

Turn this picture to the right, 90 degrees, convert to gray scale and
dim it a bit and it looks somewhat similar.
http://www.sci-trek.w-wa.pl/artykuly...bula_0015y.jpg
  #3  
Old December 24th 05, 02:37 AM posted to sci.astro,sci.astro.amateur
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Default The Crab Nebula in 1844


"John Popelish" wrote in message
...
John Schutkeker wrote:
http://www.seds.org/messier/more/m001_rosse.html

This begs the question of why the drawing so poorly represents the
familiar, modern image of the Crab. Has anybody ever managed to

recreate
the conditions leading to this particular image, and if so, are there
photos?

Turn this picture to the right, 90 degrees, convert to gray scale and
dim it a bit and it looks somewhat similar.

http://www.sci-trek.w-wa.pl/artykuly...b_nebula_0015y
..jpg

Possibly, but that is just a tiny part of the complete Crab which is
unlikely to relate to what Lord Rosse was seeing. Here is the whole HST Crab
http://us.st11.yimg.com/store1.yimg....ges_1875_58544
I tend to agree that Lord Rosses drawing does not look much like it, nor
does it look like what I see in my eyepiece or image with my CCD either. eg
http://www.leadbeaterhome.fsnet.co.u...o_image_33.htm
I too would be interested to know why Rosse saw it the way he did

Robin


  #4  
Old December 24th 05, 04:49 AM posted to sci.astro,sci.astro.amateur
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Default The Crab Nebula in 1844


Robin Leadbeater wrote:
"John Popelish" wrote in message


Turn this picture to the right, 90 degrees, convert to gray scale and
dim it a bit and it looks somewhat similar.

http://www.sci-trek.w-wa.pl/artykuly...b_nebula_0015y
.jpg

Possibly, but that is just a tiny part of the complete Crab which is
unlikely to relate to what Lord Rosse was seeing. Here is the whole HST Crab
http://us.st11.yimg.com/store1.yimg....ges_1875_58544
I tend to agree that Lord Rosses drawing does not look much like it, nor
does it look like what I see in my eyepiece or image with my CCD either. eg
http://www.leadbeaterhome.fsnet.co.u...o_image_33.htm
I too would be interested to know why Rosse saw it the way he did


I doubt very much that he saw what your CCD sees. Do you know what
size telescope he was using to observe the Crab when he made this
drawing? He may have been seeing only the brightest core of the
nebula. But I couldn't locate the stars he drew, at any scale or
orientation, including mirroring.

  #5  
Old December 24th 05, 10:49 AM posted to sci.astro,sci.astro.amateur
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Default The Crab Nebula in 1844

In message . com,
writes

Robin Leadbeater wrote:
"John Popelish" wrote in message


Turn this picture to the right, 90 degrees, convert to gray scale and
dim it a bit and it looks somewhat similar.

http://www.sci-trek.w-wa.pl/artykuly...b_nebula_0015y
.jpg

Possibly, but that is just a tiny part of the complete Crab which is
unlikely to relate to what Lord Rosse was seeing. Here is the whole HST Crab
http://us.st11.yimg.com/store1.yimg....ges_1875_58544
I tend to agree that Lord Rosses drawing does not look much like it, nor
does it look like what I see in my eyepiece or image with my CCD either. eg
http://www.leadbeaterhome.fsnet.co.u...o_image_33.htm
I too would be interested to know why Rosse saw it the way he did


I doubt very much that he saw what your CCD sees. Do you know what
size telescope he was using to observe the Crab when he made this
drawing? He may have been seeing only the brightest core of the
nebula. But I couldn't locate the stars he drew, at any scale or
orientation, including mirroring.

The link text said that it was done with the 36 inch reflector, and that
Rosse saw "filaments... springing principally from its southern
extremity" so it seems that's at least a representation of what he saw.
I wonder if it was impressionistic, meant only to give an idea of the
shape, and I wonder if William Parsons had unusual acuity, or unusual
sensitivity to red light.
Are there any published reproductions of R J Mitchell's 1855 drawing?
That's the one that apparently gave rise to the "crab" name.
  #6  
Old December 25th 05, 01:20 AM posted to sci.astro,sci.astro.amateur
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Default The Crab Nebula in 1844

Jonathan Silverlight
wrote in :

In message . com,
writes

Robin Leadbeater wrote:
"John Popelish" wrote in message


Turn this picture to the right, 90 degrees, convert to gray scale
and dim it a bit and it looks somewhat similar.

http://www.sci-trek.w-

wa.pl/artykuly/astronomia/fotografia/crab_nebul
a_0015y .jpg

Possibly, but that is just a tiny part of the complete Crab which is
unlikely to relate to what Lord Rosse was seeing. Here is the whole
HST Crab
http://us.st11.yimg.com/store1.yimg....ges_1875_58544
I tend to agree that Lord Rosses drawing does not look much like it,
nor does it look like what I see in my eyepiece or image with my CCD
either. eg http://www.leadbeaterhome.fsnet.co.u...o_image_33.htm
I too would be interested to know why Rosse saw it the way he did


I doubt very much that he saw what your CCD sees. Do you know what
size telescope he was using to observe the Crab when he made this
drawing? He may have been seeing only the brightest core of the
nebula. But I couldn't locate the stars he drew, at any scale or
orientation, including mirroring.

I wonder if it was impressionistic, meant only to give an idea of
the shape,


I was under the impression that early astronomers were very diligent
about drawing accurate pictures.

I also assume that quality control on those old optics was light years
behind modern abilities. So even though they used a 36 inch reflector,
its performance would have been much worse than the same telescope,
built with modern techniques and mateials.

Carl Zeiss didn't invented his binoculars in 1894, and when he started
selling microscopes to the medical community, economies of scale began
to rapidly lower costs of all optics. Telescopes just profitted as an
ancillary technology.

and I wonder if William Parsons had unusual acuity, or
unusual sensitivity to red light.


What does the Crab looks like through a red filter?

Are there any published reproductions of R J Mitchell's 1855 drawing?
That's the one that apparently gave rise to the "crab" name.


According to the ink, it was Parsons' drawing that gave it the name.
That picture looks a lot like like a silverfish, which is a water-
loving, terrestrial arachnid related to the tick. That was close enough
to a crab for me.
  #7  
Old December 25th 05, 04:25 AM posted to sci.astro,sci.astro.amateur
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Default The Crab Nebula in 1844

John Schutkeker wrote:

I was under the impression that early astronomers were very diligent
about drawing accurate pictures.

(snip)

Have you been able to make any sense of the stars shown in the
drawing. If you could match those up to a photograph, you woulds be
way ahead in trying to figure out what part of the nebula he was
drawing. I have made several attempts at several scales, orientations
and inversions, but come up with nothing like a reasonable match. Is
there a record of what magnification or focal length eyepiece was used
when the drawing was made? I can't figure out if the drawing is a
mental connection of widely separated wisps, larger that what is
normally included in photographs of the nebula, or a tiny central
fragment of the brightest part of the nebula.
  #8  
Old December 27th 05, 06:37 PM posted to sci.astro,sci.astro.amateur
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Default The Crab Nebula in 1844


wrote in message
ups.com...

Robin Leadbeater wrote:
"John Popelish" wrote in message


Turn this picture to the right, 90 degrees, convert to gray scale and
dim it a bit and it looks somewhat similar.


http://www.sci-trek.w-wa.pl/artykuly...b_nebula_0015y
.jpg

Possibly, but that is just a tiny part of the complete Crab which is
unlikely to relate to what Lord Rosse was seeing. Here is the whole HST

Crab
http://us.st11.yimg.com/store1.yimg....ges_1875_58544
I tend to agree that Lord Rosses drawing does not look much like it, nor
does it look like what I see in my eyepiece or image with my CCD either.

eg
http://www.leadbeaterhome.fsnet.co.u...o_image_33.htm
I too would be interested to know why Rosse saw it the way he did


I doubt very much that he saw what your CCD sees. Do you know what
size telescope he was using to observe the Crab when he made this
drawing? He may have been seeing only the brightest core of the
nebula. But I couldn't locate the stars he drew, at any scale or
orientation, including mirroring.



According to this reference he changed his description when he upgraded from
his 36 inch to the 72 inch "Leviathon"

"The Earl of Rosse at Birr Castle, Ireland observed M1 in 1844 with a 91cm
(36 inch) reflector. He described it as having claw-like appendages as a
result of which the name Crab Nebula began to be used. However, when the
Earl of Rosse in 1848 turned a 183cm (72 inch) reflector onto the object he
repudiated the earlier description. Nevertheless, the name stuck!"

From

http://www.ast.cam.ac.uk/~ipswich/Ob...j/Messiers.htm



Robin




  #9  
Old December 30th 05, 12:16 PM posted to sci.astro,sci.astro.amateur
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Default The Crab Nebula in 1844

Robin Leadbeater wrote:
"John Popelish" wrote in message
...

John Schutkeker wrote:

http://www.seds.org/messier/more/m001_rosse.html

This begs the question of why the drawing so poorly represents the
familiar, modern image of the Crab. Has anybody ever managed to


recreate

the conditions leading to this particular image, and if so, are there
photos?


Turn this picture to the right, 90 degrees, convert to gray scale and
dim it a bit and it looks somewhat similar.


http://www.sci-trek.w-wa.pl/artykuly...b_nebula_0015y
.jpg

Possibly, but that is just a tiny part of the complete Crab which is
unlikely to relate to what Lord Rosse was seeing. Here is the whole HST Crab
http://us.st11.yimg.com/store1.yimg....ges_1875_58544
I tend to agree that Lord Rosses drawing does not look much like it, nor
does it look like what I see in my eyepiece or image with my CCD either. eg
http://www.leadbeaterhome.fsnet.co.u...o_image_33.htm
I too would be interested to know why Rosse saw it the way he did


One possibility not so far been mentioned is that at the time the
brightest part really did look something more like his drawing. Secular
changes in supernovae remnants are well documented.
See for example:

http://www.seds.org/messier/m/m001.html

It is relevant that Messier started his catalogue of nuisance objects
with M1 after mistaking it for Halley's comet (a mistake repeated by
other observers on a subsequent apparation). He described it as having a
candle flame appearence. The central core mesh of filaments may well
have been brighter in the past.

Regards,
Martin Brown
  #10  
Old January 1st 06, 04:41 PM posted to sci.astro,sci.astro.amateur
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Default The Crab Nebula in 1844

In message , Martin Brown
writes

One possibility not so far been mentioned is that at the time the
brightest part really did look something more like his drawing. Secular
changes in supernovae remnants are well documented.
See for example:

http://www.seds.org/messier/m/m001.html

It is relevant that Messier started his catalogue of nuisance objects
with M1 after mistaking it for Halley's comet (a mistake repeated by
other observers on a subsequent apparation). He described it as having
a candle flame appearence. The central core mesh of filaments may well
have been brighter in the past.


Good point! The Crab has expanded by more than 10% in that time, and the
pulsar has presumably slowed.
Are there any surviving drawings by William Lassell? He apparently saw
filaments in 1852.
"With 160x it is a very bright nebula, with two or three stars in it,
but with 565x...Long filaments run out from all sides and there seems to
be a number of minute and faint stars scattered over it; the outlying
claws are only just circumscribed by the edge of the field of 6'
diameter...".
http://members.leapmail.net/~ericj/m1_saturn.html
And when was it first photographed? An early photo wouldn't be sensitive
to red light, though.
 




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