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?

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

"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

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.

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.

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.

The drawing may have been so poorly done because he was using a
telescope with a metal mirror.

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.

In message , WALTER RAVE
writes
The drawing may have been so poorly done because he was using a
telescope with a metal mirror.


The problem with that argument is that his other pictures are superb.
Look at the drawing of M51, for instance.
Are there any reports by people using speculum metal mirrors today?

Jonathan Silverlight wrote
in :

In message , WALTER RAVE
writes
The drawing may have been so poorly done because he was using a
telescope with a metal mirror.

The problem with that argument is that his other pictures are superb.
Look at the drawing of M51, for instance.
Are there any reports by people using speculum metal mirrors today?

Speculum metal?! And are you sure he used the same telescope for the crab
as for the other drawings.