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Observing >> Deep Sky Observing

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Darren Drake
Carpal Tunnel
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how bright was M1 when cataloged? new
      #5611757 - 01/08/13 11:11 AM

M1 is the only ds object that has changed significantly since its discovery. Its less than a thousand years old. I'm wondering just how much smaller brighter and different it was when Messier cataloged it on sept 12, 1758. Thoughts???

Edited by Darren Drake (01/08/13 11:13 AM)


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Tony Flanders
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Re: how bright was M1 when cataloged? new [Re: Darren Drake]
      #5611905 - 01/08/13 12:56 PM

Quote:

I'm wondering just how much smaller brighter and different it was when Messier cataloged it on sept 12, 1758.




The general assumption is that M1 has been expanding at a fairly constant rate since the light of its progenitor's explosion reached us in 1054. That would make it about 700/960 = 73% of its current size by linear measure.

I don't know about its absolute magnitude. My guess is that it's remained pretty constant since then.


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Laurent Ferrero
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Reged: 12/28/12

Loc: Marseilles, France
Re: how bright was M1 when cataloged? new [Re: Tony Flanders]
      #5611917 - 01/08/13 01:09 PM

I think when M1 extends its contrast and magnitude declines because the nebula is more deluted in space.

But we have an advantage compared to Messier, we have OIII filters !

I have made a skech of M1 in the end of 2012 with my 15" Obsession:
http://splendeursducielprofond.over-blog.com/pages/Les_objets_Messier-2493429...

Edited by Laurent Ferrero (01/08/13 04:26 PM)


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MikeBOKC
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Re: how bright was M1 when cataloged? new [Re: Laurent Ferrero]
      #5611924 - 01/08/13 01:12 PM

Here is an interesting graphic showing the very visible expansion of the crab's visible gas cloud between 1973 and 2000:

http://spiff.rit.edu/classes/phys231/crab/crab.html


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dpwoos
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Re: how bright was M1 when cataloged? new [Re: Laurent Ferrero]
      #5611926 - 01/08/13 01:12 PM

A (bona fide professional) astronomer told me that a lot of what we see when we observe supernova remnants is the shockwave heating and exciting stuff that it runs into. If that is so, then "dilution" is not a big factor and I would think the brightness could vary considerably one way or the other depending on the stuff in its path.

Edited by dpwoos (01/08/13 01:14 PM)


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drbyyz
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Reged: 11/04/12

Re: how bright was M1 when cataloged? new [Re: MikeBOKC]
      #5612219 - 01/08/13 03:59 PM

Quote:

Here is an interesting graphic showing the very visible expansion of the crab's visible gas cloud between 1973 and 2000:

http://spiff.rit.edu/classes/phys231/crab/crab.html




Now that is freaking cool!


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GlennLeDrew
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Re: how bright was M1 when cataloged? [Re: drbyyz]
      #5612707 - 01/08/13 09:01 PM

I suspect the *integrated* magnitude of the Crab's synchrotron radiation hasn't changed much in the interval, meaning the surface brightness would have decreased with the expansion. This is my supposition only.

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nytecam
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Re: how bright was M1 when cataloged? new [Re: MikeBOKC]
      #5613146 - 01/09/13 05:00 AM

Quote:

Here is an interesting graphic showing the very visible expansion of the crab's visible gas cloud between 1973 and 2000: http://spiff.rit.edu/classes/phys231/crab/crab.html


Very interesting link - especially reference to the old 36" Crossley reflector may me think Mayall's spectra of the Crab expansion was old too eg in 1938? in Wikipeadia thus...

Using his newly built spectrograph, Mayall was the first to determine the radial velocities of many knots of gas in the Crab Nebula.[17] Using these data and the previously published angular rate of expansion of the nebula, he was able to estimate its distance. Consequently, he became the first person to recognize and demonstrate that the Crab Nebula was the remnant of a supernova observed and recorded in 1054 (SN 1054), rather than a classical nova.[30][31] Walter Baade was instrumental in stimulating and counseling Mayall after around 1939, taking on the role previously filled by Hubble

Incredible work


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Tom Polakis
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Re: how bright was M1 when cataloged? new [Re: Tony Flanders]
      #5613433 - 01/09/13 10:07 AM

Quote:

The general assumption is that M1 has been expanding at a fairly constant rate since the light of its progenitor's explosion reached us in 1054. That would make it about 700/960 = 73% of its current size by linear measure.




While the slope is very nearly linear, I have read in the journals that the filaments are accelerating. In other words, if you extrapolate the positions of the filaments measured over a number of decades, they will converge in something like the 14th century rather than in 1054.

This paper is some light reading on the subject.

As others have mentioned, it seems like the surface brightness would have diminished significantly since the time of its discovery.

Tom


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sgottlieb
scholastic sledgehammer
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Reged: 07/22/07

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Re: how bright was M1 when cataloged? new [Re: nytecam]
      #5614331 - 01/09/13 07:21 PM

Quote:

Very interesting link - especially reference to the old 36" Crossley reflector may me think Mayall's spectra of the Crab expansion was old too eg in 1938? in Wikipeadia thus...

Using his newly built spectrograph, Mayall was the first to determine the radial velocities of many knots of gas in the Crab Nebula.[17] Using these data and the previously published angular rate of expansion of the nebula, he was able to estimate its distance. Consequently, he became the first person to recognize and demonstrate that the Crab Nebula was the remnant of a supernova observed and recorded in 1054 (SN 1054), rather than a classical nova.[30][31] Walter Baade was instrumental in stimulating and counseling Mayall after around 1939, taking on the role previously filled by Hubble




Speaking of Hubble, it's worth mentioning that before Mayall's work, Hubble published this in 1928:

"[the nebula] is expanding rapidly and at such a rate that it must have required about 900 years to reach its present dimensions. For, in the ancient accounts of celestial phenomena only one nova has been recorded in the region of the Crab Nebula. This account is found in the Chinese annals, the postion fits as closely as it can read, and the year was 1054!"

Edited by sgottlieb (01/09/13 07:24 PM)


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Scanning4Comets
Markus
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Re: how bright was M1 when cataloged? new [Re: sgottlieb]
      #5617516 - 01/11/13 04:06 PM

Quote:

I think when M1 extends its contrast and magnitude declines because the nebula is more deluted in space.

But we have an advantage compared to Messier, we have OIII filters !




I don't think an O-III filter is the filter of choice for M-1. I believe the UHC would be better, or none at all IIRC. I did check out your web page and you have some really nice drawings! Love the scopes too!

Cheers,


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sgottlieb
scholastic sledgehammer
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Reged: 07/22/07

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Re: how bright was M1 when cataloged? new [Re: Scanning4Comets]
      #5618048 - 01/11/13 09:27 PM

Quote:

I don't think an O-III filter is the filter of choice for M-1. I believe the UHC would be better, or none at all IIRC. I did check out your web page and you have some really nice drawings! Love the scopes too!




You're right, the overall contrast and shape is not enhanced by an OIII filter. But it is the filter of choice to see filamentary detail within M1. With my 18", the filaments go from invisible or extremely muted, to obvious (in good conditions) with an OIII filter.


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azure1961p
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Reged: 01/17/09

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Re: how bright was M1 when cataloged? new [Re: sgottlieb]
      #5618085 - 01/11/13 09:56 PM

This is very compelling Steve and others have concurred with your finds. I recall the one time I tried it and the filter killed it - but it's an 8". Still it'd be interesting to see what could come of it if I tried. At that aperture even mottling is a good find.

Pete


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Laurent Ferrero
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Reged: 12/28/12

Loc: Marseilles, France
Re: how bright was M1 when cataloged? new [Re: azure1961p]
      #5623102 - 01/14/13 05:24 PM

Thank you Markus for the sketches.
I agree with Steve, the OIII is very good for filaments. Next time I will try to compare the vision of M1 with the UHC filter.

cheers,

Laurent


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