M1 - The Crab Nebula

[steppenwolf]

M1 - The Crab Nebula

Introduction

The Crab Nebula in the constellation of Taurus is a supernova remnant (designated SN 1054) from a star that went supernova in 1054 and was originally observed by Chinese astronomers who recorded the event in some detail, describing it as a ‘guest star’. Their records show that the star shone approximately four times brighter than the planet Venus and was visible during daylight hours for 23 days. The nebula wasn't officially recorded until 1731 when it was observed by the English astronomer John Bevis and added to the Messier catalogue in 1758. We have William Parsons the 3rd Earl of Rosse to thank for its common name following his observation and subsequent sketch of the nebula in 1840 that looked rather like a crab.

During the summer of 1967 a U.S. Air Force officer, Charles Schisler,who  was on radar duty at the Clear Air Force Base in Alaska noticed a fluctuating radio source. Over the course of several days Schisler noticed that its position coincided with that of the Crab Nebula. Unfortunately, Schisler’s findings went unpublished but were unearthed in 2007. In 1968 Puerto Rican astronomers discovered the same pulsing radio source and it was determined to be a pulsar, a rapidly rotating tiny star flashing about 30 times per second. Now known as the Crab Pulsar this is a neutron star (NP0532) 100,000 times more energetic than the sun and was the progenitor of the nebula.

Because of its energy and relatively recent (in cosmology terms) appearance, the nebula has been the focus of many measurements and the filamentary expansion of the nebula is detectable in many pairs of high resolution images captured more than 20 years apart.

I have struggled to capture all the Ha data that I wanted for this image as the appalling weather during much of January and February has put a severe limit on my activities but I did capture a pleasant amount of the OIII data which shows some lovely detail in just a mono image and is included below for reference. With the object now setting on my local horizon just before 02:00 and no letup in the poor weather in sight, I have decided to call it quits for this season and just process what I have got!

Image Stats

Mount: Mesu 200
Telescope: Sky-Watcher Esprit 150
Flattener: Sky-Watcher Esprit specific
Camera: QSI 683 WSG-8
Filters: Astrodon 3nm Ha, 3nm OIII
Subframes: 16 x 1800 sec Ha, 18 x 1800 sec OIII
Total Integration: 17 hours
Control: CCD Commander
Capture: MaxIm DL
Calibration, Stacking and Deconvolution: PixInsight
Post-Processing: PhotoShop PS3

Location

Constellation	Taurus
RA	05° 34' 20.7"
DEC	+22° 00' 39.9"
Distance	~6500ly

 

 

Edited to show the correct date of the Puerto Rican astronomer's discovery of the pulsar thanks to @ollypenrice who kindly pointed out an ambiguity in the text that I consulted during my research on the write-up for this post!

[maw lod qan]

Thanks! I do enjoy reading the information describing these incredible objects.

As a think how lucky the observers in China were to witness such a sight, I keep thinking Betelgeuse just might be our chance.

[alan potts]

You really are very good Steve, a lovely image with just the right amount of everything that I try to do but always fail and even though aware of it over saturate. Great image, why didn't I get an Esprit 150 when I could have for 3k.

Alan

[Craney]

I'm a big fan of a narrowband Crab..... it is quite unlike any other technicolour  DSO that I know.   This is a beautiful example.

I have never noticed that filamentary whisp off to the right hand side in Oiii before, almost as if the nebula is expanding faster there than elsewhere.  (Maybe because I orientate my crab pictures along the longer axis. )

Hopefully if I am imaging in 20 years time I will try to show the expansion with a GIF.   I believe an amateur imager  has done this already.

[Sunshine]

That is a really nice capture!

[Brian28]

Lovely job 😉

[steppenwolf]

6 hours ago, maw lod qan said:

Thanks! I do enjoy reading the information describing these incredible objects.

Thank you, I use these posts as an excellent opportunity to brush up on my own knowledge (or lack of it!).

4 hours ago, alan potts said:

You really are very good Steve, a lovely image with just the right amount of everything that I try to do but always fail and even though aware of it over saturate. Great image, why didn't I get an Esprit 150 when I could have for 3k.

You are too kind, Alan but thanks. I have to say that the Esprit 150 continues to impress but isn't this a tiny object even at 1070mm focal length? .... and I cropped this image too.....

4 hours ago, Craney said:

I'm a big fan of a narrowband Crab..... it is quite unlike any other technicolour  DSO that I know.   This is a beautiful example.

I have never noticed that filamentary whisp off to the right hand side in Oiii before, almost as if the nebula is expanding faster there than elsewhere.

Thank you, I too believe that this makes a really excellent target for narrowband imaging. With regard to the whisp off to the right in OIII, I was originally alerted to this by @ollypenrice who produced an excellent OIII mono version recently.

4 hours ago, Sunshine said:

That is a really nice capture!

Thank you, I am pleased you like it.

1 minute ago, Brian28 said:

Lovely job 😉

Thanks, Brian.

[alan potts]

I also should have said and sort of along the lines of your reply, it is the most disappointing visual object I have ever looked at, even in my fairly large 18 inch Dob.

Alan

[jetstream]

10 minutes ago, alan potts said:

I also should have said and sort of along the lines of your reply, it is the most disappointing visual object I have ever looked at, even in my fairly large 18 inch Dob.

Alan

I just came in from observing M1 and can say that the 24" does show vg lines of structure in it. Similar but not as extensive as Steves great OIII image. Alan you might want to keep observing this one as it can show very well. Your scope will show the main bright spike and a short spur I believe. The 15 f4.8" wants to but is not quite there and your f4ish 18" will I'm sure.

[ollypenrice]

A very nice Crab and an enjoyable write-up, Steve.

Jocelyn Bell Burnell, who discovered the first Pulsar, tells the story of a woman pilot at an outreach event in the early fifties who said she could see the nebula flashing. When told it would be scintillation she said that she knew about that, and that she was detecting something different. 

Jodrell Bank's one year Introduction to Radio Astronomy Course gives you the data from a lunar occultation they observed. This gives two possible locations for the pulsar, only one of which is plausible on other grounds. Very cute!

I'm still waiting for RGB for ours. Terrible weather all over Europe this winter!

Olly

[steppenwolf]

1 hour ago, ollypenrice said:

A very nice Crab and an enjoyable write-up, Steve.

Thank you Olly and thanks also for pointing out an ambiguity in one of the documents that I used to research my text!

[MartinB]

Terrific work Steve with some very nice filamentous detail.  Did you get some decent seeing?

[steppenwolf]

11 hours ago, MartinB said:

Terrific work Steve with some very nice filamentous detail.  Did you get some decent seeing?

Thanks, Martin - the seeing for the OIII was excellent but much less so for the Ha where I was troubled with either poor transparency or when it was good and clear, rather poor seeing!

[Nova2000]

I can't stop looking at this picture .wow lots of details !

[Mr Spock]

Lovely image and write-up. I always enjoy reading about the objects I'm looking at. The Crab has so much history is such a short space of time. We sometimes forget how young and forever changing it is.

[steppenwolf]

40 minutes ago, Nova2000 said:

I can't stop looking at this picture .wow lots of details !

Thank you, I'm pleased you like it.

16 minutes ago, Mr Spock said:

Lovely image and write-up. I always enjoy reading about the objects I'm looking at. The Crab has so much history is such a short space of time. We sometimes forget how young and forever changing it is.

Thanks, Michael - in hindsight, I really wish I had thought about this object when I started imaging about 13 years ago as I could have done my own research into its continuing expansion. I guess it is never too late to start!!

[Allinthehead]

Wonderful image. Mad how small this appears at that focal length. 

[steppenwolf]

1 hour ago, Allinthehead said:

Wonderful image. Mad how small this appears at that focal length. 

Thanks, yes, it surprised me too but then I guess it is still quite 'young' and has a lot of growing to do!

[sloz1664]

Fabulous image Steve and so detailed. Processed to your very high standard also.

Steve

[des anderson]

The mono image,is just a tad better than the other one, really there`s nothing in it both first class. Des

[steppenwolf]

17 hours ago, sloz1664 said:

Fabulous image Steve and so detailed. Processed to your very high standard also.

Thank you, Steve, I'm pleased you like it!

17 hours ago, des anderson said:

The mono image,is just a tad better than the other one, really there`s nothing in it both first class. Des

Thank you Des, yes, the OIII data is very strong on this object so a mono image using just this data works very well - I much preferred the OIII data to the Ha in this case which is very unusual!

[ollypenrice]

44 minutes ago, steppenwolf said:

Thank you, Steve, I'm pleased you like it!

Thank you Des, yes, the OIII data is very strong on this object so a mono image using just this data works very well - I much preferred the OIII data to the Ha in this case which is very unusual!

Indeed so. I felt exactly the same. I'm about to shoot colour for our Ha-OIII and am thinking about leaving luminance out of the mix because it will fill the central part of the nebula with light and so reduce the striking fine filaments in the OIII.

Olly

[Jkulin]

Hi Steve, really lovely detail.

It never ceases to amaze me that with this and my mates and my M1 that with similar amounts of data that we have such vastly different images, yours bring so vastly superior😎

 

[steppenwolf]

23 hours ago, Jkulin said:

Hi Steve, really lovely detail.

It never ceases to amaze me that with this and my mates and my M1 that with similar amounts of data that we have such vastly different images, yours bring so vastly superior😎

Thank you, John. I think the biggest differences come about when using narrowband techniques as there is no 'standard' to aim for so anything goes when it comes to processing the data! For example, you have used the full Hubble Palette of SII, Ha and OIII whereas I have only used Ha and OIII to produce a bi-colour image and there are several ways of mixing just those two sets of data.

[Gina]

Superb, Steve.  Love it.