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M1/NGC 1952 Obs 11.14.2012

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#1 Special Ed

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Posted 15 November 2012 - 06:30 AM

Hello,

Since I got my 35cm Cat I've been revisiting some faint fuzzies that have always interested me. I've seen M1's ghostly shape with binoculars, a 10cm reflector, and a 20cm Cat, so I was looking forward to the larger aperture view and I wasn't disappointed.

I waited for a transparent night with no moon and was rewarded for my patience Tuesday night/Wednesday morning. I also had to wait for the object to rise above the murk and that took until 11:00 pm local (on a work night) which made the next day a little tough but worth it. :)

Transparency was excellent and I have dark, rural WV skies, but seeing was only average. Since I wasn't going to try to see the pulsar this session, the seeing wasn't a problem.

Even with the big Cat, M1 retains its ghostly appearance, so I had to study it for quite a while before I made a sketch (I spent a couple of hours on a previous night studying it too, but the transparency wasn't good enough to warrant a sketch).

I tried my UHC narrowband filter but could see more with the unfiltered view (I don't own an OIII). The southern and western portion of the nebula appeared brighter to my eye and the whole nebula appeared mottled. I got the best view at 170x. There were no sign of any filaments but that probably requires higher magnification, better seeing, and that OIII filter--maybe another night.

The sketch is here in the Sketching Forum.

I am an amateur historian as well as an amateur astronomer, so the amazing history of this object is a real bonus. Imagine a supernova four times brighter than Venus... There is lots more info about M1 here:
http://messier.seds.org/m/m001.html

Best to all,

#2 David Knisely

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Posted 15 November 2012 - 01:48 PM

The filaments are generally very difficult to see. A filter can help M1, but mainly at lower powers for an overall view. At powers over 150x in my 14 inch f/4.6 Newtonian, I will often not use my filters on M1, as much of its emission is quite broad-banded (synchrotron radiation). I generally use around 238x and do a lot of studying of the object, but even then, I only get hints of portions of two of the filaments using averted vision, with the rest of the nebula looking like an irregular tattered "W" shaped mass of dim light. The OIII filter will make M1 shrink in size a little, but the hints of the filaments may be a little easier to see. As for the Crab Pulsar, I have yet to see it in my 14 inch, although I have done it in a 20 inch f/5 Obsession. Good luck and clear skies to you.

#3 Special Ed

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Posted 16 November 2012 - 05:45 AM

Hi David,

Clear skies are forecast here this weekend, so I am going to take a high power look at M1. I going to see if I can borrow an OIII filter for the weekend, too (and put one on my Xmas list). :)

The pulsar is beyond the theoretical limits of my SCT (limiting magnitude 14.8) but I'm going to look for it anyway if conditions allow. The visitors center at the NRAO facility in Greenbank has an exhibit where you can dial in different pulsars and hear their radio signal. The neutron star at the center of the Crab is spinning 30 times per second so it sounds like a continuous brrrrrp! :cool:

Thanks for the feedback--always good to have the benefit of your experience.

#4 Feidb

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Posted 16 November 2012 - 09:53 PM

I've never had much luck with filters on M-1. Most of the time they've blotted the nebula out or severely diminished its features. My weakest LPR filters has done the best, or the least damage, I should say. As David also says, filters are not the best, but magnification, if conditions are favorable, is the better way to go for the filaments.

I usually see a distinct S shape, especially at lower powers from 70 - 102X. Above that, it starts to fill in more and I can start to see mottling within the center. I've seen hints of stranding at 220X and 390X on rare occasions when conditions were dry and stable but not often. I was actually looking for the pulsar and saw those features as a bonus. I thought I caught a fleeting glimpse of the pulsar once but couldn't say for sure it was real or just my active imagniation, so I didn't note it as a positive observation yet. It's like the central star in M-57, a real bear to spot visually unless conditions are just right.

#5 David Knisely

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Posted 17 November 2012 - 01:19 AM

Hi David,

Clear skies are forecast here this weekend, so I am going to take a high power look at M1. I going to see if I can borrow an OIII filter for the weekend, too (and put one on my Xmas list). :)

The pulsar is beyond the theoretical limits of my SCT (limiting magnitude 14.8) but I'm going to look for it anyway if conditions allow. The visitors center at the NRAO facility in Greenbank has an exhibit where you can dial in different pulsars and hear their radio signal. The neutron star at the center of the Crab is spinning 30 times per second so it sounds like a continuous brrrrrp! :cool:

Thanks for the feedback--always good to have the benefit of your experience.


Well, unless it is in less than great shape, your 14 inch should get you at least into the mid 15's if not a little fainter. Indeed, I have hit about 15.3 in my NexStar 9.25 inch SCT on a superb night, so these scopes will go a little fainter than some "theoretical" figures would indicate. With my 14 inch Newtonian, I may get to around 16.0 under superb conditions but not much fainter. Unfortunately, recent photometry indicates the Crab pulsar is around magnitude 16.6 (near the magnitude limit of an 18 inch aperture), and it sits in a mass of glowing nebulosity. That makes it even harder to see than its magnitude would indicate, so 14 inches is probably out of the question for picking that pulsar up. My very first view of the pulsar came in Behlen Observatory's 30 inch Classical Cassegrain when I was an undergraduate at the University of Nebraska, Lincoln. Since then, I did get one look at it and the faint star right next to it in a 20 inch Obsession, but it was pretty marginal even in that aperture. Clear skies to you.

#6 Special Ed

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Posted 17 November 2012 - 09:46 AM

It was very windy here last night so no go on the M1 pulsar. I'll try tonight, although I agree with David's conclusion that it's most likely beyond the reach of my C14.

In regard to what Feidb wrote, I have seen the central star in M57 with my C14 with direct vision at 391x. Seeing was 7/10 Pickering (Ant II), transparency was 5/6, the altitude of the Ring was 78°, and I needed all those conditions. :)

BTW, I forgot to mention in my original post about stumbling across Struve 742. After I centered M1 in the ep, I realized I needed brighter stars than I could see in the FOV to fine tune my focus. I moved the scope around slightly and came across a lovely pair of stars, one yellow and the other blue-white, that served my purpose well.

The next day when I was reading about M1 on the SEDS webpage, I discovered that there was a binary star, one yellow and the other white with a separation of 3.6", about a half degree east of M1--Struve 742. :cool:

#7 JayinUT

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Posted 17 November 2012 - 10:38 AM

Curious on the rotating shutter that Dan Gray used to blink the pulsar. Anyone have further information on that? I think it would be fun to do. Next new moon (clouds and more clouds in northern Utah right now) my friend Mat and I want to try for the pulsar with my 14 and his 16. I may try to talk my brother in a law in bringing the 20" up from southern Utah and give it a go in that also. All will depend on the weather and conditions.

#8 Feidb

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Posted 18 November 2012 - 09:13 PM

Mag. 16.6? David, you've shattered my hopes and dreams! LOL. The pulsar is not at the top of my list but I'd like to nail it for sure one day. Guess I'll wait until it increases in magnitude again, if it ever does? I still may give it a shot when I'm looking for filaments but I don't expect miracles. Maybe I'll score with hallucinations or "averted imagnination" as I've heard bandied around about certain eyepieces and optics (I think it was in a S&T article a while back?).

#9 George N

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Posted 21 November 2012 - 09:10 PM

I've never had much luck with filters on M-1. Most of the time they've blotted the nebula out or severely diminished its features. ......


That’s been my experience too. I’m wonder if an h-beta filter would help with seeing the filaments? I’ve not looked for the pulsar so I have know idea if I could see it. The next time I have M-1 in one of the 20-inchers I use, I’ll give it a try. Anyway….

M-1 made a nice sight in my 127mm triplet refractor a few nights ago. I've been lucky enough to have clear skies every night for the past week except for one night. I just left the ES127ED out on the front lawn, but alas, with snow coming, I'll have to bring it in soon.

#10 David Knisely

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Posted 21 November 2012 - 10:17 PM

I've never had much luck with filters on M-1. Most of the time they've blotted the nebula out or severely diminished its features. ......


That’s been my experience too. I’m wonder if an h-beta filter would help with seeing the filaments? I’ve not looked for the pulsar so I have know idea if I could see it. The next time I have M-1 in one of the 20-inchers I use, I’ll give it a try. Anyway….

M-1 made a nice sight in my 127mm triplet refractor a few nights ago. I've been lucky enough to have clear skies every night for the past week except for one night. I just left the ES127ED out on the front lawn, but alas, with snow coming, I'll have to bring it in soon.


Both a broad-band (LPR) filter and a good narrow-band nebula filter like the Lumicon UHC or Orion Ultrablock will help bring out M1 over no filter at all, although to get this to work well requires fairly low to moderate magnification (4x per inch of aperture to around 9x per inch of aperture). I find the narrow-band filter to be the best filter overall for the Crab, although again, it doesn't exactly work miracles on that particular object. It isn't as much of an improvement as is seen with some pure emission nebulae, but it is easily visible as long as you are properly dark adapted and use averted vision. The OIII filter tends to make M1 shrink just a little, becoming somewhat fainter and more round in shape, but with 10 inch and larger apertures, it can sometimes make two of the very faint filaments in the nebulae stand out a little more. The H-Beta filter is *not* recommended on M1, as it dims the object considerably more than the OIII filter does, making it rather hard to see. Clear skies to you.

#11 JayinUT

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Posted 21 November 2012 - 11:36 PM

Ed,

If your interested in SN from a science and historical perspective I recommend the following article from the Cornell Database:

The Historical Supernova by Green and Stephenson

It makes for some interesting reading.

Then there is:

The Supernova of 1054AD, the Armenian chronicle of Hetum, and Cronaca Rampona at this link.

Found at Cornell which is a 2 page paper but interesting since it is a primary document.

Finally there is my favorite:

Supernovae astrophysics from Middle Age documents found at this link.

Some fun reading for the weekend. . . ;)

#12 Special Ed

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Posted 22 November 2012 - 12:51 PM

Thanks for those links, Jay. They will be fun to read. I know that a lot of people have wondered why there were no reports of the 1054 SN from Europe (the Native Americans in the Southwest did record seeing it), but maybe one should say there are no surviving reports. This Armenian chronicle looks interesting. :)

I tried for the pulsar in M1 last night but no joy. Earlier the seeing had been 7-8/10 Pickering but deteriorated badly. I centered the nebula and cranked up the magnification to 391x. I used Struve 742 again to perfect the focus but that's when I realized the seeing was ~3-4/10 P.

I was waiting for Comet C/2012 K5 to rise anyway so I stayed with it from 4:00-5:00 AM local. Stars would pop in and out and my eyes would play tricks on me with the nebula from time to time. I know I was looking in the right place--just southeast of those two stars that flank the nebula (see this image) but I never saw the pulsar.

Transparency was quite good last night so if I can catch another night like that but with better seeing I'll try again






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