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An Observation of M1, the Crab Nebula

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#1 Rustler46

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Posted 27 January 2021 - 01:24 AM

Recently I downsized from my C-11 to a C-8. The C-8 is much easier to mount upon my Losmandy G11/G-1 mount. This difference is 15 lbs. versus 35 lbs. to heft up into the dovetail clamp. So the C-11 is in temporary retirement. Now my old Celestron Super C8 Plus has been with me around 40 years, and has proved to be very good optically.

 

So while viewing some doubles and open clusters in Taurus (Sky and Telescope, January 2021) I ended the night with an observation of M1, the Crab Nebula. Here's what I recorded in my Excel Astronomical Observations spreadsheet.

 

  • January 18, 2021, Ocean Observatory, Coos Bay, Oregon - using S&T Jan. 2021 to explore Taurus, seeing is "lively", just before 1st quarter Moon
  • Celestron-8, 85X (f/10 with TV Panoptic 24 mm)
  • SN Remnant, Crab Nebula - shows best with averted vision, no discernable edge, it just fades away to background sky, definitely oval, one of the long edges of the oval is flatter compared to the other, @ 185X (TV Nagler 11 mm T6) the sky is definitely darker, sometimes I glimpse a star just outside the nebula, averted vision helps with that, with OIII filter @ 185X I can't see anything at all except for 1 star at FOV edge, so back at 85X with OIII filter I like the view much better, sky is darkened quite nicely, AV still needed, there are a number of stars that show up better with the filter, the nebula looks vaguely "stringy, loopy", this is prejudiced by my knowing what the nebula looks like photographically - that "ropiness", this would benefit from a lot more aperture, sometimes I see within the nebula some little bits sparkling, with filter the glow is a little bit less soft, it's less amorphous, it has this ropey texture to it, just knowing what this object really is enhances my appreciation for the view, in there is that neutron star whipping around at 30 times per second, and this is what is seen now from what Chinese astronomers witnessed in the year 1054

Here is my best photo of the Crab Nebula.

 

M1 - Crab Nebula.jpg

10-inch reflector f/5.5 w/ ZWO ASI290MC video camera, best 75 of 80 frames (45-seconds each), Autostakkert! 2; no UV/IR cut filter

 

Here's the rig used for the Crab Nebula Photo.

Screen Shot 2021-01-26 at 10.23.14 PM.png

 

Russ


Edited by Rustler46, 27 January 2021 - 01:42 AM.

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#2 Michaelmas

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Posted 27 January 2021 - 05:39 AM

Great job Russ. That photo is truly amazing!  I rarely post on any of the forums I’m a member of. In fact, this is my first post on Cloudy Nights. But I’d like to comment.

 

My 12” Meade SCT gets lots of use. I have a home observatory. However I too have recently been using my 40 year old Celestron 8” SCT and I must say I’m also surprised how sharp the images are in this old scope! It’s so easy to use. I’m beginning to wonder if the optics on some of these older scopes might be a bit better quality than the newer ones today. I think my C8 was made in Japan.

 

I have also recently been really enjoying the views on my Apogee RA-88 and 25 x 100 Zhumell binoculars. Each of these tools provide views the others cannot. So now at 62 I’m realizing that bigger is not always better. By using all these tools we begin to realize how much we’re missing and how important they all are to our study of our Universe.

Thanks again Russ. Very impressive!

 

Clear skies, Michael



#3 Rustler46

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Posted 27 January 2021 - 04:32 PM

Thanks for the kind comments, Michael, and welcome to the group. Yes, I've only recently come to realize the truth of what you said - bigger is not always better. The best view I've ever had of Milky Way star clouds was with my new 20x65 Oberwerk Deluxe binoculars. The view of M24 and nearby dark nebulae was awe-inspiring last summer.

 

Best Regards,

Russ


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#4 Sheol

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Posted 28 January 2021 - 07:31 PM

                          Very nicely done. Congrats! Lots of detail in the darn thing you probably couldn't get visually with the 10 inch.

 

                      Clear Skies,

                              Matt.



#5 Rustler46

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Posted 29 January 2021 - 02:36 AM

                          Very nicely done. Congrats! Lots of detail in the darn thing you probably couldn't get visually with the 10 inch.

 

                      Clear Skies,

                              Matt.

Thanks for your kind comment, Matt. I have come to believe that observer experience and training one's eye/brain system to really see what is there - those play a big part. My right eye has benefitted from 59 years of visual observing practice. Some have stated that a goodly amount of imagination helps to ferret out difficult details. For the Crab, I really wanted to see more than just an oval glow. Also the excellent optics of my old C-8 has a bearing on seeing faint stars embedded in the nebula or sky background. I haven't checked collimation recently on the C-8. But it holds its collimation much better than my C-11. But less than perfect collimation makes the central peak of the star image more spread out, less likely rise above background levels.

 

Warm Regards & CS,

Russ



#6 orionic

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Posted 29 January 2021 - 04:55 AM

I took special interest in your description, Russ.  You've got lots of nice detail (both verbally and photographically).  The Crab Nebula is one that I have tried and failed several times to view in a 4.5" reflector and 15x70 binos (Bortle 5-6).  I'm also a real fan of crabs (I have had a pet hermit crab for quite a few years).  When I finally got EAA working last spring, it was Galaxy Season so either M1 was too low, or it had too much competition.  Now it's in the teens at night, but maybe in the next few weekends I'll find a chance.  If I get a view anything close to your ropey image, it will be a thrill!  I was delighted with how EAA captured the Eastern Veil and Iris nebulas last summer, so I'm optimistic...


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#7 Rustler46

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Posted 29 January 2021 - 04:11 PM

I took special interest in your description, Russ.  You've got lots of nice detail (both verbally and photographically).  The Crab Nebula is one that I have tried and failed several times to view in a 4.5" reflector and 15x70 binos (Bortle 5-6).  I'm also a real fan of crabs (I have had a pet hermit crab for quite a few years).  When I finally got EAA working last spring, it was Galaxy Season so either M1 was too low, or it had too much competition.  Now it's in the teens at night, but maybe in the next few weekends I'll find a chance.  If I get a view anything close to your ropey image, it will be a thrill!  I was delighted with how EAA captured the Eastern Veil and Iris nebulas last summer, so I'm optimistic...

The M1 observation that was shared is what was recorded on a small voice recorder, that I use at the eyepiece. The transcript shows how what is seen develops over the period of time I observe. Seeing conditions change along with my own dark adaptation. Also my own scrutiny of details reveals additional features not previously discerned. An example of that is where I saw for the first time that the oval glow of the Crab Nebula was flattened on one side. This was verified when I later examined the photo that had been captured at an earlier time. The photo also shows the little double star within the nebula. One of the two stars is the Crab Nebula neutron star.

 

I highly recommend use of a voice recorder to capture observations. For perhaps 35 years I used a written record that was by ball point pen on sometimes dew dampened paper. This eventually filled a small bound composition book and part of a second one. Then these observations were transcribed into an Excel spreadsheet, which is now used exclusively to record my observations. I suppose I should print a hard copy of the spreadsheet as a backup if the electronic record goes up in smoke.

 

I too am quite excited to be using EAA. My present setup is an old film era Mamiya 55mm f/1.4 @ f/2.8. This is coupled with a ZWO ASI290MC. That sensor and focal length results in a 5.8° x 3.3° FOV. I'm also waiting for a clear night. But the West coast is being hosed by an atmospheric river, particularly California. But my skies on the Oregon coast have been cloudy for some nights, and looks to be so for the foreseeable future. In the meantime there's Cloudy Nights.

 

Russ

 

Observing Notebook-02446.jpg

The Old and New record of observations

 

Notice how the voice recorder shows there are 9 separate records (audio recordings) for each of the 9 observations of that night. The first record might just be recording date, location and observing conditions. Then successive records are for different objects observed that night. The challenge is being able to record (into the spreadsheet) a lot of verbal descriptions. That takes time and inclination to transcribe. Here is a screenshot of the spreadsheet record for the night of the Crab Nebula observation.

 

Screen Shot 2021-01-29 at 12.54.30 PM.png

 

The red triangles on some cells are notes attached to that cell. The far right side shows the beginning of the verbal description of what was observed and recorded in audio form. Even though this resides in a single spreadsheet cell, it can amount to a lengthy paragraph. What I particularly appreciate about a spreadsheet record is that it can be sorted by chronological date as seen above. But it can also be sorted by object - that is all the observations of M1 over all the dates observed. This is a powerful tool to show how what is observed has varied with aperture, observing conditions and observer skill.



#8 Rustler46

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Posted 29 January 2021 - 04:30 PM

The red triangles on some cells are notes attached to that cell. The far right side shows the beginning of the verbal description of what was observed and recorded in audio form. Even though this resides in a single spreadsheet cell, it can amount to a lengthy paragraph. What I particularly appreciate about a spreadsheet record is that it can be sorted by chronological date as seen above. But it can also be sorted by object - that is all the observations of M1 over all the dates observed. This is a powerful tool to show how what is observed has varied with aperture, observing conditions and observer skill.

Here's a screen-shot of the spreadsheet sorted by object. There were 20 observations of M1 from 1966 to the present with apertures from 5-inch to 14-inch.

 

Screen Shot 2021-01-29 at 1.22.15 PM.png


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#9 Sheol

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Posted 29 January 2021 - 07:27 PM

                                 All I got in my 8 inch was an oval blur with a notch in it. I remember posting it on here some years ago. LOL

 

                      Clear Skies,

                           Matt.




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