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Comet C / 2019 Y4 Atlas

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#1 FRANC LILL

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Posted 16 March 2020 - 08:55 AM

Comet C / 2019 Y4 Atlas

 

This comet shows an increase of brightness, from Mag15 to 17 at the end of February it has just been recorded at Mag 13.4 by LESIA observers. It will pass as closest to the sun at the end of May. May be the comet of the year, according to some previsionists? At time of observing, it was located in UMa at 3° south of galaxy M81.

 

The observation is interesting, the bright nucleus is not centered and it seems to show a plume tail.

 

Live observation of March 14 with help of SiOnyx Aurora in afocal on Dobson 400, Celestron 25mm eyepiece, good conditions of seeing and transparency. Drawing on black Canson with dry and fatty pastel pencils. Redrawing of the stars with photoshop.

 

 

Clear sky,

Francis

 

 

C 2019 Y4.jpg


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#2 Mike Lynch

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Posted 16 March 2020 - 10:37 AM

Francis,

 

    Excellent sketch of this brightening comet! Looking forward to seeing it in my telescopes...

 

 

Thanks,

 

Mike Lynch

Frankfort KY  USA


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#3 frank5817

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Posted 16 March 2020 - 12:41 PM

Francis,

 

Excellent sketch.

 

Thank you for posting here.

 

Frank :)



#4 niteskystargazer

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Posted 16 March 2020 - 02:31 PM

Francis,

 

Nice sketch of  Comet C / 2019 Y4 Atlas smile.gif .

 

CS,KLU,

 

thanx.gif ,

 

Tom



#5 Heidescoper

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Posted 17 March 2020 - 02:11 AM

Hi all,

 

Francis:

which telescope did You used for this detailed sketch? 

 

CS

Christian



#6 FRANC LILL

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Posted 17 March 2020 - 02:39 AM

Thank's a lot to Mike, Frank, Tom and to all the likers!

 

Hello Christian, all information is written above the sketch...

 

 

...

Live observation of March 14 with help of SiOnyx Aurora in afocal on Dobson 400, Celestron 25mm eyepiece, good conditions of seeing and transparency. Drawing on black Canson with dry and fatty pastel pencils. Redrawing of the stars with photoshop.

 

...

 

The scope is a truss dobsonian of german factory, french mirror polisher.


Edited by FRANC LILL, 17 March 2020 - 02:44 AM.


#7 Uwe Pilz

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Posted 17 March 2020 - 05:29 AM

The most interesting comet at the time. For six weeks, it had an activity level of n=17, instead of n=6 (what would be normal). It is expected that the activity decreases in the next way and comes to a normal level. Nevertheless, it could be we get a comet of negative magnitude in may. I append a prediction which is the best I can get at the moment. It assumes, that the comet comes to a normal activity at 1.5 AE like Halley.

Attached Thumbnails

  • 200316_19y4.jpg

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#8 FRANC LILL

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Posted 17 March 2020 - 09:05 AM

The most interesting comet at the time. For six weeks, it had an activity level of n=17, instead of n=6 (what would be normal). It is expected that the activity decreases in the next way and comes to a normal level. Nevertheless, it could be we get a comet of negative magnitude in may. I append a prediction which is the best I can get at the moment. It assumes, that the comet comes to a normal activity at 1.5 AE like Halley.

Hello Uwe,

Thanks a lot for your instructive comments.

Would you please tell me more about the activity level , measurement and significance.

Thanks in advance.

 

Clear skies,

Francis



#9 sunnyday

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Posted 17 March 2020 - 09:13 AM

very well done on your part, I like your sketch.


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#10 Uwe Pilz

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Posted 17 March 2020 - 11:39 AM

Dear Francis,

 

all bodies get brighter if they come closer to the sun. For comets there are always two ways to get brightness:

1) The light source gets brighter. This counts for asteroids too. The dependency is quadratic, half the distance menas 4x the brightness. For comets, only the exponent is used to describe the brightness evolution in comparison of the solar distance. The value is called activity level or heliocentric brightness variation and described by the letter n. Sometimes the 2.5-fold of n i used and called H. I use n.

This first part is n1=2 because of the quadratic (2) dependency.

2) If the comet gets more energy from the sun its come gets larger. Double the energy means double the gas evolution. We have to think about the processes which destroy the outer parts of the coma, but in principle the gas production / coma size is proportional to the energy level, and therewith quadratic too. In reality, this n2   is slightly less than 2 (around 1.5), but this requires an extra discussion.

 

For dynamic new comets which are the first time close to the sun, that's it, and n=n1+n2=4 (or around 3,5 if we look closer).

 

For dynamic old comets we have a third mechanism

 

3) Dynamic old comets are covered by some type of crust which is rich of dust but poor of water, Considerable of gas production requires cracks and cavities in that crust. These are produced by the energy level to. And again, we may conclude that effect=cause and the amount of cracks increases with the same quadratic law, which leads to n2=2. There is a limit in this case: If all of the surface is active or the sublimation cooling is large, the destruction of the crust stops. Then n3 gets around 0.

For dynamic old comets we have first n=n1+n2+n3=6 (5.5) and later n=n1+n2=4 (3.5).

 

In this case we have n3=13 (!). This is a huge increase of active surface. I did not saw such an amount ago. All the comets I saw had n<10.

 

added: for comparision I added a heliocentric light curve / prediction curve. Solar distance is given in form of it's logarithm here. I added some real values in red for better understanding. Sorry: The jump slightly up and down smile.gif

Attached Thumbnails

  • 19y4.jpg

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#11 Mike Lynch

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Posted 17 March 2020 - 11:40 AM

Francis, there are several pages on the net about comets, their paths in the sky, and predictions of their brightness.

 

I like this one, maintained by Seitchi Yoshida: http://www.aerith.ne...9Y4/2019Y4.html

 

The link goes straight to his Comet Atlas sub-page. It probably needs updating by now!

 

Mike


Edited by Mike Lynch, 17 March 2020 - 11:40 AM.

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#12 Aquarellia

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Posted 19 March 2020 - 05:25 AM

That's a nice post!!!

A very great sketch Francis and thank you to Uwe for those precise explanations.

 

So why not continuing to post our view of this comet here ?

My first sketch was posted here : https://www.cloudyni...mag/?p=10037724

 

And the one of yesterday evening is here:

 

c2019Y4-20200318_l.jpg

 

The diameter used was 250mm only but with two different focals (f10 and f15) so I used a lot of different magnifications to make this sketch, such as 60x, 95x, 140x, 160x, and 300x.  The SWAN filter responds very well at the eyepiece.  I was able to detect a sort of small linear tail in the middle of the coma, not sure about the direction, but that is an interesting feature to follow !

 

Clear and virus-free sky to you all !

Michel


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#13 FRANC LILL

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Posted 19 March 2020 - 08:46 AM

Thank you very much Michel for your contribution to the post! Very nice to do so!

 

I also got a new observation yesterday, so we can compare smile.gif

 

The morphology is confirmed, the nucleus is not centred, the queue is more sharp. The halo is smaller (humid and less transparent sky)

Live observation of March 18 with help of SiOnyx Aurora in afocal mount on a 16" dobsonian, Celestron 25mm eyepiece, good conditions of seeing and poor transparency. Drawing on black Canson with dry and wax pastel pencils. Redrawing of the stars with photoshop.

 

Enjoy the sky!

Francis

 

200318-C2019 Y4.jpg


Edited by FRANC LILL, 20 March 2020 - 04:23 AM.

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#14 astronz59

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Posted 20 March 2020 - 12:54 AM

Impressive sketch,Francis! Did make a magnitude estimate? waytogo.gif


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#15 FRANC LILL

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Posted 20 March 2020 - 04:13 AM

Hi astroNZ and thank you for appreciation!

 

Impressive sketch,Francis! Did make a magnitude estimate? waytogo.gif

Sorry, I have no experience in mag estimation. I just noticed that the pseudo nucleus was less than 12.51, more than 9.13, closer to 12.51.


Edited by FRANC LILL, 20 March 2020 - 04:24 AM.



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