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Stellarium Comet magnitude

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#1 Emanuel

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Posted 08 July 2020 - 03:19 AM

Can someone tell me, how come i have comet Neowise on my Stellarium programme with a magnitude of 8.5, and guys are recording and observing the comet with a magnitude of 1,6? Is there a way to correct this?

Thanks



#2 DLuders

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Posted 08 July 2020 - 04:14 AM

I noticed the same thing with Stellarium, but what difference does it make?  The free program does a good job plotting the location of the comet, night after night.  There is no way of knowing whether or not the comet will split apart tomorrow (like the dud Comets Atlas and Swan).  


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#3 Waddensky

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Posted 08 July 2020 - 04:20 AM

The same question was asked in a thread on the comet. I've answered it here. There's not an easy way to correct it.


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#4 sg6

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Posted 08 July 2020 - 05:59 AM

Suppose it depends on when the data was made and so the then apparent brightness and the distance from Earth.

 

For a comet the magnitude varies, one may put out a lots of gass, water, dust another may not. Think about it Hale Bopp is still out there, but you cannot see it.

 

Stellarium likely quoted a magnitude at one time and/or one prediction. All you really want is to know where it is to go point a scope at it. After that it is simply "Can I see it or not?"

 

So as long as the positional data is correct go point a scope and have a look, forget the rest.


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#5 Emanuel

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Posted 08 July 2020 - 06:42 AM

Thanks for the answers guys.

I know that the most important on Stellarium is to know were it is and to simulate the field of view of a given camera and scope, so you can have an idea of what you can image.

My question was more related to answering someone, that made me this direct question of when you could see it, if it was naked eye visible, and at what time.

So, like i always do, i consulted Stellarium, and i told him everything correct, but i also told him to take some binoculars with him, otherwise he would not see it.

At the end, of course, its a easy naked eye target, if you know were to look.smile.gif


Edited by Emanuel, 08 July 2020 - 06:43 AM.


#6 spereira

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Posted 08 July 2020 - 07:03 AM

Moving to Astronomy Software & Computers ...

 

smp



#7 Alexander Wolf

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Posted 08 July 2020 - 12:44 PM

At the moment orbital elements from the link "Gideon van Buitenen: comets" in the Solar System Editor plugin give the correct absolute magnitude of the comet. So, you may update orbital elements through the SSE plugin (use "Overwrite existing object" option for guarantees) from this link and enjoy the realistic look of the comet.


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#8 Emanuel

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Posted 08 July 2020 - 02:01 PM

Done! Thanks Alexander, that did it!

I did update the comet files, but not with "Gideon van Buitenen: comets".

Now its ok, and with the correct magnitude laugh.gif



#9 gzotti

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Posted 08 July 2020 - 03:42 PM

I think we have this question now with any recent moderately interesting comet. The elements from MPC which you also may download with the SSE plugin include some guesses for absolute magnitude and slope factor, but for whatever reason these are not always reliable. You can always edit ssystem_minor.ini with a plaintext editor and repair those brightness factors.

Thanks Alexander for pointing out the difference with the other source.


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#10 ordep

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Posted 09 July 2020 - 03:12 PM

Can someone tell me, how come i have comet Neowise on my Stellarium programme with a magnitude of 8.5, and guys are recording and observing the comet with a magnitude of 1,6? Is there a way to correct this?

Thanks

I contacted the Minor Planet Centre today and asked them to update the data for this comet.  Should be correct now across all astro apps that use this data.  It shows Mag +1.5 in SkySafari Plus for example (after updating). Pedro


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#11 btschumy

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Posted 09 July 2020 - 03:17 PM

Excellent Pedro!  Thanks for getting them to fix that.


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