Ne Interstellar Comet 3I/ATLAS

[Dennis]

Thanks Dennis,

Those are some more excellent images. What does it look like when the comet occults the star?

I used to work with an optical engineer named Dan Grieser (the MP (10482) Dangrieser is named for him) who wanted to record an absorption spectrum of a comet as it occulted a bright star. Unfortunately we were never able to get a comet to cooperate. With today's equipment I think he would have been more successful.

Phil S.

Hi Phil
 
Thank you for sharing that story about your colleague Dan Grieser, I only wish he could have been in my back garden at the time with his spectrometer.
 
The comet occults the star on Frame 0027 in my 0001 to 0030 series.
 
For the star, SkyTools 4 writes:
 
J154050.7-145951
Single Star
R.A.  15h40m50.7s Dec. -14°59'51" (2000) in Libra
Magnitude: 15.72
Apparent Data for 2025 Aug 27  GMT+10 at Back Garden:
Apparent RA:  15h42m17.2s, Apparent Dec: -15°04'50"
Mean extincted magnitude: 16.3
 
I have included the following: 

• 1920x1200 crops of the comet aligned on the stars (Sidereal Rate) and aligned on the comet (Tracked).
  
• Tycho Tracker image file aligned on the stars, up sampled by x2 cropped 1600x1200 (Sidereal Rate) with the comet trailed.
  
• A screen copy of SkyTools 4 for the date/time of the transit.
  

 
Dennis.

1920x1200 crop Aligned on stars (Sidereal).
   

1920x1200 crop Aligned on comet (Tracked).
   

1600x1200 crop up sampled by x2  Aligned on stars (Sidereal).
   

Screen copy of SkyTools 4 showing the transit.