#interstellar comet

Finally, conditions are right to see interstellar comet 3I/ATLAS from my location. Here is a small GIF taken in the brief moments between when it emerged from behind the treetops and when the dawnlight became too overwhelming for my sensor. In just those 4 minutes, its rapid motion is readily apparent. As is the fuzzy coma made from outgassing icy material from its ancient surface.

This is a picture of 3I/atlas (also known as C/2025 N1 (ATLAS), the third interstellar comet that has ever been detected. We know that it is an interstellar object due to its speed and trajectory: it's too fast to be gravitationally bound to the sun, and its trajectory is very hyperbolic.

It's currently at about 280 000 km from Earth (about 1.8 astronomical units); its closest approach was on the 19th of December with a distance of about 270 000 km. Since it's a relatively faint comet (current magnitude of 12.5), it's not visible with the naked eye and would require a rather large telescope and a very dark sky to be observed by the eye.

With my instrument I was able to take about 1h of photos (using LRGB filters). Despite the fact that the photo is not of the best quality, which was to be expected with a faint comet.

When imaging such an object, the duration of each photo has to be rather short (2 minutes in my case) since the comet would otherwise be blurry. This is due to its movement being noticeably faster than the background stars (see below in two images taken 6 minutes apart from one another)

In addition, this movement and the changes that can occur in a comet's activity will generally prevent you from combining images taken over a long period.

Both of those limitations, in addition to how faint it is, will prevent me from getting a better image. The weird blotchy smudges in the background of the main image correspond to stars that were near the comet. I tried to minimise their visibility since they can't be stacked at the same time as the comet, making them appear as long smudges in the image.

Additional information on the comet, as well as its up to date position and magnitude: https://theskylive.com/c2025n1-info https://science.nasa.gov/solar-system/comets/3i-atlas/

Some Of My Favorite Images

This is not really too much of a surprise, however having the opportunity to validate your theories from an interstellar source is a fantastic opportunity. 

Water would be expected to be fairly ubiquitous in space, afterall, Hydrogen makes up most of the elemental pie, and oxygen being before Iron in the Periodic Table is produced in large quantities in the life of a star, that they both end up paired together shouldn’t surprise anybody. 

Had a much better imaging opportunity for the infamous interstellar comet 3I/ATLAS the other night and assembled this color composite. Just two minutes per channel, to avoid significant trailing.