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  • Asteroid 439437 (2013 NK4) makes a close approach on April 15th!

Hello everyone. In the last few days, I noticed that an asteroid named 439437 (2013 NK4) will be making a close approach to Earth on the 15th at around 0.02 AU (or 8.5 lunar distances according to SpaceWeather) away.

Something else I noticed is that according to Stellarium, it will be around it's brightest a day later on the 16th, at around magnitude 12.45, which, as I found out recently, is within the Seestar S50's magnitude range.

While I plan on attempting to image the asteroid during it's close approach with my Seestar on the 15th and 16th, weather permitting and depending on whether the telescope arrives in time at my location, I would like to see other people's images they take of the asteroid as well, since it would be great to have some images to compare to and see if I did indeed capture the asteroid in my images.

One way to tell would be the trail it creates when doing longer exposures, and to see what this could end up looking like, I did some simulations in Stellarium with 10, 20, and 30s exposures.

I will be interested to find out how accurate these simulations I did are to the real thing when I try to image it. Also, between the 15th and 16th, the asteroid will be passing near some brighter stars, so that could help with trying to locate it.

HIP 77700 is one star that the asteroid will be passing close to from my location on the 16th at approximately 10:12 PM EST, according to Stellarium.

I also mention the asteroid in this astronomy video I did at around the 8:40 mark, for anyone else who might be trying to observe it from Connecticut, which is where I'm located.

I can't wait to see what kinds of images you'll share of the asteroid with your Seestars, and if I'm successfully able to take any images of it myself, I'll be posting them here as well!

Since tommorow is the day of the close approach, I thought I would share a quick guide on how to add the asteroid as a selectable object in Stellarium for anyone who is interested. I did this on the Windows version of Stellarium 24.1, so it may differ on other platforms or versions. But anyways, let's get started.

Step 1: Open the view window in Stellarium. It's labeled as the "Sky and viewing options window" in the toolbar, and by default it can also be opened by pressing the F4 key.

Step 2: In the view window, go over to the "SSO" tab, and click on the "Solar System Editor..." button.

Step 3: In the minor solar system objects window, go over to the "Solar System" tab, and then click on "Import orbital elements in MPC format..."

Step 4: In the import data window, make sure you have the "Asteroids" type selected, and then under the source selection, select the "MPCORB: near-Earth asteroids (NEAs)" bookmark.

Step 5: After doing that, click on the "Get orbital elements" button and wait while it downloads the latest objects in that database from the internet.

Step 6: Once it's done, a list of objects will show up. In the search box, type in "2013 nk4", and the asteroid should show up as the only object to choose from. Select it by clicking the box next to the asteroid's name so it turns into a checkmark, and then click on the "Add objects" button.

Step 7: If Stellarium was able to successfully add the object, if you go back to the search window and type in "2013 nk4" or "439437", the asteroid should show up now as a selectable object.

And that's it! Now you have the asteroid in Stellarium, meaning you can plan out observation sessions and see where it will be at different points of the night from your location.

The last image shows what the asteroid might look like through the Seestar S50's field of view with a custom telescope and sensor that I set up in Stellarium to match the S50's specifications.

    And here's a look at some reference stars 2013 NK4 will be passing near between April 15th and 18th. Which should help with trying to figure out where to point your Seestar in the sky to image the asteroid.

    #1 - April 15th, 2024 (Approximately 9:45 PM EST) - The asteroid will pass near Rasalgethi, a 5th magnitude double star in the constellation Hercules.

    #2 - April 16th, 2024 (Approximately 12:30 AM EST) - The asteroid will pass near 33 Oph (HD 154228), which is another 5th magnitude double star in the constellation Hercules.

    #3 - April 16th, 2024 (Approximately 11:45 PM EST) - The asteroid will pass close to 27 Ser (HD 141004), which is a 4th magnitude star in the constellation Serpens.

    #4 - April 18th, 2024 (Approximately 4:00 AM EST) - The asteroid will pass close to 109 Vir (HD 130109), which is a 3rd magnitude star in the constellation Virgo.

    And #5 - April 18th, 2024 (Approximately 11:00 PM EST) - The asteroid will pass near HIP 70282 (HD 125981), which is a 6th magnitude star in the constellation Virgo.

    Hopefully this will be useful in helping you locate the asteroid, and also please note that these screenshots were taken in Stellarium from my U.S. observing location in Connecticut, so depending on where you live, you might have to convert the times from Eastern Standard Time (EST) to your own time zone.

      Tompilot1 Thanks, glad you found it helpful! It's currently somewhat cloudy where I am, but I'm hoping the skies will clear up and I'll be able to get some images of it tonight.

      04/16/2024 Edit: So unfortunately, I wasn't able to get any images of the asteroid last night due to cloudy weather. However, it's expected to be mostly clear tonight from my location, so I'm going to try again.

        04/17/2024 UPDATE: So, it's been mostly clear tonight on the 16th into the early hours of the 17th, and I think I've finally managed to image the asteroid with my Seestar! I'll be sharing the images here soon, and maybe someone can help confirm if it was indeed the asteroid. And anyone else is free to share their own images of the asteroid here as well.

          JohnIIIAstronomy Here are some of the images I was able to capture of the asteroid. Due to how fast it is moving, it appears as a streak in the longer exposure images.

            Fantastic work! Unfortunately here, Rasalgethi was just on the horizon at 9:45 last night. I am far enough west in the time zone I just didn't have a clear shot to the East. These NEOs just have to schedule themselves for better viewing!

            Very nice images. I managed to (visually) see it with my 12" dob on Monday night.

            JohnIIIAstronomy On April 21st, I managed to image the asteroid again. Although now it's getting fainter as it's moving farther away from Earth. From the 17th to the 21st, it's already dropped in brightness by about 1 magnitude from approximately 12.44 to 13.32 according to Stellarium. Which is still within the Seestar's magnitude range, although not for much longer.

            So as I've said before, please share your images here if you've been able to take any! I might try and image it again tommorow, although with the asteroid being near the full moon on that night, that might make it somewhat difficult to do.

              10 days later

              JohnIIIAstronomy That is very neat, thanks for sharing. All you have to do now is get the RA/Dec coordinates from Stelarium, make sure the object is visible from your location and time you want, then enter the RA/Dec coordinates and time of capture in the SeeStart app and... oh wait, SeeStar doesn't let you do that!

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