Category: Asteroids

In the early morning of December 12th, just after midnight, asteroid 22 Kalliope was in the southeast sky, well positioned for imaging from my backyard. 22 Kalliope was inside the light dome of east Oklahoma City, but the seeing (i.e., the steadiness of the atmosphere) was good. Some of the images I captured of this minor planet follow. All were captured using a Meade SN-8 (203mm f/4) telescope and ZWO ASI224MC camera with UV/IR cut filter.

Wide View

Asteroid 22 Kalliope on 12 December 2021, at 06:01:39 and 06:26:49 UT. Field of view: 20×15 arcminutes. North is up. East is left. [1]
During this session, 22 Kalliope was traveling through the constellation Gemini, showing up well against this field of mostly fainter background stars.  I measured its magnitude at 10.5.  The Minor Planet Center predicted magnitude 10.4, and NASA’s JPL Horizons System predicted magnitude 10.37.

Wide View Animation

Asteroid 22 Kalliope moves through the field of view against a background of far distant stars over a 25 minute period. Field of view: 20×15 arcminutes. North is up. East is left [2]
This wide view animation gives a sense of 22 Kalliope’s motion across the sky. The animation is a 6-image time lapse sequence covering 25 minutes. On this night, 22 Kalliope was moving across the sky at the rate of 0.54 arcseconds per minute. 

Zoomed In Animation

This is a cropped and enlarged portion of the wide view animation above. It gives a closer look at 22 Kalliope. North is up. East is left.

Asteroid 22 Kalliope is main belt asteroid with a diameter estimated as 168 km (104 miles). As a main belt asteroid, 22 Kalliope orbits the Sun between the orbits of Mars and Jupiter. Its orbital period is 4.96 years. At the time these images were captured, 22 Kalliope was 1.728 AU (258,505,100 km/160,627,600 miles) from Earth.

22 Kalliope doesn’t move through space alone. It is accompanied by a satellite asteroid named Linus. Linus is a good-sized asteroid in its own right with a diameter of 28 km (17 miles).  Linus orbits 22 Kalliope at a distance of  1100 km (684 miles) with an orbital period of 3.6 days.[3] 

Notes:

1. December 12, 2021, 06:01:39 and 06:26:49 UT. Stack of two images, each a stack of 10 frames at 30 seconds each (total 300s). Telescope: Meade SN-8 (203mm f/4). Camera: ZWO ASI224MC with UV/IR cut filter. Mount: Celestron CGEM.

2. December 12, 2021,06:01:39-06:26:49 UT. 25-minute, 6-image, animation sequence. Each image a stack of 10 frames at 30 seconds each (total 300 seconds). Telescope: Meade SN-8 (203mm f/4). Camera: ZWO ASI224MC with UV/IR cut filter. Mount: Celestron CGEM.

3.  See, JPL Small-Body Database: 22 Kalliope, https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=22

 

During the night of December 11th and into the early morning of December 12th, the asteroid 32 Pomona was positioned high in the east-southeast sky well above the trees and roofline that block the view from my backyard. Although 32 Pomona was still inside the light dome of east Oklahoma City, the seeing (i.e., the steadiness of the atmosphere) was pretty good. Here are some images I captured of this minor planet during the observing session. All images were captured using a Meade SN-8 (203mm f/4) telescope and ZWO ASI224MC camera.

The Setting

Image Credit: Stellarium.

On this night, 32 Pomona was near the ecliptic, slowly moving across the sky in the constellation Gemini beneath the feet of the twins. Comet 67P/Churyumov-Gerasimenko and Asteroid 22 Kalliope were nearby. I also grabbed some images of them. I will post those images in separate posts.

Wide View

Asteroid 32 Pomona, December 12, 04:16:05 UT.  32 Pomona is the star-like object between the blue tick marks. The only object brighter than 32 Pomona in this field is the star TYC 1328-766-1 at magnitude 11.12. TYC 1328-766-1 is inside the red circle. The inset shows a cropped an enlarged area giving a closer view of 32 Pomona. Field of view: 20×15 arcminutes. North is up. East is left.[1]
In wide view, 32 Pomona shows up prominently against a field of mostly fainter background stars.  I measured its magnitude at 11.35.  The Minor Planet Center predicted magnitude 11.4 and NASA’s JPL Horizons System predicted magnitude 11.38.

Wide View Animation

Asteroid 32 Pomona moves through the field of view against a background of far distant stars over a 36 minute period. Field of view: 20×15 arcminutes. North is up. east is left [2]
This wide view animation gives some sense of 32 Pomona’s motion across the sky. The animation is a 9-image time lapse sequence covering 36 minutes. On this night, 32 Pomona was moving across the sky at the rate of 0.55 arcseconds per minute.  At this rate, the asteroid would take one hour to move 1/100th the width of your pinky finger held at arms length. Or, at the scale of this image, the asteroid was moving approximately one-half a pixel per minute.

Zoomed In Animation

This is a cropped and enlarged portion of the wide view animation above. It gives a closer look at 32 Pomona. Field of view: 8.6×6.3 arcminutes. North is up. East is left.

Asteroid 32 Pomona is a rocky main belt asteroid with a diameter estimated as 81 kilometers (50 miles). As a main belt asteroid, 32 Pomona orbits the Sun between the orbits of Mars and Jupiter. Its orbital period is 4.16 years. At the time these images were captured, 32 Pomona was 1.683 AU (156,444,600 miles/ 251,773,200 km) from Earth.

Notes:
1. December 12, 2021, 04:16:05 UT. Stack of 8 frames at 30 seconds each (total 240s). Telescope: Meade SN-8 (203mm f/4). Camera: ZWO ASI224MC with UV/IR cut filter.  Mount: Celestron CGEM.

2. December 12, 2021, 04:04:00-04:36:13 UT. 36-minute, 9-image, animation sequence. Each image a stack of 8 frames at 30 seconds each (total 240 seconds).  Telescope: Meade SN-8 (203mm f/4). Camera: ZWO ASI224MC with UV/IR cut filter. Mount: Celestron CGEM.

I caught asteroid (623) Chimaera using the internet accessible 0.61 m (24-inch) Sierra Stars Observatory telescope located in Alpine County California.

(623) Chimaera is  near the center of the image moving toward the upper left.

This animation was made from three 60 second images taken on January 26, 2011 at 06:16, 07:03, and 07:15 UT.  The asteroid’s motion does not appear to be uniform because the images were not taken at equally spaced intervals.  The field of view for this image is approximately 20 arc minutes square, or a little bit less than the diameter of the full moon (the moon is approximately 30 arc minutes in diameter).

At the time these images were taken, (623) Chimaera was at magnitude 13.9 and was approximately 2.057 astronomical units or 307,722,818 km from Earth.