Asteroid 32 Pomona 12-12-21

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

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.

Asteroid 32 Pomona 12-12-21

Leave a Reply