Asteroid 7335 1989 JA close approach – 4x size of Empire State Building…

[Dennis]

Finally, clear skies. After an unseasonable cloudy and wet autumn in SE Qld, the skies opened up last night, 27th May 2022 so I dusted off the gear and set up in the back garden.

It was like beginning all over again, it had been some 4 or 5 months since I last used the gear.

After re-learning how everything fits together, I slewed to Asteroid 7335 1989 JA and was pleasantly surprised at how bright it was at around magnitude 12.

I grabbed 59 x 30 sec exposures with the Tak Mewlon 210 F11.5, Tak x0.8 Reducer and QHY268M camera, at a fl=2130mm (calculated).

Asteroid data
Diameter = 1.8 km
Distance from Brisbane = 10.5 LD (Lunar Distances)
Speed = 13.1 Km/sec
Earth Distance (au): 0.03
Sun Distance (au): 1.03
RA Rate (arcsecs/sec): -0.793584
Dec Rate (arcsecs/sec): -0.366786
Constellation: Centaurus

Imaging Data
2022-May-27 (UT)
2022-05-27T12:54:00Z to 2022-05-27T13:38:00Z

Data for Full Size/Resolution image stack
Centre (RA, Dec): (171.626, -44.795)
Centre (RA, hms): 11h 26m 30.347s
Centre (Dec, dms): -44° 47' 41.080"
Size: 37.9 x 25.3 arcmin
Radius: 0.380 deg
Pixel scale: 0.364 arcsec/pixel
Orientation: Up is 90.6 degrees E of N

I have included a full frame shot re-sampled down to 1280 pixels wide and a full resolution 1280 pixel crop of a central region showing the trail.

The screen capture is from The Sky X Pro.

Cheers

Dennis

[multiweb (Marc)]

Good catch Dennis and real nice presentation.

[Dennis]

Thanks Marc, I appreciate your comments.

After a few months off due to family matters then poor weather, it was good to be under the night skies again, although much had been forgotten and I struggled with the set up.

In the end, all was good and importantly, I had a lot of fun.

In my 30 sec exposures (27th May) the asteroid trail was the hypotenuse of a triangle, with sides 30 pix and 50 pix, giving a trail length of approx. 58 pixels.

This works out at 1.93 pixels per second.

At an image scale of 0.364 arcsecs/pixel, the movement is then approx. 0.7 arcsec/pixel which ties in the value reported by The Sky X Pro.

Cheers

Dennis

EDIT:
Added an enlarged view of the 30 sec trail and some calculations to estimate the rate of movement.

[Averton (P and C)]