Close Approach of 2023 FM

[PMSchu]

CNEOS predicts that the recently discovered NEO 2023 FM will make a close approch on 2023-Apr-06 13:08±00:02 UT at a distance of 0.02009 AU moving at 15.81 km/sec, H=21.7 magnitude, diameter 120 m - 270 m, 'Rarity'=1, Condition Code=8, 13 day observation arc, Earth MOID 0.0198953 AU.
This object was first observed at ATLAS Chile, Rio Hurtado on 2023-03-16.

Using MPC's elements for 2023 Mar 30 0000 UT, ST4v predicts that 2023 FM will reach peak brightness of 14.8 magnitude on April 5 ~0300 EDT at 0.02 AU distance moving through Bootes at 48.4"/min. This MP is predicted to be brighter than 15.5 magnitude from April 2 - 6, so there are several nights for observation despite the interfering full moon.

Here's the Object Info dialog for this NEO:     

Since the Condition Code=8, the orbit should be refined as the time of close approach nears.

Good hunting,

Phil S.

[bigmasterdrago]

Thanks. That rock remains ~14.8 for a ridiculous period. From my perspective from 2023-Apr-04 11:00 to 2023-Apr-05 01:00 in either daylight or heavy moonlight.

[PMSchu]

The orbit for 2023 FM has been refined. As of 2023 Apr 3, CNEOS now predicts that the close approach will occur on 2023-Apr-06 13:09±<00:01 UT at a distance of 0.02007 AU moving at V Relative = 15.79 km/sec. H=21.7 magnitude, diameter 120 m - 270 m, 'Rarity'=1 and Condition Code=7 with an 18 day observation arc. The Earth MOID = 0.019936 AU.

Using MPC's elements for 2023 April 3 0000 UT, ST4v predicts that this NEO will reach a broad maximum brightness of 14.8 magnitude on the night of April 4/5 when it will be moving through Coma Berenices into Bootes at ~50"/min. The close approach is predicted to occur (to the nearest hour) on 2023 Apr 6 at 1100 EDT when the NEO will be 15.4 magnitude moving through Bootes at 65"/min in daylight as not seen from Columbus, Ohio. The full moon will interfere with observations, but not as much as with 2004 GA.

Here's the Object Info dialog for 2023 FM:     

Good Hunting,

Phil S.

[Dennis]

Thanks Phil and BMD, we have a "mostly clear" forecast for Brisbane tonight, Tues 4th April 9:00pm AEST (UT+10) so I'll  give this a go and see if I can redeem myself after stumbling efforts on 2023 FH7.

Cheers

Dennis

[Dennis]

The weather turned out better than the forecast, so I set up for 2023 FM.

With the almost full Moon nearby, the relatively low altitude and shooting into the Brisbane light dome 2023 FM appeared quite faint at around mag. 14.8 initially, making it a little challenging to recognise. Adding to that, a thin layer of fog crept in which I only noticed when my camera fogged up, which at -10 Deg C, precipitated ice crystals inside the sensor chamber, so I had to raise the temp. to +5 Deg C to melt this. Unfortunately, I ended up with a lot of in-camera image artefacts from these, that morphed over time as the temp changed, so Flat Fields could not fix this.

However, Integrating the stack of 25 (out of 27) frames using the STD DEV Method made these go away, albeit producing a very contrasty image as all the darker pixel values tended to clump together.

I have attached a Full res 1600x1600 crop and the Full Frame, down sampled to 1600x1069 to show the position od 2023 FM in the Frame, right where ST4 predicted it would be.

The following data is a Copy/Paste from the FITs Header from the QHY268M Bin 2x2 for Frame 01 and Frame 027.

The locked-on Tracking on 2023 FM series spanned the local Brisbane times:
Start Time: 10:42 pm
End Time: 10:56 pm
Gap 01: 10:46 pm
Gap 02: 10:51 pm

NEO_2023FM_Light_2x2_L_30.000secs00000001.fit
OBJCTRA      '13 14 34.998'      / SBIGFITSEXT The right ascension of the center o
OBJCTDEC      '+12 46 23.84'      / SBIGFITSEXT The declination of the center of th
LOCALTIM      '4/04/2023 10:41:51.200 PM STD' / Local time at exposure start
UTC: 2023-04-04T12-42-50Z
LST          '+11 44 23.94'      / Local sidereal time
2023 FM Coordinates.
RA (Topocentric): 13h 15m 40.8s
Dec (Topocentric): +12° 39' 06"
RA (2000.0): 13h 14m 30.8s
Dec (2000.0): +12° 46' 34"
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
NEO_2023FM_Light_2x2_L_30.000secs00000027.fit
OBJCTRA      '13 14 55.080'      / SBIGFITSEXT The right ascension of the center o
OBJCTDEC      '+12 52 53.66'      / SBIGFITSEXT The declination of the center of th
LOCALTIM      '4/04/2023 10:55:58.380 PM STD' / Local time at exposure start
UTC: 2023-04-04T12-55-58Z
LST          '+11 58 33.45'      / Local sidereal time
2023 FM Coordinates.
RA (Topocentric): 13h 16m 00.7s
Dec (Topocentric): +12° 45' 51"
RA (2000.0): 13h 14m 50.7s
Dec (2000.0): +12° 53' 19"

Cheers

Dennis

   

   

[Dennis]

This is an example of what fog/moisture can do when it leads to ice forming in the camera sensor chamber...

2023 FM is passing through this field and I will try to see if I can tease it out tomorrow.

Sometimes, it is just better to use the Mk I eyeball.

Cheers

Dennis

EDIT:
This second (composite) image is a blend of A MEAN and a MAX stacked image where I have used a Mask to blend in the trail that was just discernible on the MAX image but was rejected by the Integration process of the MEAN image.

This has made the brightness variations non-linear.

   

   

[PMSchu]

Dennis,

Your tracking on 2023 FM looks perfect! Moisture is a real problem, especially for a cooled camera, but you seem to have extracted good data despite the challenges.

I hope that the ice inside the camera doesn't cause any other problems later. That would be unfortunate.

Most impressive job! Congratulations!

Phil S.

[Dennis]

Hi Phil

Thanks - the frosting has happened before, on other cameras that have a re-chargeable Dessicant Plug to minimise this and the camera showed no signs of damage. The effect is akin to breathing on a mirror, but I will take apart the imaging train to clean out the dust motes as they seem to settle and clump together in the presence of moisture.

Cheers

Dennis