Asteroid 3122 Florence

[WaveSoarer]

After what seems like an age of inactivity, I took the advantage of the clear skies last night and got the telescope set up so that I could have an attempt at observing Florence. There had been a rain shower just before sunset and so the air was quite humid but at least the transparency was good - which was an advantage with the near to first-quarter moon on show. I had to wait a while until Florence was sufficiently high to clear the house and I then set up about trying to find it. The moon made the sky rather bright and so the finder could only really pick out the brightest of stars. I hopped from the bright Dabih and the double Algedi/6 Cap to Albali and from there followed the line of 6 Aqr and 7 Aqr down to 13 Aqr. At this stage I had to use the main scope (with a 15 mm EP) as the sky was just too bright to make the finder scope useful. Stellarium was then essential for the rest and a little bit of careful slewing of the scope showed Florence at the apex of a tight isosceles triangle with HIP 104826 and HIP 104795 at about 10:30 BST. These stars are mag 9.2 and mag 8.65 respectively and have a similar brightness at the EP to Florence, which Stellarium estimates to be mag 8.65. Sure enough, there was a stellar-like point of light in the correct place and over the period of a couple of minutes it was fairly obvious that the geometry of the triangle was changing. I was fortunate that Florence was close to these stars as the movement was really obvious and it made the identification really easy. Infact, even a short period of viewing showed the asteroid clearly moving. This was perhaps the most mesmerising aspect of the night's session as it's unusual to see such an obvious and rapid movement of an object. Anyway, I tracked Florence for a couple of hours until well after the moon had set by which time it had progressed quite a long way. Well worth the effort considering how small, and how far away, the asteroid is from us.

[Mark at Beaufort]

Nice report - I did the same as you and needed the Heritage 130P scope to confirm that it was Florence. I looked and compared the star HIP104795 and felt that the mag was very similar. The Moon was certainly too bright using the finderscope and even the 15x70 binos was difficult.

[andrew63]

Good to read your Florence observations - these transient events are well worth viewing. I also was looking at the same triangle of stars changing shape - but in the refractor heading up.   Those two stars you mention are the same ones in this brief sketch from last night with the asteroid heading for HIP 104795 forming the triangle.

 

andrew

[WaveSoarer]

Thanks for the comments and it seems that we've had similar viewing experiences. I like the sketch by the way Andrew.

[goodricke1]

Great report, I was promised clear skies last night but got rain instead. Tonight might be another opportunity but that nuisance of a moon is encroaching.

[WaveSoarer]

I think that you'll be ok with the moon goodrick1. Florence was easy to spot with my 200p last night and I might have a go with the 100p tonight if it's clear.

[SilverAstro]

I was also out of luck last night, intermittent cloud and haze, located the area with binos but only down to mag5.5, thought there might be an improving chance, went to get BigBertha's tripod/mount and it was raining !Grrrr, put BigBertha's bits back into the house!

Anyway, for tonight I've been playing with Stellarium again and found a close pass of mag7 HIP103932 at 48min past midnight. Very close!  26 and a bit seconds of arc.  Dunno how accurate my Stellarium settings are at that level, I suppose if there were going to be an occultation somewhere we would have heard about it ???

 

[John]

I got a similar result with Cartes du Ciel so that sounds right.

My scope is out and cooling ....

[andrew63]

Just had a look between clouds - it's next to a star of 8.50 mag. and it does not appear quite as bright. Perhaps it's reached it's peak in the range  8.7 - but boy is it shifting !

 

andrew

[harrym]

Stellarium won't be accurate down to the arcsecond level because the orbital elements are being changed slightly by Earth's gravity during the approach! For the most accurate positions you can use the Minor Planet Center site or JPL Horizons. Checking the MPC site for various locations suggests that there will be an occultation but the track passes around 10 degrees east of the UK.

Unfortunately it's pretty cloudy here so not much chance of me seeing it tonight.

[SilverAstro]

29 minutes ago, harrym said:

the orbital elements are being changed slightly by Earth's gravity during the approach! For the most accurate positions you can use the Minor Planet Center

How often does MPC change the elements ?

I was expecting that, but did not notice any change in my Stellarium when I updated last night, hence wondering about Stellarium truncating last dec. places or other precision field limiting artifices ?

[John]

I think I've got florence in the FoV of my ED120 refractor at 38x (24mm Panoptic) right now. I've been watching a "suspect" for about 15 minutes and it's movement and the changing position relative to other field stars is noticable though slow to unfold.

The odd thing is, although the movement against the stars is very slow, it stood out straightway as a "suspect". Maybe our eyes are quite good at detecting slight movement ?.

Having just checked it's postion again at the eyepiece, relative to another couple of slightly fainter stars, I'm pretty confident that it's Asteroid Florence

A chunk of rock the size of a large town or small city like Truro 7 million KM away

[SilverAstro]

Haharr, I have a clear sky AT LAST (sorry the shout)  ! I'm getting the gear out, see yous guys laters > > > 

[WaveSoarer]

John, I thnk that our eyes are very good at perceiving even very small and slow movements. I found it easier when Florence was close to a group of stars or was in the direct line of a pair of stars. It was easier to see the movement when the alignment started drifting off.

[Stu]

Great reports all! I've just tried and failed with my 8x56 binos, barely getting below mag 7 with those. Trying to work up the energy to pop the Tak out. That should do it I think but skies are bright with the moon encroaching a bit. I'll see...

[Stu]

Btw, I agree John, our eyes are very sensitive to movement

[John]

This is quite useful for live tracking of Florence:

https://theskylive.com/florence-tracker

[DavidJM]

I have nothing but cloud, please clear

[andrew63]

For those clouded out there is a live link on Virtual Telescope.

https://www.virtualtelescope.eu/webtv/

 

andrew

[Stu]

I'm seeing it to the left of SAO145072 which is the bottom left of a triangle of stars. Refractor view. Not quite where SkySafari puts it!

[andrew63]

Stu - I should have mentioned it a few days ago - sky safari is a bit  off !   About 4 degrees off !!

 

andrew

[John]

Cartes du Ciel seems to be quite accuate with this one. I updated the asteroid data about an hour ago.

[andrew63]

In the refractor it's making it's way toward 2 bright stars 6 to 7 mag. HIP 103932 HIP 103926 less than 1 deg. below these.

 

andrew

[John]

Yep, thats where I have it

Like watching a snail move !

[andrew63]

Astronomy is like quality street - best shared 

 

andrew