Asteroid Florence 3 Sept 2017

[Orion]

I thought I might have a go at trying to capture this 4-5km near Earth object, asteroid Florence, that made a recent close pass with the Earth.  I missed the closest pass, but tried on the second night, early morning of the 3rd Sept.  I took photos almost every 1-2 minutes for just over an hour. I could see the asteroid on the back of the camera screen, and I watched it move through the diamond of Delphinus in an hour. It was fascinating to see it move relative to the stars, which were fixed relative to each other.

 

Because the camera was on a fixed tripod and not driven, I had to recenter (roughly), the Delphinus diamond that the asteroid was in.  This has so far made it difficult for me to make a video because I can't find "an easy way" of aligning 36 images - which first have to be cropped from the original 36 larger images.  Currently, I am trying to crop in PIPP, but because the frames are not all aligned to start with, I can't crop the same FOV.

 

Anyway, I was able to stack 36 original images in DSS, using normal alignment on the stars, which causes the asteroid to trail.  This was faint on the larger FOV (which is in the upper left quadrant), so a crop was taken, turned negative, and annotated star magnitudes for reference limiting magnitude for the conditions and equipment.

 

Technical detail

Asteroid FLORENCE. Image and crop from a stack of 36 x 2s exposures at ISO 6400, 300 mm lens at f5.6 and Canon 1100d DSLR.  Images stacked in DSS, processed in Photoshop CS2, saved as TIFF file, then converted to JPG in Irfanview.  Original large field image and cropped image (negative and positive) shows Florence as a trail against the background stars, and made up from 36 dots.  Magnitudes of stars are annotated for reference; values taken from Stellarium. Some stars can be seen down to magnitude 13.8, possibly fainter. Florence magnitude 9.1. Date 3/9/2017. Time period. Approx. 00:41 - 01:49 BST.

 

Here's the results. See third image on the second post (size restrictions of 500kb).

 

Edited September 4, 2017 by Orion
Update of observational detail

[BAZ]

Well done Derek, if anyone was going to nail it, it was you. 

[+RonC]

Quite a difficult thing to do but you seemed to have done it really well!! 

[Sheila]

nice capture there  

[Orion]

Thanks Martyn, Sheila and Ron 

[Tweedledee]

An excellent bit of work catching that Derek. 

 

Florence is a PHO (potentially hazardous object) at 5 km across passing pretty close to earth periodically. It has 2 moons between 100 and 300 metres across.

[stash]

5 hours ago, Tweedledee said:

An excellent bit of work catching that Derek. 

 

Florence is a PHO (potentially hazardous object) at 5 km across passing pretty close to earth periodically. It has 2 moons between 100 and 300 metres across.

Except it isnt (PHO) as it never gets close - unless it changes course  - its been here before but to call it "pretty close" is a slight exaggeration   - and it wont get close again until 2500ad so none of us - ,except Pete being a Cyborg, will be around.

 

  https://www.nasa.gov/feature/jpl/large-asteroid-to-safely-pass-earth-on-sept-1

[Tweedledee]

1 hour ago, stash said:

Except it isnt (PHO) as it never gets close - unless it changes course  - its been here before but to call it "pretty close" is a slight exaggeration   - and it wont get close again until 2500ad so none of us - ,except Pete being a Cyborg, will be around.

 

  https://www.nasa.gov/feature/jpl/large-asteroid-to-safely-pass-earth-on-sept-1

 

Oh, that's a relief then. Only Kim Jong-un to worry about in the short term. I'll be back.  

[Guy Wells FRAS]

On 05/09/2017 at 19:44, stash said:

Except it isnt (PHO) as it never gets close - unless it changes course  - its been here before but to call it "pretty close" is a slight exaggeration   - and it wont get close again until 2500ad so none of us - ,except Pete being a Cyborg, will be around.

 

  https://www.nasa.gov/feature/jpl/large-asteroid-to-safely-pass-earth-on-sept-1

Sorry for the late reply.

3122 Florence is certainly a PHA due to the fact that it has an minimum orbit intersection distance of .0442au and absolute magnitude of 14.1.
The criteria to be classified as a potentially hazardous asteroid:
MOID: <0.05 au
H:       22.0 or brighter.

The next close approach is in 2057, at a similar distance to the 2017 passage: 5.9 million kilometres.