3453 Dostoevsky

After taking a few comet images from Slooh.com recently, I came across a group there called the A-Team that observes and reports on minor planets – particularly Near Earth Objects or NEOs. Through this group, users can gather observations and report them to the Minor Planet Center after completing a tutorial syllabus and qualifying for submissions. I was very excited to find out about this resource, as I have been wanting to contribute to this field but really do not have the conditions and equipment to do this from my own back yard!

I don’t want to cite or reproduce the A-Team pages from the Slooh site but can mention some of the public resources the group suggests and results of some early observations.

To start, they recommend taking observations on a few brighter objects, and this is what the Minor Planet Center also requires before qualifying for a new observatory code. To help identify some candidates, I went to the JPL SB Whats Observable site. You can enter a time and location and other parameters such as a magnitude cut-off and get a list of minor planets and comets observable at a given location.

I put in the parameters of interest and generated a list of over 2000 objects! Did not see a download option but was able to take the list, save it to a file and coax it into Excel. From this list I identified some targets around mag 15 and selected a subset of the sky that would be at a good elevation – and also away from bright Jupiter and crowded star fields in the Milky way.

Many choices were available, but my eye caught 3453 Dostoevsky, whom I always enjoyed reading in college – plus evoking Mel Brooks’ The Twelve Chairs. At an expected magnitude 15.8 this looked like a reasonable choice to try.

I booked sessions at the Slooh Canary Island site but was thwarted by clouds for a few days, but then managed to get some images from their site near Santiago, Chile. I scheduled 3 sessions 30 minutes apart. The first time point looked fine but the second showed pretty severe streaking. The third set looked OK so I went with the first and third exposure times.

After entering the telescope, camera and analysis parameters recommended for the site, Astrometrica solved the images nicely and identified a clearly moving bright object as 3453 Dostoevsky with these values:

 

03453         C2016 01 15.29433 08 37 33.89 +18 20 19.2          16.0 V      W88

03453         C2016 01 15.33310 08 37 31.45 +18 20 23.6          15.9 V      W88

To check observations, the group recommends using an online tool for calculation residual values at fitsblink.net. After loading the above this site returned:

(3453) = (03453)
1. 03453 C2016 01 15.29433 08 37 33.89 +18 20 19.2 16.0 V W88 -0.16 -0.03
(3453) = (03453)
2. 03453 C2016 01 15.33310 08 37 31.45 +18 20 23.6 15.9 V W88 -0.09 +0.12

This shows differences in the measured and expected coordinates of less than 0.2 arc seconds, so it looks like I have the right object!

Next I tried choosing a fainter target and found a pair of minor planets well below mag 16 and quite close to each other: 3900 Knezevic and 2287 Kalmykia. The Chile observatory was booked up, so I set up 3 times at CI spaced about 40 minutes apart. The weather cleared up that night and I got 3 sets of very nice image files.

If you have 3 or more files from a given location, Astrometrica can reduce the images and look for objects that have a consistent displacement across the set. This identified 4 moving targets in the frames! These looked good from visual inspection, and no other moving objects could be clearly seen. (There were a number of single hot spots and streaks that were likely artifacts).

The expected targets were seen, as well as 2360 Volgo-Don at mag 16.6 and 32729 “5179 T-3” at mag 17. Volgo-Don was at the edge of the frames but clearly seen in all 3 images so this looked to be real.

So here we have 4 objects and 3 times or 12 observations from Astrometrica

02287 C2016 01 17.20921 09 39 10.29 +19 25 12.5 16.8 V G40
02287 C2016 01 17.24113 09 39 08.71 +19 25 24.9 16.8 V G40
02287 C2016 01 17.27185 09 39 07.19 +19 25 36.6 16.8 V G40
02360 C2016 01 17.20921 09 41 16.58 +19 26 19.0 16.7 V G40
02360 C2016 01 17.24113 09 41 15.08 +19 26 27.7 16.6 V G40
02360 C2016 01 17.27185 09 41 13.64 +19 26 36.3 16.7 V G40
03900 C2016 01 17.20921 09 39 45.51 +19 23 09.8 16.9 V G40
03900 C2016 01 17.24113 09 39 43.75 +19 23 14.2 16.7 V G40
03900 C2016 01 17.27185 09 39 42.07 +19 23 18.8 16.9 V G40
32729 C2016 01 17.20921 09 40 01.34 +19 17 13.1 16.9 V G40
32729 C2016 01 17.24113 09 40 00.46 +19 17 31.8 16.9 V G40
32729 C2016 01 17.27185 09 39 59.61 +19 17 49.7 17.0 V G40

Running these through Fitsblink gave:

(2360) = (02360)
   1.  02360         C2016 01 17.20921 09 41 16.58 +19 26 19.0          16.7 V      G40    -0.14    +0.07
(2360) = (02360)
   2.  02360         C2016 01 17.24113 09 41 15.08 +19 26 27.7          16.6 V      G40    -0.04    +0.06
(2360) = (02360)
   3.  02360         C2016 01 17.27185 09 41 13.64 +19 26 36.3          16.7 V      G40    +0.00    +0.31
(2287) = (02287)
   4.  02287         C2016 01 17.20921 09 39 10.29 +19 25 12.5          16.8 V      G40    -0.13    +0.02
(2287) = (02287)
   5.  02287         C2016 01 17.24113 09 39 08.71 +19 25 24.9          16.8 V      G40    -0.03    +0.12
(2287) = (02287)
   6.  02287         C2016 01 17.27185 09 39 07.19 +19 25 36.6          16.8 V      G40    -0.01    +0.01
   7.  32729         C2016 01 17.20921 09 40 01.34 +19 17 13.1          16.9 V      G40    -0.17    +0.08
   8.  32729         C2016 01 17.24113 09 40 00.46 +19 17 31.8          16.9 V      G40    -0.06    +0.12
   9.  32729         C2016 01 17.27185 09 39 59.61 +19 17 49.7          17.0 V      G40    -0.14    +0.12
(3900) = (03900)
  10.  03900         C2016 01 17.20921 09 39 45.51 +19 23 09.8          16.9 V      G40    -0.10    +0.16
(3900) = (03900)
  11.  03900         C2016 01 17.24113 09 39 43.75 +19 23 14.2          16.7 V      G40    -0.13    -0.03
(3900) = (03900)
  12.  03900         C2016 01 17.27185 09 39 42.07 +19 23 18.8          16.9 V      G40    -0.07    +0.20

Some variability, but all except one are under 0.25″. It looks like this telescope and camera yields accurate positions across the whole image frame!

The following animated GIF shows 3 of the objects closest to the center:

20160118-3900-blink-animation-r

Good fun! Next step will be to taking and stacking longer exposures to try to detect some of the many fainter objects out there.


			

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