Near Earth Asteroid 2015 TB145 will come close to Earth on 16:18 UT 31 October at distance of 0.003 AU (around 1.3 Earth-Moon distances). It is brightest at 12:30 UT on the 31st though. It has an estimated diameter of around 460m.
The asteroid is currently magnitude 19.5, and will be a reasonably bright magnitude 10.1 at closest approach.
It is visible from the Northern Hemisphere scopes for most of the time. It will be visible from SSO scopes before brightest times (around magnitude 11) until astronomical twilight on the morning of the 31st local time.
At magnitude 10, 60 second exposures may be reasonable, shorter exposures may be too dim, at its brightest it will be moving too fast for the scopes to track.
NEO 2015 TB145 as seen from Mayhill New Mexico from Astronomical twilight (4:55 am, 12:00 UT) 30 October - 31 October. The crosses mark the position of the asteroid every 30 minutes. The large rectangle is the field of view of T14. Click to embiggen.
NEO 2015 TB145 moves from Taurus to Orion, then back into Taurus (crossing the horns of the Bull) into Auriga (wehre it is brightest) then on to Lynx and beyond.
For the Northern Hemisphere scopes the asteroid is visible from around 10 pm to astronomical twilight in the morning. This allows observers to catch the NEO at its brightest.
It is moving fast (398.15 arc seconds/minute at its brightest), and is outside the reach of the tracking capability of the iTelescopes at its brightest (closest approach, when it is even faster, is in daylight). You will need to use a topocentric ephemeris and camp out on the asteroid track in this case.
There is a large parallax effect (> 30 arc minutes at closest approach), so unless your planetarium program is able to cope with close parallax (most can't), you will need to work from topocentric coordinates.
For topocentric ephemerides go to http://www.minorplanetcenter.net/iau/MPEph/MPEph.html
MPC Siding Spring Code Q62. Mayhill Code H06.
Always use the latest possible orbital elements and ephemeris. Note that at the moment the JPL and MPEC ephemeris do not converge between the 29th and 1st Nov, reflecting how current orbital uncertanties feed into their orbit models, you you will need to keep checking uuntil they substantaiily onverge.
JPL ephemeris for astronomical twilight 31st 06 10 13.22 +32 21 01.1
MPEC ephemeris for astronomical twilight 31st 05 44 46.8 +26 28 06
You will need to use unguided exposures.
Choose a point where the asteroid will pass and aim at that. Remember that it takes time for the iTelescopes scopes to get to tracking position. T12 and T14 can take up to 5 minutes (depending on there being reliable stars in the field for tracking, check your logs to see what the average slew time is), so offset you initial position by around 4 minutes or so (this will be a significant distance) so the asteroid will be in field. The asteroid will cross the T12 FOV in about 20 minutes. and the T14 in around 30 minutes at its brightest approach (due to the orientation of the CCD).