There is an opportunity to try diurnal parallax imaging of mag 14.7 Mars orbit crossing asteriod 3833 Calingasta on the night of its opposition on August 6. Opposition for 3833 occurs at about 8-6-2010 1:45 UT (8-5-2010 7:45pm MDT) per NASA JPL Horizon's emphemeris. At opposition, 3833 will be approximately 62M km from Earth (0.413 AU). The Moon will not be above the horizon. For Salt Lake City, Utah, the exact moment of opposition occurs during daylight. Astronomical twilight is begins approx. at 8-6-2010 4:30UT (8-5-2010 10:30PM MDT). The Moon rises at approx. 8:15 UT (8-6-2010 2:15AM MDT). 3833 transits for SLC, Utah at 8-6-2010 7:15 UT (8-6-2010 1:15am) To take a parallax measure by the diurnal method, one photo of the target is taken just after astronomical twilight. An optional second photo is taken at transit. A third photo is taken just before the end of astronomical twilight. In this instance, Moon rise will occur earlier and represents the time cut-off for the third photo. An SLC, UT ephemeris with RA, DEC, Az, Alt is appended for the evening-morning of 8-5 to 8-6. The second method of measuring a parallax is, what I would term, the longitude method using two stations. This involves two observers taking pictures of the same object at approximately the same time but at widely different latitudes on the same longitude, e.g. one station in North America and second in South America. Unfortunately, the Slooh Roboscope's Chile facility has not come online. Although the parallax of Mars was measured by both methods at its 2003 close opposition at 0.3731, there are no guarantees that you will have enough of a baseline to obtain a useable parallax at 0.413 AU. Another option for the longitude method might be to take two images close in time, e.g. one from SLC and a second later in the morning using the Slooh Australia roboscope. Clear Skies - Kurt SLC, UT ephemeris for 3833 2010-Aug-06 01:30 * 20 33 12.69 +07 28 58.1 88.5955 9.9332 2010-Aug-06 01:45 * 20 33 12.72 +07 28 48.0 91.0512 12.7795 2010-Aug-06 02:00 * 20 33 12.74 +07 28 37.8 93.5376 15.6234 2010-Aug-06 02:15 * 20 33 12.76 +07 28 27.7 96.0682 18.4597 2010-Aug-06 02:30 * 20 33 12.78 +07 28 17.6 98.6578 21.2825 2010-Aug-06 02:45 C 20 33 12.79 +07 28 07.5 101.3220 24.0856 2010-Aug-06 03:00 C 20 33 12.80 +07 27 57.3 104.0780 26.8622 2010-Aug-06 03:15 N 20 33 12.80 +07 27 47.2 106.9448 29.6047 2010-Aug-06 03:30 N 20 33 12.80 +07 27 37.0 109.9431 32.3047 2010-Aug-06 03:45 N 20 33 12.80 +07 27 26.8 113.0960 34.9525 2010-Aug-06 04:00 A 20 33 12.79 +07 27 16.6 116.4285 37.5369 2010-Aug-06 04:15 A 20 33 12.78 +07 27 06.4 119.9684 40.0452 2010-Aug-06 04:30 20 33 12.77 +07 26 56.2 123.7450 42.4625 2010-Aug-06 04:45 20 33 12.75 +07 26 46.0 127.7895 44.7717 2010-Aug-06 05:00 20 33 12.74 +07 26 35.7 132.1330 46.9529 2010-Aug-06 05:15 20 33 12.71 +07 26 25.5 136.8049 48.9837 2010-Aug-06 05:30 20 33 12.69 +07 26 15.2 141.8292 50.8386 2010-Aug-06 05:45 20 33 12.67 +07 26 04.9 147.2208 52.4897 2010-Aug-06 06:00 20 33 12.64 +07 25 54.6 152.9797 53.9077 2010-Aug-06 06:15 20 33 12.61 +07 25 44.3 159.0848 55.0628 2010-Aug-06 06:30 20 33 12.58 +07 25 34.0 165.4900 55.9272 2010-Aug-06 06:45 20 33 12.56 +07 25 23.6 172.1221 56.4778 2010-Aug-06 07:00 20 33 12.53 +07 25 13.3 178.8842 56.6984 2010-Aug-06 07:15 t 20 33 12.50 +07 25 02.9 185.6642 56.5824 2010-Aug-06 07:30 20 33 12.47 +07 24 52.5 192.3482 56.1333 2010-Aug-06 07:45 20 33 12.44 +07 24 42.1 198.8334 55.3644 2010-Aug-06 08:00 20 33 12.41 +07 24 31.7 205.0384 54.2968 2010-Aug-06 08:15 20 33 12.39 +07 24 21.3 210.9086 52.9573