LIGHTCURVE PHOTOMETRY OPPORTUNITIES: 2013 APRIL-JUNE

Abstract

We present lists of asteroid photometry opportunities for objects reaching a favorable apparition and have no or poorly-defined lightcurve parameters. Additional data on these objects will help with shape and spin axis modeling via lightcurve inversion. We also include lists of objects that will be the target of radar observations. Lightcurves for these objects can help constrain pole solutions and/or remove rotation period ambiguities that might not come from using radar data alone.

We present lists of “targets of opportunity” for the period 2013 April-June. For background on the program details for each of the opportunity lists, refer to previous issues, e.g., Minor Planet Bulletin 36, 188. In the first three sets of tables, “Dec” is the declination and “U” is the quality code of the lightcurve. See the asteroid lightcurve data base (LCDB) documentation for an explanation of the U code:

http://www.minorplanet.info/lightcurvedatabase.html

Objects with U = 1 should be given higher priority over those rated U = 2 or 2+ but not necessarily over those with no period. On the other hand, do not overlook asteroids with U = 2/2+ on the assumption that the period is sufficiently established. Regardless, do not let the existing period influence your analysis since even high quality ratings have been proven wrong at times. Note that the lightcurve amplitude in the tables could be more or less than what’s given. Use the listing only as a guide.

The first list is an abbreviated list of those asteroids reaching V < 14.5 at brightest during the period and have either no or poorly-constrained lightcurve parameters.

The goal for these asteroids is to find a well-determined rotation rate. The target list generator on the CALL web site allows you to create custom lists for objects reaching V ≤ 18.0 during any month in the current year, e.g., limiting the results by magnitude and declination.

http://www.minorplanet.info/PHP/call_OppLCDBQuery.php

In a general note, small objects with periods up to 4 hours or even longer are possible binaries. For longer periods (4–6 hours or so), the odds of a binary may be less, but the bonus is that the size of the secondary, if it exists, is likely larger (see Pravec et al. (2010), Nature 466, 1085–1088), thus eclipses, if they occur, will be deeper and easier to detect.

The Low Phase Angle list includes asteroids that reach very low phase angles. The “α” column is the minimum solar phase angle for the asteroid. Getting accurate, calibrated measurements (usually V band) at or very near the day of opposition can provide important information for those studying the “opposition effect.” You will have the best chance of success working objects with low amplitude and periods that allow covering, e.g., a maximum, every night. Objects with large amplitudes and/or long periods are much more difficult for phase angle studies since, for proper analysis, the data have to be reduced to the average magnitude of the asteroid for each night. Without knowing the period and/or the amplitude at the time, that reduction becomes highly uncertain. As an aside, some use the maximum light to find the phase slope parameter (G). However, this can produce a significantly different value for both H and G versus using average light, which is the method used for values listed by the Minor Planet Center.

The third list is of those asteroids needing only a small number of lightcurves to allow spin axis and/or shape modeling. Those doing work for modeling should contact Josef Ďurech at the email address above and/or visit the Database of Asteroid Models from Inversion Techniques (DAMIT) web site for existing data and models:

http://astro.troja.mff.cuni.cz/projects/asteroids3D

The fourth list gives a brief ephemeris for planned radar targets. Supporting optical observations to determine the lightcurve period, amplitude, and shape are needed to supplement the radar data. High-precision work, 0.01–0.02 mag, is preferred, especially if the object is a known or potential binary. Those obtaining lightcurves in support of radar observations should contact Dr. Benner directly at the email given above.

Future radar targets:

http://echo.jpl.nasa.gov/~lance/future.radar.nea.periods.html

Past radar targets:

http://echo.jpl.nasa.gov/~lance/radar.nea.periods.html

Arecibo targets:

http://www.naic.edu/~pradar/sched.shtml

http://www.naic.edu/~pradar

Goldstone targets:

http://echo.jpl.nasa.gov/asteroids/goldstone_asteroid_schedule.html

As always, we encourage observations of asteroids even if they have well-established lightcurve parameters and especially if they are lacking good spin axis and/or shape model solutions. Every lightcurve of sufficient quality supports efforts to resolve a number of questions about the evolution of individual asteroids and the general population. For example, pole directions are known for only about 30 NEAs out of a population of 8000. This is hardly sufficient to make even the most general of statements about NEA pole alignments, including whether or not the thermal YORP effect is forcing pole orientations into a limited number of preferred directions (see La Spina et al., 2004). Data from many apparitions can help determine if an asteroid’s rotation rate is being affected by YORP, which can also cause the rotation rate of a smaller, irregularly-shaped asteroid to increase or decrease. See Lowry et al. (2007) and Kaasalainen et al. (2007).

The ephemeris listings for the optical-radar listings include lunar elongation and phase. Phase values range from 0.0 (new) to 1.0 (full). If the value is positive, the moon is waxing – between new and full. If the value is negative, the moon is waning – between full and new. The listing also includes the galactic latitude. When this value is near 0°, the asteroid is likely in rich star fields and so may be difficult to work. It is important to emphasize that the ephemerides that we provide are only guides for when you might observe a given asteroid. Obviously, you should use your discretion and experience to make your observing program as effective as possible.

Once you’ve analyzed your data, it’s important to publish your results. Papers appearing in the Minor Planet Bulletin are indexed in the Astrophysical Data System (ADS) and so can be referenced by others in subsequent papers. It’s also important to make the data available at least on a personal website or upon request.

Funding for Warner and Harris in support of this article is provided by NASA grant NNX10AL35G and by National Science Foundation grant AST-1032896.

Lightcurve Opportunities

		Brightest				LCDB Data
#	Name	Date		Mag	Dec	Period	Amp	U
3748	Tatum	04	01.3	14.8	−1	58.21	0.54	2+
530	Turandot	04	01.8	14.4	+5	19.947	0.10–0.16	2+
1128	Astrid	04	04.9	14.4	−5	10.228	0.29	2+
739	Mandeville	04	06.0	11.9	+21	11.931	0.14	2
2896	Preiss	04	06.2	14.8	−2	24.	0.3	2
1418	Fayeta	04	06.5	14.9	−11	63.641	0.15–0.24	2+
1425	Tuorla	04	06.9	14.1	−3	6.97	0.40	2
5468	Hamatonbetsu	04	08.0	15.0	+10	42.02	0.43	2
2038	Bistro	04	08.3	15.0	+14	7.88	0.24	1
1075	Helina	04	09.0	15.0	+8
1279	Uganda	04	09.4	14.7	−14	23.2	0.16	1
871	Amneris	04	09.6	14.2	−2
1242	Zambesia	04	10.7	14.8	−15	17.305	0.24–1.36	2
936	Kunigunde	04	11.5	14.8	−6	8.8	0.25	2
838	Seraphina	04	15.8	14.6	−18	15.67	0.07–0.30	2
3260	Vizbor	04	18.8	14.7	−17	72.12	0.64	2+
5073	Junttura	04	19.1	14.8	−14
978	Aidamina	04	19.6	14.8	−15	10.099	0.10–0.13	2
1594	Danjon	04	19.9	14.2	+0	>12.	0.03	1
2678	Aavasaksa	04	19.9	14.9	−9	>24.	0.4	1
375	Ursula	04	20.7	12.1	−29	16.83	0.04–0.17	2
924	Toni	04	20.8	14.1	−1	21.1	0.1–0.14	1
555	Norma	04	21.0	14.8	−8	19.55	0.06–0.20	2+
1654	Bojeva	04	21.3	14.9	−13		0.1
806	Gyldenia	04	21.6	14.2	−7	14.45	0.10–0.27	2
331	Etheridgea	04	22.4	14.0	−14		0.05	1
605	Juvisia	04	22.5	14.9	−32	15.93	0.24–0.26	2
4710	Wade	04	22.6	15.0	−20
795	Fini	04	22.8	13.0	−21	9.292	0.02–0.06	1+
1989	Tatry	04	23.0	15.0	−14	131.3	0.22– 0.5	2
1366	Piccolo	04	23.1	14.1	−15	16.57	0.24–0.33	2
309	Fraternitas	04	23.7	13.9	−16	13.2	0.10–0.12	2
1506	Xosa	04	23.8	14.3	−20	292.	0.70	2+
248	Lameia	04	24.0	12.9	−16	12.	0.10	2
4904	Makio	04	24.0	14.9	−17	7.83	0.08	2
681	Gorgo	04	24.4	14.9	−2
2830	Greenwich	04	24.8	14.4	+3	>24.	0.5	2
764	Gedania	04	25.5	14.5	−22	24.975	0.09–0.35	2
645	Agrippina	04	26.1	14.8	−19	32.6	0.11–0.18	2
3761	Romanskaya	04	26.3	14.7	−10	15.32	0.34	2
705	Erminia	04	29.4	12.8	−38	53.96	0.05–0.17	2
1926	Demiddelaer	05	02.0	14.2	+2	18.5	0.15	2
242643	2005 NZ6	05	02.0	14.6	+17
3115	Baily	05	02.8	15.0	−24	16.22	0.08–0.14	2+
2448	Sholokhov	05	03.6	14.3	+12	10.065	0.63	2+
498	Tokio	05	04.5	12.8	−4	30.	0.10–0.18	1
1322	Coppernicus	05	04.5	14.9	−37	3.967	0.04–0.22	2
5247	Krylov	05	06.9	13.8	−12	81.5	1.5	2
395	Delia	05	07.6	13.6	−20	19.71	0.25	2
2880	Nihondaira	05	08.4	14.1	−19	17.97	0.22–0.75	2
548	Kressida	05	09.0	14.7	−12	11.940	0.44	2
1661	Granule	05	09.0	14.5	−21	>24.	0.15	2
470	Kilia	05	10.2	12.5	−7	290.	0.26	2
4437	Yaroshenko	05	11.5	14.5	−17	30.	0.3	1+
879	Ricarda	05	16.0	14.7	−31	82.9	0.37	2
3109	Machin	05	16.6	14.6	−26	20.3	0.46	2
3152	Jones	05	16.6	14.9	−36			0.09
2862	Vavilov	05	18.1	14.7	−18	>800.	0.4	2
609	Fulvia	05	18.6	14.3	−14	>12.	0.05	1+
3760	Poutanen	05	18.9	14.7	−4
2145	Blaauw	05	20.7	15.0	−29	12.141	0.18	2+
3738	Ots	05	20.8	14.0	−22
784	Pickeringia	05	21.3	12.2	−35	13.17	0.20–0.40	2
1558	Jarnefelt	05	21.4	14.9	−9	18.22	0.40	2
1269	Rollandia	05	23.3	14.1	−17	15.4	0.02–0.08	2
1354	Botha	05	23.4	14.1	−26	4.	0.21	1+
275	Sapientia	05	23.9	12.1	−14	14.766	0.05–0.06	2
2906	Caltech	05	28.8	14.9	−6	11.442	0.17	2
746	Marlu	05	28.9	13.8	−45	7.787	0.23	2
254	Augusta	05	29.9	13.6	−28	6.	0.56	2
14425	Fujimimachi	05	30.2	14.9	−25
791	Ani	05	30.3	13.6	+1	16.72	0.17–0.38	2
1001	Gaussia	05	30.3	14.6	−24	9.17	0.04–0.16	2−
3224	Irkutsk	05	31.6	14.0	−19	19.9	0.49	2
1458	Mineura	06	01.2	14.0	−1	36.	0.04	1
1114	Lorraine	06	01.4	14.7	−9	33.	0.16	1
952	Caia	06	01.6	13.9	−33	7.51	0.03–0.13	2
730	Athanasia	06	02.3	14.9	−19
285263	1998 QE2	06	02.3	10.5	−15
379	Huenna	06	02.5	13.1	−20	14.14	0.07–0.09	2
3973	Ogilvie	06	02.8	14.5	−22
1609	Brenda	06	03.0	13.7	−2	19.46	0.16–0.26	2
2942	Cordie	06	06.8	14.3	−13	80.	1.1	2
70410	1999 SE3	06	06.8	15.0	−15
314	Rosalia	06	06.9	14.6	−4	20.43	0.21–0.40	2
2728	Yatskiv	06	07.6	14.6	−19
5405	Neverland	06	08.2	14.6	−41
1057	Wanda	06	10.1	14.8	−23	28.8	0.14–0.41	2
407	Arachne	06	10.3	12.4	−30	22.62	0.31–0.45	2
3527	McCord	06	15.6	14.7	−16	321.	0.10–0.44	2
619	Triberga	06	17.0	13.5	−1	29.412	0.30–0.45	2
14668	1999 CB67	06	17.9	15.0	−20	2.89	0.06	2
2933	Amber	06	18.4	14.9	−17	13.11	0.32	2
1424	Sundmania	06	18.5	14.2	−33	93.73	0.42	2+
2639	Planman	06	19.2	14.6	−27	89.5	0.40	2+
3716	Petzval	06	19.4	14.7	−19
7021	1992 JN1	06	19.4	14.5	−22
2505	Hebei	06	20.0	14.6	−25
450	Brigitta	06	23.9	14.4	−38	10.75	0.18	2
1182	Ilona	06	24.3	14.6	−38	29.8	0.98– 1.2	2
3783	Morris	06	24.9	14.5	−30
3578	Carestia	06	25.0	13.8	−31	9.93	0.13–0.25	2
1367	Nongoma	06	25.6	13.8	−20		0.3 1
3839	Bogaevskij	06	25.6	14.6	−20
249	Ilse	06	26.3	14.4	−38	85.24	0.27–0.33	1
439	Ohio	06	26.7	14.8	+3	19.2	0.24	2
1551	Argelander	06	26.7	14.6	−22
5248	Scardia	06	27.1	14.7	−24
1029	La Plata	06	28.2	14.7	−27	15.31	0.26–0.58	2
10902	1997 WB22	06	28.7	15.0	−23
1032	Pafuri	06	29.3	13.5	−29	>24.	0.15– 0.3	1+
4157	Izu	06	29.3	14.8	−35
2816	Pien	06	29.4	14.8	−24

Low Phase Angle Opportunities

#	Name	Date		α	V	Dec	Period	Amp	U
490	Veritas	04	01.4	0.87	13.1	−02	7.930	0.33–0.58	3
203	Pompeja	04	01.5	0.69	12.5	−06	24.052	0.10	3
158	Koronis	04	03.8	0.51	13.2	−07	14.218	0.28–0.43	3
119	Althaea	04	10.3	0.22	12.0	−09	11.484	0.23–0.36	3
340	Eduarda	04	11.5	0.27	13.8	−08	8.0062	0.17–0.32	3
417	Suevia	04	12.6	0.29	12.1	−08	7.034	0.10–0.22	3
204	Kallisto	04	13.2	0.23	11.5	−10	19.489	0.09–0.26	3
33	Polyhymnia	04	21.4	0.32	13.1	−13	18.608	0.13–0.20	3
578	Happelia	04	21.8	0.19	12.4	−12	10.061	0.11–0.16	3
331	Etheridgea	04	22.3	0.48	14.0	−14		0.05	1
912	Maritima	04	23.3	0.19	13.2	−12	1332.	0.18	3−
240	Vanadis	04	25.5	0.97	13.3	−10	10.64	0.34	3
223	Rosa	04	27.1	0.18	13.9	−13	20.283	0.06–0.14	3
77	Frigga	04	28.7	0.75	12.5	−16	9.012	0.07–0.20	3
83	Beatrix	05	02.0	0.97	11.0	−17	10.16	0.06–0.27	3
586	Thekla	05	05.3	0.13	13.3	−16	13.670	0.24–0.30	3
147	Protogeneia	05	11.0	0.28	13.0	−19	7.853	0.28	3
82	Alkmene	05	11.6	0.74	11.8	−20	12.999	0.18–0.54	3
106	Dione	05	12.2	0.33	12.4	−17	16.26	0.08	3
49	Pales	05	16.3	0.91	13.0	−22	10.42	0.18	3
243	Ida	05	17.9	0.58	13.9	−21	4.634	0.40–0.86	3
1909	Alekhin	05	21.0	0.45	13.8	−19	148.6	0.45	3
1277	Dolores	05	23.8	0.49	13.3	−22	17.19	0.45	3
121	Hermione	05	25.5	0.45	12.4	−19	5.551	0.04–0.70	3
62	Erato	05	28.7	0.75	13.7	−19	9.2213	0.12–0.17	3
937	Bethgea	05	29.5	0.36	13.3	−21	7.5390	0.12–0.19	3
379	Huenna	06	02.3	0.79	13.1	−20	14.14	0.09	2
675	Ludmilla	06	09.8	0.34	12.3	−24	7.717	0.16–0.38	3
4353	Onizaki	06	10.0	0.03	14.0	−23
150	Nuwa	06	13.8	0.95	12.2	−20	8.1347	0.08–0.31	3
563	Suleika	06	14.5	0.20	12.9	−23	5.69	0.13–0.28	3
683	Lanzia	06	14.7	0.66	12.8	−21	8.630	0.12–0.20	3
1699	Honkasalo	06	15.8	0.35	13.8	−24	11.159	0.17	3−
348	May	06	19.8	0.17	13.6	−23	7.3812	0.16	3
364	Isara	06	25.2	0.87	12.8	−21	9.156	0.30–0.40	3
598	Octavia	06	28.6	0.64	13.1	−25	10.8903	0.28–0.35	3

Shape/Spin Modeling Opportunities

There are two lists here. The first is for objects for which good occultation profiles are available. These are used to constrain the models obtained from lightcurve inversion, eliminating ambiguous solutions and fixing the size of asteroid. Lightcurves are needed for modeling and/or to establish the rotation phase angle at the time the profile was obtained. The second list is of those objects for which another set of lightcurves from one more apparitions will allow either an initial or a refined solution.

Occultation Profiles Available

		Brightest				LCDB DATA
#	Name	Date		Mag	Dec	Period	Amp	U
490	Veritas	04	01.4	13.1	−02	7.930	0.33–0.58	3
530	Turandot	04	01.8	14.4	+05	19.947	0.10–0.16	2+
70	Panopaea	04	09.7	11.6	+01	15.797	0.06–0.12	3
27	Euterpe	04	10.6	9.8	−06	10.4082	0.13–0.21	3
204	Kallisto	04	13.2	11.4	−10	19.489	0.09–0.26	3
386	Siegena	04	19.4	12.4	+07	9.763	0.11–0.18	3
978	Aidamina	04	19.6	14.8	−15	10.099	0.13	2
375	Ursula	04	20.7	12.1	−29	16.83	0.17	2
578	Happelia	04	21.9	12.4	−12	10.061	0.11–0.16	3
498	Tokio	05	04.5	12.8	−04	30.	0.18	1
144	Vibilia	05	04.6	12.1	−12	13.819	0.13–0.20	3
106	Dione	05	12.2	12.4	−17	16.26	0.08	3
49	Pales	05	16.5	12.9	−22	10.42	0.18	3
25	Phocaea	05	16.7	10.0	−03	9.9341	0.03–0.25	3
334	Chicago	05	18.3	12.9	−14	7.361	0.15–0.67	3
757	Portlandia	05	28.4	13.6	−31	6.5837	0.24–0.45	3
791	Ani	05	30.3	13.6	+01	16.72	0.17–0.38	2

Inversion Modeling Candidates

			Brightest			LCDB Data
#	Name		Date	Mag	Dec	Period	Amp		U
158	Koronis	04	03.8	13.2	−07	14.218	0.28	0.43	3
391	Ingeborg	04	04.9	15.0	−16	26.391	0.22	0.79	3
2896	Preiss	04	06.2	14.8	−02	24.		0.3	2
1307	Cimmeria	04	06.7	14.9	−10	2.820		0.31	3
1860	Barbarossa	04	07.8	15.0	+07	3.255		0.28	3
1378	Leonce	04	09.9	14.1	−05	4.3250	0.49	0.50	3
936	Kunigunde	04	11.5	14.8	−06	8.80		0.25	2
2678	Aavasaksa	04	19.9	14.9	−09	24.		0.4	1
1366	Piccolo	04	23.1	14.1	−15	16.57	0.24	0.33	2
1023	Thomana	04	25.5	14.6	−08	17.56	0.27	0.36	3−
3761	Romanskaya	04	26.3	14.7	−10	15.32		0.34	2
2276	Warck	04	28.0	14.5	−14	4.054		0.20	3
7360	Moberg	04	30.7	14.6	−25	4.5842	0.38	0.41	3
586	Thekla	05	05.3	13.2	−16	13.670	0.22	0.30	3
5247	Krylov	05	06.9	13.8	−12	81.5		1.5	2
461	Saskia	05	10.9	15.0	−16	7.348	0.25	0.36	3
2911	Miahelena	05	11.6	14.9	−03	4.19		0.56	3−
247	Eukrate	05	13.1	13.2	−46	12.093	0.10	0.14	3
1277	Dolores	05	23.9	13.2	−22	17.19		0.45	3
254	Augusta	05	29.9	13.6	−28	6.0		0.56	2
1013	Tombecka	06	03.6	14.3	−36	6.053	0.44	0.50	3
373	Melusina	06	08.6	13.7	−44	12.97	0.20	0.25	3
407	Arachne	06	10.3	12.4	−30	22.62	0.31	0.45	2
1505	Koranna	06	13.4	14.0	−17	4.451		0.55	3
698	Ernestina	06	13.7	15.0	−35	5.0363	0.30	0.69	3
1150	Achaia	06	15.5	14.4	−19	60.99		0.72	3
523	Ada	06	15.6	14.5	−23	10.03	0.52	0.70	3
5754	1992 FR2	06	16.6	14.8	−20	8.898		0.97	3
706	Hirundo	06	18.9	14.6	−44	22.027	0.39	0.9	3
361	Bononia	06	23.4	14.8	−39	13.83		0.25	3
1182	Ilona	06	24.3	14.6	−38	29.8	0.98	1.2	2
364	Isara	06	25.3	12.7	−21	9.156	0.30	0.40	3
480	Hansa	06	25.8	12.3	−02	16.19	0.20	0.58	3
553	Kundry	06	29.1	15.0	−27	12.605	0.41	0.61	3

Radar-Optical Opportunities

Use the ephemerides below as a guide to your best chances for observing, but remember that photometry may be possible before and/or after the ephemerides given below. Some of the targets may be too faint to do accurate photometry with backyard telescopes. However, accurate astrometry using techniques such as “stack and track” is still possible and can be helpful for those asteroids where the position uncertainties are significant. Note that the intervals in the ephemerides are not always the same and that geocentric positions are given. Use these web sites to generate updated and topocentric positions:

MPC: http://www.minorplanetcenter.org/iau/MPEph/MPEph.html JPL: http://ssd.jpl.nasa.gov/?horizons

In the ephemerides below, ED and SD are, respectively, the Earth and Sun distances (AU), V is the estimated Johnson V magnitude, and α is the phase angle. SE and ME are the great circles distances (in degrees) of the Sun and Moon from the asteroid. MP is the lunar phase and GB is the galactic latitude. “PHA” in the header indicates that the object is a “potentially hazardous asteroid”, meaning that at some (long distant) time, its orbit might take it very close to Earth.

Some of the objects below are repeats from the previous issue of the Minor Planet Bulletin and those with opportunities extending into the next quarter may be featured again in the next.

2062 Aten (Mar-May, H = 16.8)

The orbits of the Aten asteroids lie mostly within Earth’s and so are never very far from the Sun in the sky. Therefore, it should be no surprise that the rotation period for the namesake of the group is not well-known. Mottola et al. (1995) reported a period of 40.77 h, but that is the only entry with a period in the Lightcurve Database (Warner et al., 2009; U = 2). Despite the difficulties, a successful campaign would be of enormous benefit to radar and modeling efforts.

DATE	RA		Dec		ED	SD	V	α	SE	ME	MP	GB
03/20	04	18.8	+43	17	0.57	0.99	18.1	74.0	72	33	+0.53	−5
03/30	04	43.6	+47	16	0.58	0.96	18.2	77.0	69	140	−0.91	+1
04/09	05	10.0	+50	48	0.57	0.92	18.2	80.6	65	78	−0.02	+6
04/19	05	37.2	+53	51	0.55	0.89	18.2	85.0	62	51	+0.55	+12
04/29	06	03.0	+56	24	0.51	0.86	18.2	90.6	59	143	−0.86	+16
05/09	06	24.3	+58	20	0.47	0.83	18.3	97.8	55	63	−0.01	+19
05/19	06	35.4	+59	27	0.41	0.81	18.4	106.9	50	71	+0.58	+21
05/29	06	28.8	+59	03	0.35	0.80	18.8	118.7	44	132	−0.80	+20

1685 Toro (February-April, H = 14.2)

The rotation period of this NEA is well established at 10.195 h. However, it is a good candidate for YORP spin-up/down, meaning that data from each succeeding apparition can be used to determine if the period is changing slowly over time.

It’s important to note that the shape and amplitude of the curve can change significantly over an apparition, e.g., see Warner, http://www.minorplanetobserver.com/pdolc/A1685_2012.HTM, which also shows that the synodic period can change over a relatively short time. If you plan a protracted campaign, it would be good to subdivide data into blocks of dates, each having a relatively small range of phase angles and treating them as stand-alone sets. Putting all the data into a single set may not only affect the final solution but hide critical data about the lightcurve shape and amplitude vital to good modeling.

DATE	RA		Dec		ED	SD	V	α	SE	ME	MP	GB
04/01	12	16.2	−24	21	0.82	1.79	15.8	11.5	159	62	−0.74	+38
04/11	11	58.8	−21	38	0.86	1.82	15.9	12.6	157	154	+0.00	+40
04/21	11	46.2	−18	48	0.92	1.85	16.3	16.6	148	37	+0.74	+41
05/01	11	38.8	−16	14	1.00	1.88	16.6	21.0	138	110	−0.66	+43
05/11	11	36.2	−14	10	1.10	1.90	17.0	24.7	128	118	+0.01	+45
05/21	11	37.8	−12	38	1.21	1.92	17.3	27.4	119	11	+0.78	+46
05/31	11	42.7	−11	37	1.33	1.93	17.6	29.4	111	149	−0.59	+48
06/10	11	50.3	−11	03	1.45	1.95	17.8	30.6	103	88	+0.02	+49

14 Irene (Apr-Jun, H = 6.30)

Despite its low number, the rotation period for this inner main-belt asteroid wasn’t firmly established until the work by Pilcher (2009) found 15.028 h. A shape model has been developed (Hanus et al., 2011) but additional observations at this apparition and beyond will serve to refine that model. In any event, having a lightcurve from around the same time as radar observations helps with analysis of the radar data.

DATE	RA		Dec		ED	SD	V	α	SE	ME	MP	GB
04/01	12	14.5	+16	24	1.20	2.16	9.0	9.9	158	76	−0.74	+ 76
04/11	12	06.8	+16	33	1.23	2.16	9.2	13.6	150	143	+0.00	+75
04/21	12	01.1	+16	12	1.29	2.16	9.4	17.3	140	31	+0.74	+74
05/01	11	58.2	+15	24	1.36	2.16	9.7	20.5	131	116	−0.66	+73
05/11	11	58.1	+14	13	1.45	2.16	9.9	23.1	123	112	+0.01	+72
05/21	12	00.9	+12	44	1.54	2.17	10.1	25.1	115	18	+0.78	+71
05/31	12	06.2	+11	01	1.65	2.17	10.3	26.5	107	149	−0.59	+71
06/10	12	13.7	+09	09	1.76	2.18	10.4	27.3	100	86	+0.02	+70

2002 TR190 (Apr-May, H = 19.4)

There is no rotation period given in the LCDB for this near-Earth asteroid (NEA). The estimated size is about 400 meters. As with many objects during the middle of a year, observers in the Southern Hemisphere will have the best observing circumstances.

DATE	RA		Dec		ED	SD	V	α	SE	ME	MP	GB
04/01	19	09.9	+01	01	0.13	0.99	18.2	89.6	83	41	−0.74	−4
04/06	19	13.8	−15	50	0.12	1.00	17.7	85.0	88	35	−0.20	−12
04/11	19	19.3	−36	01	0.11	1.02	17.4	79.2	95	102	+ 0.00	−21
04/16	19	27.2	−55	30	0.12	1.03	17.4	73.8	100	140	+ 0.27	−27
04/21	19	39.9	−70	56	0.14	1.04	17.7	70.1	102	112	+0.74	−29
04/26	20	09.9	−81	57	0.17	1.06	18.0	67.8	103	75	−1.00	−30
05/01	01	20.7	−88	30	0.20	1.07	18.3	66.2	104	73	−0.66	−29
05/06	06	38.4	−84	15	0.23	1.08	18.7	65.0	103	95	−0.15	−27

(7888) 1993 UC (Apr-Jun, H = 15.2)

Pravec et al. (1996) found a period of 2.340 h for this asteroid along with an amplitude of 0.10 mag. This makes it a good candidate for being a binary asteroid, so extended higher-precision observations should be made over at least three nights to look for signs of eclipse or occultation events. The estimated diameter of the NEA is 2.7 km.

DATE	RA		Dec		ED	SD	V	α	SE	ME	MP	GB
04/01	14	09.9	+82	06	0.19	1.03	14.4	76.3	93	104	−0.74	+35
04/11	14	14.1	+65	44	0.29	1.12	14.9	60.0	105	102	+ 0.00	+49
04/21	14	12.7	+56	51	0.40	1.21	15.5	50.6	111	70	+0.74	+57
05/01	14	11.7	+50	32	0.52	1.31	16.1	44.6	114	97	−0.66	+62
05/11	14	11.9	+45	14	0.64	1.41	16.5	40.4	116	111	+ 0.01	+66
05/21	14	13.8	+40	26	0.76	1.50	17.0	37.5	115	54	+0.78	+68
05/31	14	17.4	+35	57	0.89	1.60	17.4	35.4	114	115	−0.59	+70
06/10	14	22.7	+31	45	1.03	1.69	17.8	33.8	112	104	+ 0.02	+70

4034 Vishnu (Apr-May, H = 18.3)

The diameter is about 650 meters for this NEA. The period is about 13.5 hours Mottola (2011).

DATE		RA	Dec		ED	SD	V	α	SE	ME	MP	GB
04/01	20	47.1	+31	39	0.15	0.93	18.3	110.7	61	78	−0.74	−7
04/08	19	26.8	+38	47	0.16	0.99	17.4	89.2	82	65	−0.06	+10
04/15	18	06.9	+41	49	0.17	1.04	17.1	71.5	99	116	+ 0.19	+26
04/22	16	59.1	+41	22	0.20	1.10	17.1	58.0	112	90	+ 0.82	+38
04/29	16	07.7	+38	51	0.23	1.14	17.2	48.5	122	62	−0.86	+48
05/06	15	30.7	+35	24	0.27	1.19	17.5	42.4	127	116	−0.15	+55
05/13	15	04.9	+31	37	0.31	1.23	17.8	38.9	130	116	+ 0.08	+61
05/20	14	47.5	+27	49	0.36	1.27	18.1	37.4	130	57	+ 0.68	+64

(242643) 2005 NZ6 (May, H = 17.6, PHA)

The JPL NEO site gives a close approach of about 25 lunar distances (LD) on April 29. There is no rotation period in the LCDB for the 900 meter NEA. Given the size, it’s unlikely this is a superfast rotator, i.e., P < 2 h.

DATE	RA		Dec		ED	SD	V	α	SE	ME	MP	GB
04/30	08	09.9	+28	21	0.06	1.00	15.1	97.3	79	155	−0.77	+29
05/01	09	13.3	+22	32	0.07	1.01	14.8	82.7	93	155	−0.66	+41
05/02	10	00.5	+16	45	0.08	1.03	14.7	70.9	105	157	−0.55	+49
05/03	10	34.3	+11	56	0.09	1.05	14.7	62.2	113	162	−0.44	+54
05/04	10	58.8	+08	09	0.11	1.06	14.9	55.7	119	168	−0.33	+57
05/05	11	17.0	+05	14	0.12	1.08	15.1	51.0	124	175	−0.24	+59
05/06	11	31.0	+02	58	0.14	1.10	15.3	47.5	127	172	−0.15	+59
05/07	11	41.9	+01	10	0.16	1.11	15.5	44.8	129	163	−0.09	+59

(163364) 2002 OD20 (May-Jun, H = 18.8, PHA)

This NEA has an estimated diameter of about 500 meters. A close approach of about 15 LD comes on May 23. The closest approach through 2200 is in 2131 May at about 10 LD. The rotation rate is not known.

DATE	RA		Dec		ED	SD	V	α	SE	ME	MP	GB
05/15	06	55.3	−09	51	0.06	0.98	17.5	118.0	59	28	+0.21	−4
05/20	08	21.9	−22	28	0.04	1.00	15.6	98.1	79	48	+0.68	+8
05/25	11	20.2	−34	53	0.04	1.03	14.1	61.6	116	63	+1.00	+24
05/30	13	55.4	−31	42	0.05	1.06	14.0	33.4	145	99	−0.69	+29
06/04	15	04.4	−26	03	0.08	1.09	14.5	22.1	156	150	−0.19	+28
06/09	15	37.6	−22	26	0.11	1.12	15.1	19.0	159	155	+0.00	+26
06/14	15	56.8	−20	12	0.14	1.14	15.7	19.1	158	100	+0.24	+25
06/19	16	09.8	−18	47	0.17	1.17	16.3	20.4	156	38	+0.74	+24

(285263) 1998 QE2 (Apr-Jun, H = 16.4, PHA)

Of three close approaches through 2200, this is the closest, but it’s hardly a near-miss. On May 31 it will be about 15 LD from Earth. The rotation period for the 1.5 km NEA is not known.

DATE	RA		Dec		ED	SD	V	α	SE	ME	MP	GB
04/01	09	04.5	−34	17	0.33	1.21	16.2	44.9	122	98	−0.74	+8
04/11	08	55.1	−34	43	0.28	1.15	16.0	52.5	115	112	+0.00	+7
04/21	08	52.5	−34	59	0.23	1.10	15.7	59.9	108	45	+0.74	+6
05/01	08	58.7	−35	28	0.18	1.07	15.3	66.5	104	123	−0.66	+7
05/11	09	19.5	−36	25	0.13	1.05	14.7	70.9	102	94	+0.01	+9
05/21	10	22.7	−37	56	0.08	1.04	13.4	67.7	108	41	+0.78	+16
05/31	14	17.1	−24	36	0.04	1.05	10.9	29.8	149	110	−0.59	+34
06/10	17	45.2	+11	32	0.07	1.07	12.2	33.3	145	148	+0.02	+20

(152756) 1999 JV3 (May-Jun, H = 18.8)

There is no rotation period in the LCDB for this 500 meter NEA. The next close approach is not until 2088 and even then at the safe distance of 34 LD. Others before 2200 are 25 LD or more.

DATE		RA	Dec		ED	SD	V	α	SE	ME	MP	GB
05/10	17	08.2	−15	21	0.27	1.25	17.5	23.1	151	151	+0.00	+15
05/15	17	15.0	−09	22	0.23	1.22	17.1	22.8	152	149	+0.21	+17
05/20	17	22.4	−01	19	0.19	1.18	16.8	25.2	150	91	+0.68	+19
05/25	17	31.2	+09	20	0.17	1.15	16.6	31.6	143	37	+1.00	+22
05/30	17	42.1	+22	43	0.15	1.12	16.6	42.3	132	60	−0.69	+25
06/04	17	57.1	+37	55	0.14	1.09	16.8	55.8	118	99	−0.19	+26
06/09	18	19.6	+52	55	0.15	1.06	17.2	69.6	103	106	+0.00	+26
06/14	18	57.8	+65	42	0.16	1.03	17.7	81.7	89	100	+0.24	+24

(17188) 1999 WC2 (May-Jul, H = 16.4)

To repeat a common refrain, there is no period in the LCDB for this asteroid, a 1.6 km NEA that comes no closer than about 30 LD through 2200.

DATE	RA		Dec		ED	SD	V	α	SE	ME	MP	GB
05/15	04	35.5	−32	42	0.34	0.86	17.7	107.2	54	64	+0.21	−42
05/25	04	00.8	−38	53	0.24	0.92	17.1	107.3	60	122	+1.00	−49
06/04	02	15.8	−46	45	0.14	0.99	15.5	94.7	77	59	−0.19	−64
06/14	21	34.1	−32	50	0.10	1.08	13.5	49.7	126	157	+0.24	−47
06/24	19	15.6	−02	24	0.17	1.17	14.0	22.6	154	18	−0.99	−6
07/04	18	33.1	+07	42	0.28	1.26	15.3	24.4	149	129	−0.16	+8
07/14	18	15.8	+10	50	0.41	1.36	16.3	27.2	142	99	+0.28	+13
07/24	18	09.0	+11	30	0.54	1.45	17.1	28.9	136	52	−0.98	+15

(163249) 2002 GT (May-Jul, H = 18.5)

In 2172 October, this NEA will be about 8 LD from Earth. That’s the closest approach through 2200. Remember that establishing YORP spin up/down requires having good lightcurves over many apparitions, so use this opportunity to start building the data set for some future modeler. The estimated size is 600 meters. No period has been recorded in the LCDB.

DATE	RA		Dec		ED	SD	V	α	SE	ME	MP	GB
05/01	17	12.5	−11	05	0.37	1.32	18.2	28.8	141	34	−0.66	+16
05/11	17	22.9	−05	51	0.30	1.27	17.6	26.7	146	155	+0.01	+17
05/21	17	31.9	+01	47	0.23	1.21	17.0	27.0	147	81	+0.78	+18
05/31	17	40.7	+12	51	0.18	1.16	16.5	33.0	141	67	−0.59	+21
06/10	17	51.7	+28	36	0.14	1.11	16.3	46.5	128	131	+0.02	+25
06/20	18	12.6	+49	20	0.12	1.06	16.4	66.4	107	81	+0.83	+26
06/30	19	22.6	+71	51	0.12	1.01	17.1	88.5	85	80	−0.52	+23
07/10	01	50.9	+79	38	0.14	0.97	18.0	106.0	67	78	+0.03	+17