For Scientists: The Long-Term Plan


This is the current Long-Term Plan (LTP) for IXPE. The Science Advisory Team requested that transient targets be added when and if they become bright. At such time, the LTP will be adjusted, attempting to minimize the impact on the overall plan; however, nothing is guaranteed.

IXPE is telemetry limited for bright sources and this requires that observations be handled slightly differently from the way most X-ray missions operate. If IXPE is observing a bright source that could potentially fill on-board storage, we shall divide the observation into multiple segments.

COLUMNS:
P: can be A, C, L, D or T. A and C targets were assigned by peer review. T is a ToO and D is DDT time. L denotes a large project. If an A target is bumped due to a ToO, it will be replaced. If a C target is bumped, it will likely be dropped from the plan.

S: This is a segment number. If segment is zero, then the observation has not been segmented.

Pnum: This is the GO proposal number. If the observation is a DDT or a calibration, then this number will be zero.

Name: This is a common name for the target.

RA: Target RA in decimal degrees.

Dec: Target Dec in decimal degrees.

Start: The Year-Month-Day The date the observation is planned to begin. The digits after the T is the start hour, in UT, truncated to a 6 hr interval.

buffer: This is an estimate as to how much data will stll be on the spacecraft when the observation ends in MB. The on-board storage can hold just over 4500 MB and when planning we keep the usage below 4000 MB.

P S Pnum Name RA Dec Start buffer
A 02226 EX HYDRAE 193.101 -29.2492025-01-18T00 0.0
L 12158 PERSEUS CLUS 49.947 41.5132025-01-24T06 0.0
A 02067 PG 1553+113 238.929 11.1902025-02-01T12 0.0
L 22158 PERSEUS CLUS 49.947 41.5132025-02-04T00 0.0
A 02157 4U 1700-377 255.987 -37.8442025-02-10T06 0.0
C 12013 CRAB PULSAR 83.633 22.0142025-02-13T06 2629.6
L 32158 PERSEUS CLUS 49.947 41.5132025-02-15T00 387.7
C 22013 CRAB PULSAR 83.633 22.0142025-02-28T06 3017.3
L 42158 PERSEUS CLUS 49.947 41.5132025-03-01T18 2120.6
D 00000 IGR J17091-3 257.282 -36.4072025-03-07T00 1260.5
L 52158 PERSEUS CLUS 49.947 41.5132025-03-10T12 0.0
C 02219 1E 1547.0-54 237.725 -54.3072025-03-26T00 0.0
D 00000 MAXI J1744-2 266.419 -29.0132025-04-05T00 0.0
A 02103 KES 75 281.604 -2.9752025-04-08T06 0.0
A 02022 SS 433 WEST 287.672 5.0322025-04-19T00 0.0
A 02003 MCG-5-23-16 146.917 -30.9492025-04-24T12 0.0
A 02184 GRS 1915+105 288.798 10.9462025-05-10T12 0.0
C 02152 NGC 3227 155.877 19.8652025-05-13T18 0.0
D 00000 Cyg X-2 326.171 38.3212025-05-28T12 1669.8
A 02014 LIGHTHOUSE N 165.359 -61.0152025-05-30T12 0.0
C 02095 1ES 1927+654 291.831 65.5652025-06-17T12 0.0
D 00000 H 1417-624 215.300 -62.6992025-06-27T18 0.0
D 00000 Cyg X-2 326.171 38.3212025-07-03T12 2337.7
A 02067 PG 1553+113 238.929 11.1902025-07-06T06 1636.4
C 02093 UW CRB 241.441 25.8632025-07-09T00 167.6
A 12037 NGC 5506 213.312 -3.2072025-07-14T06 0.0
A 12111 CIR X-1 230.170 -57.1672025-07-24T06 0.0
A 22037 NGC 5506 213.312 -3.2072025-07-27T12 0.0
A 02111 CIR X-1 230.170 -57.1672025-08-02T00 1232.3
A 32037 NGC 5506 213.312 -3.2072025-08-04T18 0.0
A 22111 CIR X-1 230.170 -57.1672025-08-09T12 0.0
A 42037 NGC 5506 213.312 -3.2072025-08-12T18 0.0
D 00000 GX 349+2 256.435 -36.4172025-08-14T12 3501.3
A 12138 SAX J1808.4- 272.115 -36.9792025-08-19T00 2757.8
A 00000 SCO X-1 244.980 -15.6402025-08-22T18 3587.6
A 22138 SAX J1808.4- 272.115 -36.9792025-08-23T06 401.1
A 02147 GX 13+1 273.631 -17.1572025-09-08T00 315.2
A 02067 PG 1553+113 238.929 11.1902025-09-11T06 0.0
C 12013 CRAB PULSAR 83.633 22.0142025-09-13T18 2629.6
A 02081 4U 1812-12 273.776 -12.0962025-09-15T12 0.0
D 00000 GRS 1739-278 265.667 -27.7482025-09-29T12 708.6
C 22013 CRAB PULSAR 83.633 22.0142025-10-01T12 3338.2
A 02154 4U 1822-37 276.445 -37.1052025-10-03T06 672.2
A 02121 4U 0614+091 94.281 9.1372025-10-13T12 113.5
D 00000 4U 1954+319 298.926 32.0972025-10-16T18 0.0
D 10000 4U 1957+11 299.850 11.7082025-10-20T18 0.0
A 02022 SS 433 WEST 287.672 5.0322025-10-24T06 0.0
A 12142 SS 433 287.957 4.9832025-11-09T12 0.0
A 02006 1ES 1959+650 299.999 65.1492025-11-13T12 0.0
A 22142 SS 433 287.957 4.9832025-11-15T00 0.0
A 02006 1ES 1959+650 299.999 65.1492025-11-17T12 0.0
A 32142 SS 433 287.957 4.9832025-11-19T00 0.0
D 20000 4U 1957+11 299.850 11.7082025-11-21T00 0.0
NOTES:
Plan covers time up to 2025 December.
ToOs will cause planned times to shift around.
+ NASA Privacy, Security, Notices | Last Updated: November 13, 2025 | Author/Curator: Mitzi Adams, mitzi.adams @ nasa.gov