For Scientists: The Long-Term Plan
This is the current Long-Term Plan (LTP) for IXPE. IXPE is currently observing targets from GO Cycle 3. Category A targets are guaranteed to be observed. The IXPE project expects to be able to observe ~50% of Category C targets. 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 3 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 |
| D 0 | 0 | CYG X-1 | 299.590 | 35.202 | 2026-06-06T15 | 1595.1 |
| A 0 | 3175 | 1ES 1959+650 | 299.999 | 65.149 | 2026-06-08T18 | 625.0 |
| A 1 | 3260 | CEN X-3 | 170.313 | -60.624 | 2026-06-14T06 | 667.7 |
| L 1 | 3224 | MRK 501 | 253.468 | 39.760 | 2026-06-18T15 | 126.7 |
| A 3 | 3239 | MCG-06-30-15 | 203.974 | -34.296 | 2026-06-20T18 | 0.0 |
| C 1 | 3089 | 1E 1145.1-61 | 176.869 | -61.954 | 2026-06-22T06 | 0.0 |
| A 4 | 3239 | MCG-06-30-15 | 203.974 | -34.296 | 2026-06-24T18 | 0.0 |
| L 2 | 3224 | MRK 501 | 253.468 | 39.760 | 2026-06-30T00 | 0.0 |
| D 0 | 0 | Her X-1 | 254.458 | 35.342 | 2026-07-02T03 | 0.0 |
| D 0 | 0 | EP260628c | 339.498 | 53.239 | 2026-07-06T06 | 0.0 |
| A 5 | 3239 | MCG-06-30-15 | 203.974 | -34.296 | 2026-07-10T03 | 0.0 |
| L 3 | 3224 | MRK 501 | 253.468 | 39.760 | 2026-07-14T03 | 0.0 |
| A 2 | 3260 | CEN X-3 | 170.313 | -60.624 | 2026-07-16T06 | 3.6 |
| A 1 | 3001 | 4U 0115+63 | 19.633 | 63.743 | 2026-07-16T15 | 1680.1 |
| C 2 | 3089 | 1E 1145.1-61 | 176.869 | -61.954 | 2026-07-21T00 | 1085.2 |
| A 2 | 3001 | 4U 0115+63 | 19.633 | 63.743 | 2026-07-23T12 | 500.0 |
| L 3 | 3215 | 1E 1547.0-54 | 237.726 | -54.307 | 2026-07-29T15 | 0.0 |
| L 4 | 3224 | MRK 501 | 253.468 | 39.760 | 2026-07-31T12 | 0.0 |
| L 4 | 3215 | 1E 1547.0-54 | 237.726 | -54.307 | 2026-08-02T15 | 0.0 |
| L 5 | 3224 | MRK 501 | 253.468 | 39.760 | 2026-08-10T00 | 0.0 |
| C 1 | 3090 | GX 1+4 | 263.009 | -24.746 | 2026-08-12T03 | 0.0 |
| A 0 | 3016 | CRAB PULSAR | 83.633 | 22.015 | 2026-08-17T09 | 2454.4 |
| C 3 | 3089 | 1E 1145.1-61 | 176.869 | -61.954 | 2026-08-19T00 | 1300.0 |
| D 1 | 3111 | MAXI J1750-327 | 267.512 | -32.712 | 2026-08-21T09 | 2974.7 |
| C 3 | 3234 | FAIRALL 51 | 281.225 | -62.365 | 2026-08-22T06 | 1748.2 |
| D 2 | 3111 | MAXI J1750-327 | 267.512 | -32.712 | 2026-08-26T18 | 3739.8 |
| L 1 | 3224 | MRK 501 | 253.468 | 39.760 | 2026-08-28T00 | 3198.8 |
| C 4 | 3234 | FAIRALL 51 | 281.225 | -62.365 | 2026-08-30T03 | 2193.0 |
| D 3 | 3111 | MAXI J1750-327 | 267.512 | -32.712 | 2026-09-02T18 | 3664.2 |
| A 1 | 3079 | SS 433 E2 | 288.543 | 4.937 | 2026-09-04T00 | 1861.0 |
| D 4 | 3111 | MAXI J1750-327 | 267.512 | -32.712 | 2026-09-10T12 | 3332.2 |
| A 2 | 3079 | SS 433 E2 | 288.543 | 4.937 | 2026-09-11T21 | 1529.0 |
| D 5 | 3111 | MAXI J1750-327 | 267.512 | -32.712 | 2026-09-18T09 | 3490.6 |
| A 3 | 3079 | SS 433 E2 | 288.543 | 4.937 | 2026-09-20T00 | 1086.3 |
| L 2 | 3224 | MRK 501 | 253.468 | 39.760 | 2026-09-28T18 | 545.4 |
| A 1 | 3257 | V1223 SGR | 283.759 | -31.163 | 2026-09-30T21 | 0.0 |
| A 0 | 3016 | CRAB PULSAR | 83.633 | 22.015 | 2026-10-06T03 | 2454.4 |
| L 3 | 3224 | MRK 501 | 253.468 | 39.760 | 2026-10-07T15 | 1913.4 |
| A 2 | 3257 | V1223 SGR | 283.759 | -31.163 | 2026-10-09T18 | 480.8 |
| C 6 | 3234 | FAIRALL 51 | 281.225 | -62.365 | 2026-10-15T00 | 0.0 |
| A 0 | 3016 | CRAB PULSAR | 83.633 | 22.015 | 2026-10-18T03 | 2454.4 |
| A 1 | 3156 | 1E 1841-045 | 280.330 | -4.936 | 2026-10-19T18 | 1251.2 |
| L 4 | 3224 | MRK 501 | 253.468 | 39.760 | 2026-10-24T00 | 710.2 |
| A 3 | 3156 | 1E 1841-045 | 280.330 | -4.936 | 2026-10-26T03 | 0.0 |
| A 0 | 2142 | SS 433 | 287.957 | 4.983 | 2026-11-06T00 | 0.0 |
| C 1 | 3134 | CYG X-1 | 299.590 | 35.202 | 2026-11-16T21 | 2350.6 |
| L 5 | 3224 | MRK 501 | 253.468 | 39.760 | 2026-11-22T03 | 1809.6 |
Plan covers time up to 2026 Nov.
ToOs will cause planned times to shift around.