The target - MKN421 - is being observed by ACIS-S and the Low Energy Transmission Grating (LETG) for 2 hours and 55 minutes. The observation started 2 hours ago and ends in 48 minutes, and is part of the proposal AO-27 Big Dither Observation of Mkn421. The target - also called Mrk 421 - is located in the constellation Ursa Major and is a BL Lac - type object. More information on the target can be found at SIMBAD. See related observations: 31397, 31730, 31732, 31398, 32108, 31733, 32121, 31400, 31737, 31734.
This is a time-critical and monitoring observation.



| Target: | MKN421 |
| SIMBAD Type: | BL Lac - type object |
| Observation Details: | 31399 |
| Sequence Summary: | 790398 |
| Proposal Id: | 27700395 |
| Proposal: | Cycle 27, Calibration Observation, ACTIVE GALAXIES AND QUASARS |
| Instrument: | ACIS-S, Low Energy Transmission Grating (LETG) |
| Chips: | ACIS-56789 |
| Sub Array: | Start: 1 Rows: 300 |
| Data Mode: | FAINT |
| Date: | 08:34 Thursday, 23 April 2026 (UTC) |
| Exposure (approved): | 2 hours and 55 minutes |
| Right Ascension: | 11h 04m 27.2s |
| Declination: | +38° 12' 31.7" |
| Roll: | 229° |
| Constellation: | Ursa Major |
| Time critical: | Yes |
| Monitor: | Yes |
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