How do the Spotter modifiers work with units using the new TAG equipment spotting attack roll rules?
If I had a Dasher A in position to spot a POI for indirect artillery fire - if the Dasher fails the TAG attack roll, does the Unit is Spotting +1 TN apply to the Dasher's standard weapon attacks?
Does the -4 Immobile modifier apply to the Point of Impact?
Can I fire that TAG special attack shot in my rear arc?
And, if I miss is the Dasher still able to spot normally? Does this then infer a +2 TN for the artillery shot (+1 for Indirect Fire, +1 for the spotter also attacking) and the +1 to the Dasher's weapon attacks?
TAG interacts with the spotting (for indirect fire) and attack rules, and sometimes uses one, the other, or both.
As a spotter only: p44 and p47 reference “is an indirect artillery attack and spotters has TAG/LAG within range of the target..-1 modifier”: This use of TAG only requires the TAG unit to be the spotter. There is no attack roll for the spotting unit with TAG. Because there is no attack with the TAG, the use of TAG for this modifier, by itself, does not incur the spotter attacked modifier to the indirect fire attack it is spotting for, but the spotter would incur that modifier and the attacker is spotting modifier to it’s own attacks if it makes a non-TAG attack (it’s standard weapons attack for example).
As an attack: p152 has Homing Rounds. With these optional rules, the unit with TAG has to make an attack roll to “paint” a target. If successful, homing rounds can target the painted target. There is no spotting involved in this use of TAG, so none of the spotter attacked or attacker is spotting modifiers.
As a spotter and as an attack: p90, Target Acquisition Gear has an option for TAG as an attack, that also serves as a spotter. This is the new option you reference. It is new to the 6th printing, and additionally has errata (to the 6th printing) posted for it at Alpha Strike: Commander's Edition - 18 July 2023 (v6.02) (battletech.com)
I’ll include the rule with the errata incorporated:
“A successfully designated target is spotted for indirect fire by the TAG-equipped unit, with no spotter attacked modifier or spotter attacker movement modifiers. In addition, a designated target can be attacked by semi-guided LRMs (see p. 150) and homing artillery (see p. 152). If unsuccessful with a TAG designating attack, the target is still spotted for indirect fire, but will add the spotter attacked modifier.”
This use of TAG is not required. You can still use the spotter only or as an attack options above, this new rule does not remove those uses of TAG. But if you do decide to make an attack roll with the TAG, and are successful, you can spot the target without incurring the spotter attacked or spotter attacker movement modifiers.
If I had a Dasher A in position to spot a POI for indirect artillery fire - if the Dasher succeeds in the TAG attack roll, does the Unit is Spotting +1 TN apply to the Dasher's standard weapon attacks?
No. The unit is spotting modifier does not apply to the spotter’s own attacks, if the TAG attempt is successful.
Does the -4 Immobile modifier apply to the Point of Impact?
Point of Impact (POI) is defined on p47 under Artillery, and states “Attacks targeting a POI ignore all target movement modifiers, including immobile.” This is true for all attacks on a POI, including from TAG. So a TAG attack on a POI does not get the -4 Immobile modifier.
Many players have also asked why a POI doesn’t get the immobile modifier, so I’ll go ahead and answer that one here as well. In Alpha Strike, 99.9999% artillery (and other area effect attacks) target the ground, but only as a point relative to the unit(s) they are wanting to hit. They’re not really aiming to hit the ground, but hit the ground where the unit(s) are. This requires not just the ground be hit, but a specific combination of time and place based on at least one moving unit and timing where it’s going to be when the artillery lands. The rules call this a POI. Not just attacking an immobile target, but coordinating a strike on the ground to strike specific moving units. These attacks are already ignoring the target movement modifier of the moving units that are the actual targets of these strikes, they don’t also get the immobile modifier. Their actual target is not an immobile unit that they can hit whenever, but a specific point at a specific time based on moving units.
Artillery can get the immobile target modifier for attacking a unit (not a POI) that is actually immobile. If you want to hit an immobile unit with artillery, target the unit itself. Note that in standard rules, you can only direct fire artillery at units, you can only indirect fire a POI.
Can I fire that TAG special attack shot in my rear arc?
As an attack, TAG is limited to targets in the firing arc. Unless the TAG is in a turret, it can’t attack (and therefore can’t paint/designate) a target in the rear arc.
Note this only applies to TAG as an attack. Spotting is not limited to firing arcs. As a spotter only, the unit with TAG can spot a target outside the firing arc.
And, if I miss is the Dasher still able to spot normally? Does this then infer a +2 TN for the artillery shot (+1 for Indirect Fire, +1 for the spotter also attacking) and the +1 to the Dasher's weapon attacks?
Yes. Once you declare you are using TAG to designate a target (make an attack roll), you are committed to spotting that unit. If you are unsuccessful “the target is still spotted for indirect fire”. However, you then incur the spotter attacked modifier on any indirect fire attack using this unit as a spotter, and the spotter’s own attacks.
