Detecting Light Sources

[Dragontamer]

It is clear that a monster with Darkvision and normal light vision can see my rogue unless I have concealment, but I would argue I have that if I am, say, peeking around a corner. However, peeking around a corner doesn't do me any good if I can't see, and I only have low light vision. But what if I'm using a moonrod? This device casts dim light in a 30' radius, but it is considered normal light to a 60' radius for those with low-light vision. So the questions are:

1) If I peek around a corner using a moonrod for a light source, and there is an enemy further away that 30' but closer than 60', how is it determined whether he detects the light source, even if he doesn't detect me because I win the stealth vs. perception check?

2) Suppose I am approaching a corner with a moonrod, and there is an enemy without low-light vision around the corner. The monster doesn't have line of sight on the moonrod yet, but as I approach the turn, the walls will be illuminated by the moonrod when I get within 30 of them. How is it determined whether the monster detects the light source before I reach the corner, even if he can't see or hear me?

3) More generally, while the rules are clear about what areas a light sources illuminates and what level of lighting in provided, what is not clear are the mechanics for an enemy to notice that someone using a light source is coming. Is there a specific range at which it becomes noticeable that is greater than the area it illuminates? Or is there an associated DC for various light levels for a range modified Perception check?

[Avianfoo]

Moonrod wrote:

This 1-foot-long, silver-tipped tin rod glows dimly when struck as a standard action. It sheds dim light in a 30-foot radius. However, the light given off by a moonrod is particularly easily to perceive for creatures with low-light vision. For such creatures, a moonrod increases the light level by one step (to a maximum of normal) for a 60-foot radius. It glows for 6 hours, after which the silver tip is burned out and worthless.

Firstly, moonrod does not make it normal light in 60ft radius for creatures with low-light vision. It, instead increases the light level by 1 step. So if it was dark, it is now dim in 60ft and if it was dim, it is normal for those with low-light vision.

Secondly, the character is holding a light source, even though it only gives (dim) light in a 30ft radius, it is still a light. In a dark corridor, it will immediately stand out to anyone like a lighthouse's light stands out in the dark. Just because it doesn't give enough light to see by beyond 30ft, does not mean the light magically stops at the 30ft radius mark.

1) Dim light gives concealment which makes stealth allowable. Also the opponents perception DC will increase by 1 for every 10ft the sneaking character is away. If the character completely comes around the corner, stealth would not be possible against opponents with darkvision.

2) DC 0 Perception check (or there about). Usually the check is easy enough that most people will notice automatically. Unless there are circumstance penalties. But just because the light changes, does not mean they have spotted the stealthy character... though there is a strong suspicion.

3) Light is noticeable for a much longer range than it illuminates. A GM can definitely ask for a Perception check for a light very very far away (e.g. distance penalties and circumstance penalties)

[Dragontamer]

Thanks Avianfoo. You are, of course, thinking exactly as I did. A light source is visible over a much greater distance than it illuminates. That was leaving me scratching my head as to while this item would be generally useful. If we are correct, a moonrod is a very situational item...at best. Maybe only useful when moving through a very large open area where you are hoping to just avoid the notice of denizens more than 100 feet away. Is that really what we think the authors intended when they created this?

Also, can you please confirm one thing that you imply in your answer, which is that there is no formal rule for perceiving a light source; it is a DM's judgment call.