Timing and Location of Shechitah

When

Night Lights

1. Shechitah may only be performed by daylight or torchlight, not during the day in a dark room or at night with just candles. Bediavad, though, the shechitah would be kosher if it was during the day and he checked the simanim or, according to some, even at night by candlelight and he cut the majority of simanim without hagrama.
2. Moonlight and starlight are also insufficient for shechitah, but some say they can be sufficient for checking simanim.
3. Two candles held together with at least the flames touching count as a torch, as does wood smeared with oil.
4. If one started shechting by torchlight but it was extinguished or he forgot to light one altogether and only realized mid-shechitah, he may complete the shechitah to avoid making the animal a nevelah.

Shabbat and Yom Kippur

1. Strictly speaking, an animal shechted on Shabbat or Yom Kippur beshogeg (or bemezid in private) is permissible from a shechitah perspective, but one still has to overcome the penalty imposed on benefiting from Melacha performed unjustifiably on Shabbat.
2. Shechting in front of ten Jewish people in public brings one to the status of Mumar Mechallel Shabbat Befarhesia, so there is little room to permit the meat and a rabbi should be consulted.

Where

Marit Ayin

On the Water

Given pagan practices to slaughter animals (not birds or chayot) for their water deity, the Chachamim prohibited certain venues for slaughter to avoid perception of following those practices.

1. One may shecht at the top of a boat or roof but not into a rivers or large bodies of water, which gives the impression (Marit Ayin) one is shechting to deity in charge of the waters, a manner of idolatry once more common. One may, however, shecht into a filled pit or spring, as long as the water is too dirty to reflect his image. Some say they have to be filled to the top to not be categorized as a "pit."
2. One may not shecht into a keli, which would give the impression one is collecting the blood for idolatrous purposes, but shechting on top of a vessel is permissible. If the vessel has even a little clear water in it, then it is prohibited. If the water is dirty or there is no water but the vessel is dirty, then it's fine.
3. If one is on a boat or any similar venue where it's too difficult to secure a clean location to shecht, it's best to not shecht. If that's not possible one can shecht over the back of a keli and let the blood spill into the water or a different keli. If one can shecht properly without this bootstrapped set up, he must do so.
4. These details of Marit Ayin apply regardless of the presence of onlookers and of purpose for shechitah.
5. It remains problematic to catch the blood according to some after the Shechitah, as well. Therefore, a Jew may not to catch the blood in a container after the shechitah to sell it to a non-Jew due to Marit Ayin, as well as the regular prohibition to engage in commercial trade of prohibited foods (depending on the quantity).

In the Pits

Due to pagan practices to slaughter animals into a pit and drink the blood for ritual purposes, the Chachamim forbade shechting into a pit to avoid resembling their ritual.

1. It is forbidden to shecht animals into a pit, even if one's intention is to avoid dirtying the vicinity, as it may be perceived as pagan worship. Instead, inside one's home, he may make an incline (either in the dirt or via a keli) into the pit and shecht at the top of the incline. Outside, however, where people are not generally as concerned about cleanliness, there is no room for leniency.
2. Meat slaughtered in violation of this prohibition is forbidden from consumption until the intentions of the shochet are investigated. If it is revealed that he was of pagan conviction during this investigation of subsequent observation, all of his slaughter should be considered prohibited from benefit. Otherwise, one may eat of his slaughter. Nowadays, none of these Halachot are really relevant, so no major investigation is necessary, only a simple request for explanation will suffice.
3. The contents of the pit are irrelevant, unless it's filled to the top with water, in which case, there would be no issue.

Sources

Category	Topics
General Laws of Kashrut	Bishul Akum - Checking for Bugs - Gelatin - Kosher Food without Kosher Supervision - Kosher Food Packaging for Deliveries - Kosher Food Left with a Non-Jew - Koshering a Kitchen - Kashering for Pesach - Kosher in the Workplace - Medications - Pat Palter - Selling Non-Kosher Foods - Serving Guests - Sharp Foods - Shechitah (Kosher Slaughter) - Tevilat Keilim - Tzaar Baalei Chayim - Yashan
Meat and Milk	Dairy Bread - Eating Dairy and Meat at the Same Table - Kosher Cheese - Kosher Milk (Chalav Yisrael) - Milk and Meat in the Kitchen - Non-Dairy Milk - Waiting between Meat and Milk
Principles of Kashrut	Items That Cannot Be Nullified - Transferring Taste - Nullification - Zeh Vzeh Gorem - Trusting Others for Kashrut
Shechitah	Shechitah_(Kosher_Slaughter) - Who_Can_Be_a_Shochet - The_Shechitah_Knife - Modern_Day_Industrial_Shechitah - Glatt Kosher Meat - Kashering Meat

Sources

Category	Topics
General Laws of Kashrut	Bishul Akum - Checking for Bugs - Gelatin - Kosher Food without Kosher Supervision - Kosher Food Packaging for Deliveries - Kosher Food Left with a Non-Jew - Koshering a Kitchen - Kashering for Pesach - Kosher in the Workplace - Medications - Pat Palter - Selling Non-Kosher Foods - Serving Guests - Sharp Foods - Shechitah (Kosher Slaughter) - Tevilat Keilim - Tzaar Baalei Chayim - Yashan
Meat and Milk	Dairy Bread - Eating Dairy and Meat at the Same Table - Kosher Cheese - Kosher Milk (Chalav Yisrael) - Milk and Meat in the Kitchen - Non-Dairy Milk - Waiting between Meat and Milk
Principles of Kashrut	Items That Cannot Be Nullified - Transferring Taste - Nullification - Zeh Vzeh Gorem - Trusting Others for Kashrut
Shechitah	Shechitah_(Kosher_Slaughter) - Who_Can_Be_a_Shochet - The_Shechitah_Knife - Modern_Day_Industrial_Shechitah - Glatt Kosher Meat - Kashering Meat