Earliest Time for Tallis and Tefillin

The earliest time to put on a tallis (with a blessing) is when one can see through natural lighting the difference between the white and tekheles colors (Shulchan Arukh, Orach Chaim 18:3). This is sometime after dawn but before sunrise. The earliest time to put on tefillin in the morning is when once can recognize an aquaintance at a distance of four cubits (Shulchan Arukh, Orach Chaim 30:1). Both of these times are considered to be equivalent and are commonly called "mi-she-yakir". However, it is unclear exactly when these times occur.

While it seems that a matter of 15-30 minutes is not of much significance, it actually is when dealing with people who need to pray before rushing off to work. Those 15-30 minutes can mean the difference between arriving on time or late (or between being a little late and very late), and can sometimes force people to pray at work rather than at a synagogue.

Click here to read moreR. J. David Bleich, Contemporary Halakhic Problems, p. 241:

The prescribed time for donning tefillin is no earlier than such time as one can recognize a casual friend at a distance of four cubits (Orah Hayyim 30:1). There are varying opinions with regard to how long before sunrise this is possible. As previously noted, Pri Megadim maintains that this occurs 66 minutes before sunrise but this opinion is rejected by subsequent authorities. Opinions vary from 60 minutes before sunrise (Rabbi Joseph Gruenwald, cited in Taharat Yom Tov, VII, 92) to as late as 35 minutes before sunrise (Rabbi Moses Feinstein, Le-Torah ve-Hora'ah, no. 3, p. 7).

There are two essential issues in determining this time of mi-she-yakir. The first is what that time is on a standard day in Jerusalem. It could be 66 minutes before sunrise (R. Ovadiah Yosef in Yechaveh Da'as 2:8), 60 minutes (above and in Kaf Ha-Chaim 18:18 and R. Yechiel Michel Tukaczinsky's Sefer Eretz Yisrael 1:4), 52 minutes (quoted in Piskei Teshuvos 18 n. 37), 47 minutes (quoted in Piskei Teshuvos 18 n. 38), and 35 minutes (R. Moshe Feinstein above). Some stop there and use that flat amount of time all year round in every place of the world. This is actually very common among the authorities prior to the mid-twentieth century.

More recent authorities, however, take that relative time and apply it to different places and times of the year based on the position of the sun. According to Piskei Teshuvos 18:5, 60 minutes before sunrise corresponds to the sun's position of 12.9 degrees below the horizon and 52 minutes before sunrise corresponds to the sun's position of 11.5 degrees below the horizon. One then needs to consult with astronomical charts for the place and time of the year to determine at what time the sun reaches those positions.

R. Meir Posen, in his classic work on times of the day Or Meir (7:2), adopts the view that mi-she-yakir corresponds to the sun's position of 11 degrees below the horizon.

There is also another position, relayed here, that according to R. David Feinstein and R. Ya'akov Yisrael Kanievsky mi-she-yakir does not depend on any particular time of the day but on one's ability to see someone else based on the weather conditions. I do not understand this position at all.

With all these positions, which one should you follow? The most strict is R. Moshe Feinstein, who is of the view that mi-she-yakir is 35-40 minutes before sunrise, while the most lenient is that of R. Ovadiah Yosef, who holds that it is 66 minutes before. According to R. Donneal Epstein, in his Halachos for the Traveler p. 109, contemporary authorities have told him that one may rely on 60 minutes before sunrise. I do not know who those contemporary authorities are and am hesitant to rely on them. I recommend asking your rabbi.

The OU zemanim page uses 11 degrees below the horizon, MyZmanim.com uses 10.2 degrees below the horizon and Kashrut.com/zemanim uses a flat 45 minutes before sunrise. While MyZmanim has an approbation from R. Yisroel Belsky (link), I have heard that he has, in the past, refused to rule on this issue and left it up to local rabbis who know the needs of their community best.