diff --git a/cxotime/cxotime.py b/cxotime/cxotime.py
index fae7f42..c3f1b41 100644
--- a/cxotime/cxotime.py
+++ b/cxotime/cxotime.py
@@ -3,23 +3,14 @@
 import sys
 import warnings
 from copy import copy
-from ctypes import c_int
-from pathlib import Path
 from typing import Union
 
+import erfa
 import numpy as np
-import numpy.ctypeslib as npct
 import numpy.typing as npt
 from astropy.time import Time, TimeCxcSec, TimeDecimalYear, TimeYearDayTime
-from astropy.time.utils import day_frac
 from astropy.utils import iers
 
-# in astropy versions < 4.2, erfa was an astropy private package:
-try:
-    import erfa
-except ModuleNotFoundError:
-    from astropy import _erfa as erfa
-
 # TODO: use npt.NDArray with numpy 1.21
 CxoTimeLike = Union["CxoTime", str, float, int, np.ndarray, npt.ArrayLike, None]
 
@@ -33,41 +24,6 @@
 # allow auto downloads.
 iers.conf.auto_download = False
 
-# Input types in the parse_times.c code
-array_1d_char = npct.ndpointer(dtype=np.uint8, ndim=1, flags="C_CONTIGUOUS")
-array_1d_double = npct.ndpointer(dtype=np.double, ndim=1, flags="C_CONTIGUOUS")
-array_1d_int = npct.ndpointer(dtype=np.intc, ndim=1, flags="C_CONTIGUOUS")
-
-# load the library, using numpy mechanisms
-libpt = npct.load_library("parse_times", Path(__file__).parent)
-
-# Set up the return types and argument types for parse_ymdhms_times()
-# int parse_ymdhms_times(char *times, int n_times, int max_str_len,
-#                    char *delims, int *starts, int *stops, int *break_allowed,
-#                    int *years, int *months, int *days, int *hours,
-#                    int *minutes, double *seconds)
-libpt.parse_ymdhms_times.restype = c_int
-libpt.parse_ymdhms_times.argtypes = [
-    array_1d_char,
-    c_int,
-    c_int,
-    c_int,
-    array_1d_char,
-    array_1d_int,
-    array_1d_int,
-    array_1d_int,
-    array_1d_int,
-    array_1d_int,
-    array_1d_int,
-    array_1d_int,
-    array_1d_int,
-    array_1d_double,
-]
-libpt.check_unicode.restype = c_int
-
-# Set up returns types and args for the unicode checker
-libpt.check_unicode.argtypes = [array_1d_char, c_int]
-
 
 def print_time_conversions():
     """Interface to entry_point script ``cxotime`` to print time conversions"""
@@ -399,84 +355,6 @@ def print_conversions(self):
         print("\n".join(lines))
 
 
-class FastDateParserMixin:
-    def set_jds_fast(self, val1):
-        """Use fast C parser to parse time strings in val1 and set jd1, jd2"""
-        # Handle bytes or str input and flatten down to a single array of uint8.
-        char_size = 4 if val1.dtype.kind == "U" else 1
-        val1_str_len = int(val1.dtype.itemsize // char_size)
-        chars = val1.ravel().view(np.uint8)
-
-        if char_size == 4:
-            # Check that this is pure ASCII
-            status = libpt.check_unicode(chars, len(chars) // 4)
-            if status != 0:
-                raise ValueError("input is not pure ASCII")
-            # It might be possible to avoid this copy with cleverness in
-            # parse_times.c but leave that for another day.
-            chars = chars[::4]
-        chars = np.ascontiguousarray(chars)
-
-        # Pre-allocate output components
-        n_times = len(chars) // val1_str_len
-        year = np.zeros(n_times, dtype=np.intc)
-        month = np.zeros(n_times, dtype=np.intc)
-        day = np.zeros(n_times, dtype=np.intc)
-        hour = np.zeros(n_times, dtype=np.intc)
-        minute = np.zeros(n_times, dtype=np.intc)
-        second = np.zeros(n_times, dtype=np.double)
-
-        # Set up parser parameters as numpy arrays for passing to C parser
-        delims = np.array(self.delims, dtype=np.uint8)
-        starts = np.array(self.starts, dtype=np.intc)
-        stops = np.array(self.stops, dtype=np.intc)
-        break_allowed = np.array(self.break_allowed, dtype=np.intc)
-
-        # Call C parser
-        status = libpt.parse_ymdhms_times(
-            chars,
-            n_times,
-            val1_str_len,
-            self.has_day_of_year,
-            delims,
-            starts,
-            stops,
-            break_allowed,
-            year,
-            month,
-            day,
-            hour,
-            minute,
-            second,
-        )
-        if status == 0:
-            # All went well, finish the job
-            jd1, jd2 = erfa.dtf2d(
-                self.scale.upper().encode("ascii"),
-                year,
-                month,
-                day,
-                hour,
-                minute,
-                second,
-            )
-            jd1.shape = val1.shape
-            jd2.shape = val1.shape
-            self.jd1, self.jd2 = day_frac(jd1, jd2)
-        else:
-            msgs = {
-                1: (
-                    "time string ends at beginning of component where break is not"
-                    " allowed"
-                ),
-                2: "time string ends in middle of component",
-                3: "required delimiter character not found",
-                4: "non-digit found where digit (0-9) required",
-                5: "bad day of year (1 <= doy <= 365 or 366 for leap year",
-            }
-            raise ValueError(f"fast C time string parser failed: {msgs[status]}")
-
-
 class TimeSecs(TimeCxcSec):
     """
     Chandra X-ray Center seconds from 1998-01-01 00:00:00 TT.
@@ -486,7 +364,7 @@ class TimeSecs(TimeCxcSec):
     name = "secs"
 
 
-class TimeDate(TimeYearDayTime, FastDateParserMixin):
+class TimeDate(TimeYearDayTime):
     """
     Year, day-of-year and time as "YYYY:DOY:HH:MM:SS.sss..." in UTC.
 
@@ -511,14 +389,6 @@ class TimeDate(TimeYearDayTime, FastDateParserMixin):
 
     name = "date"
 
-    # Class attributes for fast C-parsing
-    delims = (0, 0, ord(":"), ord(":"), ord(":"), ord(":"), ord("."))
-    starts = (0, -1, 4, 8, 11, 14, 17)
-    stops = (3, -1, 7, 10, 13, 16, -1)
-    # Break before:  y  m  d  h  m  s  f
-    break_allowed = (0, 0, 0, 1, 0, 1, 1)
-    has_day_of_year = 1
-
     def to_value(self, parent=None, **kwargs):
         if self.scale == "utc":
             return super().value
@@ -531,7 +401,7 @@ def set_jds(self, val1, val2):
         """Parse the time strings contained in val1 and set jd1, jd2"""
         if val2 is not None:
             raise ValueError(f"cannot supply val2 for {self.name} format")
-        self.set_jds_fast(val1)
+        self.jd1, self.jd2 = self.get_jds_fast(val1, val2)
 
 
 class TimeFracYear(TimeDecimalYear):
@@ -554,7 +424,7 @@ def to_value(self, parent=None, **kwargs):
     value = property(to_value)
 
 
-class TimeGreta(TimeDate, FastDateParserMixin):
+class TimeGreta(TimeDate):
     """
     Date as a string in format 'YYYYDDD.hhmmsssss', where sssss is number of
     milliseconds.
@@ -585,12 +455,15 @@ class TimeGreta(TimeDate, FastDateParserMixin):
     # stops: position where component ends (-1 => continue to end of string)
 
     # Before: yr mon  doy     hour      minute    second    frac
-    delims = (0, 0, 0, ord("."), 0, 0, 0)
-    starts = (0, -1, 4, 7, 10, 12, 14)
-    stops = (3, -1, 6, 9, 11, 13, -1)
-    # Break before:  y  m  d  h  m  s  f
-    break_allowed = (0, 0, 0, 1, 0, 1, 1)
-    has_day_of_year = 1
+
+    fast_parser_pars = dict(
+        delims=(0, 0, 0, ord("."), 0, 0, 0),
+        starts=(0, -1, 4, 7, 10, 12, 14),
+        stops=(3, -1, 6, 9, 11, 13, -1),
+        # Break before:  y  m  d  h  m  s  f
+        break_allowed=(0, 0, 0, 1, 0, 1, 1),
+        has_day_of_year=1,
+    )
 
     def _check_val_type(self, val1, val2):
         if val2 is not None:
@@ -600,18 +473,11 @@ def _check_val_type(self, val1, val2):
             raise TypeError(
                 "Input values for {0} class must be string or number".format(self.name)
             )
-        return val1, None
 
-    def set_jds(self, val1, val2):
-        """Parse the time strings contained in val1 and set jd1, jd2"""
-        # If specific input subformat is required then use the Python parser.
-        # Also do this if Time format class does not define `use_fast_parser`
-        # or if the fast parser is entirely disabled.
-        # Allow for float input
         if val1.dtype.kind in ("f", "i"):
             val1 = np.array(["{:.9f}".format(x) for x in val1.flat]).reshape(val1.shape)
 
-        self.set_jds_fast(val1)
+        return val1, None
 
     def to_value(self, parent=None, **kwargs):
         if self.scale == "utc":
@@ -625,7 +491,7 @@ def to_value(self, parent=None, **kwargs):
     value = property(to_value)
 
 
-class TimeMaude(TimeDate, FastDateParserMixin):
+class TimeMaude(TimeDate):
     """
     Date as a 64-bit integer in format YYYYDDDhhmmsss, where sss is number of
     milliseconds.
@@ -655,13 +521,15 @@ class TimeMaude(TimeDate, FastDateParserMixin):
     # stops: position where component ends (-1 => continue to end of string)
 
     # Before: yr mon  doy     hour      minute    second    frac
-    use_fast_parser = True
-    delims = (0, 0, 0, 0, 0, 0, 0)
-    starts = (0, -1, 4, 7, 9, 11, 13)
-    stops = (3, -1, 6, 8, 10, 12, -1)
-    # Break before:  y  m  d  h  m  s  f
-    break_allowed = (0, 0, 0, 1, 0, 1, 1)
-    has_day_of_year = 1
+    fast_parser_pars = dict(
+        use_fast_parser=True,
+        delims=(0, 0, 0, 0, 0, 0, 0),
+        starts=(0, -1, 4, 7, 9, 11, 13),
+        stops=(3, -1, 6, 8, 10, 12, -1),
+        # Break before:  y  m  d  h  m  s  f,
+        break_allowed=(0, 0, 0, 1, 0, 1, 1),
+        has_day_of_year=1,
+    )
 
     def _check_val_type(self, val1, val2):
         if val2 is not None:
@@ -677,10 +545,6 @@ def _check_val_type(self, val1, val2):
 
         return val1, None
 
-    def set_jds(self, val1, val2):
-        """Parse the time strings contained in val1 and set jd1, jd2"""
-        self.set_jds_fast(val1)
-
     def to_value(self, parent=None, **kwargs):
         if self.scale == "utc":
             out = super().value
diff --git a/cxotime/parse_times.c b/cxotime/parse_times.c
deleted file mode 100644
index 2fe052a..0000000
--- a/cxotime/parse_times.c
+++ /dev/null
@@ -1,358 +0,0 @@
-#include <stdio.h>
-#include <string.h>
-
-// ASCII codes for '0' and '9'
-const char char_zero = 48;
-const char char_nine = 57;
-
-// Distutils on Windows automatically exports ``PyInit_parse_times``,
-// create dummy to prevent linker complaining about missing symbol.
-// Based on convolution/src/convolve.c.
-#if defined(_MSC_VER)
-void PyInit_parse_times(void)
-{
-    return;
-}
-#endif
-
-int parse_int_from_char_array(char *chars, int str_len,
-                              char delim, int idx0, int idx1,
-                              int *val)
-// Parse integer from positions idx0:idx1 (inclusive) within chars, optionally
-// starting with a delimiter.
-//
-// Example: "2020-01-24"
-//                  ^^^
-//           0123456789
-//
-// int day, status;
-// status = parse_int_from_char_array("2020-01-24", &day, 10, '-', 7, 9);
-//
-// Inputs:
-//  char *chars: time string
-//  int str_len: length of *chars string
-//  char delim: optional character at position idx0 when delim > 0
-//  int idx0: start index for parsing integer
-//  int idx1: stop index (inclusive) for parsing integer
-//
-// Output:
-//  int *val: output value
-//
-// Returns:
-//  int status:
-//    0: OK
-//    1: String ends at the beginning of requested value
-//    2: String ends in the middle of requested value
-//    3: Required delimiter character not found
-//    4: Non-digit found where digit (0-9) required
-{
-    int mult = 1;
-    char digit;
-    char ch;
-    int ii;
-
-    // Check if string ends (has 0x00) before str_len. Require that this segment
-    // of the string is entirely contained in the string (idx1 < str_len),
-    // remembering that idx1 is inclusive and counts from 0.
-    if (idx1 < str_len) {
-        for (ii = idx0; ii <= idx1; ii++) {
-            if (chars[ii] == 0) {
-                str_len = ii;
-                break;
-            }
-        }
-    }
-    // String ends before the beginning of requested value,
-    // e.g. "2000-01" (str_len=7) for day (idx0=7). This is OK in some
-    // cases, e.g. before hour (2000-01-01).
-    if (idx0 >= str_len) {
-        return 1;
-    }
-
-    // String ends in the middle of requested value. This implies a badly
-    // formatted time.
-    if (idx1 >= str_len) {
-        return 2;
-    }
-
-    // Look for optional delimiter character, e.g. ':' before minute. If delim == 0
-    // then no character is required.
-    if (delim > 0) {
-        // Required start character not found.
-        if (chars[idx0] != delim) {
-            return 3;
-        }
-        idx0 += 1;
-    }
-
-    // Build up the value using reversed digits
-    *val = 0;
-    for (ii = idx1; ii >= idx0; ii--)
-    {
-        ch = chars[ii];
-        if (ch < char_zero || ch > char_nine) {
-            // Not a digit, implying badly formatted time.
-            return 4;
-        }
-        digit = ch - char_zero;
-        *val += digit * mult;
-        mult *= 10;
-    }
-
-    return 0;
-}
-
-int parse_frac_from_char_array(char *chars, int str_len, char delim, int idx0,
-                               double *val)
-// Parse trailing fraction starting from position idx0 in chars.
-//
-// Example: "2020-01-24T12:13:14.5556"
-//                              ^^^^^
-//           012345678901234567890123
-//
-// int status;
-// float frac;
-// status = parse_frac_from_char_array("2020-01-24T12:13:14.5556", &frac, 24, '.', 19);
-//
-// Inputs:
-//  char *chars: time string
-//  int str_len: length of *chars string
-//  char delim: optional character at position idx0 when delim > 0
-//  int idx0: start index for parsing integer
-//
-// Output:
-//  double *val: output value
-//
-// Returns:
-//  int status:
-//    0: OK
-//    1: String ends at the beginning of requested value
-//    3: Required delimiter character not found
-//    4: Non-digit found where digit (0-9) required
-{
-    double mult = 0.1;
-    char digit;
-    char ch;
-    int ii;
-
-    *val = 0.0;
-
-    // String ends at exactly before the beginning of requested fraction.
-    // e.g. "2000-01-01 12:13:14". Fraction value is zero.
-    if (idx0 == str_len) {
-        return 1;
-    }
-
-    // Look for optional delimiter character, e.g. '.' before fraction. If delim == 0
-    // then no character is required. This can happen for unusual formats like
-    // Chandra GRETA time yyyyddd.hhmmssfff.
-    if (delim > 0) {
-        // Required start character not found.
-        if (chars[idx0] != delim) {
-            return 3;
-        }
-        idx0 += 1;
-    }
-
-    for (ii = idx0; ii < str_len; ii++)
-    {
-        ch = chars[ii];
-        if (ch < char_zero || ch > char_nine) {
-            // Not a digit, implying badly formatted time.
-            return 4;
-        }
-        digit = ch - char_zero;
-        *val += digit * mult;
-        mult /= 10.0;
-    }
-    return 0;
-}
-
-static inline int is_leap_year (int year)
-// Determine if year is a leap year.
-// Inspired by from https://stackoverflow.com/questions/17634282
-{
-  return ((year & 3) == 0)
-          && ((year % 100 != 0)
-              || (((year / 100) & 3) == 0));
-}
-
-int convert_day_of_year_to_month_day(int year, int day_of_year, int *month, int *day_of_month)
-// Convert year and day_of_year into month, day_of_month
-// Inspired by from https://stackoverflow.com/questions/17634282, determine
-{
-    int leap_year = is_leap_year(year) ? 1 : 0;
-    int days_in_year = leap_year ? 366 : 365;
-    const unsigned short int _mon_yday_normal[13] =
-        { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
-    const unsigned short int _mon_yday_leap[13] =
-        { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 };
-    const unsigned short int *mon_yday = leap_year ? _mon_yday_leap :_mon_yday_normal;
-    int mon;
-
-    if (day_of_year < 1 || day_of_year > days_in_year) {
-        // Error in day_of_year
-        return 5;
-    }
-
-    for (mon = 1; mon <= 12; mon++) {
-        if (day_of_year <= mon_yday[mon]) {
-            *month = mon;
-            *day_of_month = day_of_year - mon_yday[mon - 1];
-            break;
-        }
-    }
-
-    return 0;
-}
-
-int parse_ymdhms_times(char *times, int n_times, int max_str_len, int has_day_of_year,
-                   char *delims, int *starts, int *stops, int *break_allowed,
-                   int *years, int *months, int *days, int *hours,
-                   int *minutes, double *seconds)
-// Parse a string time in `chars` which has year, (month, day | day_of_year),
-// hour, minute, seconds components.
-//
-// Examples: "2020-01-24T12:13:14.5556", "2020:123:12:13:14.5556"
-//
-// Inputs:
-//  char *times: time characters (flattened n_times x max_str_len array)
-//  int n_times: number of time strings (each max_str_len long)
-//  int max_str_len: max length of string (may be null-terminated before this)
-//  int has_day_of_year: time includes day-of-year instead of month, day-of-month
-//  char *delims: array of delimiters preceding yr, mon, day, hr, min, isec, frac
-//      components. Value of 0 means no preceding delimiter.
-//  int *starts, *stop: arrays of start/stop indexes into time string.
-//  int *break_allowed: if true (1) then the time string can legally end just
-//      before the corresponding component (e.g. "2000-01-01" is a valid time but
-//      "2000-01-01 12" is not).
-//
-// Outputs:
-//  int *year, *month, *day, *hour, *minute: output components (n_times long)
-//  double *second: output seconds (n_times long)
-//
-// Returns:
-//  int status:
-//    0: OK
-//    1: String ends at the beginning of requested value
-//    2: String ends in the middle of requested value
-//    3: Required delimiter character not found
-//    4: Non-digit found where digit (0-9) required
-//    5: Bad day of year
-{
-    int str_len;
-    int status = 0;
-    int isec;
-    double frac;
-    char *time;
-    int *year, *month, *day, *hour, *minute;
-    double *second;
-    int i, ii;
-
-    for (ii = 0; ii < n_times; ii++)
-    {
-        time = times + ii * max_str_len;
-        year = years + ii;
-        month = months + ii;
-        day = days + ii;
-        hour = hours + ii;
-        minute = minutes + ii;
-        second = seconds + ii;
-
-        // Initialize default values
-        *month = 1;
-        *day = 1;
-        *hour = 0;
-        *minute = 0;
-        *second = 0.0;
-
-        // Parse "2000-01-12 13:14:15.678"
-        //        01234567890123456789012
-
-        // Check for null termination before max_str_len. If called using a contiguous
-        // numpy 2-d array of chars there may or may not be null terminations.
-        str_len = max_str_len;
-        for (i = 0; i < max_str_len; i++) {
-            if (time[i] == 0) {
-                str_len = i;
-                break;
-            }
-        }
-
-        // Get each time component year, month, day, hour, minute, isec, frac
-        status = parse_int_from_char_array(time, str_len, delims[0], starts[0], stops[0], year);
-        if (status) {
-            if (status == 1 && break_allowed[0]) { continue; }
-            else { return status; }
-        }
-
-        // Optionally parse month
-        if (! has_day_of_year) {
-            status = parse_int_from_char_array(time, str_len, delims[1], starts[1], stops[1], month);
-            if (status) {
-                if (status == 1 && break_allowed[1]) { continue; }
-                else { return status; }
-            }
-        }
-
-        // This might be day-of-month or day-of-year
-        status = parse_int_from_char_array(time, str_len, delims[2], starts[2], stops[2], day);
-        if (status) {
-            if (status == 1 && break_allowed[2]) { continue; }
-            else { return status; }
-        }
-
-        if (has_day_of_year) {
-            // day contains day of year at this point, but convert it to day of month
-            status = convert_day_of_year_to_month_day(*year, *day, month, day);
-            if (status) {
-                return status;
-            }
-        }
-
-        status = parse_int_from_char_array(time, str_len, delims[3], starts[3], stops[3], hour);
-        if (status) {
-            if (status == 1 && break_allowed[3]) { continue; }
-            else { return status; }
-        }
-
-        status = parse_int_from_char_array(time, str_len, delims[4], starts[4], stops[4], minute);
-        if (status) {
-            if (status == 1 && break_allowed[4]) { continue; }
-            else { return status; }
-        }
-
-        status = parse_int_from_char_array(time, str_len, delims[5], starts[5], stops[5], &isec);
-        if (status) {
-            if (status == 1 && break_allowed[5]) { continue; }
-            else { return status; }
-        }
-
-        status = parse_frac_from_char_array(time, str_len, delims[6], starts[6], &frac);
-        if (status) {
-            if (status != 1 || ! break_allowed[6]) { return status; }
-        }
-
-        *second = isec + frac;
-    }
-
-    return 0;
-}
-
-int check_unicode(char *chars, int n_unicode_char)
-// Check if *chars is pure ASCII, assuming input is UTF-32
-{
-    char *ch;
-    int ii;
-
-    ch = chars;
-    for (ii = 0; ii < n_unicode_char; ii++)
-    {
-        ch++;
-        if (*ch++) return 1;
-        if (*ch++) return 1;
-        if (*ch++) return 1;
-    }
-    return 0;
-
-}
diff --git a/setup.py b/setup.py
index 77790e6..c4369ed 100644
--- a/setup.py
+++ b/setup.py
@@ -1,40 +1,11 @@
 # Licensed under a 3-clause BSD style license - see LICENSE.rst
-import sys
-
-from setuptools import Extension, setup
+from setuptools import setup
 
 try:
     from testr.setup_helper import cmdclass
 except ImportError:
     cmdclass = {}
 
-# NOTE: add '-Rpass-missed=.*' to ``extra_compile_args`` when compiling with clang
-# to report missed optimizations.
-if sys.platform.startswith("win"):
-    extra_compile_args = []
-    extra_link_args = ["/EXPORT:parse_ymdhms_times", "/EXPORT:check_unicode"]
-else:
-    extra_compile_args = ["-fPIC"]
-    extra_link_args = []
-
-# Set up extension for C-based time parser. Numpy is required for build but is
-# optional for other things like `python setup.py --version`.
-try:
-    import numpy
-
-    ext_modules = [
-        Extension(
-            name="cxotime.parse_times",
-            sources=["cxotime/parse_times.c"],
-            extra_compile_args=extra_compile_args,
-            extra_link_args=extra_link_args,
-            include_dirs=[numpy.get_include()],
-            language="c",
-        )
-    ]
-except ImportError:
-    ext_modules = []
-
 entry_points = {
     "console_scripts": [
         "cxotime = cxotime.cxotime:print_time_conversions",
@@ -47,7 +18,6 @@
     description="Chandra Time class base on astropy Time",
     author_email="taldcroft@cfa.harvard.edu",
     use_scm_version=True,
-    ext_modules=ext_modules,
     setup_requires=["setuptools_scm", "setuptools_scm_git_archive"],
     zip_safe=False,
     packages=["cxotime", "cxotime.tests"],