I get very nice focus curves with the new focus routine using 12 second exposures for all my NB filters using my TV127 refactor at /f 5.2. I would guess something else is going on.
Do you find a difference using your NB versus your LRGB? Are any of them focusing for you?
Here is a plot of the Temperature dependence of my filters on the TV127, provided by the wonderful SGP AutoFocus Viewer program developed by @mikaelA
The “Analyze filter” drop list cycles through each filter, showing it’s regression line and formula.
I used the following exposures for these focus runs: L=5, RGB=7, NB=12.
And the filter offsets are calculated automatically:
SUMMARY OF RESULTS:
FOUND 158 COMPLETE AUTO FOCUS RUNS.
ANALYSIS OF TEMPERATURE COEFFICIENTS --------------------------------------------------------------------------------------------
HFR = a*T + b
a: slope
b: intercept at T = 0
SGP temperature compensation factor: -a
(Negative temperature compensation ratios in SGP indicate that your focuser will move INWARD as temperature drops)
Filter Lum : a = 5.4 steps/deg, b = 20977 steps, SGP factor: -5.4 steps/deg
Filter Red : a = 5.4 steps/deg, b = 20986 steps, SGP factor: -5.4 steps/deg
Filter Green : a = 5.2 steps/deg, b = 20989 steps, SGP factor: -5.2 steps/deg
Filter Blue : a = 5.2 steps/deg, b = 20977 steps, SGP factor: -5.2 steps/deg
Filter Ha : a = 5.0 steps/deg, b = 20979 steps, SGP factor: -5.0 steps/deg
Filter OIII : a = 5.2 steps/deg, b = 20964 steps, SGP factor: -5.2 steps/deg
FILTER OFFSET CALCULATION -------------------------------------------------------------------------------------------------------
Filter offset calculation using the linear regressions.
Offsets are calculated at the middle temperature of 45.1 deg
Filter Lum : 0 steps
Filter Red : 7 steps
Filter Green : 3 steps
Filter Blue : -10 steps
Filter Ha : -17 steps
Filter OIII : -24 steps
AF Run Date Time Pos HFR Temp Filter Misc Target
File ID = 20191015195556
1 10/15/19 20:02:39 21269 2.62 52.88 Lum Successful
2 10/15/19 20:05:54 21268 2.89 52.88 Lum Successful
3 10/15/19 20:11:20 21266 2.94 52.52 Lum Successful
4 10/15/19 20:14:48 21272 3.16 52.34 Red Successful NGC6914 Reflection Nebula
5 10/15/19 20:18:37 21265 2.72 52.16 Green Successful NGC6914 Reflection Nebula
6 10/15/19 20:22:15 21251 2.84 51.98 Blue Successful NGC6914 Reflection Nebula
… (all focus runs are listed)