View Single Post
  #10  
Old 14-01-2012, 05:02 PM
RickS's Avatar
RickS (Rick)
PI cult recruiter

RickS is offline
 
Join Date: Apr 2010
Location: Brisbane
Posts: 10,584
Robin,

The bias values in the old master bias are significantly higher than in the new master bias (see mean and median values below). Also, the old master bias is quantized (see histograms).

Quote:
Image Statistics for [1] Master_Bias 1_3348x2496_Bin1x1_Temp-25C_ExpTime0ms.fit:
Image Type: Greyscale
Image Width: 3348
Image Height: 2496
Data Bytes: 33426432
Minimum: 2150.0
Maximum: 2251.0
Mean: 2189.51
Median: 2189.0
Std Dev: 5.64228
Skew: 0.563879
Ignore: 5.0%
Camera Type: Unknown
Pixel Width: 5.4
Pixel Height: 5.4
Original image: Master_Bias 1_3348x2496_Bin1x1_Temp-25C_ExpTime0ms.fit
Cal Master Bias, 33 inputs

Image Statistics for [2] New Master_Bias 1_3348x2496_Bin1x1_Temp-25C_ExpTime0ms.fit:
Image Type: Greyscale
Image Width: 3348
Image Height: 2496
Data Bytes: 33426432
Minimum: 1483.375
Maximum: 1756.292
Mean: 1524.401
Median: 1523.999
Std Dev: 5.48821
Skew: 1.035608
Ignore: 5.0%
Camera Type: Unknown
Pixel Width: 5.4
Pixel Height: 5.4
Original image: New Master_Bias 1_3348x2496_Bin1x1_Temp-25C_ExpTime0ms.fit
Cal Master Bias, 24 inputs
I don't have an explanation for the difference. If you still have the original bias frames then it might be worth taking a look at them to see if there is anything odd about them. I wonder if your original master bias got overwritten somehow and that's when your problems started happening?

Cheers,
Rick.
Attached Thumbnails
Click for full-size image (Old Master Bias histo.jpg)
91.8 KB3 views
Click for full-size image (New Master Bias histo.jpg)
62.4 KB3 views
Reply With Quote