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NGC 2403763 viewsThis is all the data that I took to find the limiting magnitude of various exposure lengths

Imaged at: Escondido and Blair Valley

Optics - 8" F5
Mount - Takahashi NJP
Camera - SBIG STL-11000

Exposure Information: approx. 25x10min, 7x5 min for L, 7x5 min each RGB

Image Processing Software:
I used Registar to register the color data to the luminance, then used Photoshop to do some Curves/Levels adjustments.
Plot of Limiting Magnitude vs. Exposure Time For Various Sky Brightnesses492 views
magnitude info.JPG
Procedure for Finding Limiting Magnitude499 views1. Set up and polar align Tak. NJP mount with 8" Newt. with SBIG 11000
2. Locate NGC 2403
4. Locate guide star and calibrate guider
5. Take sequence of 5, 10, 30, 60, 120, and 600 sec.
6. Open dark-subtracted images in MaxIm
7. Using the settings above, find magnitude and SNR of the three circled stars
8. Record Magnitude and SNR of each in Excel
9. insert the formula "=(LOG(SNR Star x/3)/LOG(2.51))+Magnitude Star x for each star to find the limiting magnitude using a SNR of 3 as the limiting magnitude
Summary of Sky Brightness Results1275 viewsAcquired using an SBIG ST-2000 with a Borg 45mm.
Calibrated using a normal night on Palomar Mountain.
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