Search the Community
Showing results for tags 'witchs broom '.
Found 1 result
DaveS posted a topic in Imaging Challenge #6 - Narrowband DSO (Now Closed)Already put this in the DSO imaging section, but what the heck, I doubt I'll get more data, and may want to move on. TS 130mm f/7 Triplet Apo, 0.75x APM-Riccardi reducer, SX Trius 694 camera and Astrodon 3nm filters. 2 hours each of [NII], HII, and [OIII] in 10 min subs, ASA DDM60 mount, with a 120 point whole-sky model and local models for each run, controlled by the ASA software suite and Pinpoint within Maxim DL, which was also used for the capture. The sky conditions were pretty dire, with haze reducing transparency and making the LP worse. The moon was also starting to get in the way. Ironically the last night was the "best" with a NELM of about 4.35. All stacking and post was carried out in AstroArt 5 Each group was stacked using Sigma Add, with Auto align and hot-pixel removal. Calibration was Bias only, as the Flats and Darks I had were making things worse. After stacking Gradient Removal > Adaptive Divide was applied before the RGB synthesis, putting [NII] into Red, HII into Green, and [OIII] into Blue, basicly the HST palette. After Trichromy, the image was cropped to remove some alignment errors (The [OIII] data was captured on 2 nights, both after meridian flip) and another Gradient Removal > Adaptive Subtract was applied. The heavy lifting was done with DDP, with a close eye on the screen visualisation range, in several iterations. There was some colour noise remaining which was evened out with Butterworth Low-Pass filtering. Finally another Gradient Removal > Adaptive Subtract was applied before a gentle Histogram Stretch to just knock the noise into the black, and lift the highlights a *little*. Phew! If you've got this far, thanks for reading, well, we *were* asked to provide as much detail as possible!