September 1st, 2022 – Going after NGC7822
Objective
Second night trying to capture NGC7822 in HaRGB.
First night (Sept 27th, 2022) started perfect with 2.5h of exposure through Ha filter. The intention was to capture 5 hours of total exposure through the Ha, R, G and B filters.
However, when the automated sequence performed the automatic focusing routine through the second filter (Red), the Moonlite focuser slipped due to the weight of the camera/field flattener. The telescope pointing up exacerbated the gravity effect on the camera as well as the lower temperature. The acquisition was aborted.
The next day, the tensioning screws on the focuser were tightened by 1/8th of a turn each to hopefully eliminate the problem.
Tonight’s objective is to capture an additional 4.5h through all the filters.
Steps
- Reset the SGP sequence and moved the Ha acquisition event after the R, G and B filters events
- Reset focuser to 0 in Moonlite driver
- Remove caps & Install Dew Shield Extension on guide-scope
- Put the kids to bed
- Power on computer and all devices
- Launch Sky Planetarium +Open Location File + Connect to mount + Star tracking
- Launch SGP and connect equipment
- Move focuser to position 2882 (i.e. rough focus approximation)
- Scheduled the sequence to start at 20h45
- Ran sequence
- Sequence ran with no
Notes
- Centering of the object failed. Had to solve and synch manually.
- Perform a polar alignment before next run. Should help for GoTos precision, centering and autoguiding. A multiple star alignment should also be done to improve the sky modelization within the mount (i.e. OnStep).
- Multiple meteorite/satellite traces throughout the acquisition. Must analyze and select images before stacking.
- 2 minutes sub-exposures bin 2×2 through red filter are quite bright even with low stretching settings. Should include a sky background measurement step before launching the sequences to calculate the best exposure.
- Autoguiding performing ok (i.e. 0.68″ RMS). Should run Guiding assistant again to improve guiding a little.
- Stars seem to have four or five small spikes (not normal with refractors). I suspect the four small locking screws attaching the threaded rings to the carbon fiber tube (i.e. they are protruding inside the tube and might be the cause) . Will try to grind the tip of the screws and “re-paint” the tube’s interior.
