The 400Mpixels mosaic Challenge, 27 panels 5 minutes perfilter
Posted: Sat Sep 07, 2024 10:27 am
Today, Victor Sabet and I are pleased to present you one of our most challenging and biggest project. Not big because of the integration time but big due to the data processing. Indeed, here is a mosaic of 27 panels.The challenging side of this project comes from the story of this picture. So let me talk a little bit about it.One year ago, our astronomy team (Olympus Mons) apply for a mission in St Veran (in the Alps, France). In the submitted project, one pane was dedicated to astrophotography. The aim was to do a mosaic of 30 panels (initially) from the lagune nebula to the Eagle Nebula for a total of 400MPixels.
Unfortunately, after our first night, we noticed that this project would be impossible because of the latitude, the down part of our mosaic was to low on the horizon. After a quick analysis of the situation we have changed completely the Field of View, for a mosaic of 27 panels from the Swan Nebula. Altought, the field is less rich in Nebulae... we were there for this project so we did it.
You are maybe wondering "where is challenging part of this picture?" Victor has a Askar FRA 600 with a reducer to reach a focal of 420mm, I have a FSQ 85 EDX with a focal of 450mm. We both are shooting with a 2600MM, it means in monochromatic. Maybe you understand where we are going. It means that for one pic we usually shoot with at least 6 filters RGB-SHO. But we’ve planed to shoot 27 panel, with 6 filters i.e. 162 pictures are needed to complete all the FOV before our leaving.
To be able to do that in record time, only one picture in S, H and O have been taken. So, we have only 5 minutes per filter per panel. Concerning RGB, we did 10*30s per filter + 1*60s (with a lot of issues, gradient, startrails,...). Finally, each panel corresponds to maximum 33minutes of integration time (some RGB frames have been discarded), knowing that the back ground is only 15minutes, the 18 minutes are only for the stars (but it was not enough, a lot of default was visible in the final mosaic, a color camera should have been perfect). We hope this picture, that is clearly not perfect, will convince you based on the very low exposition time.
https://www.astrobin.com/pgg154/0/
Unfortunately, after our first night, we noticed that this project would be impossible because of the latitude, the down part of our mosaic was to low on the horizon. After a quick analysis of the situation we have changed completely the Field of View, for a mosaic of 27 panels from the Swan Nebula. Altought, the field is less rich in Nebulae... we were there for this project so we did it.
You are maybe wondering "where is challenging part of this picture?" Victor has a Askar FRA 600 with a reducer to reach a focal of 420mm, I have a FSQ 85 EDX with a focal of 450mm. We both are shooting with a 2600MM, it means in monochromatic. Maybe you understand where we are going. It means that for one pic we usually shoot with at least 6 filters RGB-SHO. But we’ve planed to shoot 27 panel, with 6 filters i.e. 162 pictures are needed to complete all the FOV before our leaving.
To be able to do that in record time, only one picture in S, H and O have been taken. So, we have only 5 minutes per filter per panel. Concerning RGB, we did 10*30s per filter + 1*60s (with a lot of issues, gradient, startrails,...). Finally, each panel corresponds to maximum 33minutes of integration time (some RGB frames have been discarded), knowing that the back ground is only 15minutes, the 18 minutes are only for the stars (but it was not enough, a lot of default was visible in the final mosaic, a color camera should have been perfect). We hope this picture, that is clearly not perfect, will convince you based on the very low exposition time.
https://www.astrobin.com/pgg154/0/
