Here is another consecutive clear night... this is so awesome!
Tonight my friend Miquel and I were talking about getting larger field higher resolution images. We discussed larger chip cameras, smaller focal lengths, drizzling, and the like. We ended up talking about mosaics. I've never done one. He's never done one. I can't imagine how folks get them to be seamless - particularly the sky background.
So I took the plunge and decided to try my hand at a mosaic. Since there aren't that many large targets up right now, I decided to wait until the wee hours and shoot the North American Nebula and the Pelican Nebula.
I mocked it up with a screenshot from StarryNight and the reticle's overlaid in Photoshop (image in the gallery). Since it's an Ha target and my sky isn't that dark, coupled with the fact that I didn't want to take that much time to do the experiment, I decided to shoot a single hour of H-alpha on each frame. We're talking about 3 subs each panel at 20 minutes per sub.
I set up the first frame (NGC 7000), shot for an hour, and tried about a 15% to 20% overlap when setting up the next frame (IC 5067). I got it as close as I could to the screenshot I mocked up. I missed it by a little, and I didn't take cropping the edges for the stacking lines into consideration, or that as RA shifts, the angle of the camera shifts a little, but in the end it worked out fine. Also, it turns out that I could have done it with less overlap I think.
I don't really know what to call this shot from a time stand point. each frame was 1 hour, so it's kindof 2 hours of data. But as a whole, the shot is one hour "deep" (if that makes sense). So it seems like a 1 hour, 2 panel shot to me. I don't know... anyway...
NGC 7000 / IC 5067 Two Panel Mosaic in H-alpha
Scope: AstroTech AT65EDQ
Mount: Orion Sirius EQ-G with GoTo
Guiding: Meade DSI Pro and PHD Guiding
Guide Scope: ATM 60mm f/4.1 Achromat
Camera: Canon EOS 1000D (Modified) w/ Astronomik 12nm H-alpha EOS Clip-In Filter
Special Settings: None
Exposure: 1 hour per panel for a total of 2 hours (6 x 1200 seconds)
Processing Software: Acquired in Nebulosity with Extreme Dither, Calibration and Stacking of each panel in Deep Sky Stacker, Mosaic combine in PixInsight, Levels/Curves/Enhancements in Photoshop
Support Files: 30 flats, 30 bias, 1 dark used as a Bad Pixel Map