Noel Carboni
March 2nd, 2007, 11:05 AM
Some time ago I took literally hundreds of photos of the brightest part of M42, the area around the Trapezium.
I was just experimenting with the demo version of Maxim DL, restacking parts of the exposure set, as well as all of it. In the past I have been using a licensed copy of Images Plus by Mike Unsold, but it does not have an "auto star alignment" feature like Maxim has.
Anyhoo, these images were taken with my Canon EOS-20D on my 10" Meade LX200 GPS UHTC telescope and with my Powermate 2x (yielding 5000mm f/20). The telescope is in alt-az configuration and is not guided. They are stacks of 20 of my shortest exposures of 4 seconds at ISO 200, and 180 or so of the best of the entire set, which ranged all the way up to 10 seconds at ISO 3200. The shortest exposures of course resolved the stars more clearly, while the nebula is more prominent in the longer exposures.
By the way the biggest problem with exposures this short is that the telescope shakes a tiny bit when the shutter opens, yielding a slight out-of-round shape to the stars. I am using mirror lockup, but there's still that physical shutter in the dSLR that moves everything a little, at at 5000mm one doesn't need to move things much to end up with non-pinpoint stars.
-Noel
I was just experimenting with the demo version of Maxim DL, restacking parts of the exposure set, as well as all of it. In the past I have been using a licensed copy of Images Plus by Mike Unsold, but it does not have an "auto star alignment" feature like Maxim has.
Anyhoo, these images were taken with my Canon EOS-20D on my 10" Meade LX200 GPS UHTC telescope and with my Powermate 2x (yielding 5000mm f/20). The telescope is in alt-az configuration and is not guided. They are stacks of 20 of my shortest exposures of 4 seconds at ISO 200, and 180 or so of the best of the entire set, which ranged all the way up to 10 seconds at ISO 3200. The shortest exposures of course resolved the stars more clearly, while the nebula is more prominent in the longer exposures.
By the way the biggest problem with exposures this short is that the telescope shakes a tiny bit when the shutter opens, yielding a slight out-of-round shape to the stars. I am using mirror lockup, but there's still that physical shutter in the dSLR that moves everything a little, at at 5000mm one doesn't need to move things much to end up with non-pinpoint stars.
-Noel