Over the weekend, I finally scanned the Acros from Calstar XX.
The good news is that the 400mm takumar lens performed very well with the light pollution filter. There is better contrast with nebulosity. This is surprising, given the poor Ha response of the film. I think that the filter's removal of skyglow helps to improve the image by keeping the film from fogging early. With the filter in place, a 60 minute exposure is easily within the limits.
The bad news is that there is trailing on every single photo. I'm not sure what's the cause of this problem. When reviewing the digital images in the field, I saw little indication of trailing and the tracking graphs were solid.
I will need to do analysis on the frames and see if I can figure out if the trailing is all in RA or a mix of RA and DEC. This camera changed mounts, so I'm expecting to see different behavior.
I will also need to check the digital frames during this time and see if they also show the trailing.
This does not bode well for the color film results, which is a bummer.
I guess I have my work cut out for me over the coming months to prepare for spring Calstar when I try this all over again.
If it turns out that the trailing is in DEC, then the challenge will be to tighten up that axis. Anthony DLC has recently gone with a bungee cord to apply tension in DEC. In the past, I've used gravity to apply a bias. I can see how the bungee cord may be a better solution, since it would give tension in all positions, even when gravity doesn't give much offset.
In talking with my neighbor about the challenges, I mentioned that this kind of photography is much like any other "spray and pray" because there's a lot of guesswork about whether the focus is right, framing is good, no airplane trails, and that there was no camera shake. This last part is the biggest challenge that I have.
Now I'm wondering if I should be going back to drift alignment after doing the polemaster work. Wouldn't hurt to check it once or twice. The PM is fine for digital work where the exposures are shorter.
At least when viewing at 1:4 size in Lightroom I can't see the trails.
The good news is that the 400mm takumar lens performed very well with the light pollution filter. There is better contrast with nebulosity. This is surprising, given the poor Ha response of the film. I think that the filter's removal of skyglow helps to improve the image by keeping the film from fogging early. With the filter in place, a 60 minute exposure is easily within the limits.
 |
| As Seen on the Screen |
The bad news is that there is trailing on every single photo. I'm not sure what's the cause of this problem. When reviewing the digital images in the field, I saw little indication of trailing and the tracking graphs were solid.
I will need to do analysis on the frames and see if I can figure out if the trailing is all in RA or a mix of RA and DEC. This camera changed mounts, so I'm expecting to see different behavior.
I will also need to check the digital frames during this time and see if they also show the trailing.
This does not bode well for the color film results, which is a bummer.
I guess I have my work cut out for me over the coming months to prepare for spring Calstar when I try this all over again.
If it turns out that the trailing is in DEC, then the challenge will be to tighten up that axis. Anthony DLC has recently gone with a bungee cord to apply tension in DEC. In the past, I've used gravity to apply a bias. I can see how the bungee cord may be a better solution, since it would give tension in all positions, even when gravity doesn't give much offset.
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| Starry Trails... not the good kind. |
In talking with my neighbor about the challenges, I mentioned that this kind of photography is much like any other "spray and pray" because there's a lot of guesswork about whether the focus is right, framing is good, no airplane trails, and that there was no camera shake. This last part is the biggest challenge that I have.
Now I'm wondering if I should be going back to drift alignment after doing the polemaster work. Wouldn't hurt to check it once or twice. The PM is fine for digital work where the exposures are shorter.
At least when viewing at 1:4 size in Lightroom I can't see the trails.
 |
| Nice how the Acros shows the full tail of the cocoon nebula. |
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