Last night I took some images of Saturn using CCDSoft and the ST-i - it was a sequence of 100. I was using a 3x Barlow as well.
Each shot was 0.25 seconds.
A sample cropped image:
So, while I'm happy I managed to get something, I've got a couple of questions:
1. Was 0.25 seconds too long for the exposure? I should have looked more closely last night while I was doing this and tried a few different exposure times, but this Saturn imaging was not my main aim for the night.
2. Is it worth trying to combine these images together to see if anything better can be obtained?
3. Even if it's not really worth it, I may try combining as a learning exercise. CCDSoft saved these as 100 individual FIT files. What's the best way of handling this? I did some Moon imaging a while back with my 6D taking a video - Autostakkert processed that fine, but I'm not sure about these individual files.
Hi Chris. Exposure time depends on a lot of variables, damn that's bright for 1/4 sec's. That STI is really sensitive!
Looks a little over exposed and out of focus. A 3x barlow makes getting this right, difficult to do. Depends on the native FL of the scope. A 3x on an F4...yeah should be ok but a 3X on a F8~F10, stretching the limits and you will need very clean & still air for this.
The only way to tell is to review your subs as you take them and adjust from there.
Combining subs from slightly underexposed images will brighten the final image and you can manipulate the brightness etc but it's much harder to reverse this on an over exposed image.
I was out in Brisbane last night and the seeing for high resolution imaging was pretty atrocious.
I had the ASI120MM operating at an effective focal length of 3456mm and even at that relatively short focal length (for planetary imaging) the disc of Saturn was like a rubber ball bouncing around inside the rings.
In terms of processing your images, you probably won’t get the best Saturn, given the conditions, but it might be an opportunity to practice establishing a good processing workflow for when the seeing does get good.
Yes, I'm very happy with the ST-i. I've got bits on order to put the final guiding solution in place with the OAG, but I was using it with PHD last night to guide while the 6D was piggybacked to the scope. Very impressed with the results so far (3 min subs, no star trails, etc).
Last night the sky was quite clear here, but there was some wind about. At the time I was pointing at Saturn I hadn't "refined" the alignment, so it was drifting and jumping around a bit.
I'll give this another go sometime with lower exposure times. That may make focusing a bit easier too.
I was out in Brisbane last night and the seeing for high resolution imaging was pretty atrocious.
I had the ASI120MM operating at an effective focal length of 3456mm and even at that relatively short focal length (for planetary imaging) the disc of Saturn was like a rubber ball bouncing around inside the rings.
In terms of processing your images, you probably won’t get the best Saturn, given the conditions, but it might be an opportunity to practice establishing a good processing workflow for when the seeing does get good.
Well, there you go. And I thought other than the wind it was pretty good last night. I'm still a newb.
Planetary photography isn't particularly easy. They tend to be fairly small targets and are greatly affected by atmospheric disturbance. It is quite hard to get a sharp focus also - especially in poor conditions. On the bright side - you don't need to take hours of exposure time like dso's.
Unless conditions are near perfect you probably won't get a great image from a single shot. When I have taken single exposures with a canon 550d I used 0.1 s @ iso1600 @ a focal length of 4700mm with a 9.25" sct.
The best way is to take a video and stack say the best 50% (I use registax) - this will take out most of the disturbances and then you can use wavelet filters to sharpen the image.
Planetary photography isn't particularly easy. They tend to be fairly small targets and are greatly affected by atmospheric disturbance. It is quite hard to get a sharp focus also - especially in poor conditions. On the bright side - you don't need to take hours of exposure time like dso's.
Unless conditions are near perfect you probably won't get a great image from a single shot. When I have taken single exposures with a canon 550d I used 0.1 s @ iso1600 @ a focal length of 4700mm with a 9.25" sct.
The best way is to take a video and stack say the best 50% (I use registax) - this will take out most of the disturbances and then you can use wavelet filters to sharpen the image.
What movie settings do you use for the 550D? I've been avoiding use of the 6D for this type of imaging since I thought the pixel size wouldn't be the best.
I haven't had much luck with Registax (v6) - it crashes on me a lot. I may give it another go and hope for the best.
I just did a search for your images and saw the Saturn pic - impressive and inspiring.
I use the cameras default settings.
Movie rec. size - 1920 x 1080. Apparently webcams can be good for lunar and planetary imaging - but I haven't tried that.
The main part is to get a good focus - what scope are you using?
Unless you have exceptional optics then you need quite a long focal length - which makes it harder to focus.
If you get a good image you can enlarge it using photoshop - but enlarging the image does magnify any faults.
Registax should work - but you still need a good in-focus video (about 5 minutes is enough). Wavelet filters help a lot with the stacked image. When you select the reference points in registax make sure you use a frame that isn't distorted.
I'm using the RC10 and in this case also a 3x Barlow. I think I might have gotten better focus if I realised I was over exposing the image, and I had done better alignment to stop the drift.
As for Registax, perhaps one of the reasons it doesn't work for me is that I'm giving it rubbish to work with.
I can confirm the seeing in SEQ Saturday night was awful. I wasted an hour trying to get some useful images of Saturn, but neither Registax 6 or Autostakkert! 2 could salvage anything.
It feels like there's about 1 or 2 days a year that you can do anything worthwhile after you eliminate all the bad stuff! Clouds, rain, wind, Game of Thrones, etc :p
