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DSLR AVI's for Solar System objects


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I was wondering exactly the same thing myself.

Was also wondering about using an HD camcorder that I've got but I've just realized that it has a CMOS sensor so presumably not ideal in terms of low-light sensitivity.

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I would have thought the image would be very small.

That's not so much of an issue, the pixel density of modern DSLRs is actually a bit bigger than that of most dedicated cameras like the DMK21; however you are recording an awful lot of black space; also, you really need to record "raw" to be able to stack & enhance images, and I don't think DSLRs do that (not enough memory bandwidth). The frame rate is also lower than we would like to use on the brighter targets.

The movie mode of DSLRs is a bit of a feature rather than something useful IMHO. If you want a movie camera, buy one.

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The frame rate is also lower than we would like to use on the brighter targets.

What's the frame rate of a webcam? My DSLR is quoted as 60 FPS at both 640x480 and 1280x720 resolution (I'm presuming the former would be more suitable in this case).

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Interesting stuff, especially the link to Canon-40D-webcam from Merlin66. That makes the video function sound quite useful. I'm thinking about getting a new DSLR with 'liveview' but many are now including video - which to me would be an added bonus if it works ok in Registax or DSS. Still seems worth thinking about.

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I'm not sure exactly how many frames was stacked, but it wasn't many, as i had a very bad seeing conditions that day. I think i limited the stacked frames to around the ~150-200 best frames out of nerly 6500 frames.

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Can anyone tell me if it is possible to use the short video function on a digital SLR camera (if it has one of course) to record AVI's of Solar System objects for stacking? If so what are the results like?

I use the "crop" movie mode on my Canon 550d for planetary imaging, along with a celestron 8-24mm eyepiece. The eyepiece has T-adapter threads which makes it easy to use. With eyepiece projection you can get a reasonable size image.

With crop mode the DSLR uses the center portion of the CCD which gives a better scale than using the whole CCD.

Better than crop mode (i think) is recording the liveview output with something like eos_movrec. This method can give a similar crop but with advantages when trying to center the planet in the record window. Maybe this isn't clear... Part of the difficultly at high mag is getting the planet centered in the small area of the CCD, but with eos_movrec you can see the whole CCD area and move around the record window until the planet is centered the way you want.

Here are two images I made with my Canon DSLR using the native crop mode. eos_movrec yields results that appear identical to me, but eos_movrec is easier to use. This is with a 8" newtonian telescope. Focus appears off a little for Jupiter; notice the smear on Io. Now that I'm using a Bahtinov mask my focus is much better. I would highly recommed the B mask even for people that use liveview for focus.

Good luck!

Doug

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it works fine. here's one with explorer 200 (1000mm F/5) pds and canon 550d. taken at 640*480 crop 50 fps, no barlows used.

I don't know if I am missing something in the menus but I tried Jupiter the other night with my 200P and 550d but just could not get a good image. Jupiter was just too bright and in the movie record mode I could not see how to change this.

I am a newbie with DSLR's and as I said I may have missed something. I done some avi's of the moon and these were fine as the camera adjusted the exposure? so it wasn't so bright but didn't do it with Jupiter.

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I don't know if I am missing something in the menus but I tried Jupiter the other night with my 200P and 550d but just could not get a good image. Jupiter was just too bright and in the movie record mode I could not see how to change this.

I am a newbie with DSLR's and as I said I may have missed something. I done some avi's of the moon and these were fine as the camera adjusted the exposure? so it wasn't so bright but didn't do it with Jupiter.

Using auto exposure will work OKish on the Moon, as it is large enough to fill the frame (or fill a substantial portion of it). The way auto-exposure works is that (depending on the a-e mode used- centre-weighted/spot/average) the camera works out the exposure based on a relatively large portion of the image. The moon appears big enough to give the a-e a fighting chance.

With a planet, the actually image is so small on the sensor that the a-e hasn't got a chance, and it tries to expose for the majority of the frame- which of course, is black. This means that the camera over-exposes the planet completely. Use manual exposure for planets...just play around with the settings until you get the correct one.

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Thanks for the suggestions. Found movie exposure in the settings for the camera and I think I just need to set this to manual and play about with the settings.

Just need a clear night to try it !!

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Thanks for the suggestions. Found movie exposure in the settings for the camera and I think I just need to set this to manual and play about with the settings.

Just need a clear night to try it !!

Hi Geno,

I have this camera too, and wondered where did you find the movie exposure settings?

Thank you

Carol

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Make sure you are in movie mode, press the menu button, second tab across, first item in list is Movie Exposure. I set this to manual, haven't had chance to try it yet. Hopefully it's the right setting for what I want ??

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Very nice picture of Jupiter there.

I was using EOS movie record but as I said I could not get the exposure to work, hopefully the clouds will clear soon to have another go.

What adapter do I need to connect my DSLR to my barlow (2x Tal). I have a 2" T adapter and T ring which obviously does not fit my 1.25" barlow. Will something like this work??

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Thanks for the suggestions. Found movie exposure in the settings for the camera and I think I just need to set this to manual and play about with the settings.

Just need a clear night to try it !!

Forget this post should have RTFM. Was setting camera to movie mode as I ASSumed this is what I needed. With EOS movie record you set the camera to manual :).

Hopefully clear night tonight to try again.

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Yep, it's a bit of a balancing act between exposure time and gain. As little gain as possible while maintaining as fast an exposure time as possible. I never use automatic gain unless I'm hunting for my "target", and haven't yet established what manual settings to use.

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