Taking high number of shots for stacking with Canon 350d - possible?

[bradfrankshaw]

Hi all - I've been using our family Canon 350d for long (60 second) exposures over the last week to see what I can get. Stacking is the next thing to try out - I have a ToUCam Pro II but no adaptor yet. I've looked up in Stellarium and Jupiter rises over my location around 4am, so I was thinking of giving that a go.

From what I understand you have about 3 minutes to get as many shots as possible before Jupiters high turn rate starts to affect the shots. With that in mind, and I think the shutter speed has to be about 1/125th ish otherwise the light from Jupiter will wash out the bands, colours etc.

But will I physically be able to fire off enough shots to count? The 350d doesn't a) have Live view and can't take avi files. So it'll need to be manual firing from the cable release.

So do I try or wait until I get the webcam adaptor?

cheers

frank

[JKB]

Hi Frank

Hey anything is worth a go and I have tried this method before with DSLR on Jupiter with the 150P. Focusing is a real pain and due to atmospheric instability you might get a shot in focus only to find all the rest are really poor and out of focus. Also due to the sensor size Jupiter will still seem painfully small. With the webcam the image will be bigger (albeit not much) and you will find focussing 'easier'.

HTH

Cheers

Jamie

[todd8137]

I think the big chip will yield a very small image

[ollypenrice]

Hi Frank

Hey anything is worth a go and I have tried this method before with DSLR on Jupiter with the 150P. Focusing is a real pain and due to atmospheric instability you might get a shot in focus only to find all the rest are really poor and out of focus. Also due to the sensor size Jupiter will still seem painfully small. With the webcam the image will be bigger (albeit not much) and you will find focussing 'easier'.

HTH

Cheers

Jamie

No no no, the image will be exactly the same size! With the larger chip you will just have more sky round it. Downloading all this unwanted sky will slow you down no end, which is where a fast frame camera comes into its own.

Sure, a planet will look small on a large chip but only becaue your PC zooms out the image so it all fits on your PC screen. The real image scale is dependent only on the focal length of the optics. (If you were to pinch the Mona Lisa and cut a six inch strip off each side, would the face get any bigger?)

Planetary imaging does need a fast frame rate (video capture) to beat atmospheric turbulence.

Olly

http://ollypenrice.s...39556&k=FGgG233

[jetstream]

No no no, the image will be exactly the same size! With the larger chip you will just have more sky round it. Downloading all this unwanted sky will slow you down no end, which is where a fast frame camera comes into its own.

Sure, a planet will look small on a large chip but only becaue your PC zooms out the image so it all fits on your PC screen. The real image scale is dependent only on the focal length of the optics. (If you were to pinch the Mona Lisa and cut a six inch strip off each side, would the face get any bigger?)

Planetary imaging does need a fast frame rate (video capture) to beat atmospheric turbulence.

Olly

http://ollypenrice.s...39556&k=FGgG233

I just learned some more again,thanks...

[JKB]

No no no, the image will be exactly the same size! With the larger chip you will just have more sky round it. Downloading all this unwanted sky will slow you down no end, which is where a fast frame camera comes into its own.

Sure, a planet will look small on a large chip but only becaue your PC zooms out the image so it all fits on your PC screen. The real image scale is dependent only on the focal length of the optics. (If you were to pinch the Mona Lisa and cut a six inch strip off each side, would the face get any bigger?)

Planetary imaging does need a fast frame rate (video capture) to beat atmospheric turbulence.

Olly

Sorry Olly.

I said 'seems' smaller but didn't make myself clear. Of course the actual image size is dependant on FL of the optical train.

Having a video capture of say 800x600 of the Webcam compared to say 3504x2336 of a DSLR (using my personal kit as reference) makes the point of interest appear different sizes.

I think the scale confusion is over exaggerated in the human mind: For example if you put a DSLR at prime focus through, say the 150P, and image the moon it will fit on a single image frame. Doing the same with a webcam and you will only see a smaller part of the moon, and hence appears magnified by around 4x compared to the DSLR (using the pixel ratio mentioned above).

Possibly this diagram might help explain better?

Hope that made sense? One thing though. Quite often webcams have a smaller imaging pixel size compared to DSLR's which increases the resolution. Although this increase might be small our brain will interpret it along with the 'bigger' image it sees.

Hope I have cleared that up

Cheers

Jamie

[hobsey]

But will I physically be able to fire off enough shots to count? The 350d doesn't a) have Live view and can't take avi files. So it'll need to be manual firing from the cable release.

Unfortunately I cant help you out with anything else but as for trying to count the shots, I think a programmable would be more suited than a single one button remote.

I have the same camera and I have this remote,

http://www.amazon.co.uk/Digital-Timer-Remote-EZA-C1-Canon/dp/B003VIEDRO/ref=sr_1_3?ie=UTF8&qid=1378505907&sr=8-3&keywords=350d+remote

I have yet to try any astrophotography with it.

[ollypenrice]

I was responding to the phrase 'on the webcam the image will be bigger' which, of course, it won't. But point taken. Sure, small pixels improve resolution and drizzle stacking of fast frame data can allow you to resize (upwards) an image.

I'm banging on about this a bit because, having paid a lot of money for a full frame camera for folks to use, I've a number of people saying objects might now look too small. It doesn't work like that!!

Olly