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Afocal basics.


Sobel

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So I have an 8SE and it has been a lot of fun to use. But I wanted to at least document things I look at for 2015 so bought myself a universal camera mount for my point and shoot camera, Panasonic TZ40.

Question is (not yet managed a clear night to try it) do I either take a standard photo? Use the night sky feature (15 or 30 second exposure) or use the video function.

First target will be the Moon with a neutral density filter (which helps massively with the viewing) shall I keep the filter on and record a video and try breaking it down into individual files to use in something like registax or do I simply use the standard photo feature, or even a 15 second exposure?

Same question for planets, I imagine a video would be best then import to registax? 

But for DSO object, like say Orion Nebula, what sort of image would a 30 second exposure get from a point and shoot, I appreciate this is a "How long is a piece of string question"

I'll probably end up experimenting, just wondering what other people may have experienced.

Peter.

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The piece of string is the easy one to answer! It will be  twice as long as half its length? The rest might just come down to trial an error.

I have managed a few simple shots with Android and Nikon, both hand held. As for my Nikon, If I used Movie, I would have to convert the file into data that registax can understand, as for the rest, keeping the camera/ phone stable is my problem without a solid mount attached to the focuser.

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Hello Peter,

I would recommend taking standard photos (with shutter delay, rather without a ND filter) of the Moon and record a video of planets. DSOs are a bit more difficult, the camera's software can also add a bit of pain. You have to check whether you'll be getting longer exposure times WITHOUT software lowering ISO (as Canon point-and-shoots behave) in order to capture as many photons as possible, otherwise it's useless to even start trying.

Regards,

Marcin

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Here are some afocal shots of DSOs I did many years ago with an Olympus 2020z http://community.dur.ac.uk/nigel.metcalfe/astro/web.php which had a maximum of 15 secs exposure (and had very high thermal noise). I imagine modern cameras can do much better - the trick is getting the eyepiece and camera well matched. Some combinations work well and some don't. I wouldn't worry too much about ISO - you still get the same number of photons whatever ISO you are at. Aperture is probably more important - you need to try and ensure the camera aperture is as big as the exit pupil of the eyepiece, or you will lose light.

NigelM

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Here are some afocal shots of DSOs I did many years ago with an Olympus 2020z http://community.dur.ac.uk/nigel.metcalfe/astro/web.php which had a maximum of 15 secs exposure (and had very high thermal noise). I imagine modern cameras can do much better - the trick is getting the eyepiece and camera well matched. Some combinations work well and some don't. I wouldn't worry too much about ISO - you still get the same number of photons whatever ISO you are at. Aperture is probably more important - you need to try and ensure the camera aperture is as big as the exit pupil of the eyepiece, or you will lose light.

NigelM

Impressive!

Olly

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