visual image v photo image

[Budding Star Gazer]

just a quick question about astro photography.

when you look through the image forums there are some amazing photo's and i was wondering what the difference is between the visual image and the photo is, do you see the image as you do in the photo or is the use of the zoom function on a camera employed.

you may think it's a daft question but i know zip about astrophotography

thanks.

[Keiran]

No, you dont see the same in an AP image as with your eyes.

At night you only use the black and white cones in your eyes. These are more sensitive to detail at night, this is why everything you see in the dark looks monochrome.

A camera is more sensitive than your eyes at night, and most of the images you will see in the imaging section are made up of numerouse photos (for example 50photos (or subs)) and each photo the cameras sensor has been imaging for a length of time (for example 5 min). So e photo on the imaging section could be made up of 100's of subs and over 20hoirs.

Keiran

[Matt Scunthorpe]

You will see a grey fuzzy blob . Still pretty amazing though when you think what your actually looking at.

[Pete Presland]

when i am imaging, my images are transfered to my laptop as soon as they are taken.while they are stacked and processed after the session, you can still see much more detail via the PC viewing than you would looking directly through the eyepiece.

[Moonshane]

just a quick question about astro photography.

when you look through the image forums there are some amazing photo's and i was wondering what the difference is between the visual image and the photo is, do you see the image as you do in the photo or is the use of the zoom function on a camera employed.

you may think it's a daft question but i know zip about astrophotography

thanks.

if you mean do you see the image through your scope with your eyes (no camera) then it's definitely no. if you mean do you see the final image on the preview screen of your camera then it's pretty much a definite no also. most top quality images take many hours of processing, stacking of different images and then more processing and then gathering more data and then you see the final image.

[RikM]

Shane has it exactly right. Most deep sky images are built up from many hours exposure time and are nothing like what you can see through the scope withyour own eyes or even what you get from a single exposure.

Here is a screen shot from a single 5min exposure straight off the camera:

And if you stack about 50 of those together and spend a few hours working on it you end up with:

This image is more or less the full frame from a Canon 1000D DSLR fitted to telescope with 750mm focal length. So no on-camera 'zoom' but the equivalent of a big telephoto lens on the front.

[Budding Star Gazer]

sounds like a lot of work but the results are amazing, i know they do stuff like photographer of the year but i have to wonder why you don't see more of these images in national art galleries, i'm going to pay a vist to the greenwich observatory http://www.rmg.co.uk/visit/exhibitions/astronomy-photographer-of-the-year/ one day next week, fascinating stuff.

cheers for the replies.

[Ant]

When people ask me what the difference is (in what you see), I usually point them towards the sketching section.

This generally a much more accurate guide as to what you'll see in the eyepiece. But even then some of the sketchers are very good at it and have learnt how to see more.

cheers

ant

[RikM]

Here is a little side by side I did a while ago, showing the difference between an hours exposure time with a camera on a 6" Newtonian vs. a sketch through a 10" Newtonian with a UHC filter.

[Budding Star Gazer]

When people ask me what the difference is (in what you see), I usually point them towards the sketching section.

This generally a much more accurate guide as to what you'll see in the eyepiece. But even then some of the sketchers are very good at it and have learnt how to see more.

cheers

ant

if you had not pointed out that the right was a sketch i'd have never guessed, thats pretty blumming good.

i thought i knew what i wanted from a scope but now i'm not so sure, photography will mean spending way more money and learning a whole new aspect of astronomy, like my head isn't pounding enough already, but it will be worth the time and effort.

[ollypenrice]

When it comes to faint detail the camera wins hands down because it can collect light over time which the eye cannot. So you can reach far deeper into the faint details outlying M42 with a camera once it's been drinking photons for 18 hours or so...

But, and this is imortant, the same small telescope (85mm aperture) with an eyepiece in it will easily resolve the four bright Trapezium stars at the heart of this nebula whereas it is only just possible to resolve them in an image. The same scope will, thereofore, split double stars better with an eyepiece than a deep sky camera. It will also give you a different kind of buzz!

Olly

[nephilim]

Beautiful photo Olly, I've just made my first small step into AP by buying 'Making every photon count'.

[ollypenrice]

Beautiful photo Olly, I've just made my first small step into AP by buying 'Making every photon count'.

It is most certainly the right step. You've made the perfect start. It wasn't around when I started so I did an awful lot of fumbling and mis-spending to start with!

Olly