A couple more shots from Christmas day's astrophotography experiment at Otford. Canon 450D again. Sigma DC 18-200mm lens. These were quick trial shots so I didn't play around with the settings much.
Cygnus and Lyra (25/12/2014 18:19, Otford. 18mm, f/5.6, 30 sec, ISO-1600)
(http://gallery.orpington-astronomy.org.uk/albums/userpics/10063/IMG_5628_Cygnus_and_Lyra_cropped.jpg)
Taurus and M45 Pleiades (25/12/2014 17:57, Otford. 48mm, f/5, 10 sec, ISO-1600)
(http://gallery.orpington-astronomy.org.uk/albums/userpics/10063/IMG_5601_-_Taurus_and_M45_cropped.jpg)
They're pretty good Kenny, shows the light pollution of London when looking west. How did you trigger the shutter ?
Quote from: MarkH on Dec 26, 2014, 18:15:50
They're pretty good Kenny, shows the light pollution of London when looking west. How did you trigger the shutter ?
Capture details above the pics.
Cygnus and Lyra were descending towards the western horizon but even the North Downs to the northwest of Otford hiding London couldn't shield the glow.
Duncan showed me a good trick with the canon ... in settings you can lock the mirror in the up position between exposures which cuts down on vibration.
Ooh, thanks. That's useful to know. Where in the menu is that?
I was manually pressing the shutter release with 2 second delay to give me time to let go of the camera and for it to stop moving. About to invest in a remote control. But keeping the shutter open will help more.
Oh bugger the battery on my camera has gone dead. I think it was under settings, exposure, also the use of an intervalometer is useful as you can pre programe your exposures.
Nice photos, even a hint of the Milky Way!
Mirror lockup is on the Custom Function menu. An intervalometer is a tenner on ebay, also doubles as a remote release. Both help avoid camera shake.
Another go last night. Still single frames (stacking is another story / challenge).
Orion and Canis Major from Otford. Canon EOS 450D. 18mm, f/3.5, 15 seconds. 28th Dec 2014, around 1am!
(http://www.sharpfamily.org.uk/Astronomy/IMG_5691%20Orion%20and%20Sirius%20-%20cropped.jpg)
Original is here (http://www.sharpfamily.org.uk/Astronomy/IMG_5691.JPG)
p.s. I found the mirror lock setting. Plus the Long Exposure and High ISO Noise Reduction settings.
Getting a lot better Kenny!
Do you go down to Otford specially? I thought you lived around the corner to me
Fay
Nice image Kenny!
Very nice hunter and dog!
The full size version even shows colour in the Orion Nebula. However it also shows the stars to be distorted across the whole field, even in the centre of the frame. It looks to me like coma. It might indicate a problem with the lens itself or the way it is mounted on your camera.
Mark
Quote from: Fay on Dec 28, 2014, 14:51:05
Do you go down to Otford specially? I thought you lived around the corner to me
Yes and yes. It's not dark enough in my back garden and the house, trees, streetlights block the southern horizon.
Quote from: MarkS on Dec 28, 2014, 15:04:48
The full size version even shows colour in the Orion Nebula. However it also shows the stars to be distorted across the whole field, even in the centre of the frame. It looks to me like coma. It might indicate a problem with the lens itself or the way it is mounted on your camera.
Noted. I've seen that as well. Will add to my list of things to look into. Worth comparing the Nikon with the Canon kit lens.
p.s. could it be a focus problem?
Quote from: Kenny
Noted. I've seen that as well. Will add to my list of things to look into. Worth comparing the Nikon with the Canon kit lens.
p.s. could it be a focus problem?
Focusing might or might not improve things slightly. Defocused stars in the centre of the field should look "blobby" but not distorted.
Mark
I've just read that inceasing the aperture a couple of stops from its lowest value can help reduce coma. Is that something you've seen?
Closing the aperture down a couple of stops will increase the depth of feild and focusing at that distance will be much easier.
Quote from: Kenny
I've just read that inceasing the aperture a couple of stops from its lowest value can help reduce coma. Is that something you've seen?
Yes, stopping the lens down i.e. decreasing the aperture size i.e. increasing the f-ratio will reduce coma and other aberrations near the edges and corners. It will also help near the centre of the image.
Mark