Noctilucent clouds - issues with taking snaps and other photographic questions

[JOC]

There doesn't seem to be a forum for discussion of how to take photo's of the night sky and related stuff - I'm not an 'imager' as such and wouldn't want to contaminate their 'image' with my clumsy snaps, hence posting here.

Now I recall the competition on Noctilucent clouds and remember thinking that I knew nothing of these.  Anyhow as a result of that thread I found out about them, but still couldn't clap eyes on any.  Then last night (when I was off out with very little time to experiment) the most amazing 'glow-y' clouds appeared almost completely blanking out the sky.  Thinking that I'd be able to post a picture and post it asking if I had finally seen some proper noctilucent clouds I raced outside with the DSLR, Tripod, 18-55mm lens (took it 150 yards to beyond the hedge) and had a quick snap.  To begin with I left the focus on auto - thought I'd got it - difficult to tell in the dark on the small camera screen and raced back in to the computer.  Really disappointed to find that the autofocus had let me down entirely, but I'll post below the best I took whilst the clouds covered the sky as someone might still be to say if these were these noctilucent clouds.

So I'm really running out of time at this point, but have realised that manual focus is the best way forwards.  Changed the camera setting, and then realised that I didn't know how to turn the little screen off on the camera and consequently I am blinded when it comes to focussing through the eyepiece and I can't find the controls in the dark to focus through the camera screen.  In addition, most of the huge cloud coverage had miraculously vanished to leave just the odd wisp.  That a photo of that is below, but you can see that my focus is definitely still out - lovely sharp trees!!! though.  LOL  Again given this further example were these noctilucent clouds?

Appearing above was a lovely starry sky and Orion was hanging in front of me - I had just a few minutes left - snapping on my 'auto' settings didn't cut the mustard and I remembered reading about needing a fast ISO speed - so I stuck it on manual settings, managed to fiddle it to an ISO 800 and the max aperture of f5.6 - this gave an auto exposure of a good few seconds, but it didn't seem excessive.  I was still struggling with he same focus issue as the clouds.  So what I did was to manually alter the focus minutely over a number of photos I the hope of getting one good one.  The two best are below.  I'd be interested to know if the blurriness that still remains is the product of the relative movement of the stars over a few seconds or because I missed the focus or both!

Finally it must be possible to 'snap' a widefield view of a starry sky (or night-time clouds!) with a DLSR and a tripod (I've seen pictures of it done).  How is the focus achieved please?  As I get the impression that success is within my grasp, but I'm clearly missing something vital - many thanks.

 

[oobydooby]

Sadly these were not NLC.  They are very distinct and I am sure you would know them when you see them. Also this is the wrong season for NLC, which is starts round about April/May. One of our society members is the co-ordinator for NLC for the British Astronomical Association, I will have a chat and see if he can give you any advice on what to look for as I have very little experience of NLC.

You did, however get a good couple of shots of Orion.

[JOC]

1 hour ago, oobydooby said:

Sadly these were not NLC.

That's a shame.  I wonder what was illuminating them then.  It was pitch dark outside and all the clouds were lit from the underside and I don't think we have sufficient large towns nearby to account for it via light pollution.

[Gina]

Clouds can be lit up long after the sun has set from ground level.  Likewise I've seen clouds lit by the moon a couple of hours before moonrise.

[LukeSkywatcher]

I've only seen NLC once and I'm not 100% sure if they were NLC. I'm 90% sure. 

[Gina]

I don't think I've ever seen them.

[JOC]

Well at least that makes me feel a bit better - they are clearly not a common phenomenon.

[Gina]

Indeed not.

[Mognet]

It's currently out of season for noctilucent clouds, but they are very distinct. They are quite high in the atmosphere; thin, whispy and iridescent. I've only knowingly seen them once, but before last summer I had never looked for them. The SGL NLC competition thread has some good examples https://stargazerslounge.com/forum/227-imaging-challenge-4-noctilucent-clouds-now-closed/ These look more like clouds illuminated by lights from a nearby town whereas NLC are lit by the sun from below the horizon.

When I do astrophotography with my DSLR and normal camera lenses, focus is mostly by guesswork. Modern DSLR lenses are apparently able to focus 'over infinity' which is something to do with the auto focus system, so a bit of manual intervention is required to find out where the real infinity focus is. If you have a distant light, the use automatic focus on that to get the approximate focus for the stars, or if that's not an option just find one of the end stops of manual focus, and then switch to manual focus and put the camera on the tripod. Use the 400 rule for exposure time (400 divided by the focal length is the approximate number of seconds before star trailing becomes evident) and after taking each photo, check the image, including zooming in and checking the corners, and make subtle adjustments to the focus before trying again. Even though I've been doing it a while it can still take a dozen attempts before I have sharp focus. I generally use ISO 1600 and go down two or three stops from the widest aperture to get sharper stars.

Saying you used the maximum aperture of f5.6 suggests you had zoomed in as much as possible (55mm focal length). Going to the opposite end at 18mm FL will capture more light from a wider field, and with the 400 rule will allow for longer exposures (22 seconds vs 7 seconds)

It's also handy to have a remote trigger, or use the ten second timer, to prevent camera shake interfering with the image sharpness