Star Trails in the Field

[iceman]

Hi all

I've never done any star trail images before, and wanted to give some a try at SPSP. I didn't know what ISO to use, how long each exposure should be etc, so I just guessed.

23 images x 5 min exposures @ ISO400, with an unmodded Canon 350D on a fixed tripod (obviously). No dark frames or flats applied.

I'm pretty pleased with how it turned out, but I wanted to do more.. My run was cut short by the lens fogging up :(

Anyway it was good practise for next time. Next time i'll use longer exposures, and take some darks and flats. I'll also use a dew strap on the lens, and i'll use a timer remote (or the laptop).. I didn't have one, so I was running back and forth between this camera and my scope to press the button every 5 minutes :lol: I also had to change batteries a few times which caused some gaps when one exposure wouldn't write out to the card because of low battery.

1200px image here:
Star Trails in the Field at South Pacific Star Party (http://www.iceinspace.com.au/mygallery/displayimage.php?pos=-680)

800px version attached. The second attachment was a test shot from the Friday night using Chris' modded 350D, but when the smoke came I had to stop. The third attachment is an example of a ruined exposure thanks to Rod wandering over with his red-light torch and wondering what i'm doing :lol: thanks Rod :D

Thanks for looking.

[matt]

Pretty cool shots, Mike:)

I really like the first one in terms of overall composition...although the second is good in terms of the area of sky and stars covered. It's interesting to see the Milky Way with one of the MCs down to the right...with all those stars trailing.

Good stuff.

[middy]

Very nice Mike, I love star trail photos. The third one looks like a genie coming out from a magic lamp. So what did you wish for? :)

[iceman]

lol I wished for Rod to get out of my bloody shot ;)

John (xstream) came over and stood in front of the camera in the next shot, but luckily he didn't have any lights on :)

[Terry B]

Nice images.
This is where the film camera still has the edge. Just put it on bulb and leave it for a few hours. No problems with darks etc.

[[1ponders]]

Classy shots Mike. Just imagine what they would look like if you did some at the Qld Astrofest. You could start a collection going. "Startrails from Australian Amateur Astronomy Festivals and Parties" ;)

[RB]

You're lucky you didn't trip over your own setup this year Mike.........:poke: :lol:

They turned out nicely in the end.

[erick]

Nor, for the older cameras, are flat batteries a problem - no batteries to worry about for star trails shooting!

[omnivorr]

Those are really interesting shots Mike! ..even the 'ruined' one is educational ;) I notice the small gaps between frames (?) in each individual trail... I guess this is the time it takes for enuff photons to register.. also, it's fascinating to see the difference in trail from the SCP to the outer edges of the frame, and the additive effect of overlapping trails.. now if you had two identical cameras, ideally aligned, shuttering at alternate intervals, and interleaved their 'stacks'.. mmmm....;) Damn these clouds!! I wanna see that SCP!! Another point that crosses my mind.. longer exposures would effectively 'hide' the lag gaps, I'd expect.. but judging by the length of the trails at 5min, ..something p'haps longer than 20min would be needed(?).. how would this effect the noise and soforth?

Inspirational stuff Mike :) ..and aesthetically, I like your framing of foreground etc.. lovely 'solarised' outlines.. just a couple of reflections from that nearer light to subtract from it.

Cheers Russ

[iceman]

Thanks for the comments guys. I really enjoy doing star trails now.. I've bought the $40 timer remote from ebay, and i'll work out how to power the camera off 12v so i'll be able to do more.

Problem is I need to travel to do them - Sydney to the south = skyglow!


Hi Russ
The gap is the time taken to finish one exposure and start the next, probably with a little time before it starts registering. Ideally I should've done 10min subs instead of 5, to reduce them.


Yes, 20 minutes would be better, but the noise would increase and unless the sky was really dark, you'd get a lot of skyglow. Ideally they need flats and darks with them too.

[Omaroo]

I like these shots Mike. Well done!

Here's a copy of something I put up on a photographic forum a while ago. It lets you perform really short exposures - so in theory you shouldn't need to take darks. I think the package has been mentioned here somewhere before too.

[omnivorr]

...really informative Mike and Chris!! thanks very much!! ..now something more to be DOING rather than wrestling with the envy monster that inhabits the clouds..

..and CLEAR SKY wishes to all, this International Sidewalk Astronomy Night!!! :D

[dugnsuz]

I love that first shot Mike.
Promotional poster material that is!!
Doug

[iceman]

Thanks guys, and thanks Chris. StarTrails.de is actually the software I used to create the images above. Really great software - lets you subtract darks, does an ADD for the star trails or an AVG for the foreground, and can turn it into a movie if you want to.

Steve Mogg did a nice movie with very short exposures (hundreds of them) with the camera set up at one end of the field and using a little gadget he made to control the shutter. Check it out at www.moggadapters.com. I reckon it would've looked even better if it was pointing more towards the south, but he wouldn't have got as much of the field in.

[Tamtarn]

The first image is a ripper Mike. Look forward to your next session.

Also thanks for the link to Steve's movie