Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: Carole on May 18, 2015, 22:55:01

Title: Star trails - Cairds Campsite
Post by: Carole on May 18, 2015, 22:55:01
My first attempt at doing star trails. 
I was restricted as to where I could place the camera as I wanted to use the laptop and don't yet have Red plexi glass for my 2nd laptop, so I had to place the laptop in the van which meant I could only place the camera close by and trail the cables through the window.

On one side was Fay's glamping POD and car in the foreground obscuring the trees so I imaged the opposite side looking at the trees towards the SW and also looking at the trees that were lit from time to time by passing cars.

My new laptop went to sleep during one image which ended up 20 minutes long, so I presume the laptop didn't tell the camera to stop the capture!!!  (Had to tweak that sub as it was far too pale as I didn't want a 20 minute gap in the trails) and also tweak the laptop so it wouldn't do it again. 

Anyway, here it is:

49 x 2min subs 800 iso F5.6 modified Canon 450D

(http://cdn.astrobin.com/images/thumbs/6f4d258ad53f30861f2570a9cbf7ea1b.1824x0_q100_watermark.jpg)
Title: Re: Star trails - Cairds Campsite
Post by: Fay on May 18, 2015, 23:08:14
That looks ok Carole, what the red bit?
Title: Re: Star trails - Cairds Campsite
Post by: Carole on May 18, 2015, 23:29:21
Do you mean the red on the trees? 
That's where the passing cars lit up the trees. 

Carole
Title: Re: Star trails - Cairds Campsite
Post by: doug on May 19, 2015, 09:17:42
Are the little lines on the trails pauses between different exposures?? Or summat else???

Doug.
Title: Re: Star trails - Cairds Campsite
Post by: Mike on May 19, 2015, 09:43:50
Very nice Carole.
Title: Re: Star trails - Cairds Campsite
Post by: JohnP on May 19, 2015, 14:14:47
nice colourful star trails :-) John
Title: Re: Star trails - Cairds Campsite
Post by: Carole on May 19, 2015, 17:35:06
Thanks Mike and John.

QuoteAre the little lines on the trails pauses between different exposures?? Or summat else???
Yes they must be Doug, next time I'll try to make the gap smaller. 

Carole
Title: Re: Star trails - Cairds Campsite
Post by: MarkS on May 19, 2015, 19:49:17
That's come out really nicely!
Title: Re: Star trails - Cairds Campsite
Post by: RobertM on May 19, 2015, 20:42:48
Good colour in there Carole.  Looks like a fairly narrow FOV, what optics did you use ?

Title: Re: Star trails - Cairds Campsite
Post by: Carole on May 19, 2015, 21:31:46
Thanks Mark and Robert.

QuoteLooks like a fairly narrow FOV
Yes I thought that.

I used the kit lens that came with the DSLR, 18 - 55mm it says on the lens.  I know absolutely nothing about lenses, so that's about as technical as I get ha ha!

I wasn't using the zoom - at least I don't think I was. 

Carole
Title: Re: Star trails - Cairds Campsite
Post by: Kenny on May 19, 2015, 22:16:48
Lovely Carole. The colouring has a really nice, almost cartoon-painted effect because of the colouring of the tree.

I had the same question about field of view. It doesn't look like 18mm but that could simply be because the tree dominates the fov, you appear to have the same breadth of stars as my startrail.
Title: Re: Star trails - Cairds Campsite
Post by: Kenny on May 19, 2015, 22:20:29
What app did you use to combine the exposures into a star trail? If you use Startrails or Starstax they both have a fill mode where they will fill in the short gaps between the exposures.
Title: Re: Star trails - Cairds Campsite
Post by: Carole on May 20, 2015, 00:33:59
I used Startrails Kenny and used the mode that's not supposed to leave gaps.  I only had 5 sec gaps, what do you normally do?

Carole
Title: Re: Star trails - Cairds Campsite
Post by: MarkS on May 20, 2015, 05:52:33
Those gaps are a bit too big for Startrails to cope with.  In PS rotate a copy very slightly along the trails directions and use the rotated version to fill the gaps.

Mark
Title: Re: Star trails - Cairds Campsite
Post by: julian on May 20, 2015, 06:47:14
Very nice Carole.
Title: Re: Star trails - Cairds Campsite
Post by: Kenny on May 20, 2015, 10:39:19
Quote from: Carole on May 20, 2015, 00:33:59
I used Startrails Kenny and used the mode that's not supposed to leave gaps.  I only had 5 sec gaps, what do you normally do?

Ditto as you have described. 5 second gaps between 2 minute exposures.

Q: Are the gaps really 5 seconds? Did you have RAW or JPG enabled? I've started switching off RAW for star trails because I have a suspicion it's taking longer than 5 seconds to save the exposure and on a star trail JPG is good enough.
Title: Re: Star trails - Cairds Campsite
Post by: Carole on May 20, 2015, 10:44:01
I was using Raw - force of habit.

Thanks Julian, and thanks for the advice Mark. 

Carole
Title: Re: Star trails - Cairds Campsite
Post by: Mike on May 20, 2015, 11:04:35
You don't need RAW for a star trail image.

Kenny - I would make sure all of the noise reduction and hot pixel reduction settings are turned OFF. These will increase the time plus the algorithms often screw up the image anyway. You want to do noise reduction in post processing rather than in camera that way you have control over it.
Title: Re: Star trails - Cairds Campsite
Post by: Kenny on May 20, 2015, 15:37:03
Agreed.
Title: Re: Star trails - Cairds Campsite
Post by: MarkS on May 20, 2015, 22:14:09
Quote from: Mike
You don't need RAW for a star trail image.

True,  but if the jpg doesn't work out for one reason or another then you have the RAW in reserve.

For that reason,I always shoot raw+jpg nowadays.

Mark
Title: Re: Star trails - Cairds Campsite
Post by: Kenny on May 20, 2015, 23:18:55
Quote from: MarkS on May 20, 2015, 22:14:09
Quote from: Mike
You don't need RAW for a star trail image.

True,  but if the jpg doesn't work out for one reason or another then you have the RAW in reserve.

For that reason,I always shoot raw+jpg nowadays.

Yes, but don't you think that's wasted on a star trail, unless you expect to need to adjust the exposure in post processing?