Desperately need help with these Star Trails

kevin2845

New member
Hey guys im new to this fourm and not sure if this is the right place to post this but mods feel free to move it if its an issue.

So recently ive been interested in capturing some star trails so i went out and did a few test pics but everytime i take the pics and come back to post process them i get these huge gaps in my trails it is very frustrating and i am not sure where im going wrong

here is an example of the gaps
test 2.jpg

as you can see the gaps are pretty substantial so software like star stax are not much use to me at all.

I am using the Nikon D7000 with a 50mm 1.8

the setting were 30 second exposure at f6.3 ios 100 in manual, i dont own an intervelometer so i used the one built in and the setting in that were at an interval of 31seconds and select intervals x no. of shots 70x1=70

Please help me with this situation, i wasted two nights trying to get this to work.
 

SteveL54

Senior Member
Did you have your Long Exposure Noise Reduction turned on?
A 30 second exposure will also result in the camera taking about 30 seconds to process the noise out, therefore giving you 30 sec on and 30 sec off.
This is only a guess. I'm sure that someone that knows much more than me will be along shortly
 

kevin2845

New member
Did you have your Long Exposure Noise Reduction turned on?
A 30 second exposure will also result in the camera taking about 30 seconds to process the noise out, therefore giving you 30 sec on and 30 sec off.
This is only a guess. I'm sure that someone that knows much more than me will be along shortly

Yeah i made sure that Long Exposure NR was turned off, i was reading somewhere that at the interval setting you have to put your shutter speed plus how long of a delay you want in so thats why i put in 31 second because my shutter speed was 30 second but even if what your saying is the case would a 30 second delay really cause such big gaps? I am very new to astrophotography really hoping someone specialized can chime in.
 

WayneF

Senior Member
the setting were 30 second exposure at f6.3 ios 100 in manual, i dont own an intervelometer so i used the one built in and the setting in that were at an interval of 31seconds and select intervals x no. of shots 70x1=70

A big part of your problem is that the 30 second shutter speed is actually 32 seconds, and it will require a 33 second interval. The gaps are when it misses whole intervals because the shutter time is longer than the interval. Interval has to be longer than the shutter duration. I know you planned to do it right, but it's tricky. :)

Each shutter stop is 2x the light. So it obviously has to run 1, 2, 4, 8, 16, 32 seconds. No other numbers that include 1 second will work.

It is marked in nominal numbers easy for humans who don't know, don't care, but the camera does it precisely, and 30 seconds is 32 seconds.

In the same way, 1/30 second is 1/32, and 1/2000 second is 1/2048 second.

But we can time the 30 seconds. Time it yourself. Then use 33 second interval.

Everyone makes the same mistake. :)
 
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SteveL54

Senior Member
Yeah i made sure that Long Exposure NR was turned off, i was reading somewhere that at the interval setting you have to put your shutter speed plus how long of a delay you want in so thats why i put in 31 second because my shutter speed was 30 second but even if what your saying is the case would a 30 second delay really cause such big gaps? I am very new to astrophotography really hoping someone specialized can chime in.

I went back and looked at some older posts here, and @WayneF is absolutely correct.
 

kevin2845

New member
A big part of your problem is that the 30 second shutter speed is actually 32 seconds, and it will require a 33 second interval. The gaps are when it misses intervals because the shutter time is longer than the interval. Interval has to be longer than the shutter duration. I know you planned to do it right, but it's tricky. :)

Each shutter stop is 2x the light. So it obviously has to run 1, 2, 4, 8, 16, 32 seconds. No other numbers that include 1 second will work.

It is marked in nominal numbers easy for humans who don't know, don't care, but the camera does it precisely, and 30 seconds is 32 seconds.

In the same way, 1/30 second is 1/32, and 1/2000 second is 1/2048 second.

But we can time the 30 seconds. Time it yourself. Then use 33 second interval.

Everyone makes the same mistake. :)

Wow thats is crazy, i just timed it and the shutter closed right at 32 seconds, would have never guessed it thought it was post processing problem and i was going through everything i did to see where i was slipping up, I honestly just have to say thank you so much for the tip, i guess im going to have another sleepless night today! stayed up till 3 in the morning the first two days :sleeping:
 

Bourbon Neat

Senior Member
@kevin2845 Welcome to the forum and I hope you get a resolution to your issue.

I believe I get quicker processing between long shutters than 1:1 with the D700 and D7200. Do you own a laptop and Lightroom software? If so, tethering might be an option to explore. There are other software developers with tethering software available for trial periods too.

Another option would be a remote shutter release. With that you can set your shutter to bulb, the shutter duration in bulb can be minutes long, pretty much to your choosing.

Another option, set shutter to bulb and have a black card covering your lens, activate shutter, wait 3 seconds for shake to subside and remove the black card. Count down the shutter time you would like or have a timer, activate shutter again to close.

Best of luck.
 

Scott Murray

Senior Member
Use starstax and tick the gap filling mode, also try comet mode at the same time. I am confident it will look better.

As for having a 30sec gap with a 30 sec photo is only true when in camera noise reduction it active, when I do my startrails I will set my camera (D800E) to 20-30sec and have a 1-2 sec gap using fast cards I find that even the large files of the D800E will be processed prior to the next 30sec exposure. Also I always use gap filling and comet mode as I like that effect.
 
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kevin2845

New member
A big part of your problem is that the 30 second shutter speed is actually 32 seconds, and it will require a 33 second interval. The gaps are when it misses whole intervals because the shutter time is longer than the interval. Interval has to be longer than the shutter duration. I know you planned to do it right, but it's tricky. :)

Each shutter stop is 2x the light. So it obviously has to run 1, 2, 4, 8, 16, 32 seconds. No other numbers that include 1 second will work.

It is marked in nominal numbers easy for humans who don't know, don't care, but the camera does it precisely, and 30 seconds is 32 seconds.

In the same way, 1/30 second is 1/32, and 1/2000 second is 1/2048 second.

But we can time the 30 seconds. Time it yourself. Then use 33 second interval.

Everyone makes the same mistake. :)

Orb Star trail insta.jpg

Worked like a chram!:D
 

WayneF

Senior Member
Another way, if the camera does not have an interval timer, or if it is too complex to mess with, is to simply use a shutter release cable ($5 or $6 on Ebay, from Hong Kong). Set camera to 30 seconds and set it to do Continuous shutter, and click the cable, and while holding, slide the cable lock to hold the shutter down continuously. Probably a bit faster than the one second between intervals. Unlock the cable to stop it.
 
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