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Seanelly

Help: DSLR shutter remote control interval time?

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Just got a new remote control timer for my Canon T6i DSLR shutter, and in the manual it says that when using long exposure noise reduction selection on the camera, which I have done, the interval time between exposures should be set to at least twice the exposure time. This method will produce only an hour of data over a three hour session!

1. Is it wise to gain more data at the expense of interval times?

2. Does the noise reduction selection on the camera make much of a difference, and if not, can interval times be reduced with it off?

3. Are dark images expected to be produced under the same procedure?

This is what I'm dealing with weatherwise here in Ottawa, Ontario: It's been raining or snowing on 22 of the last 26 days. Two of those clear evenings saw a near full moon. So you can see, I'm having a hard enough time trying to get data without throwing away two of every three precious hours I can scrounge up!

Thanks in advance for any help you can offer to get me more data.

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Personally, i find leaving a 10 sec delay between exposures sufficient for the temp to stabilise at about 5 deg above ambient (which will be pretty cold for you soon anyway 😉).  i know this because on  a canon, APT records the exif temp with each frame.  i agree with you any more time delay is wasted time in my view.  in fact, these days i use dithering rather than dark frames with good results, 

hope that helps, of course, there will be other opinions

Mike

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1 hour ago, Seanelly said:

Just got a new remote control timer for my Canon T6i DSLR shutter, and in the manual it says that when using long exposure noise reduction selection on the camera, which I have done, the interval time between exposures should be set to at least twice the exposure time. This method will produce only an hour of data over a three hour session!

1. Is it wise to gain more data at the expense of interval times?

2. Does the noise reduction selection on the camera make much of a difference, and if not, can interval times be reduced with it off?

3. Are dark images expected to be produced under the same procedure?

This is what I'm dealing with weatherwise here in Ottawa, Ontario: It's been raining or snowing on 22 of the last 26 days. Two of those clear evenings saw a near full moon. So you can see, I'm having a hard enough time trying to get data without throwing away two of every three precious hours I can scrounge up!

Thanks in advance for any help you can offer to get me more data.

Turn off LENR as it doubles any exposure by taking a dark after every shot.

As mikeyj1 above, use dithering, this will help to reduce colour noise in processing.

Dark's may or may not help depends on how accurate the temperature is.

BTW have gone a lot longer than 22 days without a clear sky, that's not unusual in this game. 😉

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3 hours ago, mikeyj1 said:

Personally, i find leaving a 10 sec delay between exposures sufficient for the temp to stabilise at about 5 deg above ambient (which will be pretty cold for you soon anyway 😉).  i know this because on  a canon, APT records the exif temp with each frame

I like this - I've been adopting the 'half-exposure length' approach without thinking about optimising this based on actual exif temperatures... This way is a bit more scientific. ☺ 

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Turn noise reduction off and just take light frames. You can capture your dark frames by just capping the lens/camera body while its snowing/raining - do your bias and flat frames then too...

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Agreed, turn the noise reduction off. It captures a dark frame and applies that correction to your light frame individully. It doubles your capture time as you're essentially capturing a dark frame for every light frame and you certainly don't need that many dark frames. You can significantly reduce your imaging time by capturing fewer dark frames later and averaging them during stacking. I usually set the interval for just a couple seconds longer than the actual exposure rather than double in this case.

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Agree with all of the above - turn off the in-camera noise reduction and either dither your subs or generate dark libraries at different temperatures during cloudy periods.  I've read of people putting their camera in the fridge (or freezer, depending where they live) to take darks.  The EXIF temperature data from a DSLR isn't a perfect measure, but should be a good enough way of matching your darks with your lights.

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15 hours ago, mikeyj1 said:

Mike

 

14 hours ago, wxsatuser said:

Turn off LENR as it doubles any exposure by taking a dark after every shot.

As mikeyj1 above, use dithering, this will help to reduce colour noise in processing.

Dark's may or may not help depends on how accurate the temperature is.

BTW have gone a lot longer than 22 days without a clear sky, that's not unusual in this game. 😉

 

11 hours ago, adyj1 said:

I like this - I've been adopting the 'half-exposure length' approach without thinking about optimising this based on actual exif temperatures... This way is a bit more scientific. ☺ 

 

10 hours ago, fwm891 said:

Turn noise reduction off and just take light frames. You can capture your dark frames by just capping the lens/camera body while its snowing/raining - do your bias and flat frames then too...

 

6 hours ago, Buzzard75 said:

Agreed, turn the noise reduction off. It captures a dark frame and applies that correction to your light frame individully. It doubles your capture time as you're essentially capturing a dark frame for every light frame and you certainly don't need that many dark frames. You can significantly reduce your imaging time by capturing fewer dark frames later and averaging them during stacking. I usually set the interval for just a couple seconds longer than the actual exposure rather than double in this case.

 

5 hours ago, GraemeH said:

Agree with all of the above - turn off the in-camera noise reduction and either dither your subs or generate dark libraries at different temperatures during cloudy periods.  I've read of people putting their camera in the fridge (or freezer, depending where they live) to take darks.  The EXIF temperature data from a DSLR isn't a perfect measure, but should be a good enough way of matching your darks with your lights.

Thank you all for your input, my mind is eased and my path is clear. I had a feeling something was off with the instructions I was reading, but in having the kit for only a couple of months and with very limited time to experiment with only the 30 second maximum exposure time on the DSLR until I got this timer, I was at a loss to put my finger on the problem. But I knew I could count on the practical advice that makes this site a delight to be part of!

This evening (12/07/18) is forecast to be clear (finally!), though cold (-15C), and I plan to target the Pleiades hopefully for several hours as my first long exposure test, while I stay warm inside the house, albeit with my fingers crossed the whole time. Wish me luck!

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On 06/12/2018 at 23:46, mikeyj1 said:

Personally, i find leaving a 10 sec delay between exposures sufficient for the temp to stabilise at about 5 deg above ambient (which will be pretty cold for you soon anyway 😉).  i know this because on  a canon, APT records the exif temp with each frame.  i agree with you any more time delay is wasted time in my view.  in fact, these days i use dithering rather than dark frames with good results, 

hope that helps, of course, there will be other opinions

Mike

 

On 07/12/2018 at 00:42, wxsatuser said:

Turn off LENR as it doubles any exposure by taking a dark after every shot.

As mikeyj1 above, use dithering, this will help to reduce colour noise in processing.

Dark's may or may not help depends on how accurate the temperature is.

BTW have gone a lot longer than 22 days without a clear sky, that's not unusual in this game. 😉

 

On 07/12/2018 at 03:31, adyj1 said:

I like this - I've been adopting the 'half-exposure length' approach without thinking about optimising this based on actual exif temperatures... This way is a bit more scientific. ☺ 

 

On 07/12/2018 at 05:01, fwm891 said:

Turn noise reduction off and just take light frames. You can capture your dark frames by just capping the lens/camera body while its snowing/raining - do your bias and flat frames then too...

 

On 07/12/2018 at 09:02, Buzzard75 said:

Agreed, turn the noise reduction off. It captures a dark frame and applies that correction to your light frame individully. It doubles your capture time as you're essentially capturing a dark frame for every light frame and you certainly don't need that many dark frames. You can significantly reduce your imaging time by capturing fewer dark frames later and averaging them during stacking. I usually set the interval for just a couple seconds longer than the actual exposure rather than double in this case.

 

On 07/12/2018 at 09:46, GraemeH said:

Agree with all of the above - turn off the in-camera noise reduction and either dither your subs or generate dark libraries at different temperatures during cloudy periods.  I've read of people putting their camera in the fridge (or freezer, depending where they live) to take darks.  The EXIF temperature data from a DSLR isn't a perfect measure, but should be a good enough way of matching your darks with your lights.

 

19 hours ago, adyj1 said:

Good luck! 

Don't judge too harshly, as this is the first long exposure image I've taken since acquiring the new kit a couple of months ago, and even though it didn't go according to plan, it does show an incremental progress I was counting on.

I got the new DSLR shutter release remote activated for the first time, removed noise reduction selection from the DSLR, and was hoping for several hours of data. What I did get was 16x180s decent lights out of 32 taken before the laptop, hence the guider, shut down on me, and having forgotten to charge the backup batttery (so many things to keep in mind for a newby!), my night was done without even getting any dark images, bias or lights.

Half my images were useless from star trails, probably from a jostling of the tripod that I thought was not as serious as it seemed to turn out, and even this image shows signs of it.

So this is 16 stacked images of 3 minutes each, with 30s between exposures (is this enough time between exposures?) with no help other than some adjustment in DeepSkyStacker to acquire some contrast, with some false blue added in a totally inadequate microsft photo editor, because my wife won't let me get Adobe Photoshop CC until Christmas!

I opened my first album, called Beginnings, and this is the first entry, but I thought you might like some proof that your advice has not fallen on deaf ears, though I realize I have a LONG way to go.

M45 12-07-18 - Copy (4).jpg

Edited by Seanelly
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Well, firstly well done for getting something, and you are starting to get some nebulosity around the sisters... We all suffer from those 'forgot to charge', 'didn't set up correctly', 'forgot to take the bahtinov mask off' moments, and it is worse if you don't find out until after the session! You've made a good start and you will get better the more you do it. 

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30 minutes ago, adyj1 said:

Well, firstly well done for getting something, and you are starting to get some nebulosity around the sisters... We all suffer from those 'forgot to charge', 'didn't set up correctly', 'forgot to take the bahtinov mask off' moments, and it is worse if you don't find out until after the session! You've made a good start and you will get better the more you do it. 

The first time I set up the mount/scope and tried a synscan 3-star alignment, I spent a frustrating ten or so minutes trying to find focus before discovering that I had left the cap on the scope. I envision many more goofs like this in future, but they should lessen in frequency and severity as time goes by. My wife says I should write down the step-by-step process (I'm occasionally running back into the house for something I forgot, etc.), but I think we often don't give our brains enough credit for learning lengthy routines and jump too quickly for outside help when things don't always work out or if backtracking is necessary, which is why, discounting the above due to precious time-or the lack of it more precisely-I will usually try to work these issues out before asking for advice here. Besides which, it is more satisfying to solve a problem on your own.

Thanks for your help and support.

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