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A clue to "Star Bloating"?
Jun 24, 2017 12:52:37   #
SonnyE Loc: Communist California, USA
 
Last night I did an overnight run with the Tamron 150-600 mm lens, and DSLR camera.
Since all I wanted was a test and a circular star trails result, I decided to run off a series on Polaris.
What I got was more of a lesson in vibrations....
I noticed I was getting a "clear" picture about every 2-4 images. I thought shutter wiggles?
Going to Live View which locks the mirror up is supposed to cure the wiggles. And surely a 2 second delay should have calmed things down.
But deep in the night ticking away, here's some of the results....
I'm wondering about other sources of vibrations being induced into the mount from the ground.
Everything was off, except the electronics, and the camera. Should have been dead still.

Thinking outside the box, because I haven't been able to get in the box yet.
I can't stack, no I can't stack....

Middle of the night squiggles... 10s exposures, ISO 400
Middle of the night squiggles... 10s exposures, IS...
(Download)

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Jun 25, 2017 02:42:36   #
JimH123 Loc: Morgan Hill, CA
 
SonnyE wrote:
Last night I did an overnight run with the Tamron 150-600 mm lens, and DSLR camera.
Since all I wanted was a test and a circular star trails result, I decided to run off a series on Polaris.
What I got was more of a lesson in vibrations....
I noticed I was getting a "clear" picture about every 2-4 images. I thought shutter wiggles?
Going to Live View which locks the mirror up is supposed to cure the wiggles. And surely a 2 second delay should have calmed things down.
But deep in the night ticking away, here's some of the results....
I'm wondering about other sources of vibrations being induced into the mount from the ground.
Everything was off, except the electronics, and the camera. Should have been dead still.

Thinking outside the box, because I haven't been able to get in the box yet.
I can't stack, no I can't stack....
Last night I did an overnight run with the Tamron ... (show quote)


Were you doing this on a stationary tripod? Or your equatorial mount? This doesn't look like vibration. But it is is cool that they are all synchronized. It is very difficult for an equatorial mount to point exactly at the pole star and maintain tight tracking. If you were on a solid tripod, with mirror up, there should have been no dancing around. And with enough exposures, they should be making circles.

And yes, you can stack. Yes you can stack. Not sure why this simple procedure is biting you so much?

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Jun 25, 2017 12:10:00   #
SonnyE Loc: Communist California, USA
 
Hi Jim,
Yes, I was using my AVX. Once centered, I actually shut off the drive on it in case it decided to do any galactic wondering of it's own.
The AVX is set-up in a one spot place. And once started, I just let it sit and run so no human vibrations and blur the image.
Plus, these were relatively short exposures for me, only 10 seconds.
Normally, everything is very stable. But I've long thought that the minute corrections of the mount would cause 'star bloating' as the guiding and control deals with gear lash and time delays.
But with everything stopped mount wise, there is only the camera shutter, or natural vibrations, left to see. But the camera is all-telling and absolute during exposure. It records everything.
I'm just at a loss to explain yet what was occurring to make these odd images. But it was a waste of 'shutter clicks' on the camera's odometer...
I could surmise it could be ground vibrations, up to magnetism induced into the bar of steel I'm using for a Vixen Bar under the lens and camera.

It warrants further play, if I have hopes of trying to get some images of the Sun or the eclipse. (Which would definitely be much shorter exposures.)

Edit In: Stacking does seem to work with my DSLR, but there is a gremlin in the files from the G3.
As they use to say in early computing, Garbage in = Garbage out. Seems to hold true.
Say, maybe that's the G in the G3?

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Jun 25, 2017 18:22:11   #
CraigFair Loc: Santa Maria, CA.
 
SonnyE wrote:
Last night I did an overnight run with the Tamron 150-600 mm lens, and DSLR camera.
Since all I wanted was a test and a circular star trails result, I decided to run off a series on Polaris.
What I got was more of a lesson in vibrations....
I noticed I was getting a "clear" picture about every 2-4 images. I thought shutter wiggles?
Going to Live View which locks the mirror up is supposed to cure the wiggles. And surely a 2 second delay should have calmed things down.
But deep in the night ticking away, here's some of the results....
I'm wondering about other sources of vibrations being induced into the mount from the ground.
Everything was off, except the electronics, and the camera. Should have been dead still.

Thinking outside the box, because I haven't been able to get in the box yet.
I can't stack, no I can't stack....
Last night I did an overnight run with the Tamron ... (show quote)

I find I get wiggles when I move my chair the most and little ones when I walk around too.
Wind??? is the worst. I went to the mountain last night and had wind problems.
Craig

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Jun 26, 2017 02:24:52   #
SonnyE Loc: Communist California, USA
 
CraigFair wrote:
I find I get wiggles when I move my chair the most and little ones when I walk around too.
Wind??? is the worst. I went to the mountain last night and had wind problems.
Craig


Hi Craig. Me too. I use to really notice the wiggles when I use to sit out at the mount.
One night I discovered the wiggles, so I began checking. If I so much as moved at all during an exposure it would bloom the stars, or worse.
But now, I run my mount remotely from the house, so no human induced vibrations.
That's what I found so odd. No mount interference, The wind wasn't a factor either. My weather station shown <1 MPH wind, and my mount is greatly shielded from the prevailing wind direction.
The camera and lens was being run by a wireless Intervalometer, and I just start it and let it gather all night. Then delete (trim) back the beginning and ending images.
But this was bad all the way along. Too many squiggly images to bother sorting.

I'm running a sequence tonight with all systems normal of the Filamentary Nebula.
So far, so good. (Well, better than previous attempts...)

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Jun 26, 2017 12:20:21   #
CraigFair Loc: Santa Maria, CA.
 
SonnyE wrote:
Hi Craig. Me too. I use to really notice the wiggles when I use to sit out at the mount.
One night I discovered the wiggles, so I began checking. If I so much as moved at all during an exposure it would bloom the stars, or worse.
But now, I run my mount remotely from the house, so no human induced vibrations.
That's what I found so odd. No mount interference, The wind wasn't a factor either. My weather station shown <1 MPH wind, and my mount is greatly shielded from the prevailing wind direction.
The camera and lens was being run by a wireless Intervalometer, and I just start it and let it gather all night. Then delete (trim) back the beginning and ending images.
But this was bad all the way along. Too many squiggly images to bother sorting.

I'm running a sequence tonight with all systems normal of the Filamentary Nebula.
So far, so good. (Well, better than previous attempts...)
Hi Craig. Me too. I use to really notice the wiggl... (show quote)

I find that the squiggles in Stars will cause DSS too not function. So I have to survey each of the lights.. It's what went wrong on my Swan Nebula stacking. The wind got me. Good luck tonight Sonny can't wait to see your shots.
Craig

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