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Equipment Discussions >> Equipment

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Raginar
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Reged: 10/19/10

Loc: Rapid CIty, SD
Re: Best way to piggyback 4SE on EdgeHD 8"? new [Re: Jon Isaacs]
      #5792001 - 04/11/13 09:35 AM

Jon,

Argue much? I've used a C5 to guide and image through. I didn't experience any mirror flop or image shift.

Sedat,
Perhaps it's a cultural thing. The way you talk is antagonistic.


Chris


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Jason B
Proud father of 5!!
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Reged: 06/21/04

Loc: Mid-Michigan
Re: Best way to piggyback 4SE on EdgeHD 8"? new [Re: Raginar]
      #5792678 - 04/11/13 04:05 PM

I will never guide with a moving mirror telescope unless it is with an OAG. In my experience, if the mirror even moves a hair it messes up the frame. It will move slowly if you pass the meridian as well as the center of gravity shifts.

I was always having issues with my 90mm Mak when guiding and it had very little mirror flop, if any visually. As soon as I switched guidescopes (after several weeks of trying and trying to get it working), all my problems went away.


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WarmWeatherGuy
Carpal Tunnel
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Reged: 08/27/11

Loc: Orlando, FL 28° N, 81° W
Re: Best way to piggyback 4SE on EdgeHD 8"? [Re: Jason B]
      #5792765 - 04/11/13 04:33 PM

Quote:

I will never guide with a moving mirror telescope unless it is with an OAG. In my experience, if the mirror even moves a hair it messes up the frame. It will move slowly if you pass the meridian as well as the center of gravity shifts.

I was always having issues with my 90mm Mak when guiding and it had very little mirror flop, if any visually. As soon as I switched guidescopes (after several weeks of trying and trying to get it working), all my problems went away.




Earlier in this post I talked about my problem guiding with a C5 and I gave a link to this animation of the horsehead nebula that I made. Each frame is a 10 second exposure and the total elapsed time of the animation is over 3 hours.

Is it possible this is due to mirror "flop?" This "flop" would have to be incredibly slow, smooth, and even because I never lost track. Each image has about the same amount of star streaking, except for one image in the middle which has a little more. It would have to last for 3 hours and the total angle change from start to finish seems fairly large. Is this something similar to what you experienced?


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Jason B
Proud father of 5!!
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Reged: 06/21/04

Loc: Mid-Michigan
Re: Best way to piggyback 4SE on EdgeHD 8"? new [Re: WarmWeatherGuy]
      #5794609 - 04/12/13 02:20 PM

Is this guided? This looks like an unguided shot that did not have an exact polar alignment. You could experience drift such as that over the course of 3 hours without guiding. The drift amount would vary dependent on the preciseness of your polar alignment. Mirror shift would not be this slow IMHO.

I shoot much longer exposures than 10 seconds. Mine would show itself as streaked stars, double images or a lost guide star. There were all kinds of problems, especially when shooting through the meridian. Since switching to the much more stable refractor, no issues!


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WarmWeatherGuy
Carpal Tunnel
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Reged: 08/27/11

Loc: Orlando, FL 28° N, 81° W
Re: Best way to piggyback 4SE on EdgeHD 8"? new [Re: Jason B]
      #5797503 - 04/13/13 09:27 PM

Yes this is guided. North is up and the drift is left/right. I am thinking it could be because I left the wires to the guide camera dangle. As the rotation in RA occurs the pull of gravity on the wires changes and would "bend" my guide camera to point gradually to a different place than my camera scope. I'm not ruling out mirror flop though. I will experiment with wrapping the wires to keep them from changing any force on the guide camera during the process.

I used an AT72ED and a C5 on a side-by-side bar on a CGEM. The C5 is the guide scope and the AT72ED is what took the images. I estimate that the middle of the 3 hour period is when the scope went through the meridian.


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