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  #21  
Old 01-03-2011, 05:44 PM
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multiweb (Marc)
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Yes - I was thinking the same thing. I pause guiding between subs. I always do dithering this way. Rotational (poor PA) or Translation (poor balance)
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  #22  
Old 01-03-2011, 05:53 PM
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There is definitely flexure in there Fred as I was loosing images because of it. But even when the stars are beautifully round there is still movement between the images.

After changing a few things around last night (screw in attachment, shorter subs) I managed to get more keepers than throwers (20 / 20 in fact ) but still had the creep across the page.

Its just strange that I very rarely had this with the G11, but then I wasn't imaging at 2000mm focal length then.
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  #23  
Old 01-03-2011, 06:06 PM
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Bassnut (Fred)
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Quote:
Originally Posted by [1ponders] View Post
But even when the stars are beautifully round there is still movement between the images.

.
Well then, what were the sub exposure times and what was the time between exposures?.
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  #24  
Old 01-03-2011, 06:13 PM
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sub exp were 5 min and the time between exposures 5 sec
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  #25  
Old 01-03-2011, 06:26 PM
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I'm with Fred, if your 5 minute shots are round, then this isn't flexure to me. You haven't requested dithering have you, inadvertently, somewhere in that new Maxim 5?
Does this happen if you capture with other programs, Nebulosity and PHD?
Does it happen if you use the SX?
Gary
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  #26  
Old 01-03-2011, 06:50 PM
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Quote:
Originally Posted by gbeal View Post
if your 5 minute shots are round, then this isn't flexure to me. You haven't requested dithering have you, inadvertently, somewhere in that new Maxim 5?
Exactly
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  #27  
Old 01-03-2011, 06:50 PM
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I think its got to be the mount Paul. I'll bring up my Heq5 to swap yours out for a while and try to sort it out on the AP from here.....
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  #28  
Old 01-03-2011, 06:53 PM
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Lol cheers thanks rob, I'd rrreeeaaallly appreciate that lol

Nope no dithering turned on
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  #29  
Old 01-03-2011, 06:54 PM
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Quote:
Originally Posted by [1ponders] View Post
There is definitely flexure in there Fred as I was loosing images because of it. .
Definitely no. more likely awefull PE, or a mechanical problem (for loss of images that is). Flex doesnt cause sudden loss of guideing

Last edited by Bassnut; 01-03-2011 at 07:15 PM.
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  #30  
Old 01-03-2011, 07:11 PM
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the elongation with the stars varies in direction Fred, sometimes Dec, sometimes RA sometimes both. The movement movement between frames though is fairly consistent in its direction.

What i might do is put together an animation over a few hours, including bad frames and see what come up.
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  #31  
Old 02-03-2011, 05:31 AM
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Any capture program, and any imaging camera? Or just this program, and that camera?
If it is all over the place, I keep harping back to something like dithering?
Gary
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  #32  
Old 02-03-2011, 06:39 AM
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It does it in both Ver of Maxim I have, I've not tried any other. Not sure about the camera. Though it doesn't appear that the guide camera star moves, just the image received from the SX

I noticed last night that when shooting ngc2442 that the drift was almost parallel to the Dec. Next clear night I will spend the night taking 6 / 5 min shots from all around the sky and see if there is any sort of pattern to the direction of the drift.
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  #33  
Old 02-03-2011, 01:39 PM
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I do find similar symptom when guiding through a seperate scope. following link might help answering some of the questions http://www.stark-labs.com/blog/files/tag-flex.php

I don't think its possible to zero out the flex, but definetely you can improve on it. Once you have done all the things that you possibly can do to reduce flex, Knowing how long you can expose before the error creeps up in the subs will be the key.

Regards
Sad
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  #34  
Old 02-03-2011, 03:19 PM
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thanks for that Sad. That will give me something to work with. I'm going to spend some time this weekend going over everything on the rig and eliminate or tighten if i can't eliminate everything that could be causing flex (like switching back to a star diagonal) and then start taking some measurements. Cheers
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  #35  
Old 02-03-2011, 04:36 PM
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OK, since you have my pea sized brain going, why not try the SBIG with Maxim (you still have it??).
Then also try PHD/Nebulosity with the SX.
Gary
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  #36  
Old 02-03-2011, 04:43 PM
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thanks Gary, all part of my cunning plan
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  #37  
Old 02-03-2011, 04:49 PM
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What to get the pea sized brain going, or to exhaust all possibilities?
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  #38  
Old 02-03-2011, 05:12 PM
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I'll pop the ST-7 on the VC200 and self guide and use that as my control.

I also plan to take the WO 72 out of the equation (might be movement in the focuser) and using the much lighter SV50 both on top and SBS. I've also got other programs available to try as well. CCDSoft can operate the SX as well now (though not ideal). I also haven't been able to get the little EXView to work yet with Maxim. I'll work on that as well. All I need are some clear nights.
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  #39  
Old 02-03-2011, 05:16 PM
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Good plan, keep us in the loop.
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  #40  
Old 02-03-2011, 06:05 PM
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Merlin66 (Ken)
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Paul,
Also record the time and the Hour angle of the object....you'll be able to see if gravity is your friend....
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