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Old 12-11-2009, 03:55 PM
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pmrid (Peter)
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QHY8 takes a holiday in LaLa land.

I need calm and reassuring words from QHY8 buffs. Have a look at the attached. Lat night I had a crack at IC434 trough my ED127 North Group APO. 10 minute subs. The image is not processed beyond some curves to bring up the weirtd stuff. But what the %^$%# is all that spurious light and light effects?
So today I have spent the past 4 hours with it, trying to track down the culprit. The next 2 images are:
1. The one with the red/brown hue and the very bright vertical band is the starting point. It's only a 60 sec sub;
2. This is one after I have put black tape on everything - and in particular around the S-Video, USB and power connectors on the camera. That seems to have supressed the more patent vertical band. That image, with the blue corners is a 5 min sub.

{Edited in] These last 2 are taken with the lens cap firly on and all possible entry points for external light blocked (as far as I can tell).

It isn't internal reflections. The same pattern persists in the same place whichever way I turn the camera on its axis. So whatever it is, it's coming from the camera housing or the chip.

Anyone seen anything like this?

Peter

Last edited by pmrid; 23-11-2009 at 02:54 PM.
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Old 12-11-2009, 04:08 PM
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multiweb (Marc)
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Does it do that on all the subs or on the very first time you use it and download the first sub?
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Old 12-11-2009, 04:10 PM
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Quote:
Originally Posted by multiweb View Post
Does it do that on all the subs or on the very first time you use it and download the first sub?
The first sub, or preview in Nebulosity is always a white top half and some horizontal colour bands. The second one is 'usually' normal if I can use that word.
Peter.
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Old 12-11-2009, 04:18 PM
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Quote:
Originally Posted by pmrid View Post
The first sub, or preview in Nebulosity is always a white top half and some horizontal colour bands. The second one is 'usually' normal if I can use that word.
Peter.
Ok. It's normal then. I have this too. Seems that when the camera is turned on after having been off a long time some charge must be left somehow in it. You can get rid of it by shooting a bias or go in frame focus mode and "purge" it so to speak. Nothing to worry about.
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Old 12-11-2009, 04:22 PM
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pmrid (Peter)
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Quote:
Originally Posted by multiweb View Post
You can get rid of it by shooting a bias or go in frame focus mode and "purge" it so to speak. Nothing to worry about.
That's OK with that 'first frame' image. But the rubbish I'm getting in the pics on this thread are in every image.
Peter.
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Old 12-11-2009, 04:29 PM
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Where did you buy it Peter? And how long ago?
Not frosting at all is it, just a thought?
Gary
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Old 12-11-2009, 04:45 PM
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Quote:
Originally Posted by pmrid View Post
That's OK with that 'first frame' image. But the rubbish I'm getting in the pics on this thread are in every image.
Peter.
ha... so there's something else going on. Might wanna talk to Theo (gama) on this site.
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Old 12-11-2009, 04:50 PM
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ha... so there's something else going on. Might wanna talk to Theo (gama) on this site.
Yes. He'd certainly be able to throw some light on the problem.
Peter
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Old 12-11-2009, 04:55 PM
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Originally Posted by gbeal View Post
Where did you buy it Peter? And how long ago?
Not frosting at all is it, just a thought?
Gary
It does frost up, as they all do. But I try to be sure to assemble it in a warm dry environment and store it in a sealed box with plenty of dessicant.
It's been behaving erratically now for some days, now that I look back. I junked 4 hours worth a few nights ago because the camera just didn't seem to be taking in the light. The 12x10min subs were dark, grainy and just rubbish. And last night, I did 2 groups of 4 x 10 mins of IC434 and with no other changes in settings between one group and anpther (I had a guiding issue which is why I stopped and started) the second batch were noisy rubbish whereas the first batch were reasonably clear and had good data - except for those crazy light shows s in the image on this thread.

Peter
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Old 12-11-2009, 06:22 PM
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Hi Peter,
DO NOT take shots with the lens cap on and expect dark clean images .
Why i hear you ask , its because IR light goes right thru the cap. Not to mention that the lens cap is not totally light proof. The cap serves only one function, to stop dust setting on it.
Even the tiniest light thru a pin head, will show up like what you have.

With your moisture issue, are you getting a dew spot on the outside of the filter, or on the CCD ?.
If its on the CCD, then theres a air leak. If its on the front of the nose/filter, then there are other ways to get rid of this for your humidity levels during the night.

If you need more help, send me a PM and we can take look at it properly.


Theo.
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Old 12-11-2009, 06:30 PM
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Hi Gama, and thanks for these remarks.
The lens cap on these scopes (it's a North Group ED127 APO) is solid aluminium and it actually screws down onto the lens cell so the chance of light getting through is pretty minimal and am I right that IR won't go through the Aluminium cap?
I'm n ot sure I have a moisture issue. I'm not getting dew drops on anything (touch wood). But in any case, how do you sugest making the camera air-leak proof?
Finally, I still have that dreadful pattern of interference on light frams as well - see that IC434 shot in the thread.
Peter
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Old 12-11-2009, 06:35 PM
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put the camera under a thick blanket or similar and take a 10 or 20 second image. Its the only way to check out the light leak issue. Dont use the aluminium cap, leave it off.
Also make sure in the camera setup, you enable "Anti amp" light to ON.


Further, when ever you power up the camera, the buffers will contain junk, so the first shot is always junk. Do what Marc said, either a bias frame or very quick exposure, like .5 sec etc.. to clear the buffers.


To add further again, sorry, the light leaks are not consistant, meaning it may not be the camera, and something externally, as the light sources are moving indicating its an external source hampering your images. Maybe look into the scope during the exposure of your images, and see if theres a bright light comming down the scopes focuser, etc.

Theo
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Old 12-11-2009, 06:42 PM
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Thanks Theo. I'll give that a run and see what happens. Our weather forecast for next week is 35degres ++ so the dark heavy blanket will have to be a very late night exercise.

Peter
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Old 12-11-2009, 06:51 PM
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One thing i dont like Peter, is the corners of the top.
This usually means the CCD has some moisture/residue on the sensor, and when it freeezes, it ices up and shows a similar pattern.

This goes away with a clean with alchohol or similar spirit.
In any case, see how you go, and if your still getting nowhere, PM or email me to organise a look at properly. Wont take long either, normally a day and then its sent back to you.
We'll have you churning out images soon.

Need to fix the colour balance too, its just too blue, and maybe why the cameras giving you the blues . Bad joke....couldnt help it.

Theo
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Old 12-11-2009, 06:58 PM
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Quote:
Originally Posted by pmrid View Post
Hi Gama, and thanks for these remarks.
The lens cap on these scopes (it's a North Group ED127 APO) is solid aluminium and it actually screws down onto the lens cell so the chance of light getting through is pretty minimal and am I right that IR won't go through the Aluminium cap?
.......
Peter
It just takes the tinest of holes Peter, and this is where your troubles just may be.

The camera should be totally removed from the telescope and only the camera should be under a thick blanket or even a closet etc.. As long as no light gets in..


Theo
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Old 12-11-2009, 07:19 PM
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Pete, whenever I get hoky images coming out here I go straight for the s-video connections. It seems to me it's usually a crappy connection in the socket on the white box regardless of the cable I use.
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Old 12-11-2009, 09:27 PM
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Pete, whenever I get hoky images coming out here I go straight for the s-video connections. It seems to me it's usually a crappy connection in the socket on the white box regardless of the cable I use.
Peter, would agree. Have a good look at your cabling. Are you running the power and USB cables together? This can cross feed and give really weird shots. Were you using the clamps on the side by side bar for your cables, if so then separate the power and USB cables as much as possible.
Regards, Allan
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