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black spot help on m42 image


red dwalf
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hi all,


i had a go at m42 last night for an hour before total cloud cover and went for 4 x 2 minute subs with the atik titan in luminace filter


but i have a very strange black spot which is worrying me, i thought it might come out in processing but it hasn`t.


here is a picture of 4 x 2 minutes with some 5 seconds for the core.


 


kbje.jpg


 


and here is one image taken from deepsky stacker showing the black spot, anyone know what is causing it ? camera looks clean so does scope. 


i`m alittle bit worried.


 


aos3.jpg


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fingers crossed for dust bunny's !


all subs are exactly the same, i could do a flat, i take it you mean a light flat and not a dark, i don`t take many flats even though i`ve got a light board, still finding my feet with lights and darks L.O.L.


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Is the CCD cooled? in which case I would say it's the same issue I had at Belper last time. A little moisture on the chip which froze. I had to keep taking it off to dry it out in the van, in the end I put the dew band around it and that cured it.


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it is cooled but not to 314l plus standards, just a little blower on the back, also i did have a dew band around the camera but it does struggle to get enough heat to the class cover in front of the ccd chip, it seems to heat up the camera body more the the bit you want to keep clear


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It is peltier cooled, so would easily get to sub-zero temperatures in this weather. Fingers crossed, it is as Mike said, just a bit of ice. I can't help with the flats though - I've not moved to CCD just yet (though will when I can afford it!)


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Ok, possibly a daft question from a non astro photographer, if it was dust bunnies or ice etc, would that not block everything out?

Reason I ask is you can still see the star that is inside the black spot!

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Rob's captured a Black Hole with gravitational lensing! :lol:


 


I reckon Mike's right, just a bit of ice. Have a look at the chip, if it's clear now it might be OK. If not, and it presents again in the same spot it might be the sensor. :( 


 


Look on the bright side, you might need to upgrade, it's natural selection at work, nature say's go better! :D


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Hang on,I've just thought about this again, surely it can't be the chip cause it's took photos of the stars inside the "black hole", but stars don't give off luminescence, so logically it must be something on the filter, or the filters damaged?

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most likely ice


 


if you have one stick i in the airing cupboard for a few days


or a plastic box with a few of those desiccant packs in it and leave it on a radiator for a couple of days


 


 


Mike if you read this do the same with the H9


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The more I think about it the more upset I'm getting !

Stuck at work till 11pm tonight, so can't look at it till later on.

Luckily if it is the chip it should be covered, bought it new from FLO not too long ago, not really tried and imaging with it due to bad weather and using the canon 1100d instead, but have used it a few times to guide the canon with no problems.

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Yep another one for Ice. Had the same meself some time back on my IMGOH, drove me to distraction thinking I had bought a duff camera. I also get fogging in warm weather behind the sensor window which gives hazy effect over some of the image area. Sorted now with a little silica gel pack in the nosepiece everytime I pack away.


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Guest Kheldar

Are all the subs the same? Could you do a flat to test the sensor?

 

Yup, this will be the best test

 

Is the CCD cooled? in which case I would say it's the same issue I had at Belper last time. A little moisture on the chip which froze. I had to keep taking it off to dry it out in the van, in the end I put the dew band around it and that cured it.

 

Agreed that dark blob is pretty distinctive

 

Ok, possibly a daft question from a non astro photographer, if it was dust bunnies or ice etc, would that not block everything out?

Reason I ask is you can still see the star that is inside the black spot!

 

No, you can see through dust bunnies

 

Hang on,I've just thought about this again, surely it can't be the chip cause it's took photos of the stars inside the "black hole", but stars don't give off luminescence, so logically it must be something on the filter, or the filters damaged?

 

Stars don't give off luminescence?

 

The more I think about it the more upset I'm getting !

Stuck at work till 11pm tonight, so can't look at it till later on.

Luckily if it is the chip it should be covered, bought it new from FLO not too long ago, not really tried and imaging with it due to bad weather and using the canon 1100d instead, but have used it a few times to guide the canon with no problems.

 

No need to get worked about this yet Rob - put the flat panel over the end of the scope and take a sub of around 0.5s

 

Whatever software you are using check the ADU (average) value - you want to increase/decrease the sub length until you get about 30,000 to 40,000 for your average

 

(Please note this is not a post on how to take optimal flats, just how to get a flat you will be able to see the problem on) :)

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Stars don't give off luminescence?

 

 

Did I really type that ???????   :facepalm::facepalm2:

 

What was in my head was obviously not what I typed - what a Muppet!

 

Really should stop meddling in the dark arts............ :P

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Guest Kheldar

Did I really type that ???????   :facepalm::facepalm2:

 

What was in my head was obviously not what I typed - what a Muppet!

 

Really should stop meddling in the dark arts............ :P

 

:lol: Nooo, follow your heart ... look at Felix - proper darksider now he is what with his NEQ6 and Meg72 :D :D :D

 

I really should find the post where he was most adamant he would NEVER turn to the dark side :whistle:

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:lol: Nooo, follow your heart ... look at Felix - proper darksider now he is what with his NEQ6 and Meg72 :D :D :D

I really should find the post where he was most adamant he would NEVER turn to the dark side :whistle:

Now now peeps! I'm no "proper dark sider" I just like the portability and contrasty views the Meg 72 gives-great quick grab and go visual setup. I was having this discussion with Dawson yesterday-I just do not earn enough to venture into the dark arts in the way I would like to so I am quite content with carrying on with planetary for the foreseeable future. Should I come into a significant windfall then yes I will go straight down that path though! Until that happens I will spend my clear nights trying to emulate Damian peach but on a much less grand scale as I don't have a C14! :D

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ok people i`ve had a look at the scope optics, the reducer, the filters and the titan camera, little dust on all but not enough to show a horrible black spot, i but the camera cooler on and noticed almost straight away that the chip of the camera, not the glass on the front, was starting to fog up, left it running for 20 minutes and it`s cleared lovely, now i also took a flat at 0.5 seconds and can`t see anything only a blueish screen, but i don't know how to get the ADU readings if thats what they are called as Stephen suggested, a reading of between 30,000 and 40,000. please can anyone tell me how i can tell what reading i`m getting.


i haven`t a clue.  


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