#21  
Old 14-11-2009, 01:29 AM
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Wow .. 5Kg cameras ...
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  #22  
Old 14-11-2009, 01:49 AM
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Wow .. 5Kg cameras ...
Astro 40D = 1020g
Am I missing a CCD v's DSLR in-joke?
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  #23  
Old 14-11-2009, 01:53 AM
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The fan on the side of that thing is the size of a qhy8 doug.

And how can you compare the 2. The qhy8 is 16 bit and vitually noise free ... You can stretch the images to tomorrow and back.
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Old 14-11-2009, 01:03 PM
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Both cameras have their merits... The cooled DSLR's offer fantastic results and the ease of use that keeps most people imaging with a DSLR. As robin mentioned, the CCD's are 16bit.. thats just for starters... cooling in a CCD is far more serious than the cooling in the cooled DSLRs.. Couple that with the price factor... why buy a DSLR that has been heavily modified, and had its warranty voided so that its capable of reasonable quality astro images, when for a lower price you can buy a dedicated astro imaging camera that is designed and built with astro imaging in mind... It amazes me that Central DS sell cameras to be honest.. Especially due to the fact that now you can get an 8.3mp SBIG colour or monochrome ccd for about $400 USD less, the QHY8 is cheaper, the Orion Starshoot Pro is cheaper... You'd be flippin mad to pay 2K USD for a cooled DSLR in my opinion... The only reason you would ever consider it is if all your imaging (or most of your imaging) was done through Canon EF series lenses. Then you would simply for convenience... I have a EOS Lens adapter here to connect EF lenses to my SBIG... it takes more time to set it up, but again, 8.3mp mono ccd, much more sensitive, lighter, designed for the task and cooled much more efficiently with much less noise, at less cost..

Perhaps we are the ones missing the CCD v DSLR joke?
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  #25  
Old 15-11-2009, 05:15 PM
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DSLRs produce results. So do CCDs.

It's all up to how much time the operator wishes to invest in capturing the light, calibrating their images correctly and processing properly.

Note: I am not inferring that DSLRs are equivalent to dedicated CCDs.
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  #26  
Old 15-11-2009, 05:22 PM
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anyway guys, its finally coming together, and i am getting there.


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Old 15-11-2009, 05:32 PM
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Thats the way Duncan, keep at it. Once you knock out a few images it will all make sense .

Mark
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  #28  
Old 15-11-2009, 05:36 PM
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As they say, Practise makes Perfect.. Resist the urge to fall back to your DSLR, stick it out with the QHY8 and the results will improve! Good to hear you're making some headway.
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  #29  
Old 17-11-2009, 05:41 PM
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Quote:
Originally Posted by Tandum View Post
The fan on the side of that thing is the size of a qhy8 doug.

And how can you compare the 2. The qhy8 is 16 bit and vitually noise free ... You can stretch the images to tomorrow and back.
Central DS website quotes camera+cooler weight as 1020g. Not too sure how accurate that is - cooler unit must only weigh around 300-400g for that figure to be accurate
But Robin I have to concede that with the high ambient imaging temperatures I experienced last week, an ultra-cooled CCD does seem very appealing. My SMC had lots of blue and red smaller stars - not pretty.
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Old 17-11-2009, 05:53 PM
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Both cameras have their merits... The cooled DSLR's offer fantastic results and the ease of use that keeps most people imaging with a DSLR. As robin mentioned, the CCD's are 16bit.. thats just for starters... cooling in a CCD is far more serious than the cooling in the cooled DSLRs.. Couple that with the price factor... why buy a DSLR that has been heavily modified, and had its warranty voided so that its capable of reasonable quality astro images, when for a lower price you can buy a dedicated astro imaging camera that is designed and built with astro imaging in mind... It amazes me that Central DS sell cameras to be honest.. Especially due to the fact that now you can get an 8.3mp SBIG colour or monochrome ccd for about $400 USD less, the QHY8 is cheaper, the Orion Starshoot Pro is cheaper... You'd be flippin mad to pay 2K USD for a cooled DSLR in my opinion... The only reason you would ever consider it is if all your imaging (or most of your imaging) was done through Canon EF series lenses. Then you would simply for convenience... I have a EOS Lens adapter here to connect EF lenses to my SBIG... it takes more time to set it up, but again, 8.3mp mono ccd, much more sensitive, lighter, designed for the task and cooled much more efficiently with much less noise, at less cost..

Perhaps we are the ones missing the CCD v DSLR joke?
Must admit Alex, I'm slowly coming round to your way of thinking.
The 40D was originally purchased with an equal mix of terrestrial and astro work in mind. In reality, the DSLR has stayed fixed to the mount pretty much permanently! So this fact in conjunction with the market shift toward more affordable high quality CCDs becoming available presents an (almost predictable in astrophotography!) dilema.
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  #31  
Old 17-11-2009, 11:44 PM
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Doug,

I see no problem in saving your money and mastering the DSLR. You are getting fabulous results. And, besides, with every image you capture, you hone in on your processing skills. Capturing the data is only 50% of the problem. It'd still be the same whether you continue to use a DSLR or a CCD camera.

I, too, am in two minds about jumping ship, but, then think what I might be able to do with the 5D Mark II...

Regards,
Humayun
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  #32  
Old 25-11-2009, 01:45 AM
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Gain/Offset

Becoming a new owner of a QHY8 myself, when its mentioned the maximum pixel value should be between 400-1000, is this best to be closer to 400 as can be achieved ?

I followed the instructions and was able to achieve Gain 2 Offset 109 of what I thought was reasonable.
See screenshot...

I noticed I have a few dead pixels? White dots seen when the image is dark.
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  #33  
Old 25-11-2009, 07:12 AM
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Quote:
Originally Posted by leinad View Post
Becoming a new owner of a QHY8 myself, when its mentioned the maximum pixel value should be between 400-1000, is this best to be closer to 400 as can be achieved ?

I followed the instructions and was able to achieve Gain 2 Offset 109 of what I thought was reasonable.
See screenshot...

I noticed I have a few dead pixels? White dots seen when the image is dark.
Get your gain to 0 or 1. The offset will determine the position of your histogram in respect to the left side. Varies on cameras and sky conditions. I use 60 to 70, that gives me a sky background of 900-1000ADU typically. You want that margin on the left, no more no less. 1000ADU is comfortable to play with. No clipping.

Last edited by multiweb; 25-11-2009 at 07:24 AM. Reason: spelling
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  #34  
Old 25-11-2009, 11:55 AM
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Originally Posted by multiweb View Post
Get your gain to 0 or 1. The offset will determine the position of your histogram in respect to the left side. Varies on cameras and sky conditions. I use 60 to 70, that gives me a sky background of 900-1000ADU typically. You want that margin on the left, no more no less. 1000ADU is comfortable to play with. No clipping.
Ok thanks, I'll try again tonight.
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  #35  
Old 25-11-2009, 12:17 PM
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Managed to purge the TVDE QHY8 drivers from my system/laptop and load the straight drivers from QHY. The reason that I did this was in Nebulosity you could only get 1x1 or 2x2 binning. I wanted to use the 4x4 binning mode but the TVDE drivers caused Nebulosity to crash. Now have all 3 binning modes for the QHY8 and am a happy chappy. Really loving this camera
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  #36  
Old 25-11-2009, 01:40 PM
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................

I noticed I have a few dead pixels? White dots seen when the image is dark.

You will always get hot pixels in any CCD, this is normal, no need to pack up and run to the hills. The Sony sensors have very low hot pixel counts..


Theo
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  #37  
Old 25-11-2009, 01:53 PM
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You will always get hot pixels in any CCD, this is normal, no need to pack up and run to the hills. The Sony sensors have very low hot pixel counts..


Theo

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  #38  
Old 25-11-2009, 06:15 PM
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Especially due to the fact that now you can get an 8.3mp SBIG colour or monochrome ccd for about $400 USD less,
Where? tell me tell me
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  #39  
Old 27-11-2009, 11:06 AM
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another question....

A quick question of gain/offset

In Nebulosity I found that
Gain 0 Offset 50 I get a Max value just on 1000. I believe thats right from what Craig Stark mentioned.

At bias 0.001 secs, this puts the histogram right to the left. Pity you cant zoom to view the histogram like MaximDL does.

http://i611.photobucket.com/albums/t...orion_test.jpg

Above was a quick stack (flat/bias calibrated and stretched) with a couple of 2min, 5min (Gain 0 Offset 55) and 1 10min (Gain 5 Offset 55).

I seemed to get similar results as well at Gain 1 Offset 110 compared against the Gain 5 Offset 55, though this wasnt good with the bias test shots.

If I understand this all correctly, I should find the right Offset with Bias frames then use that, and just boost the Gain with lights to get the best results with exp time.

Feedback welcome, thanks.
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  #40  
Old 27-11-2009, 11:17 AM
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That's a great Orion, especially for a 'quick stack'!!
Interesting that you mentioned the lack of histogram zoom in Neb compared to Maxim. I like and use Neb, however I wish it would allow me to zoom the histogram. Perhaps a quick email to Craig...

Cheers,

Rob
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