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Old 20-09-2009, 12:37 PM
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toryglen-boy (Duncan)
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QHY8 Gurus in here

Hi guys

Ok i picked up my QHY8 yesterday, a big thanks to mtodman who was very helpful regarding getting it going! Am wading through the mire that is the very begginers end, of a steep learning curve, and i have a few questions for the experts.

1. Is the camera meant to get as hot as it does? it feels really quite warm to the touch, all over front and back

2. How do i know if the cooling is working? how can i check the temp?

3. is there a correct procedure for switching it off? i dont want the TEC to turn off, and for all that heat to go straight to the sensor

4. Can someone please demystify taking flats with this, and a good method for doing so, infact, if anyone can point me at any good begineers tutorials, that would be better.


thanks

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Old 20-09-2009, 12:43 PM
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1_ Yep. it's normal.
2_ It get's hot on the outside. You'd need to install a DIY temp sensor.
3_ Just common sense - don't induce any thermal shock by opening the freezing camera straight away and putting it into a hot environment. Usually switch it off. As sson as you see water droplets on the cold finger you're good to go.
4_ Best and easiest way in an EL sheet. Aim for 9000-10000 ADU in the brightest part of the bayer matrix.

Quote:
Originally Posted by toryglen-boy View Post
Hi guys

Ok i picked up my QHY8 yesterday, a big thanks to mtodman who was very helpful regarding getting it going! Am wading through the mire that is the very begginers end, of a steep learning curve, and i have a few questions for the experts.

1. Is the camera meant to get as hot as it does? it feels really quite warm to the touch, all over front and back

2. How do i know if the cooling is working? how can i check the temp?

3. is there a correct procedure for switching it off? i dont want the TEC to turn off, and for all that heat to go straight to the sensor

4. Can someone please demystify taking flats with this, and a good method for doing so, infact, if anyone can point me at any good begineers tutorials, that would be better.


thanks

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  #3  
Old 20-09-2009, 01:02 PM
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toryglen-boy (Duncan)
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thats what i mean Marc, point 4 you made could have been in double dutch!! can you explain it any simpler?

thanks

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  #4  
Old 20-09-2009, 01:27 PM
dpastern (Dave Pastern)
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Quote:
Originally Posted by toryglen-boy View Post
thats what i mean Marc, point 4 you made could have been in double dutch!! can you explain it any simpler?

thanks

agreed, lost me as well!

Dave
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Old 20-09-2009, 01:28 PM
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It was all double-dutch to me to start off. Read the Nebulosity manual (free) and it explains the whole shebang. I made a light box with the assistance of Peter_4059 (thanks Peter) and made my flats using this. Ive included one of my recent flats made in nebulosity. If you run pix maths over it you will see it had a pix 0f ~9200 max. This is what I aimed for according to Marc and it worked brilliantly resolving the vignetting and small dust spots. Took Bias frames which you also need to determine the gain and offset to use (again see nebulosity manual). For the QHY8 I would get Nebulosity as it makes image aquisition very easy.
Regards, Allan
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Old 20-09-2009, 01:35 PM
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El sheet = electro luminecence sheet
http://www.elec2go.com.au/prod10.htm
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Old 20-09-2009, 01:40 PM
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Quote:
Originally Posted by toryglen-boy View Post
thats what i mean Marc, point 4 you made could have been in double dutch!! can you explain it any simpler?

thanks

Oops - sorry guys. Got carried away Here's what works for me.
An EL (Electro Luminescent sheet) is great coz it's small/compact and you can shoot your flats under controlled conditions anywhere anytime. Don't have to wait for twilight (evening or morning).

When you shoot a flat, let's say 1s You get a big bright spot in the center dimming towards the edges with the occasional black dust spots there and there. If you use nebulosity do a preview then roll your mouse over the brightest part of the frame and note the ADU value for the pixels you roll over (bottom right in the status bar). Aim for 9000 approx.
When you've determined your ex time, shoot 40 of them and stack them into one master flat. To learn about calibration frames you'll need to do a bit of reading. There are tutorials on this site in the resources section.
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Old 20-09-2009, 01:45 PM
dpastern (Dave Pastern)
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Quote:
Originally Posted by allan gould View Post
It was all double-dutch to me to start off. Read the Nebulosity manual (free) and it explains the whole shebang. I made a light box with the assistance of Peter_4059 (thanks Peter) and made my flats using this. Ive included one of my recent flats made in nebulosity. If you run pix maths over it you will see it had a pix 0f ~9200 max. This is what I aimed for according to Marc and it worked brilliantly resolving the vignetting and small dust spots. Took Bias frames which you also need to determine the gain and offset to use (again see nebulosity manual). For the QHY8 I would get Nebulosity as it makes image aquisition very easy.
Regards, Allan
Is this what you're referring to Allan?

http://www.stark-labs.com/downloads_...osity2Docs.pdf

Dave
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Old 20-09-2009, 02:34 PM
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whats a good gain, and offset?
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Old 20-09-2009, 02:52 PM
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Quote:
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Is this what you're referring to Allan?

http://www.stark-labs.com/downloads_...osity2Docs.pdf

Dave
Yes - and the gain and off set determination is explaned in there as well.
I use 1% gain and 65 offset as determined from my bias frames of ~0.001 sec, however each camera is an individual and you need to determine whats best for yours.
Allan

Edit:- I forgot to mention, once you have determined your flats for an imaging session you dont chance camera orientation, focus, etc or you have to do new flats for that setup. They are easy to so once you get the hang of it. B dont do what I did and have the scope pointing up with the ligh box balancing on top. Got messed up with the power lead and it came off and hit me on the head. Ouch.
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Old 20-09-2009, 02:56 PM
dpastern (Dave Pastern)
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More to read, doh! Thanks Allan.

Dave
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Old 20-09-2009, 03:04 PM
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Quote:
Originally Posted by toryglen-boy View Post
whats a good gain, and offset?
Depends on your camera. But I use Gain 1 Offset 60 for everything (RGB, Narrowband). With this camera there is absolutely no point pushing the gain. I use 1 but you could use 0. I only use 1 because it gets written into the FITS header and CCDStack chucks a BF if the gain is 0 in the file. Other than that Craig S. says Offset 110 works fine. In my case I try to get the background ADU to 900 or 1000ADU max. Offset 110 gives me too bright backgrounds. But hey, that's my cam. Experiment with yours.
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Old 20-09-2009, 06:20 PM
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ok, now this is a FAR steeper learning curve than i thought ...

my flats come out in negative, white background with a dark splodge in the middle, and after trying an image of NGC 6357 (as its the redest thing i have ever seen) it came out blue! as did the Horsehead last night ...

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Old 20-09-2009, 07:38 PM
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ok, M8 and M16 have came out blue, and TBH i dont see an advantage with this over a DSLR, although maybe thats just me. the bit rate of the image looks indentical.

I wanted this to be a hobby, not something thats unfathomable and makes me pull my hair out !!

will give this a couple of days, then if still no joy, put it up for sale.

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Old 20-09-2009, 10:17 PM
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Ha ha! I tried to do 6357 last night also, with my QHY8 that arrived Thursday from Gama. Great service and expedient delivery!
I have had all the trouble in the world doing the flats until I contacted a more experienced imager. I had an ok colour to the nebula, but I had red rings around the edges of my image. I too thought that the transition from DSLR to QHY8 was gonna be easy, WRONG! What software are you using to capture & stack your files?
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Old 20-09-2009, 10:43 PM
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Duncan, what format are you saving the images in and what software are you using? If you are saving in FIT's format the image will be grey scale. When you convert to colour the result may depend on your software settings. For example I use MaximDL and in the convert to colour window I can choose a lot of different camera models. If I choose some of the canon options it delivers images from mild red to over the top red. If I choose SBIG every thing is blue on the same image. Be patient the learning curve is not that steep. It won't be long before you will see the difference cooling makes.

Mark
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Old 20-09-2009, 10:49 PM
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Quote:
Originally Posted by TheDecepticon View Post
Ha ha! I tried to do 6357 last night also, with my QHY8 that arrived Thursday from Gama. Great service and expedient delivery!
I have had all the trouble in the world doing the flats until I contacted a more experienced imager. I had an ok colour to the nebula, but I had red rings around the edges of my image. I too thought that the transition from DSLR to QHY8 was gonna be easy, WRONG! What software are you using to capture & stack your files?
Exactly

I am using MaximDL 5, and DSS. I have worked out the colour thing, i had to set the X and Y offset when debayering. Any advice on flats would be good mate, mine are currently white, with a black splodge in the middle ...

Here is my first attempts ...
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Old 20-09-2009, 10:59 PM
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Duncan, what format are you saving the images in and what software are you using? If you are saving in FIT's format the image will be grey scale. When you convert to colour the result may depend on your software settings. For example I use MaximDL and in the convert to colour window I can choose a lot of different camera models. If I choose some of the canon options it delivers images from mild red to over the top red. If I choose SBIG every thing is blue on the same image. Be patient the learning curve is not that steep. It won't be long before you will see the difference cooling makes.

Mark
I hear you mate, i have had all sorts of obstacles. first off was getting the MPCC at exactly the right spot, although i am still convinced its not right, secondly was getting the focus sorted, and as you can see thats still not right. third, i am starting to realise that to get the accuracy that i want, i will need a better mount than an EQ6.

as for converting to colour, i am going to the option called "convert to RGB" and just checking the offsets.



hmm !


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Old 20-09-2009, 11:01 PM
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Have you read this?

http://www.iceinspace.com.au/forum/s...ad.php?t=50012

Black splog??? The camera is not icing up is it? Usually the centre will be best illuminated with vignetting toward the outsides depending on your scope.

Mark
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Old 20-09-2009, 11:03 PM
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If you look to the right next to the offsets there is a drop down menu that lets you select camera type, it sets the offsets for you.

Mark
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