Thalestris24 Posted January 8, 2018 Share Posted January 8, 2018 1 hour ago, LightBucket said: well not that good, as loads of noise, is the camera being cooled as looks more like a DSLR image with no darks ? if I bring the curves up a bit and make the background more natural looking, the noise is much worse, hence the black background... Well, the qhy8l, I guess, as that's the thread topic. However, the OP didn't say whether the cooling was on or what it was set to, or how many subs and length of them. Louise Link to comment Share on other sites More sharing options...
LightBucket Posted January 8, 2018 Share Posted January 8, 2018 4 minutes ago, Thalestris24 said: Well, the qhy8l, I guess, as that's the thread topic. However, the OP didn't say whether the cooling was on or what it was set to, or how many subs and length of them. Louise Yes realise it’s the QHY8L,was just saying it looked like a DSLR image because of the noise.. Link to comment Share on other sites More sharing options...
Andymod Posted January 8, 2018 Author Share Posted January 8, 2018 6 hours ago, LightBucket said: well not that good, as loads of noise, is the camera being cooled as looks more like a DSLR image with no darks ? if I bring the curves up a bit and make the background more natural looking, the noise is much worse, hence the black background... 5 hours ago, Thalestris24 said: Well, the qhy8l, I guess, as that's the thread topic. However, the OP didn't say whether the cooling was on or what it was set to, or how many subs and length of them. Louise 5 hours ago, LightBucket said: Yes realise it’s the QHY8L,was just saying it looked like a DSLR image because of the noise.. Hi Thankyou for all your help, I set the cooling at -20C. The fact that you managed to get anything is a great help. I can try and achieve an image knowing there is data there. Should I be worried about the level of noise?. Link to comment Share on other sites More sharing options...
Thalestris24 Posted January 8, 2018 Share Posted January 8, 2018 11 minutes ago, Andymod said: Hi Thankyou for all your help, I set the cooling at -20C. The fact that you managed to get anything is a great help. I can try and achieve an image knowing there is data there. Should I be worried about the level of noise?. Hi What was your sub length and how many did you stack? Link to comment Share on other sites More sharing options...
Andymod Posted January 8, 2018 Author Share Posted January 8, 2018 2 hours ago, Thalestris24 said: Hi What was your sub length and how many did you stack? 300 secs and only 4 in stack. As soon as I can I am going to setup my camera gain etc again and capture a decent amount of subs and a full suite of calibration frames. My interest in the QHY8L has been resurrected. A Massive thanks for everyones input. Link to comment Share on other sites More sharing options...
carastro Posted January 8, 2018 Share Posted January 8, 2018 I presume you are guiding, IF so, with a cooled CCD camera, you probably should do 600sec exposures, you'll get better data that way. Carole Link to comment Share on other sites More sharing options...
Andymod Posted January 10, 2018 Author Share Posted January 10, 2018 On 8 January 2018 at 21:14, carastro said: I presume you are guiding, IF so, with a cooled CCD camera, you probably should do 600sec exposures, you'll get better data that way. Carole I will go 600 secs next time out and get a full suite of calibration frames, although now my laptop charger has decided to give up charging, it will have to wait until I get another charger. Just my luck at the moment. Link to comment Share on other sites More sharing options...
sloz1664 Posted January 10, 2018 Share Posted January 10, 2018 High Andy Have a read of the attached gain & offset procedures for your type of CCD camera Steve Gain & Offset.pdf gain and offset.pdf Link to comment Share on other sites More sharing options...
Andymod Posted January 12, 2018 Author Share Posted January 12, 2018 On 10/01/2018 at 21:37, sloz1664 said: High Andy Have a read of the attached gain & offset procedures for your type of CCD camera Steve Gain & Offset.pdf gain and offset.pdf Thanks Steve I will have a read now I have a working laptop charger Link to comment Share on other sites More sharing options...
Andymod Posted February 25, 2018 Author Share Posted February 25, 2018 On 10/01/2018 at 21:37, sloz1664 said: High Andy Have a read of the attached gain & offset procedures for your type of CCD camera Steve Gain & Offset.pdf gain and offset.pdf So I finally found some spare time to have a go at setting up the gain and offset of my QHY8L following the guide above. Everything appeared to be going well until the final step "Complete a photon response plot of CCD". With the camera capped and an exposure of 0.001secs my mean pixel value is 637 which is above 400 so uncapped the camera and began exposures with 0.025secs, my mean pixel value was 64996. increasing exposure to 0.050 secs and the mean value hits max 65535. I calculated my gain to be 11 and offset 108. The guide suggests the mean pixel value should gradually rise?. Whats going on?. Link to comment Share on other sites More sharing options...
AKB Posted February 25, 2018 Share Posted February 25, 2018 Those seem like reasonable numbers? I use a gain of 14 and offset of 113, so not much different. Link to comment Share on other sites More sharing options...
sloz1664 Posted February 25, 2018 Share Posted February 25, 2018 Agree with AKB those figures look fine. My gain is 10 & offset of 121. Steve Link to comment Share on other sites More sharing options...
Andymod Posted July 1, 2018 Author Share Posted July 1, 2018 I think I am finally making small amounts of progress with the QHY8L. This image is 7x600s stacked. I used darks, flats and bias. Still trying to get to grips with processing but finally seem to be making progress. North American Nebula from a light polluted Sheffield. Link to comment Share on other sites More sharing options...
carastro Posted July 1, 2018 Share Posted July 1, 2018 Much better Andy, and pretty good from Sheffield. Onwards and upwards. I did have to put my sun glasses on though because of the very bright red ha ha. Carole Link to comment Share on other sites More sharing options...
ebdons Posted July 1, 2018 Share Posted July 1, 2018 Hi, keep at it my friend, I have a QHY10 and were having issues about sensitivity amp on amp off etc, and I would be happy if I got something like your North American neb, I learn't that you can take too many darks and bias and not concentrate on the light, luminance and imaging data exp, especially when I was using an 80mm edt as an imager, now have an astrograph and much better results for me I found it more important to get a good flat frame library for that scope setup, Tony. Link to comment Share on other sites More sharing options...
Thalestris24 Posted July 1, 2018 Share Posted July 1, 2018 The qhy8l is certainly well sensitive in the red part of the spectrum The nights are gradually getting longer here! I might be able to do some imaging again in about a month or so.... Louise Link to comment Share on other sites More sharing options...
Andymod Posted July 6, 2018 Author Share Posted July 6, 2018 Thanks to everybody who commented, I had more or less given up with the QHY8L. I spent so many of my limited imaging nights getting no images it destroyed my confidence and almost made me give up altogether. I defaulted to using 600D to rebuild confidence. After everyone's help and calculating the gain and offset for the camera, I just needed a night to grab some data. I hope to practice more at processing and maybe tone down the Ha a bit. My excitement at finally grabbing an image may be the reason the Ha was extreme. Thanks everyone. Link to comment Share on other sites More sharing options...
russellhq Posted July 8, 2018 Share Posted July 8, 2018 Andy, did you ever solve your original issue of "rings of varying brightness". I only ask because I have seen something like this my self and it seemed to be a quirk of Photoshop. If I recall, it happened at different zoom levels. I think I was able to get rid of it by zooming to 100% but then the image didn't fit on the screen. Link to comment Share on other sites More sharing options...
Andymod Posted July 9, 2018 Author Share Posted July 9, 2018 19 hours ago, russellhq said: Andy, did you ever solve your original issue of "rings of varying brightness". I only ask because I have seen something like this my self and it seemed to be a quirk of Photoshop. If I recall, it happened at different zoom levels. I think I was able to get rid of it by zooming to 100% but then the image didn't fit on the screen. Hi Russell, I didn’t get to the bottom of the rings to be honest, I did wonder if it was condensation on the glass in front of the sensor. When there’s a heavy dew I wrap a small heater band around the spacers between the camera and Flattener. Link to comment Share on other sites More sharing options...
Andymod Posted July 9, 2018 Author Share Posted July 9, 2018 A good friend at Sheffield Astronomical Society, took my stack that I used above and processed it in Pixinsight. Wow what a difference. I have a lot to learn. Link to comment Share on other sites More sharing options...
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