Folks,
Attached is my first serious first light taken with my newly acquired QHY8L.
It was taken last Tuesday night when I could see stars. It is a combination of 13 x 7 minutes hovering around the -15 mark. This image contains no darks, bias or flats but having said that, I do need them?
Stacked in DSS and processed in CS3. The image is cropped only to bring out the nebula.
Very nice, you have to be happy with an image like this as a first light. Things will only improve from here so to take the same image in a years time would be an interesting comparison.
I have several from my early images with a CCD and looking back yours is a masterpiece.
Well done.
Do you need them, it depends on how hard you want to push the image. The qhy8 is actually a very smooth and almost noise free camera, I can still say though that for the extra effort your images can only be that little bit better.
In this image the outer loop is easily visible when stretched, the issue becomes how far can I stretch it until the noise becomes objectionable. More frames and quality calibration will extend your possibilities.
I will strongly endorse the use of flat frames, at the very least. I know that this camera is supposed to be very good insofar as dark noise goes, but, your image can only be better with the use of calibration.
It is quite evident that there is vignetting in this image and flat frames will fix that up.
Very nice, you have to be happy with an image like this as a first light. Things will only improve from here so to take the same image in a years time would be an interesting comparison.
I have several from my early images with a CCD and looking back yours is a masterpiece.
Well done.
Thanks Doug, your input is encouraging and taken on board.
Quote:
Originally Posted by TrevorW
At least someones collecting photons, well done
Trevor, it was a last minute effort, all day the clouds came and went and we ended up with that misty stuff but a slight breeze picked up and blew it all away, until gone 11pm at least.
Quote:
Originally Posted by desler
Congratulations Paul, Getting first light under your belt is always a bit of an accomplishment. Onward and upward.
Darren
Many thanks Darren, I still have a few steps to go yet but small steps first.
Quote:
Originally Posted by cventer
Very nice. Was that with the f4 bintel?
Yes Cventer, this is with the f/4 8" Bintel scope using a Coma Corrector and Deep Sky Filter. The QHY8L sticks out a fair bit from the focuser so its worth keeping an eye on.
Quote:
Originally Posted by Alchemy
Nice first light. Worthy target too.
RE the flats darks and bias etc.
Do you need them, it depends on how hard you want to push the image. The qhy8 is actually a very smooth and almost noise free camera, I can still say though that for the extra effort your images can only be that little bit better.
In this image the outer loop is easily visible when stretched, the issue becomes how far can I stretch it until the noise becomes objectionable. More frames and quality calibration will extend your possibilities.
Enjoy your new camera.
Thanks Clive, I have tried stacking with Darks and Bias frames and when I did stack them the image came out way too dark almost clipped down to the black end of the histogram and this couldn't be processed out so I don't know where I am going wrong? I still have not got around taking my flats but desperately need them.
Quote:
Originally Posted by mill
That looks very good for a first light
And if you can, it is better to take at least some flats (yeah i know, i have to do them too ).
Thanks Martin, the flats are the sword in my side as well as they will make the world of difference.
Quote:
Originally Posted by Ross G
Hi Paul,
Great "first" shot.
Judging by this, some amazing photos are to follow.
The main reason I use darks on my QHY8L is to get rid of some amp glow.
Good luck.
Ross.
Thanks Ross, Amp glow? when do you get this? And how are you stacking your darks? I have had nothing but trouble trying to understand the concept, I never had a problem with my DSLR and yes, this is a new ball game to me.
Quote:
Originally Posted by Octane
That's a great effort for a first light.
I will strongly endorse the use of flat frames, at the very least. I know that this camera is supposed to be very good insofar as dark noise goes, but, your image can only be better with the use of calibration.
It is quite evident that there is vignetting in this image and flat frames will fix that up.
Keep it up!
H
Thanks H, Flats are on the top of my todo list as well as trying to figure out the darks and bias calibration thing works, I need to read up on all this as its still a new and major step up from the DSLR.
I had taken some shots of The Leo Triplet earlier this year and I noticed a small area of amp glow in one corner. I closer look of other shots also showed it. I have read that the QHY8L does have a small amount of amp glow.
I keep my processing simple. I use Deep Sky Stacker. I just click on my lights, darks and flats and it does it all automaticaly. Maybe it's not as good as more advanced programs, but I have been happy with the results.
I had taken some shots of The Leo Triplet earlier this year and I noticed a small area of amp glow in one corner. I closer look of other shots also showed it. I have read that the QHY8L does have a small amount of amp glow.
I keep my processing simple. I use Deep Sky Stacker. I just click on my lights, darks and flats and it does it all automaticaly. Maybe it's not as good as more advanced programs, but I have been happy with the results.
Ross.
Thanks Ross,
Maybe that is where I am going wrong, When I stack using DSS only with darks and bias frames added the image after the stack is black pointed, way to the black end of the histogram and this cannot be processed out so maybe I need to add the flat frames to even everything out?
What are the length of exposures you are taking to get this amp glow? This is something I need to look out for.
Thanks Clive, I have tried stacking with Darks and Bias frames and when I did stack them the image came out way too dark almost clipped down to the black end of the histogram and this couldn't be processed out so I don't know where I am going wrong?
DSLR.
It's quite possibly a result of your camera settings
You need to have your gain and offset correctly done. It's quite possible your offset is too low . Other things to check is that the settings for all your calibration files as far as offset and gain goes is the same.
As a security measure you should use the same program for collection of all your frames during shooting, offset and gain may vary from program to program
Just a suggestion, if you are confident about all your settings you might have to look elsewhere.
Oh and another thing, i'm digging way into the past here, but I found DSS wasn't so great without all the differing kinds of calibration files. As I said it was a long time ago so that may have improved but I since then always used the full calibration set.
I don't think using flats makes a big difference to the look of your photo. I only use them because the WO field flattener gives me vignetting in the corners.
All my exposures so far have been 10min at -20c. I did a set of 15 dark frames at these settings back in February and I have used the same ones ever since. It seems to still work.
I don't manipulate the shots at all in DSS. Once they are stacked I save a Tiff file and import it into Photoshop CS3
In DSS's "recommended Settings" I always make sure I have chosen "RGB background calibration". This lines up the histograms for the 3 colours, given me less colour balance problems in CS3.
It's quite possibly a result of your camera settings
You need to have your gain and offset correctly done. It's quite possible your offset is too low . Other things to check is that the settings for all your calibration files as far as offset and gain goes is the same.
As a security measure you should use the same program for collection of all your frames during shooting, offset and gain may vary from program to program
Just a suggestion, if you are confident about all your settings you might have to look elsewhere.
Hi Clive, I'm using the standard settings as outlined in the QHY8L manual for my offset and gain, this is with the Ezycap software, I have tried Nebulousity2 and MaximDL. I think you may be on to something there I might add because I have been jumping from one program to another feeling out the one I am most comfortable with and this is were I could be going wrong.
I don't think using flats makes a big difference to the look of your photo. I only use them because the WO field flattener gives me vignetting in the corners.
All my exposures so far have been 10min at -20c. I did a set of 15 dark frames at these settings back in February and I have used the same ones ever since. It seems to still work.
I don't manipulate the shots at all in DSS. Once they are stacked I save a Tiff file and import it into Photoshop CS3
In DSS's "recommended Settings" I always make sure I have chosen "RGB background calibration". This lines up the histograms for the 3 colours, given me less colour balance problems in CS3.
I use EZYCAP to capture my shots.
Ross.
Hi Ross,
The steps you have outlined in stacking and leading up to your processing are exactly the steps that I take minus the darks etc.
What are the setting, if you don't mind me asking do you use for gain and offset with Ezycap? Clive has just pointed something out that could solve a couple of issues.
I really do appreciate you and Clive taking the time to answer and put on the straight and narrow with this.
Hi Clive, I'm using the standard settings as outlined in the QHY8L manual for my offset and gain, this is with the Ezycap software, I have tried Nebulousity2 and MaximDL. I think you may be on to something there I might add because I have been jumping from one program to another feeling out the one I am most comfortable with and this is were I could be going wrong.
Paul
Ok I have got a copy of ezycap (2.4) something to be aware of is that the planner table and the capture output vary.
You should shoot ALL your frames through the planner table, even though the settings are done through the capture tab.
Offset settings is so that during a bias frame ( fastest possible fully covered frame) you should get a reading that in a histogram shows a value of say 600 give or take it will be a bell shaped curve that MUST have all values greater than 0 preferably >400.
Your gain setting will be set by doing a fully exposed shot say 5 sec with a torch shining down the tube of your scope, you can do 10 and more just to check. But you will possibly find nearly all pixels at one value, it needs to be set so value is about 65000, if you find your max value is 58000 or so you will need to increase the gain.
The two can be somewhat interrelated so go back and forth until set right. Again you must do this through the planner table, I found doing single exposures through just the capture tab to be WILDLY different.
Ok I have got a copy of ezycap (2.4) something to be aware of is that the planner table and the capture output vary.
You should shoot ALL your frames through the planner table, even though the settings are done through the capture tab.
Offset settings is so that during a bias frame ( fastest possible fully covered frame) you should get a reading that in a histogram shows a value of say 600 give or take it will be a bell shaped curve that MUST have all values greater than 0 preferably >400.
Your gain setting will be set by doing a fully exposed shot say 5 sec with a torch shining down the tube of your scope, you can do 10 and more just to check. But you will possibly find nearly all pixels at one value, it needs to be set so value is about 65000, if you find your max value is 58000 or so you will need to increase the gain.
The two can be somewhat interrelated so go back and forth until set right. Again you must do this through the planner table, I found doing single exposures through just the capture tab to be WILDLY different.
Hope this helps.
Thanks Clive,
This helps a big deal...many thanks again.
For the sake of avoiding in turning this deep sky images post into a QHY workshop and not upsetting the Mods I will play around with the program and settings and see how it unfolds.
).
I still have not got around taking my flats but desperately need them.
