Imaging problem

Discussion of using SharpCap for Deep Sky Imaging
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neilbarber
Posts: 13
Joined: Wed Oct 27, 2021 8:59 am

Imaging problem

#1

Post by neilbarber »

269850105_5392285200801409_1083268346403602734_n.jpg
269850105_5392285200801409_1083268346403602734_n.jpg (254.09 KiB) Viewed 887 times
after some help and advise please.
Using sharpcap to image. When I do live stacking everything seems to work fine but if I do image capture and set the number of frames i get images like this one.
I would think that because the live stack saved images are ok but not the capture images, it would point to a problem with Sharpcap but I thought i would ask just in case anyone else has come across this.
Sharpcap settings
[ZWO ASI533MC Pro]
FrameType=Light
Debayer Preview=On
Pan=0
Tilt=0
Output Format=FITS files (*.fits)
Binning=1
Capture Area=3008x3008
Colour Space=RAW16
Hardware Binning=Off
Turbo USB=91
Flip=None
Frame Rate Limit=Maximum
Gain=117
Exposure=20.000s
Timestamp Frames=Off
White Bal (B)=95
White Bal (R)=52
Brightness=1
Cooler Power=95
Temperature=-5.3
Target Temperature=-5
Cooler=On
Auto Exp Max Gain=300
Auto Exp Max Exp M S=30000
Auto Exp Target Brightness=100
Mono Bin=Off
Background Subtraction=Off
Planet/Disk Stabilization=Off
Banding Threshold=35
Banding Suppression=21
Apply Flat=None
Subtract Dark=None
Display Black Point=0
Display MidTone Point=0.5
Display White Point=1
Notes=
EQMOD ASCOM HEQ5/6=RA=07:34:33,Dec=+10:56:05 (JNOW)
TimeStamp=2021-12-25T13:51:11.0947788Z
SharpCapVersion=4.0.8472.0

Hopefully the image shows up
procyon12
Posts: 253
Joined: Tue Jan 14, 2020 11:32 am

Re: Imaging problem

#2

Post by procyon12 »

Hi,

Try to shut off "Banding Suppression" (currently 21 > 0). Maybe it is gone then. If so, find the right "Banding Suppression" settings ("Banding Suppression"/"Banding Threshold").

Christian
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admin
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Joined: Sat Feb 11, 2017 3:52 pm
Location: Vale of the White Horse, UK
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Re: Imaging problem

#3

Post by admin »

Hi,

yes, it looks like you have adjusted the banding suppression settings and ended up with values that are doing more harm than good - turn the 'banding suppression' down to zero and see if that improves things. Using the banding suppression requires some careful adjustment to avoid problems - see the documentation here : https://docs.sharpcap.co.uk/4.0/#!2!Pre-processing.

cheers,

Robin
neilbarber
Posts: 13
Joined: Wed Oct 27, 2021 8:59 am

Re: Imaging problem

#4

Post by neilbarber »

Hi ... thank you for the replies and yes it was the problem. I have that sorted but there is another question I would like to ask.

I'm having a job to understand part of it. It's in the Sharpcap settings under Guiding. I am using 'Dither only using Ascom mount pulse guiding' I'm having a job to understand the settings in there. I have the HEQ5 with the WO Z61ii & asi533mc. It's the first 2 boxes that I'm have a problem with. At the moment, without guiding with PHD2 or any other program I can get 120sec to 180sec exposures without the stars elongating. I have 'Max dither step' set to 10 and 'Settle Threshold set to 2 (Oh I have the Minimum Settle time at 6 sec.) but I'm getting some star trailing in some of my image ( dither every other image @ 120sec exposures). Have I got these settings about right and should I expect a few shots to have the star trails.
Thanks for any help.
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admin
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Location: Vale of the White Horse, UK
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Re: Imaging problem

#5

Post by admin »

Hi,

good to hear that you got the banding issue sorted.

Answer to your guiding/dithering question here : viewtopic.php?p=27419#p27419

cheers,

Robin
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