EQUIPMENT
♦ Skywatcher Star Adventurer Pro 2i Wifi
♦ Skywatcher Evostar 72ED DS-Pro [420mm F/5.8]
♦ Zwo ASI 183MC Pro (cooled)
♦ Sharpcap Pro 4
Before I start, I'd like to say that Polaris is visible in the alignment clock reticule and (more or less) where it should be for the time of night I'm setup.
So, I thought I'd try and do a Polar Alignment using Sharpcap Pro...
No matter what I do, the Alignment part of SC never gets beyond the first step - at most only ever finding 3 stars - but, usually only Polaris itself!
Things I've tried:
♦ Increased Exp from 1-2s right up to around 10-15s
♦ Increased Gain to max
♦ Increased sensitivity
♦ Reduced Noise threshold
♦ Altered Display Stretch
Preview in SC (set to Auto) shows Polaris as a nice round star approx 4mm dia, other stars are similar size but a faded Grey in appearance - possibly the reason for SC Polar Align not detecting them?
Polar Alignment Blues
Re: Polar Alignment Blues
just an update: things are a little clearer now, but now it's almost impossible to align.
is there a "dark art" involved in this? best I can usually get is "FAIR", I did manage a "GOOD" once but when tightening the Latitude Lock Handle appears to throw everything off.
is there a "dark art" involved in this? best I can usually get is "FAIR", I did manage a "GOOD" once but when tightening the Latitude Lock Handle appears to throw everything off.
Re: Polar Alignment Blues
Just a wild guess:
4mm stars tells me that you are out of focus.
Can you take a screenshot next time?
Brian
4mm stars tells me that you are out of focus.
Can you take a screenshot next time?
Brian
Re: Polar Alignment Blues
Hi Brian
thanks for your reply. As I said in my second post, Focus is now fine. they're pin-sharp.
It's the Alignment itself that's bugging now
thanks for your reply. As I said in my second post, Focus is now fine. they're pin-sharp.
It's the Alignment itself that's bugging now
Re: Polar Alignment Blues
Yeah, I read what you wrote:
"just an update: things are a little clearer now, but now it's almost impossible to align."
I didn't quite make out what you meant by "things are a little clearer now." I figure that you had less-cloudy skies. Now I see you meant "focus".
Still, if you could post a screenshot, it would be very helpful.
Brian
"just an update: things are a little clearer now, but now it's almost impossible to align."
I didn't quite make out what you meant by "things are a little clearer now." I figure that you had less-cloudy skies. Now I see you meant "focus".
Still, if you could post a screenshot, it would be very helpful.
Brian
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Re: Polar Alignment Blues
Hi,
yes, a screenshot (and even better, a saved image captured using the 'snapshot' button) would help us work out why you are having trouble. Do also see the troubleshooting guide for further hints : https://docs.sharpcap.co.uk/4.0/#Troubl ... 0Alignment
cheers,
Robin
yes, a screenshot (and even better, a saved image captured using the 'snapshot' button) would help us work out why you are having trouble. Do also see the troubleshooting guide for further hints : https://docs.sharpcap.co.uk/4.0/#Troubl ... 0Alignment
cheers,
Robin
Re: Polar Alignment Blues
Okay, I've now managed to get SC Polar Alignment to work - to the point that the tool confirms my alignment as "Good". What happens once I get a "Good" - am I supposed to confirm anything within the tool? I've just exited the tool and gone to Capture.
I've attached a captured image.
the problem I now have is that the maximum exposure time i can use before stars begin to lose their roundness is 10secs. anything longer than 10secs results in oval stars and around 20secs they're becoming dashes.
obviously that's not right. clearly, I'm missing something here.
SETTINGS
[ZWO ASI183MC Pro]
FrameType=Light
Debayer Preview=Off
Pan=0
Tilt=0
Output Format=FITS files (*.fits)
Binning=2
Capture Area=5496x3672
Colour Space=RAW16
Hardware Binning=Off
High Speed Mode=On
Turbo USB=100
Flip=None
Frame Rate Limit=Maximum
Gain=318
Exposure=10.102s
Timestamp Frames=Off
White Bal (B)=57
White Bal (R)=59
Brightness=25
I've attached a captured image.
the problem I now have is that the maximum exposure time i can use before stars begin to lose their roundness is 10secs. anything longer than 10secs results in oval stars and around 20secs they're becoming dashes.
obviously that's not right. clearly, I'm missing something here.
SETTINGS
[ZWO ASI183MC Pro]
FrameType=Light
Debayer Preview=Off
Pan=0
Tilt=0
Output Format=FITS files (*.fits)
Binning=2
Capture Area=5496x3672
Colour Space=RAW16
Hardware Binning=Off
High Speed Mode=On
Turbo USB=100
Flip=None
Frame Rate Limit=Maximum
Gain=318
Exposure=10.102s
Timestamp Frames=Off
White Bal (B)=57
White Bal (R)=59
Brightness=25
Re: Polar Alignment Blues
Hi,
I tried running your image through nova.astrometry.net but I'm getting "Server Error (500)". It looks like they are having network troubles. I'll try later. In the meantime...
A 10-second exposure makes Polar Alignment almost impossible to manage. What do you get with a 2-second exposure? That's what I use.
How soon after sunset are you attempting P.A.? I generally have to wait for the Sun to drop below 12 degrees below the horizon. (Astronomical Darkness begins at 18 degrees below the horizon.) If I attempt P.A. when the sky is brighter, SC can't find enough stars for P.A. So, for me at least, the sky needs to be a certain darkness.
What is your light pollution? Are you in a city or suburbs?
Brian
I tried running your image through nova.astrometry.net but I'm getting "Server Error (500)". It looks like they are having network troubles. I'll try later. In the meantime...
A 10-second exposure makes Polar Alignment almost impossible to manage. What do you get with a 2-second exposure? That's what I use.
How soon after sunset are you attempting P.A.? I generally have to wait for the Sun to drop below 12 degrees below the horizon. (Astronomical Darkness begins at 18 degrees below the horizon.) If I attempt P.A. when the sky is brighter, SC can't find enough stars for P.A. So, for me at least, the sky needs to be a certain darkness.
What is your light pollution? Are you in a city or suburbs?
Brian
Re: Polar Alignment Blues
Brian
I think you misunderstand. Alignment is (supposedly) fine now. These were done around 8pm (UK time) sky was dark and there is no western aspect from our back garden.
SC Polar Alignment is showing as "Good". I did this using the SC Polar Align tool - using the 1-2sec recommended exp.
The image I've posted is a 10sec exp from my capture session. The point being that:
10 secs is the maximum exp I can capture before the stars begin to go oval and then trail...this can't be right, surely?
I think you misunderstand. Alignment is (supposedly) fine now. These were done around 8pm (UK time) sky was dark and there is no western aspect from our back garden.
SC Polar Alignment is showing as "Good". I did this using the SC Polar Align tool - using the 1-2sec recommended exp.
The image I've posted is a 10sec exp from my capture session. The point being that:
10 secs is the maximum exp I can capture before the stars begin to go oval and then trail...this can't be right, surely?
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- Site Admin
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Re: Polar Alignment Blues
I have done some moderating in this thread as the discussion was getting over heated and into regions that might be considered in breach of the forum rules.
Winding back, it looks like @brenski found the issues stopping him from polar aligning, but is still getting a lot of drift when trying to image.
It's worth checking your PA by working through the suggestions in the 'I get the wrong results...' section of the PA troubleshooting : https://www.sharpcap.co.uk/sharpcap/fea ... leshooting . Getting drift in a 10s image would indicate about 1 degree of polar misalignment (ballpark), so if it is polar alignment, it's a big error. Other possibilities are mount tracking rate, flex of camera/telescope mounting, etc.
cheers,
Robin
Winding back, it looks like @brenski found the issues stopping him from polar aligning, but is still getting a lot of drift when trying to image.
It's worth checking your PA by working through the suggestions in the 'I get the wrong results...' section of the PA troubleshooting : https://www.sharpcap.co.uk/sharpcap/fea ... leshooting . Getting drift in a 10s image would indicate about 1 degree of polar misalignment (ballpark), so if it is polar alignment, it's a big error. Other possibilities are mount tracking rate, flex of camera/telescope mounting, etc.
cheers,
Robin