Hi!
I'm doing some test of guiding and I'm not sure about size of pixels on screen. When max zoomed there are squares with cross in the center. Are these pixels? My image scale is 1 arc second per pixel. With crosshair on one square is the size of second circle. Two squares are of diameter of the biggest circle. So by my calculations small circle is 0.5", middle 1" and biggest circle is 2 arc second. Is this right?
Br,
Andrej
astrosatch wrote: Hi! I'm doing some test of guiding and I'm not sure about size of pixels on screen. When max zoomed there are squares with cross in the center. Are these pixels? My image scale is 1 arc second per pixel. With crosshair on one square is the size of second circle. Two squares are of diameter of the biggest circle. So by my calculations small circle is 0.5", middle 1" and biggest circle is 2 arc second. Is this right? Br, Andrej
Hi! I'm doing some test of guiding and I'm not sure about size of pixels on screen. When max zoomed there are squares with cross in the center. Are these pixels? My image scale is 1 arc second per pixel. With crosshair on one square is the size of second circle. Two squares are of diameter of the biggest circle. So by my calculations small circle is 0.5", middle 1" and biggest circle is 2 arc second. Is this right? Br, Andrej
Hello Andrej,
There is no relationship between the image scale and the Crosshair.
[quote=Ji.zwo post_id=36212 time=1575950367
Ok. What about pixels? Is there any way to determine them?
astrosatch wrote: [quote=Ji.zwo post_id=36212 time=1575950367 Hello Andrej, There is no relationship between the image scale and the Crosshair.
[quote=Ji.zwo post_id=36212 time=1575950367 Hello Andrej, There is no relationship between the image scale and the Crosshair.
Nope, they are pixels but not the true size.
I see. Is there any way to measure drift? I was making 10 min subs and have this constant drift. I zoomed in to maximum and monitoring star in the center of crosshair. I was trying to determine drift in arc sec per sub to see if there is small enough drift for my system to make 10 min exposures.
Why not take 2 short bin4 shots 10 minutes apart and plate solve each one?
You will then know how far you have drifted and in which direction.
Thanks Suttonrog. That just might work. Is platesolve that accurate?
It is supposed to be accurate to the second.
You can always do the plate solve at one hour intervals and divide the result by 6
Will try that. Thank you.
Another thing. Why bin4?
You didn't say what camera you are using. But for plate solving you should use the highest Bin your camera will support. It cuts down the image size and speeds up the plate solve. My 23mp Canon plate solves in 2 seconds on Bin4.
Then revert to Bin1 for your subs and Bin in your processing software if you are oversampling.
I have asi1600mm. Doesn't bin4 cut resolution to 1/4? Isn't accuracy compromised because pixels are merged together?
astrosatch wrote: I have asi1600mm. Doesn't bin4 cut resolution to 1/4? Isn't accuracy compromised because pixels are merged together?
Yes, the BIN4 will cut the resolution and reduce the pixels.
