View Full Version here: : PHD Guiding and QHY5v - help!
20-10-2011, 06:44 AM
I have just started down the GUIDING route.
I have QHY5v camera
using PHD guiding
all through ascom.
I have set the equipment and software up. I connect to the camera and mount OK in the PHD software.
My problem is when i press on the loop button, the camera is capturing the images, but all i can see on the images are a very light screen( not dark ) and because of this you cannot see any stars...screen is just too bright.
I must be doing something basic wrong. I have tried different time exposures from 0.2 secs up to 5 secs and its always the same. I have played also with the gain and gamma settings. I am really puzzled.
Any help would be very much appreciated
20-10-2011, 08:54 AM
You can have a fiddle indoors with the camera...just set it up with the guide-scope main lens around 80% covered. Just leave camera settings at std.
This reduces amount of light input to the camera and you should get some image.
The other thing is that the camera is probably not focused. Do the above and point the camera at something distant, loop exposures (lets say .5sec) and focus it. Once done mark approximately where the drawtube is for future reference. If it's still too bright bring exposure time down.
Sometimes when I turn on my QHY5 when it is still twilight it washes out with light.
Lastly put on the guide-scope lens cap and take a dark frame with PHD.
20-10-2011, 09:05 AM
thanks for info
It was a focus prob. I put the diagonal in st80 and i could get to focus. Next problem:
I locked on star (green box)
but when i looked at the graph the RA and declination were 4 lines from the centre.
RA 3.5 lines above centre line and declination 4 lines below.
I reduced RA hysteris and the declination line rose to the central line and stayed on it precisley. How do you get the RA line down to the centre. Does it matter?
Oscillation index after 15 mins shows 0.03. Is that good or bad?
To be honest i am not sure what i am doing here , am i getting a good guide?
i am finding just a little hard to get to grips with this GUIDING . I am sure it will click in to place with practice.
20-10-2011, 09:36 AM
If you entered the correct FL of the guide scope and pixel dimension then the lines in PHD graph represent 1 pixel deviation from the centre line...4 lines 4 pixels.
If you run a correct PHD calibration then the star is generally locked on the centre graph line (and centroid of the guide star) and the Ra and DEC oscillate somewhat above and below the centre line.
However it probably doesn't matter if the the graph RA or Dec is above or below as long as the Ra and DEC are not oscillating wildly around with large deviations.
If the Ra and DEC are not on the centre graph line then something is up with the PHD settings or calibration.
As long as you are happy with you image (they do not trail stars) and since you are beginning with PHD guiding I suggest that you ignore the PHD graph and just deal with the basic PHD interface at this stage.
If you Osc is .03 then that appears a bit low (but not necessarily) ..something is probably not right but do not worry unnecessarily unless you are unhappy with your guiding and images.
Looking at the graph and putting all you attention into it will have a newbie running in circles for something that may not be an issue. Again if you guiding is ok spend you time with the basic interface (http://www.stark-labs.com/wiki/doku.php?id=tutorials:phd:faq) and with experience (or if you are having issues) then move on to the graph.
What I would do is try another calibration star and see how it goes.:thumbsup:
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