White light glass sun filter
10" f6 DOB
QHY 174M GPS
Latest version of SharpCap
I am trying to set up my scope for the transit of Mercury on the 11th. I have the proper white light filter and have reduced the aperture to about the size of a quarter (US). I am using a .5 focal reducer. The Sun is well focused as I focused on a star last night. The sun is blank, I don't see any sunspots.
There is a small black rectangle in the lower left corner of the view area inside the disk of the sun. It is about 1 mm x 2mm and is at a small angle to the vertical. If I bump the scope, the sun vibrates but the spot doesn't. I can slew the scope but the spot doesn't move. That said to me that the spot is in/on the screen rather than in the image. I marked the spot with a piece of tape and turned off SharpCap. The spot disappeared. If I unplug the camera the view area goes gray, the spot disappears.
Any suggestions as to what this might be? And how to get rid of it?
I should capture an image and see if the spot appears in the image outside of SharpCap.
Spot On The Screen
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Re: Spot On The Screen
Hi,
It could be a spot of dust on the sensor of the camera that is preventing the light from getting to that part of the sensor, although a photograph showing the problem would make it easier for me to be sure. There are ways to clean camera sensors, but you have to be careful to avoid making things worse by putting even more dirt on them. Certainly a spot of dirt on the sensor would show the behaviour you see which is that it doesn't move when you jog the telescope.
If the spot has sharp edges then it is probably on the sensor itself. If it has edges that blur out then it may be further from the sensor – for example on a piece of glass in the imaging train or on the filter in front of the sensor itself.
Hope this helps, Robin
It could be a spot of dust on the sensor of the camera that is preventing the light from getting to that part of the sensor, although a photograph showing the problem would make it easier for me to be sure. There are ways to clean camera sensors, but you have to be careful to avoid making things worse by putting even more dirt on them. Certainly a spot of dirt on the sensor would show the behaviour you see which is that it doesn't move when you jog the telescope.
If the spot has sharp edges then it is probably on the sensor itself. If it has edges that blur out then it may be further from the sensor – for example on a piece of glass in the imaging train or on the filter in front of the sensor itself.
Hope this helps, Robin