Drifting Focus
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If you have a problem or question, please check the FAQ to see if it already has an answer : https://www.sharpcap.co.uk/sharpcap-faqs
Drifting Focus
Hi, I'm new to this Forum and SharpCap. I have an old Orion 150 x 700 reflector and a brand new Svbony SV105. I have been playing with it during the day to get a feel for the controls and noticed that the image (a street light about 100 yards away) drifts in and out of focus both in live view and playback. This has never happened while using an eyepiece. So, I'd like to know if this is just a characteristic of the camera or are there settings to stop the drift. Thanks!
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Re: Drifting Focus
Hi,
there are a number of reasons why you might see this effect, to begin with you are going to be looking at the image in much finer detail than you would with the naked eye, so you would tend to see this sort of effect much more easily.
If the change between in and out of focus is happening over a fairly short amount of time – a few seconds or even more rapidly than that, the most likely cause is convection movements of their either within the telescope tube or in front of it. These would be particularly noticeable if you'd just taken the telescope out of a warm house and placed it outside into cooler air.
You can also get longer term shift of focus from expansion/contraction of the metal telescope tube as the temperature changes and finally from focuser slip if the focuser is pointing up or down, but these seem less likely in your case.
cheers,
Robin
there are a number of reasons why you might see this effect, to begin with you are going to be looking at the image in much finer detail than you would with the naked eye, so you would tend to see this sort of effect much more easily.
If the change between in and out of focus is happening over a fairly short amount of time – a few seconds or even more rapidly than that, the most likely cause is convection movements of their either within the telescope tube or in front of it. These would be particularly noticeable if you'd just taken the telescope out of a warm house and placed it outside into cooler air.
You can also get longer term shift of focus from expansion/contraction of the metal telescope tube as the temperature changes and finally from focuser slip if the focuser is pointing up or down, but these seem less likely in your case.
cheers,
Robin