Unable to find stars to focus in Live View

[Ettaswell]

I spent 4 hours last night trying to find and focus stars in live view. Telescope is Mak127 on AZ GOTO mount using a SVBony 305C. It all started very well. Focused on trees about 200m away in daylight. Then - once dark slewed up to find stars to do the 2 star alignment. Finderscope (visual) 50mm Starwave with an Omni 30mm plossl on it found the first star, but laptop screen was just black. Swapped out the camera for the eyepiece in the Mak, refocused and found nice pinpoint stars.

I then put the camera back in, but still nothing. I tried 2s exposures and gain high and then went up and down the Mak focus knob - but nada!

What am I doing wrong please?

[Menno555]

Hello and welcome.

I'm afraid you are doing nothing wrong.
The combination of your telescope and camera gives a very smal Field Of View (FOV). This is great for the moon and planets but less good for astro objects. You can add a reducer between your scope and camera (this gives a bigger FOV) but it still will be a small FOV.
To illustrate, see the image below (used https://astronomy.tools/calculators/field_of_view/ for that) . I used the Andromeda galaxy as example.
The green box is with a 0.33x reducer and the red box your current combi.
When you use your eyepiece, you have a much bigger FOV, so that explains why you see stars through your eyepiece.

Is it impossible to find star(s) to focus with your combi of telescope and camera? No. It takes more effort though.
During daytime, try to get an object as far away as possible, preferable a couple of kilometers, in your scope view.
Put this object in the middle of your screen and focus.
Now use the adjustment knobs on your finderscope to get the same object in the center of the finderscope view.
If both are in the middle, don't change that anymore. In principle the center of your finderscope is now also the middle of your telescope view.

It's no guarantee though that at night a star in the middle of your finderscope, is also visible in your scope. But you're at least (very) close.
Indeed use a fairly short exposure time and relative high gain.If it's not visible, then use very small movements with your mount until you find it.

Maybe a bit lengthy answer but I hope it helps a bit
Menno

astronomy_tools_fov.jpg (221.49 KiB) Viewed 2921 times

[admin]

Hi,

another thing that helps massively (providing the date is suitable!) is to use the moon as your first target, since it is bright enough to see something in the camera even if badly out of focus and/or not quite pointing in the right direction. See viewtopic.php?p=12082#p12082 for more info.

cheers,

Robin

[Ettaswell]

Awesome answers - and of course obvious when you think it through. I was just surprised I didn't at least accidentally land on a star by mistake

[archer1960]

Did you adjust your camera exposure when you were trying at night? If you left the camera at the settings you used on the trees, you will almost certainly not see anything at night, except maybe the moon or Venus.