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Phisci

Can a lodestar be focused during the day?

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Just had a difficult time consuming situation trying to get stars in focus with a refractor and wanted to check if its possible to get this done during the day? |From my limited experience, I know the camera is hugely light sensitive. 

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I think that would be very difficult, if not impossible. As you say, the light sensitivity of the sensor would overexpose any image when you tried to focus on a distant object. I now use a Bahtinov mask while pointing at a bright star. The method was recommended to me by SGL members and it is easy to do and works well.

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Hi

It may be possible by making a mask for your scope to create a much smaller aperture, start with a 15mm hole and see how you get on.

Focus on a distant object and this should get you near enough.

The standard starlight software will allow very short exposures which will also help (I do not think that Starlight Live will go as short).

Once you are in the right ball park, using a Bahtinov mask on a bright star wil get the focus you need, however if this is really far out then you'll not be able to see any stars.

I've used the moon or bright planets to get the focus near, even when the image is overladed, them moving to a dimmer star you should be close enough to see it and focus manually without a Bahtinov mask.

HTH

 

Paul 

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3 hours ago, Phisci said:

Just had a difficult time consuming situation trying to get stars in focus with a refractor and wanted to check if its possible to get this done during the day? |From my limited experience, I know the camera is hugely light sensitive. 

Be cognizant that you may be a long way away from focus, depending on how you are trying to attach the Lodestar to the telescope (e.g. into the star diagonal).  If you are placing the camera into a 1-1/4" compression fitting (i.e. an eyepiece holder), the fastest way to find approximate focus may be moving the camera manually in and out without tightening the holder.  I'd suggest putting an eyepiece in the scope, centering a bright star like Vega, then swapping in the camera, with the thought in mind that the chip plane of the camera should wind up at the same place as the field stop of the eyepiece.  Slide the camera back and forth with the SLL software set to frame and focus mode with very short exposure, like 0.1 sec, so you can see what changes in real time.  You will quickly find the point of approximate focus.  Now clamp the camera in place and use the focus knob to fine tune.  Good luck!

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Thanks everyone, got it to work with a 0.5x focal reducer last night. Terrible conditions for video (bright moon, high thin clouds, suburbia), but I went ahead anyway. NGC 6231, M6 and M23; White areas are clouds

Scorpius ngc6231.jpg

Scorpius m6.jpg

Sag M23.jpg

Edited by Phisci
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