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can i image mercury during the day?

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#1 bill w

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Posted 26 June 2019 - 08:03 PM

Having seen venus through a scope at its superior conjunction last? summer, i assumed this would be a great time to image mercury.

So i set up my C11, aimed my computerized mount at Mercury mid day on 6/22 and couldn't see anything but blue sky. 

Same on 6/23/19 at 1 pm.  Repeatedly confirmed scope alignment and focus with a solar filter.  followed it all the way down and didn't see a thing until ~7:52 PM (checking every 5 minutes) when it appeared in the eyepiece only 21 degrees above the horizon ~12 minutes before sunset with the sun well below my local horizon.  It was visible in the finder shortly thereafter. 

skies were clear, but i am at sea level near the ocean with some particulate and humidity. 

 

was it just a bad day? is it possible to image mercury high in the sky?

 

thanks

 

-bill w


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#2 Tom Glenn

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Posted 26 June 2019 - 08:12 PM

It is possible, and in fact most Mercury imaging is done during the day.  That being said, it requires some attention to details that aren't necessary for normal imaging.  Above all, you need to be mindful of the Sun.  It is useful to align on the Sun, but be careful with your solar filer so you don't accidentally cross paths with the Sun while it is not in place.....this will destroy your camera in the best case, and yours eyes in the worst case.  

 

I'm considering doing some Mercury imaging this summer, but haven't gotten around to it yet.  Whether or not it's easy to find on the camera depends on your mount, and the size of your camera sensor.  You will be blindly pointing at Mercury, and if you can't get it on the sensor it will be impossible to locate manually.  Careful alignment to the stars the night before the attempt is useful to ensure that your pointing accuracy is good enough.  From there, you have several available methods.  You could align on the Sun the next day and then slew to Mercury, but this depends upon the accuracy of the solar alignment and your camera sensor size.  Alternatively, you could align very accurately on stars the night before, and then slew to the RA and Dec coordinates that you know Mercury will be located at a very specific time the next day, and then leave the scope locked in that postion, and only turn it on and start tracking again at the aforementioned time the following day.  Needless to say, it can take quite a bit of work to achieve this.  Mercury is located some 25 degrees from the Sun right now, so this is plenty of room, although its magnitude is about 0.67, so it's not very bright against the sky.  Good luck! 


Edited by Tom Glenn, 26 June 2019 - 08:14 PM.

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#3 bill w

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Posted 26 June 2019 - 09:34 PM

Thanks for your detailed reply

just to clarify, i'm using an ASA mount on a semi permanent pier.  there is no doubt in my mind that mercury was in the center of my field all afternoon on the second day, but i could not actually see it until shortly before sunset.  are special conditions in terms of transparency/haze required to see it (and image it) during the day?

 

It is possible, and in fact most Mercury imaging is done during the day.  Mercury is located some 25 degrees from the Sun right now, so this is plenty of room, although its magnitude is about 0.67, so it's not very bright against the sky.  Good luck! 



#4 Tom Glenn

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Posted 26 June 2019 - 11:42 PM

Thanks for your detailed reply

just to clarify, i'm using an ASA mount on a semi permanent pier.  there is no doubt in my mind that mercury was in the center of my field all afternoon on the second day, but i could not actually see it until shortly before sunset.  are special conditions in terms of transparency/haze required to see it (and image it) during the day?

OK Bill, thanks for the clarification.  However, from your description, it seems as though you are attempting to view Mercury through the eyepiece, rather than the camera?  If that is the case, than this is likely impossible during the daytime, with Mercury at +0.67 magnitude and 25 degrees from the Sun.  You will need to view it through the live view of a camera, using an infrared filter to cut down on the sky glare.  685nm pass filters are commonly used on Mercury, if not 740nm because of the daylight conditions.  

 

Perhaps those that have practical experience imaging Mercury will chime in.  I hope to gain some experience in the near future.  Right now, all I can offer as far as practical considerations of what to expect are with the Moon.  I took the following during daylight, while the Moon was 19 degrees from the Sun.  A naked eye search was impossible, although I could see the Moon in the live view of the camera, using a 610nm pass filter, but I must emphasize that it was only barely visible with the bright sky.  It would be easy to miss if you weren't looking for it.  Only after processing could I bring out the details.  Mercury will be similar in that respect.  

 

https://www.cloudyni...28-illuminated/


Edited by Tom Glenn, 26 June 2019 - 11:43 PM.


#5 KiwiRay

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Posted 27 June 2019 - 12:33 AM

I've seen Mercury in the eyepiece in daylight (at least by 4pm in summer) at mags similar to 0.67.  You'll see a tiny, bright crescent.  Locating it first in the eyepiece is essential for me, as aligning on the just Sun doesn't give me an accurate enough slew to Mercury for ensuring that it's within the camera's frame. 




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