objects drifting across FOV during solar observing

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objects drifting across FOV during solar observing

Post by Kaustav »

I'm borrowing my local astro soc's Coronado PST at the moment and enjoying all the solar observing I'm able to carry out. Today is the first sunny day since I acquired the 'scope. In the two hours that I have been popping in and out in-between the clouds I have noticed twice that a very tiny pin prick of a dark dot slowly drifts across the disk of the sun. It takes about 8-10 seconds to traverse the full disk and travels in a straight line, showing no erratic deviations in movement or speed. I've been wondering what these objects are. They cannot be aircraft as they'd show up much larger, and would move much faster. They cannot be planets as they're moving way too fast. Could they be asteroids transiting the sun? Again I would hazard a guess that they're not asteroids as the dots are moving way too fast? Or perhaps something more mundane like dust or an insect moving across the main objective lens? I would guesstimate that the dot is about 0.5% or less of the total size of the solar disk as observed through the PST using a 12mm eyepiece.

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Post by Davej »

Hi Kaustav,
Post the timings and your location (co-ords if poss) I love a challenge and I hope we can nail this one between us :)
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Post by A »


The following might be of interest.
http://www.ips.gov.au/IPSHosted/neo/inf ... ransit.htm
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Post by 12dstring »

Half a degree in 10 seconds sounds a bit too fast to be a NEO :?:

To me it sounds most likely that they could be satellites - albeit 10s sounds a little slow for that (maybe high earth orbit?). As Dave said, if you could say your location and times of observations, someone could find out if this was the case.

Anything on the main objective lens lens would be completely out of focus, so that can be ruled out.

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Post by A »

12dstring wrote: Anything on the main objective lens lens would be completely out of focus, so that can be ruled out.
I actually think that the object observed was Earth based. Several years ago I observed with a 70mm refractor and white light filter, was amazed to see a tiny black dot transit the Sun, even more amazed when another one went the opposite way across the sun. Turned out to be tiny bugs
on the front of the filter.

Also seen tiny round silver objects around the sun, these turned to be flies with the sunlight shining through the wings.
The famous obsever Denning recorded the same thing happening to him.
I have an account of such sightings in an old astronomy book, just trying
to find it at the moment.

I think a PST is too small to see a NEO, just added the link so Kaustav
could rule out the observation for himself.
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Post by markt »

Maybe a balloon? - not a hot air balloon, a helium - sort of thing you get at birthday parties... These things can get reasonably high, and with sufficient altitude could appear to cross the face of the sun at the rate you said...

What direction was it moving across the face of the sun? ie with the wind or against it...
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Post by MartintheMartian »


sorry, it had to be done by someone haha :wink:
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Post by mike a feist »

Could they be floaters in you eyes?maf
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