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Mirages during recent solar ecplise?

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#1 flincken

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Posted 14 June 2021 - 04:53 AM

Hi, I am pretty new to solar photography so please excuse a newbie question. During the recent eclipse I was shooting with my Solarmax 90mm and ZWO174 and it is usually very straight forward to find and focus on the sun. During the ecplise I had a lot of issues with solar flares and weird "mirages" when trying to find the sun. When I found what I thought was the sun (including the shadow of the moon) I was not able to find focus (on the 90mm I usually have to extend it fully + extend the camera a bit more to find focus, now to find the closest i could to focus I had to retract the full tube quite a lot) + it was much dimmer than usual and I had to push the gain to over 300 (usually have it at 0-30 for 10ms exposures)

 

After giving up on finding focus I started to move the telescope around a lot and found the real sun, and all was back to normal

 

Any ideas of what was going on?



#2 rigel123

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Posted 14 June 2021 - 04:58 AM

Is this a double stacked unit?  If so, it sounds like you were trying to focus on the “ghost” image that is in DS setups.  If not, I have no idea what you might have seen.


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#3 hopskipson

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Posted 14 June 2021 - 06:08 AM

Is this a double stacked unit?  If so, it sounds like you were trying to focus on the “ghost” image that is in DS setups.  If not, I have no idea what you might have seen.

That was my thinking as well.  It's happened to all of us I'm sure.


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#4 flincken

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Posted 14 June 2021 - 08:01 AM

Is this a double stacked unit?  If so, it sounds like you were trying to focus on the “ghost” image that is in DS setups.  If not, I have no idea what you might have seen.

Hi yes it is, never heard of the ghost image, (havent seen it before the eclipse =), but that should explain it, thanks!



#5 rigel123

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Posted 14 June 2021 - 08:45 AM

Hi yes it is, never heard of the ghost image, (havent seen it before the eclipse =), but that should explain it, thanks!

Typically the ghost image will show up near or overlapping the real image until you tune your second etalon to just move it off the real image



#6 flincken

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Posted 14 June 2021 - 11:19 AM

Typically the ghost image will show up near or overlapping the real image until you tune your second etalon to just move it off the real image

what confused me was that the ghost image was in a "fixed" position on the sky (did not move when I moved the scope) and that it was far enough from the actual sun so that you didnt see them both at the same time. I tried to generate the same phenomena again by tuning the etalons without success yesterday



#7 rigel123

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Posted 14 June 2021 - 11:50 AM

what confused me was that the ghost image was in a "fixed" position on the sky (did not move when I moved the scope) and that it was far enough from the actual sun so that you didnt see them both at the same time. I tried to generate the same phenomena again by tuning the etalons without success yesterday

So if you moved your scope the image stayed in the field of view at the same position?



#8 flincken

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Posted 14 June 2021 - 12:08 PM

So if you moved your scope the image stayed in the field of view at the same position?

not sure if I get your meaning, what I was trying to say was that the ghost image felt like it had a "fixed" position on the sky in the same way the sun has, i.e needed to track the ghost and i could frame it in the same way I can the sun



#9 flincken

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Posted 14 June 2021 - 12:14 PM

here is a pic of the ghost, you can also see some other artifacts on the sides (not sure how I insert a pic so I add a dropbox link) 

 

https://www.dropbox....g?role=personal



#10 rigel123

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Posted 14 June 2021 - 12:34 PM

not sure if I get your meaning, what I was trying to say was that the ghost image felt like it had a "fixed" position on the sky in the same way the sun has, i.e needed to track the ghost and i could frame it in the same way I can the sun

OK, interesting.  The Dropbox link you posted takes me to my Dropbox for some reason and says the file doesn't exist.  If you can make your image a jpg and under 500kb you can just use the Full Editor and choose the file to insert in your post.



#11 flincken

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Posted 14 June 2021 - 03:13 PM

trying again =)

Attached Thumbnails

  • ghost.jpeg


#12 vincentv

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Posted 14 June 2021 - 04:42 PM

Next time you are in doubt use the tilt tuner:

-image moves -> it's a reflection

-image stays -> it's the sun smile.gif


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#13 rigel123

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Posted 14 June 2021 - 08:56 PM

That looks like the ghost image in a double stack scope, the actual image is out of the FOV.




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