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A Very Disappointing Day

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#1 BeltofOrion

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Posted 10 October 2019 - 08:52 PM

Took a two hour drive this morning to try to capture an ISS solar transit. Got set up in a perfect little place right on the line with about ten minues to spare. ISS angular size: 43.15″; distance: 640.32 km Seeing was great. Watched it on the laptop as it passed directly through the center. Did a 2 1/2 video that overlapped the transit. It looked great. Thought it was going to be the best one I've done yet. Got home and found a great video of the sun ... but no ISS.  frown.gif  Anyone have any idea of what could have gone wrong?

 

This was the consolation prize.

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#2 scngc7317

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Posted 10 October 2019 - 10:06 PM

Totally guessing but that black streak at the top could be it = frame rate to slow ?   hmm.gif  


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#3 hopskipson

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Posted 11 October 2019 - 06:01 AM

Totally guessing but that black streak at the top could be it = frame rate to slow ?   hmm.gif  

No, that's a nice capture of a filament!

 

Belt, did you take any video before or after the transit?  I'm guessing that maybe you forgot to hit record at the critical moment.


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#4 BeltofOrion

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Posted 11 October 2019 - 09:02 AM

Totally guessing but that black streak at the top could be it = frame rate to slow ?   hmm.gif  

 

No, that's a nice capture of a filament!

 

Belt, did you take any video before or after the transit?  I'm guessing that maybe you forgot to hit record at the critical moment.

Thanks, James and scngc7317. Definitely hit record 1 1/4 minutes before. Sat there watching the green bar scroll across while waiting for the transit to happen. But, I'm pretty sure I have it figured out now ... and you are both right.

 

I was rushing ... never a good thing where this stuff is concerned ... and I didn't notice I had my gain set way too low. As a consequence, the exposure (shutter speed) was too high and since the ISS is moving so fast I totally missed it. Comparable in terrestial photograph to trying to capture a fast moving object ... race car, arrow in flight, hummingbird's wings, etc ... with the shutter speed set too low. Just aren't going to stop the motion.

 

But I didn't think that ... ie low gain and high exposure  ... would introduce artifacts into the video. That is, I was pretty sure it was a filament ... but you had me questioning myself there for a while scngc7317. :-) 


Edited by BeltofOrion, 11 October 2019 - 09:03 AM.


#5 descott12

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Posted 11 October 2019 - 10:31 AM

 

 

But I didn't think that ... ie low gain and high exposure  ... would introduce artifacts into the video. That is, I was pretty sure it was a filament ... but you had me questioning myself there for a while scngc7317. :-) 

I am pretty sure that is real as I saw something identical yesterday and I think the day before.


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#6 rigel123

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Posted 12 October 2019 - 07:51 AM

That’s a shame, but nice shot! The daytime transit I caught across the moon had me looking for the thing dozens of times until I finally saw it zooming across the disk. What was the duration of the transit?

#7 PilotAstronomy

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Posted 12 October 2019 - 10:47 PM

Same thing happened to me on the moon about 6 months ago. Set up perfect, hit record, even saw it come across on the screen! Very exciting! Then when I went to pull the frames it skipped a bunch of them during the transit. Got a couple of the ISS approaching the moon then SKIP to just past it. So disappointing. Later, I figured it out I needed to use the buffer in Firecapture better. It was skipping all kinds of frames during every capture. Might be worth trying that for the next one. The good thing about ISS transits is as long as you're willing to move the scope around to different locations, you're bound to capture one before too long.


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#8 BeltofOrion

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Posted 12 October 2019 - 10:53 PM

I have FireCapture, but I don't use it much. I use SharpCap. How do you use the buffer better? Is there a setting ... or do you just use a small ROI so that no ... or very little ... buffering takes place?



#9 PilotAstronomy

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Posted 13 October 2019 - 06:51 AM

I think it had something to do w RAM. I'll take a look when I get home.

#10 Terra Nova

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Posted 19 October 2019 - 12:50 PM

No, that's a nice capture of a filament!

 

Belt, did you take any video before or after the transit?  I'm guessing that maybe you forgot to hit record at the critical moment.

Doesn’t look like any filament I’ve ever looked at and I’ve seen a lot of them. Here’s an enhanced i,age.Look at the bifurcation at the bottom into three lines that converge again at the top.  It looks to me like an artifact produced by something passing between the sun and he camera.

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#11 BeltofOrion

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Posted 19 October 2019 - 01:06 PM

Doesn’t look like any filament I’ve ever looked at and I’ve seen a lot of them. Here’s an enhanced i,age.Look at the bifurcation at the bottom into three lines that converge again at the top.  It looks to me like an artifact produced by something passing between the sun and he camera.

Interesting, terraclarke, but I took a 2 1/2 minute video with the ZWO ASI183 so that I would overlap the transit ... and it was there the whole time. So if it were something passing between the sun and the camera, it must have been moving VERY slowly.  And just how far away from the camera? What did you have in mind? A bird? Plane? I took a video of the moon a week or so ago with my 70 mm SolarMax and caught a bird transit. That was FAST! Over in less than a second and I had to separate it out into frames with PIPP in order to identify it.



#12 Terra Nova

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Posted 19 October 2019 - 01:16 PM

Interesting, terraclarke, but I took a 2 1/2 minute video with the ZWO ASI183 so that I would overlap the transit ... and it was there the whole time. So if it were something passing between the sun and the camera, it must have been moving VERY slowly.  And just how far away from the camera? What did you have in mind? A bird? Plane? I took a video of the moon a week or so ago with my 70 mm SolarMax and caught a bird transit. That was FAST! Over in less than a second and I had to separate it out into frames with PIPP in order to identify it.

I was thinking a satellite. Are you sure it didn’t move during the collection of the image sequence used to stack your final image? I’m thinking along the lines of Poster #2’s idea:

 

Totally guessing but that black streak at the top could be it = frame rate to slow ?   hmm.gif  



#13 BeltofOrion

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Posted 19 October 2019 - 01:35 PM

I didn't break the video down into individual frames, but while I was waiting for the ISS transit I certainly didn't notice anything strange happening in the area in question (ie movement, oscillation, wavering, etc). Just rock steady. And, if the frame rate were too slow, would it just happen in one area? And why that particular area? I'm pretty sure I still have the video ... those files are quite large and I regularly remove them from my laptop and save them to an external hard drive ... some of them anyway ... so I'll see if I can find it and have another look at it. I appreciate you had a look and took the time to comment, though. [Curious about the Terra Nova Observatory thing. Terra Nova is actually another name for this place. And there is a town on the island called Terra Nova. And a national park. smile.gif ]


Edited by BeltofOrion, 19 October 2019 - 01:41 PM.


#14 MalVeauX

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Posted 19 October 2019 - 01:39 PM

Heya,

 

I can corroborate that the phenomenon in the image is not a sattelite or artifact. it is a faint but large dark filament that extended near the limb that day. I have data on it, a little higher resolution where you can see individual spicules and fibrils, so its not artifact, where it's plainly visible.

 

waytogo.gif

 

Filamprom_limb_10102019.jpg

 

Very best,


Edited by MalVeauX, 19 October 2019 - 01:41 PM.

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#15 BeltofOrion

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Posted 19 October 2019 - 01:54 PM

Heya,

 

I can corroborate that the phenomenon in the image is not a sattelite or artifact. it is a faint but large dark filament that extended near the limb that day. I have data on it, a little higher resolution where you can see individual spicules and fibrils, so its not artifact, where it's plainly visible.

 

waytogo.gif

 

attachicon.gif Filamprom_limb_10102019.jpg

 

Very best,

Wow! That's excellent, Marty! Thanks for the corroboration. (Dave) descott12 pretty much did the same thing up above there. But your shot is the icing on the cake.


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#16 Terra Nova

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Posted 19 October 2019 - 02:02 PM

That does make it clearer. I think the way it showed up in the original image and the way it was stacked made it look like diverging and converging lines that were just intensified when I enlarged, sharpened, and contrast enhanced the original stacked image.



#17 MalVeauX

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Posted 19 October 2019 - 02:20 PM

When it comes to ISS or any object transit in front of the sun, it will happen in seconds (or less in reality!!). You need very fast FPS to grab a clean equal bit of data on each moment of transit. It will be plainly visible, if you're remotely in focus. The only explanation for not seeing ISS across the disc is because it was not there at the time you were capturing frames. You were clearly in focus. So if you missed the transit, it was due to time being incorrect or location on the disc missing the transit, or something of that nature. Nothing wrong with your scope, etc. Consider how profoundly significant it is to put a football field size object in front of your imaging kit facing our star at precisely the right moment and capturing frames during its transit. It's no small task. But the only thing lacking from your image is the actual ISS. So my suggestion is to review your time and transit potential data, if it were there, you would have captured it.

 

I capture transits of objects like that by accent often enough. They are so fast.

 

Example at similar image scale:

 

get.jpg?insecure

 

Very best,


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#18 BeltofOrion

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Posted 19 October 2019 - 03:02 PM

No, it was there, Marty. Both my wife and I watched it on the laptop as it passed directly through the center (we were set up right on the line). The gain was set too low and as a consequence the exposure wasn't fast enough. 



#19 bunyon

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Posted 19 October 2019 - 03:13 PM

What was your exposure? I think on my capture a few weeks ago it was about 1ms. Worked okay.

The ISS crossed the disk in less than a second.

#20 PhotonJohn

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Posted 22 October 2019 - 12:01 PM

Could this have been a buffering problem?



#21 EricCCD

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Posted 22 October 2019 - 01:02 PM

No, it was there, Marty. Both my wife and I watched it on the laptop as it passed directly through the center (we were set up right on the line). The gain was set too low and as a consequence the exposure wasn't fast enough. 

Did you go frame by frame on the video? At least that way you can verify if it did show up, albeit blurry from your exposure time? I did use your lessons learned from this post to capture my Oct 13 transit - I set the gain high and the exposure times really fast. Unfortunately, buffering/write issues made my video choppy (similar to Marty's sample video). I ended up missing the "first/second contact" moments because of this.



#22 bunyon

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Posted 23 October 2019 - 06:49 AM

In my one and only attempt thus far, I didn't start capture until 15 seconds before transit to avoid buffering problems. I think transit-finder is accurate enough to do that. At least, it was in my case.



#23 PhotonJohn

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Posted 25 February 2020 - 04:22 PM

Took a two hour drive this morning to try to capture an ISS solar transit. Got set up in a perfect little place right on the line with about ten minues to spare. ISS angular size: 43.15″; distance: 640.32 km Seeing was great. Watched it on the laptop as it passed directly through the center. Did a 2 1/2 video that overlapped the transit. It looked great. Thought it was going to be the best one I've done yet. Got home and found a great video of the sun ... but no ISS.  frown.gif  Anyone have any idea of what could have gone wrong?

 

This was the consolation prize.

I have been lucky enough to capture two ISS solar transits since May 2019. In my first transit there were skips in the data due to buffering. I had my capture rate set at maximum. My second transit I set the capture rate at 15 fps. My ZWO ASI 174 mm caught 13 frames equally spaced using SharpCap. Both transits were less than one second in duration.  Hope this helps with your next try.

 

20191223_152354 (4)1200.jpg


Edited by PhotonJohn, 25 February 2020 - 06:23 PM.



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