Video and Sound?

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dbunna2
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Joined: Wed Feb 22, 2017 2:06 pm

Video and Sound?

#1

Post by dbunna2 »

There is going to be a lunar graze visible from here next week (Theta 2 Tau on 9/12). I thought it might be fun to try to record it. I'd like to record the WWV signal from a SW radio at the same time so I know when the actual events occur.

I'm good with recording the video part of the process with SharpCap, but as for the audio I don't have a clue. I assume that an external microphone near the SW radio would be a good idea, but will SharpCap also record the audio or do I need to do something else?

TIA
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oopfan
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Re: Video and Sound?

#2

Post by oopfan »

I need Robin to confirm what I am about to say but SharpCap with my ZWO ASI120MC offers a control for timestamping video frames. It should be very accurate if you have NTP time service enabled on your PC which most if not all do. (I haven't actually tried the timestamping feature -- just saw the control.)
dbunna2
Posts: 26
Joined: Wed Feb 22, 2017 2:06 pm

Re: Video and Sound?

#3

Post by dbunna2 »

I know about the time stamping but the International Occultation Timing Association (IOTA) would like GPS or WWV time. From their website:

"The best method of establishing time on the video is with a GPS based time inserter which inserts the time on each frame of the video. In lieu of GPS time inserter for a time base, observers can record the NIST radio station WWV on the audio track of the video recorder. A video camera and GPS time inserter are currently the best tools for observing occutlations."

I should also mention that I could record the event with my Canon T7i which will get the audio I need. I just happen to like SharpCap's controls better than the camera's.
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oopfan
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Re: Video and Sound?

#4

Post by oopfan »

Thanks for the heads-up on the occultation. For my location, according to KStars I get a graze of Theta 1 Tauri beginning at 4:45am LT but not Theta 2 Tauri. Aldebaran gets the same treatment at 8:59am LT -- too bad the Sun will be up.
dbunna2
Posts: 26
Joined: Wed Feb 22, 2017 2:06 pm

Re: Video and Sound?

#5

Post by dbunna2 »

If you are interested in occultation observation do you know about Occult 4?
http://www.lunar-occultations.com/iota/occult4.htm

It does a wonderful job of prediction. I try to run it monthly.
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oopfan
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Re: Video and Sound?

#6

Post by oopfan »

I have used OccultWatcher for asteroid occultations. At one point last year I was really into asteroid occultations but lately I've gotten bitten by the bug to image DSOs using less than optimal equipment just for the challenge!
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admin
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Re: Video and Sound?

#7

Post by admin »

Just to confirm that SharpCap *DOES NOT* record sound from any source (even webcams that have microphones), sorry.

Captured frames do get given high resolution timestamps, and if you keep your system clock sync'd to a GPS time source these should be highly accurate, although the time recorded is the time that the frame is delivered to SharpCap and unfortunately there is no easy way of knowing the delay between the frame being captured by the camera and it being delivered to SharpCap.

The gold standard is of course the QHY series of cameras with built in GPS, in which case SharpCap records the actual time of the frame starting being captured.

For recording frame times accurately you should record to FITS or SER format.

cheers,

Robin
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