Author Topic: Strange object in the sky - need help to identify  (Read 3629 times)

Offline Philip de Louraille

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Strange object in the sky - need help to identify
« on: 2014 April 26 16:31:41 »
I take nightly shots of my night sky using the All Sky Oculus Starlight Express camera. 30 second exposures, about 1200 per night and I use PixInsight to "develop" each frame. Then I gather the frames into a movie which I then review for meteors and the like.
At sunset and dusk, it is amazing the number of satellite trails I see. Busy skies. They cross the sky in around 2 frames so within one minute.
On April 24, I saw a moving object that gathered in brightness but moved *very slowly* in the sky. I have it for about 15 minutes all together so about 30 frames and it barely moved maybe 10° in the sky before it fainted below what the camera could register.
So obviously a satellite, below geostationary position but not too far below...
I have tried an Internet search but cannot identify the object and I am wondering if some of you have better resources to help identify the thing. Starry Night did not help.
I have a rough Youtube video here http://youtu.be/XWfiG3H7QSk (but you can barely see the object move)
and a much better data source here: https://dl.dropboxusercontent.com/u/9654016/moving-object.mov  (32 Mbytes)
The object is around the 1o'clock position of the image. North is up, West is right
You can see the Milky Way rising. I like this camera. Money well spent.

Location: Los Gatos, CA - USA
37°13'39", 121°57'50"W
4/24/2014  3:38am to 3:56am

So this is not really a PixInsight question (though I am using the software to get a much better image than what the camera gives (16-bit monochrome)) so feel welcome to ignore.

Thanks for any help.
Philip de Louraille

Offline Astrocava

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Re: Strange object in the sky - need help to identify
« Reply #1 on: 2014 April 27 12:18:12 »
Try some of the list for your location here:

http://www.heavens-above.com/AllSats.aspx?lat=37.2358&lng=-121.9624&loc=Los+Gatos&alt=111&tz=PST

You can also use: www.calsky.com

Have fun!

Sergio
Moonfish ED80 over a Meade LX200GPS 8"

Offline rfrancis

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Re: Strange object in the sky - need help to identify
« Reply #2 on: 2016 April 16 05:44:15 »
Hi Philip,
I won't be able to help you with this specific object, but I do have some comments and a question.

You say that you have many satellites crossing the sky in one minute. That's really fast! These must be really, really low altitude, and there aren't so many of these as they re-enter rather quickly.

Huge numbers of visible satellites are in the classic orbits, sun-synchronous in the altitude range 650-850 km. Sun-synchronous means that their orbit plane keeps the same angle to the sun, by using the orbital precession (caused mostly by the Earth's equatorial bulge) to exactly compensate for the Earth's revolution around the sun. To do this the inclination has to be close to 98 degrees (it's a weak function of orbital altitude), so conveniently polar, which suits many Earth observation satellites, and makes them visible over much of the world.

At such altitudes the time to cross the sky, from horizon to horizon (although we usually take a 2 degree elevation instead of the horizon for reliable telemetry) is abut 10 minutes. A higher orbit, like Jason-3 at 1336 km, takes about 15 minutes. Then there's quite a large gap with few satellites in circular orbits because of the van Allen radiation belts, which seriously shorten the life of electronics, solar arrays etc. Further out there are GPS, Galilleo etc. navigation satellites with 12 hour orbits.

More interesting, perhaps, are some satellites with highly elliptical orbits, like any astronomy satellites.

Anyway, on to my question:
I've just bought an Oculus and I'm using a Mac. Could you outline your PixInsight workflow, as well as the software you use to acquire images from the Oculus?

cheers,
Richard

Offline Philip de Louraille

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Re: Strange object in the sky - need help to identify
« Reply #3 on: 2016 April 16 06:11:17 »
Hi Richard! I take it you work with NASA or, perhaps, with a 3 letter agency... ;-)

The software I used is developed by Simon Taylor. He can be reached via feedback@coreastro.org.
It is called SX IO. I have version 1.0d7d. I correspond a fair amount with him and he is quick at fixing bugs or even adding new functionality and pointing me to where the new software is.

As (un)luck would have it, I just moved houses. My Oculus is still at the other house and, hopefully, so is my memory stick where I have stored the PixInsight project file I use to process the data... because I can't find it here right now and that is ... annoying...

More later when I find it!
Philip de Louraille

Offline rfrancis

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Re: Strange object in the sky - need help to identify
« Reply #4 on: 2016 April 16 14:10:24 »
Hi Philip,

I take it you work with NASA or, perhaps, with a 3 letter agency... ;-)

Close! In fact it's a 3-letter agency, one that starts with an E, ends with an A, and has an S somewhere in there ;-)

However, since 1 year I'm retired and now live in southern France where the skies are much better than The Netherlands.

I'll look into SX IO. I have been experimenting with TheSkyX for data acquisition, but it's a bit like using a sledgehammer to crack a nut.

I hope you find the memory stick as I'd appreciate guidance on the PI approach. I've been using Blink, but there's sure a learning curve, starting with installing FFMPEG on the Mac. I can get it working as a terminal command line but not yet with Blink.

cheers,
Richard

Offline Philip de Louraille

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Re: Strange object in the sky - need help to identify
« Reply #5 on: 2016 April 16 17:52:57 »
Being from Nice originally, how rude not to have considered ESA!  :P

I found my stick!

Here is the archive with all the necessary files. Obviously my 360° mask for my horizon will have to be ignored or replaced by your equivalent.
Ditto with the defect map.

This is the process I use.

1) I take a 30 sec. shot every 30 sec when the sky is dark with the Oculus, using SX IO as the controlling program.
    So I end up with hundreds of fits.
2) I then fire PI, load the .xsom file
    I then select the all raw fits with PI  with the ImageContainer and select the target dir.
    I then drag the small triangle at the bottom left of the Image Container onto the desktop, near the current container (labelled ImageContainer3) in the current project. I then delete the now old container instance (03)
   I then drag the new instance onto Process07 which has all the process steps programmed (apply my defect map, apply my mask for the horizon, does a HDRMT, adjust the histogram, and reapply a slightly bigger masked horizon to get rid off artifacts created by the diverse processes when they hit the original mask.
3) I then re-use SX IO to then make a movie of all the fits into a .mov (under Tools | Make Movie...) which I then peruse with QuickTime.

Have fun and when you improve the process, do share!

https://www.dropbox.com/s/z8d44a7gtqrluvv/PI-whole-sky-camera.zip?dl=0

Another movie I made of an exploding Perseid:  https://www.dropbox.com/s/yn6wpvlwldibgbi/Perseid.mov?dl=0

Cheers!
Philip de Louraille

Offline rfrancis

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Re: Strange object in the sky - need help to identify
« Reply #6 on: 2016 April 17 05:41:19 »
Hi Philip,

thanks for that! I will try this approach, though I doubt I'll be needing a horizon mask: my horizon here has very few obstructions. That was one of the selection criteria for the property (together with dark skies etc.).

I have been experimenting with the blink tool in PI to make movies and now have found some necessary arguments to give a high quality movie. I'm still working on it though. This could eliminate the necessity to go back to SX-IO to make the  movie. Thanks for that, by the way, SX-IO is just the type of software I need for capture from this device.

When I have it working I'll report back.

cheers,
Richard

PS: that exploding Perseid is pretty spectacular!

Offline Philip de Louraille

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Re: Strange object in the sky - need help to identify
« Reply #7 on: 2016 April 17 06:26:53 »
So where are you now located?
Philip de Louraille