View Full Version here: : Asteroid Anneliese occults 6m star
22-04-2010, 12:58 PM
Perhaps this was mentioned already somewhere, but just in case..
I thought it was mentioned somewhere, but I can't find the thread.
I'm going to give it a crack. Do you know how I add Anneliesa to TheSky6??
22-04-2010, 03:12 PM
Not in particular..
But I assume it is just a matter of entering the latest orbital elements (like in CdC).
They are available on http://www.alpheratz.net/murison/calculators/OrbitalElements.php
Just type 910 for number..
22-04-2010, 05:35 PM
This is long winded, I know what I am trying to say.... see if you can follow otherwise give me a pm and I will send you my phone number and talk you through it.
If you go to this site below you can download the entire 509,000 extended minor planet list (can be very handy & up to date daily) for the Sky6 just ensure you have the latest Sky6 update installed - (ver 6.065)
There are 2 files
mpcorb.dat = 98 meg unzipped or mpcorb.gz = 24 meg zipped.
Once downloaded replace the old mpcorb.dat file under extended minor planets then run it. It will update positions for all minor planets.
You then simply do a search in The Sky6 for MPL910 and centre it on The Sky6.
Otherwise you maybe able to just download Anneliesa by importing it directly into The Sky6 while connected to the net. In Data under Comets and Minor Planets choose the tab Minor Planets then you can either choose to manually put all the details in under ADD or go further down the list and choose BY NAME - type in Anneliesa and it should find it and you just add it to the list already in The Sky6 and so long as it has an X in the checkbox you should be able to search as above by name or by MPL910.
Thanks Peter - very clear.
I was searching for 'Anneliesa' and that was not working. Searching for 'MPL910' works.
22-04-2010, 10:30 PM
Part of your search problem is the fact that the name of the asteroid is Anneliese, not Anneliesa.
Info on the occultation is available at these sites:
Yes, that looks like a typo in the ASV PDF document.
I managed to simulate it in TheSky and set it up in Occult Watcher. I just need to dust off the web camera and check that it still works...
23-04-2010, 07:03 AM
Ron had also sent the document to me as an article, which I've now loaded on IceInSpace:
Minor Planet Anneliese (910) Occulting Star HIP 74600, 8th May 2010 (http://www.iceinspace.com.au/63-590-0-0-1-0.html)
Cheers and good luck to those attempting to observe and record it!
23-04-2010, 07:32 AM
Ron gave a very enthusiastic talk at the monthly MPAS meeting last Wednesday (April 21). As he said, this event is only visible in Victoria and it goes right through the middle of the state.
23-04-2010, 09:13 AM
[QUOTE=pdthomas23;584686]Part of your search problem is the fact that the name of the asteroid is Anneliese, not Anneliesa.
Oops that doesn't help (sorry, I carried that forward to). But even putting Anneliese into the Sky6 search wont work as by default it only allows the first 100 named minor planets to be searched by direct name. There is probably a feature that can be turned on to achieve this, so it appears you are left with MPL in front of the catalogue number/name MPL910 or MPLAnneliese.
It is still well worth going to the Minor Planet Centre and updating the latest positions of all the asteroids for The Sky6 particularly if you haven't for a while.
24-04-2010, 12:00 PM
This is a very cheeky (ad)venture for me. You see, I thought that at m6 it wuld a good subject for a first-timer - like me. This site really works. issues are being solved I had no hope of solving myself. Thanks Mike
25-04-2010, 12:59 AM
A couple of emails have asked about beeper bowes. The last I heard they were out of stock in NZ. Is that so?Beeper box supply possibly via Graham.Blow@actrix.gen.nzFor those who have the skill Original description http://occsec.wellington.net.nz/videotime/beeper.htm Alternative GPS http://users.tpg.com.au/users/daveg/Sv6.htmlHowever if you are a beginner DON'T CHASE EXCESS ACCURACY. The following is a quote from IOTA I would much prefer the largest number of observers using video to time occultations to an accuracy of 0.1 second guaranteed, and often to 0.05 second, than to have only a few who have the electronic background to achieve absolute timing accuracies of +/-half a video frame. In other words, don't struggle to get 1/60 sec when 1/10 sec is good. The gain is not that great.The important thing is to get a record submittedRon
25-04-2010, 09:26 AM
I was playing with timing software..
After synchronisation, it produces beeps (via audio card) and outputs the timing pulses on LPT port.
I will try to bring those beeps (via longer cable and small speaker) to the microphone of the camera (coupled afocally via 10mm eyepiece).
As for pulses, I will drive a small LED with this signal, and its light will be captured in the optical fibre, which will shine into the camera FOV as an artificial star, blinking in one of the corners of the frame to provide frame timing.
I haven't check yet, how long the whole event will last (my guess is couple of sec maximum). So, two minutes video with 30 f/s should be enough (the time resolution will be 33ms.. I do not see how it can be better than this using video.
The only way to increase the resolution would be to use single photodiode in the scope focus instead of camera, but this may take some time to design and build the electronics (and recording method - ADC), so as far as I am concerned, not feasible for this occultation)
25-04-2010, 10:03 AM
Bojan, you seem to be well on the road.
The IOTA concept is the questionable one - if the star is seen on one frame but not the next it is assumed to have disapeared half-way between frames. So referred to half-frame accuracy. Of course the event cannot be seen on one frame (dimming??) so the time resolution is and must be full-frame, as you said.
Besides, NTSC is I think 29.9 fps but PAL is often 25 fps.
By the way, what software were you working with?
25-04-2010, 12:41 PM
It was http://hristopavlov.net/BeeperSync/
The camera I plan to use will be my Kyocera M400R, with its own video (AVI) format, 30f/s. I was using it for Moon and planet imaging in the past, and I still need to confirm it has enough sensitivity to capture 6m stars.... If not, then I have some other options, like small B/W CCD surveillance camera (PAL output, 25f/s) and USB capture interface ($9 on ebay, very good value: I tested it by converting some of my old VHS tapes, works OK... http://cgi.ebay.com.au/Easycap-USB-2-0-Video-TV-DVD-VHS-Audio-Capture-Adapter_W0QQitemZ180494762641QQcmdZ ViewItemQQptZLH_DefaultDomain_15?ha sh=item2a06538291), or TouCam.
26-04-2010, 12:27 AM
BeeperSync is the best, and the flashing led is very good. I had intended to make my own up but been too busy - and will be til Friday week. If you come to club night this week, show off your flashing red lights.
26-04-2010, 01:17 AM
Hey Guys, Just spotted this thread. I'll try to clear up a few issues now, but if I havent, please remind me!
Ron - You are dead right. Don't get hung up on timing. Observing the event is the most important thing. And report it even if you had a 'miss'.
I'm going to do my sums in PAL (25fps) please convert if necessary.
PAL takes 25 frames every second. That means that each frame is 40ms in duration. The half frame accuracy means that if you 'know' that the event happened on a certain frame (the extinction of most stars is as good as instantaneous), then the reported time is the median time +/- 20 milliseconds. Interlaced cameras like the GSTAR-EX actually take two FIELDS per frame, so it is possible to get a timing of +/- 10 milliseconds or 0.01.
Back to reality - if you are not using specialist timing equipment, you are unlikely to realise these numbers. there are inbuilt latencies in any computer system and AV is designed to be self healing it will insert duplicate frames or loose the odd one as it sees fit if the system so that it can maintain a steady stream.
Beeper Sync will do a fantastic job of setting your pc clock, and let you know its level of accuracy. Unfortunately the beep coming out of your computer is when your commuter decides based on processor priorities, and not when the actual time occurred - it may not be far out, but who knows. Beeper boxes are designed to overcome these issues but unfortunately Pauline is inbetween batches.
But Bojan, if you capture using GSTAR capture (free from the myastroshop website) it has built in millisecond timing overlay from the computer clock and I recommend giving it a go in conjunction with beeper sync.
To be honest, the old method of using a tape recorder and just shouting gone and back when the event happens with a short wave radio time signal in the background is plenty good enough…
I have a youtube channel with a few of these things: http://www.youtube.com/user/astrojunk
26-04-2010, 01:50 PM
Thanks Jonathon for the input.
Video well handled is good. but guys, be careful what camera you use. The common webcams give jerky movement!! That means (and check me if I'm wrong) it is NOT giving you the 25 or 30 fps!
To make up for poor sensitivity they (usually?) integrate over perhaps 1/6 second and replace the missing frames with copies of the last frame. Just like the integrating systems people are using for deep space video. The Meade DSI/LPI series are presumable of this type. For timing with this sort of camer you MUST know ...
The half frame issue niggles me. You can never KNOW something happened AT frame A OR AT frame B so I feel uncomfortabe ...
But then, the accuracy of the combined many observations is really what matters.
28-04-2010, 06:27 PM
Do I detect that you are still sceptical Ron :)
These results I took from last year demonstrate (I hope) just how immediate and obvious an occultation can be. I admit they are all not as good as this one, but many are.
Further - the system is also calibrated to account from the delays introduced but the electronics inside the camera itself! We are very particular.
29-04-2010, 01:40 AM
In fact, you gave me an idea I needed.
I have 15 names on my list at present and would dearly like a few more.
So, listen up all you sceptics out there. Worried what you are up for? Well you can easily find out. You can practice the real thing ANY TIME, DAY OR NIGHT.
Get onto www.YouTube.com (http://www.YouTube.com) and seach for "Asteroid Occultation" and you will be presented with numeroud short videos of - asteroid occultations!
With a voice recorder running CONTINUALLY you can set mock pre-event mark time, start the video, declare GONE and BACK, then set a post-event mark time.
With a watch or stopwatch you can extract the times of the eclipse and compare duration with the 'official' time given.
IT REALLY IS THAT EASY. Personal error cancels out (almost). YOU HAVE NO EXCUSE!
Thanks Jonathan, I have been looking for something like this for ages.
Does anyone have advice for the best setting for a Philips ToUCam (SPC900NC)
The defaults seems to be:
Format I420 (other options: IYUV, YUY2)
Resolution 320x240 (other options: 640x480, 352x288, 176x144,160x120)
Frame rate 25fps
No matter what I select, the output avi always seems to be 25fps, for example in the attached screen print I selected 15fps, but the output looks like it was still 25fps.
30-04-2010, 12:09 AM
Glad you found it useful James.
Record a sequence and look at the times on each frame - that will give you an indication of what is going on regarding the timing. If you are running 25fps then there should be increments of 0.040 seconds each frame.
Some playback video software ignores the timing signal in the avi and will play back at 25 fps regardless, so it may have recorded at a lower speed and effectively been sped up on playback.
I find the free program VirtualDub very good for closer examination, editing and capture too.
01-05-2010, 08:22 AM
Note that Steve Preston has updated his path prediction (latest monthly update to the asteroid files was released by the MPC on April 28).
Predicted path has shifted a little southward. Probably doesn't really matter much. Melbourne is still mostly in the 1-sigma zone but the main path is now south of a line from Berwick to Aspendale and now includes Phillip Island. Mornington Peninsula and Latrobe Valley are right in the path however so the more of you who can check it out the better.
05-05-2010, 10:48 PM
To date I have heard from probable observers from Apollo Bay to the La Trobe valley. There is a chance of a hole in the clouds somewhere. Don't leave it to the last minute to find problems in gear or method. Be prepared a few minutes either side of predicted times. The shadow is moving at some 10km/sec.
Regards and good sky, at least at about 00.22 on 8th May,
06-05-2010, 09:59 PM
pity the occultation is not on now.. clear skies across most of the path but not for long! hopefully enough people get gaps tomorrow night!
i have tested my routine.. Q-guide camera on my rough as guts finderscope can comfortably see 6th mag stars in 0.2 sec integrations. have beeper sync running on the laptop and cam studio to capture to video the combination of the output from guide camera and timestamp from beeper sync.
need to work out the delay in getting image from camera to screen but can work that out afterwards if i get a hit. good luck..
I hope you're outside right now Phil!
I'm all ready too: Camera - SPC900NC, GSTAR capture software and ED127 scope, Dimension 4 time sync for the PC. I managed to find and capture a test video of the correct star no problems.
I couldn't work out how to capture a video file from my QHY5 (is it possible?) so I'll stick with the ToUCam this time.
I also registered in OccultWatcher.
I spoke too soon - you were right Phil - totally clouded out in record time.
06-05-2010, 11:56 PM
half an hour to go - lets hope you get a break in the clouds...
07-05-2010, 09:51 AM
still another 14+ hours to go unless i've got things completely wrong!
james - i'm sure there would be a way to capture Q-guide to video file, but i'm doing it the hacks way.. using free Cam Studio to 'screen capture' everything on my laptop screen to AVI.
with the quality set to high, pretty much the full resolution of the PHD window is captured, with accurate time from BeeperSync in the window next to it.
i've also installed and registered for observing this event with Occult Watcher.. cool program! There's another event for Melbourne on Tue 18th May.. 9th mag star but still very do-able with longer integrations.
07-05-2010, 02:03 PM
Skippy sky says CLUDS in Melbourne..
However I do not need skippy to tell me that ... a glance through the window is enough.. rainy, grey, miserable day..
07-05-2010, 02:40 PM
Ooops - it's that daylight savings trial they keep talking about in Qld. Gets me confused...
Good luck tonight!
08-05-2010, 01:25 AM
First attempt at an occultation by an asteroid. Unfortunately totally clouded out with rain at the critical time from eastern Melbourne. Still, that's visual astronomy!
08-05-2010, 02:11 AM
Four of us stayed to the end at the Lodge with mostly heavy cloud. But at the very last minute there wa a break in the cloud and Antares shone through then the last minute ended.
Odd, the BOM sat pics showed the cloud almost only everywhere along the path. Did anyone see anything of the event?
I was very badly clouded out here as well for my first attempt. But I'm all set up now - Occult Watcher is really great and I have a whole list of new targets to keep me busy. As Phil said, (1464) Armisticia on 18 May is mag 9.6.
I need to test my camera and see what magnitude I can go down to.
08-05-2010, 10:09 AM
yep.. no good here either.
i had given up but then with five minutes to go some gaps appeared, so i hooked everything up and pressed record but all i got was cloud and a wet laptop.. i've never tried to observe while it was actually drizzling before :sadeyes:
next time maybe..
can't get focus with my Q-guide on the Epsilon so will either have to get an adaptor or pull the old Maksutov out of the cupboard if i'm going to see 9th mag stars like Armisticia on 18th May..
08-05-2010, 07:42 PM
The trouble with inegration over 0.2 sec or more is the loss of time resolution, error increasing to 200ms or more. Then visual/audio methods become more accurate - 20 to 50ms. With a 27km asteroid shadow travelling at c10 km/sec diameter error becomes .5km or more
There is also the mag 10.1 star by Ethiopia just before midnight on Monday 10th
08-05-2010, 09:05 PM
Sorry to hear about the cloud situation guys. :sadeyes:
I hope you all keep at it, there is a very frustrating Melbourne shaped hole in our occultation network that needs filling :thumbsup: And believe me, they are all the more exiting events because of the difficulty in observing them.
Well I had a go at (1432) Ethiopia tonight. The star was only a mag 10.1, but I **think** might have snagged it. In the attached image, the star has dimmed a lot, but it is still just visible. The time looks like it's in the ball park too.
I did a test and found my Philips ToUCam SPC900NC can only go down to mag 8.5 ish on my scope. So I changed over to the QHY5 and used the QCVideo software.
11-05-2010, 07:23 AM
looks promising. analyse the video with limovie which will let you take a light curve of your video so all will be clear. it's a free download, but the instructions are a little light, so give me a shout if you get stuck!
11-05-2010, 05:19 PM
We seem to have had 2 misses. You probably heard that Dave Herald went to Sale for a "miss". We had another site a Apollo Bay on the S edge of the path with a clear sky but no event. I'll make sure he sends in a report.
I'm going to start a thread "Occultations Victorian" - NOT parochial, just recognising the "hole " you mentioned and the fact that these things are very locally visible.
11-05-2010, 10:13 PM
Nice one Ron :thumbsup:
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