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.
Part of your search problem is the fact that the name of the asteroid is Anneliese, not Anneliesa.
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...
James
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.
[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.
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
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
Last edited by Ron Garrett; 25-04-2010 at 01:10 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)
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?
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...item2a06538291), or TouCam.
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.
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…
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.
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.
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.
Here's how.
Get onto 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!
Ron
