Dear observers, is it possible to use AAVSOnet telescopes for asteroidal occultation timing? Of course, it is not field of AAVSO activity, but it is important task and it may bring valueable results.
For example, is there a sence to send proposal for observing event
with FSM-SRO50, which will be very close to predicted shadow path?
In this case about 1 min of instrumental time is enough, but fast unfiltered shooting is needed - with exposures 50 ms (or better even 20 ms), better with binning 2, with exact time mark for each image. I hope FSM-SRO50 can catch 11,4V star with so short exposures, but I do not know camera possibilities - and I'm not sure in possibility to use AAVSOnet for this kind if observation.
So I kindly ask your decision. If observing of occultatuons is possible - clear criterias for events and proposals will be needed, I think.
1. Location obviously critical. Portable systems and team approach better. Most importantly, SRO050 is not currently active. :-(
2. Need CMOS camera for fast exposures and download. Many systems have that now. Not a lot of clear filters.
3. Doesn't use up much time so okay in that regard. Not sure how accurate the time stamp will be?
4. A test run would be useful.
5. Not a classic AAVSO variable but fun!? (My opinion only.)
I agree, this would be fun.
But what is normally used for this kind of observation is a video camera with a timestamp inserter tagging every video frame, going for 16ms accuracy.
AAVSOnet systems have MaximDL running the cameras. It might be able to do video, but I would not warrant the time stamping.
Unless you have other insight, I don't see the AAVSOnet as suited for this kind of observation.
Thank you, Ken and George!
I understand problems but I think that better to use every chanse for occultation observing, IF:
1. AAVSOnet telescope is placed in the 3 sygma band;
2. aperture is enough for getting unfiltered images of target and comp stars with 10-20 fps;
3. computer time is GPS synchronized.
I will consult with experienced occultists and hope to find suitable event sometime. It is not so easy for stationary instruments :)
Hope for AAVSOnet support!
Though I see you still want to pursue this, I can only offer the following additional practical observations:
1. After a quick search of asteroid occultations and IOTA, it looks like it is best to use camera video mode and a GPS time stamp inserter to get reliable data.
2. Although both our ASI183 cameras and MaximDL may be able to do this, the need to set up different modes for each to be able to accomplish this is not practical in light of our need to maintain the AAVSONet system in a condition which meets the needs of normal variable star photometry.
3. The systems do not have such GPS time stamp devices. We use NTP software for time adjustment.
4. I doubt we are going to purchase and set up the extra hardware, and modify the camera software modes for an infrequent observation like this.
Just trying to be honest and practical.
Thank you, Ken, for your detailed explanations.
Indeed, occultations are not suite for AAVSOnet long exposures, it's a pity...
However there is drift scan method: getting stars trecks with stopped clock drive. In this case just single image is needed, with exposure about 1 min. Is it possible for AAVSOnet instruments to make one unfiltered exposure with motionless telescope? Look please paper:
BTW, there is other task, more suitable for AAVSOnet: close approaches of asteriods to stars. Usual serial shooting with comparely long exposures before and after possible occultation helps to improve orbits of small planets. But IOTA does not collect close approaches, and astometrists did not prepare website like SODIS or OWC yet. And, of course, it is not field of AAVSO activity.