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My cloud predicts for tonight are highly variable depending on who you believe. It it is clear, I hope to try both of these from home--they are both too faint for my little Astrid systems. Garrett, the first has its south 1-sigma zone go over the LVAAS observatory: https://cloud.occultwatcher.net/event/1596-6103-254588-647725-U071538/2352312 The second I don't think gets near anyone else on this list: https://cloud.occultwatcher.net/event/1596-106497-251542-646934-U105155/2337829 Note that after tonight, I'll be traveling until 5/28. Steve C

I may have a clear night tonight, and there are two possible events to travel for (too close in time and in different directions from home--so I have to pick one). Which to pick? I'd be using my two Astrid/C-5 systems. Both are at equally painful times to me. (26261) Tinafreeman https://cloud.occultwatcher.net/event/1581-26261-218298-646626-T00885-1/2376831 7:15 UTC Rank 100 Mag 11.7 Tmax 0.4 sec Elevation 24 degree in the SSW 15 minute drive to state park where I'd put two stations at -0.54 and -1.82 km on a ~7 km wide shadow Doesn't get close to anyone else on this list except maybe Kia (62160) 2000 ST25 https://cloud.occultwatcher.net/event/1581-62160-265994-647679-J3338142/2424175 8:13 UTC Rank 75 Mag 10.4 Tmax 0.7 Elevation 41 in the SSE 50 minute drive two 2 state parks where I'd put two stations at +4.4 and -2.1 km on a 7.5 km wide shadow Doesn't get close to anyone else on this list except maybe the Charlottesville folk I figure I'd crowd source it, rather that make the decision myself--that way I don't have to blame myself if it goes awry. Steve C

Folks: Here's AMPLE 'advance notice' on an event for NEUS folks... As of this writing 2025 April 3, predictions show that the important PHA (3200) Phaethon [also the parent body of the Geminid Meteor Shower] will present an occultation opportunity for NEUS observers on 2025 October 9th UT. The event involves a 12.4 mag star and has a Max Dur of 0.29 sec. Nice sky location - 44d Up, Az 67d. There's a bright 94% Moon 24 degrees away, but it shouldn't be a problem for a 6 to 8-inch and up scope. It appears that Paul Walker's club (Vermont Astronomical Society) observing site is very near the path's center, and Steve Conard won't have to travel much to set a (or several) mobile sites. I also have a site I've used in the past that's "in the shadow". Maybe there are others who can join in. Mark your calendars, and hope for clear skies. George

Folks: Here's an interesting situation to be aware of (and that I realized some time ago). ....And the recent occultation of (93) Minerva [a rock that's 154km in size!!] on March 3rd serves as a prime example........ In OW Desktop you can go to "Configuration". Under "Event filters" you can set a 'search distance limit' - such as how I have it set ---- "My site is more than 19 miles outside the 1-sigma zone". Beside the 1-sigma zone, there is also the choice of "outside the path edge" and "from the centerline". The choice of "from the centerline" might look enticing, but note that in the positive I hit on this rock, I was 46 miles from the centerline (and right on the predicted path edge). If I had selected "from the centerline" this event would have never shown up on my OW Desktop(!!!!). [Tho I would have noticed it in my Occult34 search]. So if you select "from the centerline" (and you have a value like 15 miles or so) you may miss seeing some events on larger rocks where you are actually IN the predicted path (and maybe have a 100% chance). George

I finally went mobile (beyond the suburb's park) and drove out ~20 minutes for an occultation. I picked out a location by finding a park near the centerline that looked like there would be no eastward obstructions from trees (thanks Google map imagery!): https://cloud.occultwatcher.net/event/1522-54727-138468-649673-T00010-1/Horizons;GaiaDR3 The star was mag ~10 and the predicted mag drop was 8.9. Event was up at 54° E, so this seemed doable with an 8" SCT with f/6.3 reducer plus 0.5x IOTA reducer on ASTRID at 30 fps. I guess the limiting factor may have been the duration which was a predicted max of 0.2 s. 30fps=0.0333 s per frame so a max duration of 6 frames is predicted (could certainly be less than the max). The highest DNR result (1.76) I could get was from a dynamic aperture on the target. The red line is left of the 3-sigma level, so I suppose this is most likely noise. D: 01:28:11.3636 R: 01:28:11.6301 Duration: 0.2665 Duration Error: 0.0626 DNR: 1.76 Would you mark this as a miss or no observation? I view "miss" as concretely stating that the shadow did not go over my location whereas "no observation" would indicate I'm not comfortable stating it as a miss as perhaps the shadow did go over my location but my equipment/analysis was inadequate. I'm leaning toward "no observation" but figured I would check with others who have more experience judging these calls. Light curve attached. I can provide the video file if anyone is interested. I could try integrating from 30 fps to 15 fps if someone thinks it would help. I know how to do that using the script provided on ASTRID. Best, Garrett

Hi All, In the spirit of collaboration, here are the current locations I do asteroid occultations from. My home site obviously is my preferred site. The VAS Observing Site in Hinesburg, VT is not accessible when there is snow, which is most of the winter. As George showed us in our recent Skype meeting in Occult 4 you can create 1 or more Site Files, each with multiple locations. Go to "Maintenance", "Edit Site files" (top center), "Add New site" (below big "box"). Enter a Site name, Longitude, Latitude, Altitude. Don't think you need telescope aperture for the purposes of showing the sites on the map. Select Accept (bottom left) For a 2nd, 3rd, etc site: Select "Add New site" again Enter a Site name, Longitude, Latitude, Altitude. After all sites are entered and accepted select "Save as..." (far right side) Remember to see these on the map that comes up when you click on an event on the List & Display window, you have go to the pull-down in the upper right corner. Paul Walker, Middlebury VT (home) d m s -73 9 19.5 44 0 55.2 Alt 132 m Paul Walker, VAS Obs Site d m s -73 4 32.6 44 19 22.4 Alt 200 m

I decided to take the plunge and try out Occult4. This is mainly out of curiosity to see what OWC misses (Steve Conard says OWC captures most of it pretty well). When searching through "all" asteroids, I get a small list of events that does not match what I see on OWC. Keeping all of the same settings and the searching for only one asteroid ID shown as a predicted event on OWC, I am able to see that event for that particular listed in OWC (when it wasn't in the "all" asteroid search). I don't understand what I am doing wrong here. All settings are kept the same (at least by my direct user input) between the two searches besides searching "all" asteroids or for a particular asteroid ID. Here's an example screenshot of the "all" asteroid settings and list of generated events. Notably, the event for (164167) 2004 BE46 But then if I select that specific asteroid (164176) and rerun the search then I do see the event listed in Occult4: The answer may be obvious to some of you experienced users, so I would appreciate any pointers. If the answer is not obvious as to why this is happening, I can post in the general IOTA chat and see if Dave Herald responds. Best, Garrett

Did anyone give 2024 YR4 a try? ----- Forwarded Message ----- From: Dave Herald via groups.io <d.herald@...> To: "dunham@..." <dunham@...>; IOTAoccultations <[email protected]> Cc: Planoccult <planoccult@...> Sent: Saturday, February 1, 2025 at 04:37:55 AM EST Subject: Re: [Planoccult] Re: [IOTAoccultations] 2024 YR4 occultation on Feb 6 and later.... I have attached a GoogleEarth .kmz file for the elevation-corrected path for this event. Unfortunately, this will not be included in the Planoccult posting The Occultation elements for the event are: <Event> <Elements>JPL#40+Ephem,0.14,2025,2,6,1.3986657,-0.4693720,0.3626722,0.3148293,0.4074784,0.0013077,0.0002313,0.0000011,-0.0000002</Elements> <Earth>-37.7753,12.7035,162.53,-15.59,False</Earth> <Star>UCAC4 514-045124,7.95267625,12.7714277,11.66,11.06,10.32,0.1,0,,7.97635635,12.7034992,12.31,12.60,0,0,0</Star> <Object>0,2024 YR4,23.37,0.128,0.3883,0,0,0.490,9.21,,0.0,0,-5.00,-5.00,</Object> <Orbit>0,18.6605,2025,2,6,134.3644,271.3672,3.4083,0.66161,2.51639,0.85152,23.95,5.0,0.15</Orbit> <Errors>23.728,0.0313,0.0103,39,0.0330,Known errors,0.90,0,0,0</Errors> <ID>20250206_045124,60707.33</ID> </Event> If anyone is serious about the event, they should generate their won prediction about 24 hours before the event. The JPL Small Bodies DataBase contains the following useful bit of info: The next version of Occult will enable a 1-click access to the relevant web page of this database. Peripheral to this. The star that was previously suggested as being occulted on Feb 6, is not Occulted. Short-arc orbits are inherently unreliable. Dave Herald Murrumbateman Australia From: dunham@... Sent: Saturday, February 1, 2025 1:26 PM To: IOTAoccultations Cc: D Herald ; Planoccult Subject: Re: [Planoccult] Re: [IOTAoccultations] 2024 YR4 occultation on Feb 6 and later.... Dave, It looks like this path may be over the Boston area; could you provide the Occult input file for the event, or a more detailed map of the path? Of course, it's a long shot that anyone will get an observation. David _ _ _ _ _ You wrote: Frank. when you specify dates in an email, PLEASE recognize the different way dates are used around the world. I initially treated 1:41 AM UT on 2/06/2025 as being 2 June.... There is an occultation on 6 Feb. With a diameter/path width of 100 meters, (i) Fresnel diffraction will make the mag drop much less than expected for a large body, and the probabilities of being in the path are rather small, with the current formal uincertainty in path location being 25 times larger than the diameter. Dave Herald Murrumbateman Australia -----Original Message----- From: Franck Marchis via groups.io Sent: Saturday, February 1, 2025 10:08 AM To: Planoccult ; IOTAoccultations Subject: [IOTAoccultations] 2024 YR4 occultation on Feb 6 and later.... Hello, Several years ago I mentioned at the Planetary Defense conference the importance of occultation to nail down the precise orbit of a PHA. The news about 2024YR4 is spreading (1% of impact in 2032) and I wonder if someone has calculated any potential upcoming occultation event of bright stars by this asteroid . I know it’s a long shot due to the uncertainty of its orbit, but we have enough telescopes on this planet to maybe detect such events and more importantly refine the probability of collision if we detect one. For instance, based on a brief study of a Unistellar Citizen Astronomer (Stephen Lawrence), the asteroid will pass within 0.6 arcs of a V=11.41 star TYC 0788-0020-1 at around 1:41 AM UT on 2/06/2025. Will the center line of the shadow cross our planet? What will ne the duration of this event? Just a thought for those who have time to run such calculations (I may try this weekend) and discuss this here. regards Franck M.

NEUS folks: __IF__ (by some miracle) it's clear early on the evening of Jan 23rd, it seems that several NEUS observers have the chance to try for an occultation of (617) Patroclus. This Jupiter trojan will be visited by the Lucy spacecraft in 2033. It's also a binary asteroid with similar sized components (the other component is Menoetius). More info can be found at: https://en.wikipedia.org/wiki/617_Patroclus The event occurs early in the evening, near the end of twilight and there will be no Moon to interfere (it seems it should be dark enough by then to image the event). Combined mag is 14.9, but it could be up to a 4.8 second event. (Note: I have no idea how the binary nature might influence the path, duration, etc.). The event will be in Cetus, lower in the SSW. This is a Lucy Star event and is listed on OW. https://cloud.occultwatcher.net/event/1483-617-9361-647616-U000769/2184091 The east coast ONLY has a chance at this... as folks in AZ, CA will still be in daylight. George