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I would like to thanks those planning or attempting observation of this remarkable asteroid pairing, and to those passing on information to possible observers. We where clouded-out, which was disappointing, but at least we tried:
S Kidd nr Cambridge
A Cook nr Newtown
T Haymes nr Banbury
T Haymes (Mobile) – with thanks to the Solihull Riding club for permission.
A.R Pratt nr Leeds
R Stuart nr Rhayader
W Stewart nr Crew
W Stewart (Mobile – for investigating a possible location on Cannock Chase )
Mansfield Astronomical Society
Newtown Astronomical Society (Wales)
Salford Astronomical SocietyAttachments:
Thin cloud prevented a good view of both the D and R. So no observation to report from North Oxfordshire
Thanks for the update Alex, i am looking forward to the Saturn occultation. Best of luck to all.
Please send reports to me: tvh dot observatory AT btinternet com, or the lunar Section Director.The email address occultations AT stargazer.me.uk no longer exists.
For the Atlas Graze, here is a link to zip file with the limb profile, text file, and the Google Earth mean limb. (computed with Occult4 )
For best view, observer from anywhere between 1 and 9km inside the mean limb. If you are on the mean limb line – there is no occultation !
The limb is very rugged and lots of ins-and-outs should be seen.I hope the shared link works 😉
https://1drv.ms/u/c/cf6c8ab7497dcb5c/ESOWhoVGqIBCvPvRpGBkyGYBfU7o5W5AZiVgRGSAYo98jQ?e=zE6Xqk
Tim Haymes
Lunar Section Occultation Coordinator.Denis, I did sign that petition.
There is a Dundee Council survey form linked to the link i gave, which provides boxes for comments.
Cheers…HaHa. No observatory is complete without a fire extinguisher at the ready !
Yes the 902H Ultimate is sensitive but a bit noisy i believe. It will need a 12V DC supply and a phono cable ( also a BNC plug to phono maybe).
Ive not used one, but it may be possible to smooth out some noise when processing the video (Binning)
Feel free to contact the Section.Tim
Asteroids and Remote Planets Section (Occultations)Hi Lars,
Perhaps you have a WAT-902 ? Yes this could be used. My setup is:
Camera => GPSBOXSPRITE-3 (Time overlay) => Pinnacle Dazzle video digitizer (for W10/11) => Laptop with IOTA video capture.
Free software: IOTA capture, Tangra (Hristo Pavlov) for video analysis. (light curve and timed event).There are on-line sources for brighter predictions E.G. asteroidoccultations.com, but I use OccultWatcher (free software) which takes predictions from a server. I then filter them down to the ones near me.
Happy to help out.
My setup in 1991 with DIY video. Your WATEC would have the same sensitivity.
Attachments:
I observed from a carpark at Beacon Hill Hillfort just off the A34 South of Newbury. It was close to the mid-shadow line. Transparency was poor with thin cloud moving through but it was clear enough to see the pole star and the major constellations.
Equipped with a Vixen Polarie and WAT-910HX + 135mm F2.8 lens attached, i was able to find the target by star hopping. To do this I compared SkyMapPro and the video display. The occultation itself was not seen live on the monitor. When i got home, I analysed the AVI recording. There is a small brief dip at the predicted time. No fade was recorded.
It was more of challenge than i had expected, and i was pleased that the 50 mile drive from home resulted with a successful recording although no clear event.
Hi Jeremy,
Thanks for the comment. I’ve asked for clarification on the magnitude sources. The magnitude drop could be smaller than anticipated, owing to the “partial eclipse”. So a visual observer might not see any change – but without observing, we dont know. I video camera would be preferable to catch the drop.I got mine from Postie about a week ago (ca Oct 23). The packaging was battered, but the contents intact. It could be a post-office difficulty – not sure. Im wondering if the enclosed handbook causes a hiatus.
The occultation times in the table on page 337 are for an observer at Greenwich. See the HBAA page 39 and note under the table. Why the 0.1 minute precision? Well this is the format (as suggested by David) that is produced by Occult4 software. There is a routine that produced the tabulated data used by the Handbook. This format is historical, and goes back to the 1960s, but a good summary for two stations.
Predicted times can be computed to better than 1 sec if the observer coordinates are used in the software, so the tabulated times are only a guide. For other locations the times will differ by up to 2 minutes depending on how far the observer is from Greenwich.
Im grateful to Nick Hewitt for including Lunar prediction on his Sky Notes page. I find them fascinating to observe. The Lunar Section Circular contains predictions to 8th magnitude for those seeking more opportunities. The time format for these are dd hh mm ss.s for a single station – again a guide only.
I offer a service to keen occultation observers. In that i can produce predictions to 1 sec precision for their site via email.
Tim –
Lunar Section.When observing/recording, the event will occur near 2309 UT. so best to record video from 2308 to 2310 UT in the UK (see the graphic).
For most observers with access to NTP, it would be best to use the Meinberg software to keep the computer clock sync’ed to UT.
https://www.meinbergglobal.com/english/sw/The recording software of my choice is SharpCap, where SER or FITS images can be selected with recording between 10 and 3 fps. (dependent on the instrument and camera). With a 20cm and mono CMOS, an exposure of 100ms may be possible. All depends on transparency and light pollution levels, so the only way to tell is at the telescope. As long as the 12.6 mag target is detected clearly, a result is possible. The ARPS section can perform the analysis and help prepare a report.
Cheers – Tim
ARPS (Occultations)I have done some photometry and i aim to start with a nice clean sensor window. Any other shadows may be from the filters. I don’t clean the filters and if in a filter changer, are protected somewhat.
For sensor window cleaning, I use a Delkin-Devices Digital Duster kit (They can found on e-bay). The “wand tips” are of card-like material to which a few drops of cleaner solution is added (It soaks in). The damp wand is then drawn cross the sensor slowly in one direction. The tip can be cut down to fit the sensor. Then test the camera, or if you have a eyepiece or something under a bright light, its possible to see any dust or hairs. It may be an idea to used the blower, but the danger then is that you blow material back on the window.
If you have a camera serviced in the UK (Starlight Xpress, ATik) then it may be possible to send the camera to them for cleaning. I know Starlight used to do this. Its worth asking.
This link helps to identfy the source of shadows: https://astronomy.tools/calculators/dust_reflection_calculator
Yes! You might be able to blow some of it off, but i would use a DSLR camera sensor cleaning kit to remove the remainder.
-and keep the glass covered up !
Cheers – TimDavid,
Thanks for the alert for this TNO !
There are a some us in ARPS who hope to observe this, and the more observers we have, the better the chances of a success.If no occultation is recorded this is as important as a positive. From Oxfordshire the altitude is 12 degrees and with my mobile 8″ F/4 i should be able to reach this star in 0.5 sec on a CMOS mono camera (FITS is preferred by Pro-am). I will aim for a S/N of 5 at least, which is the minimum to clearly confirm a detection or not.
I have a rule-of-thumb (or eye), that provided the star image is above the noise (or transparency) threshold of the camera/scope and “visible” on the monitor throughout the recording period, this should provide the S/n desired. This can be tested by dropping the exposure down until the image is unclear and then increasing it enough to become a stable image. The mid-time for UK is 2218 UT and i would suggest recording for a minimum of 2 min either side (4 minutes in all). That would be about 240 FITS files. Test images on stars of mag 14 would be a guide.
Timing the frames can be done using the computer clock recently synched to NTP. Timing data will be put in the FITS header by the recording software.
Best of luck David, and to all observers,
Tim
Asteroids and Remote Planets Section (Occultations)Thanks Alan. This is a shock!
I was one of many, and shared a cabin on one of the upper decks. The full-board cost for the 2 week cruise was £140.
In the end we had a great eclipse despite some local fisherman removing the buoys careful positioned on the center-line (no GPS then).
Alan Sidi made the film “Line to the Sun” Thanks to Martin for putting it on his channel. Great memories indeed.Pink Floyd had just released Dark side of the Moon, and some folk on board were raving about it. To my embarrassment I’d never heard of the them !
Tim.
The sub frame calculator is helpful. Thank you. When you plug in numbers i can see the range of possibilities to try
TimThanks to all for reporting. So far no positive events but there are -ve ones (to be confirmed), and some reports to come in.
Considering the difficult conditions, many thanks for effort to observer, its much appreciated. The -ve results will help restrict the orbit better
for the next prediction.
TimNot sure Robin. Molecular absorption will be in the IR 2-20 u looking at my university notes. Interesting thought though.
Images of the target star taken last night (May 01/2), have been added to the page. http://www.stargazer.me.uk/call4obs/29PUK20230507.htm
They indicates an aperture from 8 to 10″ could image the star with exposure 100 to 200ms, even in poor transparency.I hope some observations will be possible and we get some chords. This will be my last update to the page prior to the event.
To be clear, a “chord” across an asteroid profile is two time points: Disappearance and Reappearance of the star, as seen by the unique position of an observer.
Good luck and clear Skies !
