2 October 2018 at 10:59 am #574136
I have received a request from Bob Argyle (researching double stars) to observe a lunar occultation of 104 Tau on October 28th at 02h. (see table ). This is Aitken 1934 (ADS 3701). A close double star unresolved by speckle interferometry 1983.93.
A planetary camera, video or a mobile phone recording at 25 to 30 fps (or faster ) through a telescope will be helpful in attempting to confirm a companion. The recording of the reappearance dark limb (RD) could be a step-wise egress which would then indicate the secondary star. A method used by lunar occultation observers. The star is magnitude 4.9
The occultation isn’t observable from S/SE UK (Greenwich), but a graze on the bight limb (or miss) is expected in this area. Observers north of Birmingham will see the reappearance on the dark limb with the star being further from the Southern cusp.
The Lunar Section will be please to receive reports of this occultation.
Reading and Greenwich – no occultation ( approximate UT )
Location Ph UT Cusp Angle
Oxford RB 0231 bright limb
Birmingham RD 0237 CA 3 S
Manchester RD 0241 CA 15S
Leeds RD 0243 CA 17S
Carlisle RD 0246 CA 20S
Edinburgh RD 0248 CA 30S
Aberdeen RD 0252 CA 35S
Lunar Section (Occultation group)8 October 2018 at 6:20 pm #580063
I have mentioned this event in the danish astro forum.
Now they ask for an instruction – how to do it.
Is there a manual or something similar somewhere?
Lars13 October 2018 at 11:31 pm #580069
Thanks for publicizing this occultation. The dark limb reappearance for an observer in Aalborg is 0304h 12s UT and the cusp angle in 29 S. Someone with some experience in Lunar occultations who is able to use a planetary camera (or team up) would be equipped to record the star appearing. The observer would need a field of view of say 1/3 degree to be sure of including the limb where the star appears. I would suggest a frame rate of 25fps or 30fps. from 0303 to 0305 hrs. If this is successful then we can do some photometry – i would need a copy of the AVI or SER file.
There is only one previous recording of the star being occulted (by Brian Loader – NZ) and it was not double, or not time resolved. We seek further recordings. This event is one of the last few opportunities, then the saros ends in 2019. If you are Lunar observer (Imager?), perhaps your experience can help others observes to record the occultation. I am too far South to attempt this.
Good luck and clear skies – Tim (Reading, UK)14 October 2018 at 1:01 pm #580070
The IOTA North America web site has many useful publications and links to occultation observing techniques. There may not be much info’ on the use of USB-CCD planetary cameras in these publications. Only with Windows 8 and 10 does the timing facility of these systems become more reliable (another story). Anyway we are not looking for exact UT for 104 Tau to help solve the double star question. (in my view). We will use a light curve measured from an AVI recording.
Visual impressions would also be nice too, if no video camera is available. All observations sent to the BAA Lunar Section will be acknowledged.15 October 2018 at 3:17 pm #580071
Thank you. I will pass this info on and hope that someone will give it a try. If the weather permits….28 October 2018 at 3:51 am #580106
I watched the occultation of 104 Tau tonight in a 14″ SCT with af 8.8 mm eyepiece (323x).
Clear sky and 0˚ C.
I observed both ingress and egress.
The star reappeared instantaneous, there was no step-wise egress.
I believe other observers in Denmark had the same experience.
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