Found 2 more close approaching MPs noted above. 

2021 VQ26 has a close approach on Nov 22 according to CNEOS. ST4 predicts it will reach 15.5 mag on Nov 22 moving 66"/min & may be visible from Nov 21-24 ~16 mag.

2017 KM27 doesn't appear in the CNEOS list of close approaches & JPL doesn't list it as having a close approach to earth this year. Curious for sure. ST4 predicts a close approach on Nov 24 at 16.2 mag moving at 42"/min. It may be visible on Nov 23 & 25 as well. The epoch of the elements in the ST4 MP DB is 2022 Jan 21, so it wasn't included in the NEAs at Today's Epoch that I downloaded today. It would be interesting to see if this MP will really have a close approach or not.

Phil S,

Hi MP watchers. There are 2 more MPs visible now & coming closer. (4660) Nereus is currently 14.3 magnitude in Perseus with close approach on Dec 11. (163899) 2003 SD220 is currently 15.3 magnitude in Draco with close approach on Dec 17. Both objects are currently moving at several arcsec/min despite the present distance from earth.

Good hunting,

Phil S.

Hello,

During development, the minor planet database evolved continuously, and it continued to do so even during testing. As a result, some years later now, I had forgotten some changes that were made to the final design. The struggle was to make SkyTools work as fast as possible, even when very large numbers of minor planets were loaded.

I have recently been spending time digging around in that code looking for a lingering bug, and was surprised by something that I discovered. In fact, the minor planets don't  work they way that I remembered. I apologize for the confusion that this has likely caused. The last time I did this kind of observation myself, for a very close pass, was before the final changes were made, so my suggestions proved to be out of date.

Here is what I discovered:

1. In addition to the main minor planet database, minor planets are also sorted into "Saved Epochs," that are primarily used for plotting on the charts. Each of these is defined for a "standard epoch," covering a period of 200 days.

2. By design, for speed, these "Saved Epochs" can only have one set of elements for each minor planet

3. When you add orbital elements for a minor planet for the first time, these elements are sorted into the appropriate 200-day standard epoch.

4. When you add a new set of elements for this same minor planet, presumably for a more recent epoch, if the new elements still fall into the same period of time as before--the same standard epoch--the new elements will always overwrite the old ones. That is because of (2) above.

This has obvious implications for very close passes of asteroids. For very close passes, the elements may be perturbed (or changed) significantly by the gravitational attraction of the earth and moon. I had previously suggested that you could store three sets of elements, one created for an epoch just prior to the pass, one during the pass, and one after the pass, and SkyTools would use the appropriate set of elements for each of these time periods. But, in fact, adding new sets of elements with epochs that are that close together, will always overwrite the current elements (during the the standard epoch).

Updated Procedure for Very Close Passes of Minor Planets
It is important to recognize that only the very closest passes of asteroids are going to have a significant change in their orbits (one significant enough to affect the accuracy of the predicted positions) and that for the vast majority of asteroids making a close pass, the elements are not very accurate in the first place, so generating different sets of elements for different times of the night is not appropriate. You can't improve on something that isn't accurate in the first place.

What I suggest is to use a single set of elements defined for an epoch near the time of close pass for planning. As the date of the pass approaches, upload new elements regularly, overwriting the ones you have been using, and update your plan. This should be sufficient for 90% of all close passes.

For a very close pass of an asteroid with well-determined elements, I suggest adding a set of elements calculated  at an epoch during the start of your observing period. If you will be observing it at a later time, update the elements again, computed for the epoch of that later time. Repeat as needed. In other words, just keep updating the elements in real time during the pass.

I am updating the help to make this behavior clear in the future.

The MP (3361) Orpheus will reach magnitude 14.3 for the next few days. Currently low in the sky in Fornax. Not particularly fast moving or close, but pretty bright for an Apollo.

Phil S.

Our team was unable to observe or image 2019XS from the Houston area due to cloud interference both nights. One of our team members was able to, from west Texas, grab a 100 minute exposure using an 8" Celestron RASA f/2 and a ZWO 2600 Color Camera. The image begin time was 05:57UT and end time was 07:28UT November 10th. The track was 1.4° long (average motion = 57"/min) and is the blue-green line near center running from 5:00 to 11:00.

The image is at https://www.dropbox.com/s/mtqxf67hae0249...l.jpg?dl=0

Still working on getting satellite IDs. I counted 16 other distant asteroid trails in the image along with a handful of faint PGC galaxies.

The minor planet 2021 VC7 is predicted to reach 15.8 mag tonight, moving at ~11"/sec from SE to NW through Andromeda around midnight EST.

Good hunting,

Phil S.

Hi all,

I am sort of a newbie and I am trying to make obstructed horizon closer to what I can really see in my restricted observing area.

This is my file:

0 90
30 90
45 90
60 90
100 0
170 0
210 90
225 90
240 90
300 90
330 90
359 90 

Try different ways but gets out of shape.

and below is a picture of what it looks like.
Above the dotted lines is what I can not see.
Straight or curved, anyone can help?

Thanks in advance!

Attached Files

Thumbnail(s)
   

Hi Greg,

Is there a way to show the Algol minima within a given time frame ? There are online resources for this, but it'd be nice to have the info inside ST, for instance in the Event Finder or Ephemerids (if there isn't a way already, which I tried finding prior to posting).

Thank you.

The above occurred today as was streamed live from Japan (I think).

When I tried to show it in the Event Finder (2 bodies) I come up blank. Everything is set to the defaults.

What am I missing?

Thanks
Bob

   

This little rock (12') just screamed by in the dawn hours of November 1, moving 40'/min just b4 twilight. Well below my horizon and for a very short time, magnitude 13!

Discovered just a day after by ATLAS-MLO, Mauna Loa and only 54 observations over 2 days. 

Interactive flyby: https://minorplanetcenter.net/neo/view?d...ig=K21V00H