Here we are on this subject again. I want to hunt down the asteroid Nysa (44). Probably a binocular object high in the SE tonight. I've tried searching its name (Nysa, 44 & Nysa (44)) using the Object Search in the Position Ephemeris and the Data/Minor Planets (Number & Designation). It does not even come up in the nightly planner - Current Bright and Interesting Minor Planets, filter Asteroids & Minor Planets.

   

MPCORB, MPC NEA Today & MPC NEA have all been updated yesterday but not necessarily in that order if that matters. As small things definitely matter in complex software. The Minor Planet Database indicates there are 28,972 minor planets with 4 saved epochs.

Hello,

Here is a quick guide to obtaining the data needed in SkyTools to as accurately as possible plot the path of an asteroid as it passes close to the earth.

Here are a few things to know first:

1. SkyTools uses Osculating Orbital Elements to plot the position of an asteroid or minor planet. These elements are calculated as if only the asteroid and the sun exist. With time, other objects in the solar system will begin to tug (or perturb) the motion of the asteroid, and that will change the orbit. So you always need a fresh orbit, and this is why SkyTools has options available for downloading elements regularly. The moment in time when the orbit is valid is called the epoch of osculation (or just the epoch).

2. SkyTools accumulates orbital elements over time. The set of elements with an epoch that best matches the date of your calculation will be used. That way you can get new elements in the future, but SkyTools will still be able to accurately plot the position on the night you observed it, even if that was long ago.

3. The orbit of a Near Earth Asteroid is being perturbed by the earth and moon as it makes its close pass. This will cause a change in the orbital elements as it passes by the earth, so it is often critical to update the orbital elements just prior to when you are going to observe the asteroid.

4. Many Near Earth Asteroids don't actually have well defined orbits in the first place. This is because many of them are too faint to observe except when they are close to the earth. Many have only just been discovered as they approach the earth. As they approach, astrometry (carefully measured positions) is obtained every possible night, and these new positions are used to update and improve the orbital elements. As important as point No. 3 is, the improvements of the orbital elements as the asteroid approaches us can be even more important to accurately plotting the position of the asteroid as it passes by the earth. This is yet another reason to update your elements just prior to observing.

4. In order to make the database efficient, orbital elements are sorted into different "standard epochs" when they are stored. This is a period of time, 200 days long, that orbits are sorted into. The epoch dates in general that you see from the Minor Planet Center's MPCORB download are typically these same standard epochs.

SkyTools will only store one set of orbital elements for each standard epoch. This is where it gets a little tricky when it comes to Near Earth Objects (NEOs), because the MPC recently began publishing elements at a standard epoch date in the future when you download the MPCORB data. Aside: the alternative ASTORB database from Lowell Observatory is computed for an epoch close to the current date.

As a result, SkyTools needs some rules to follow to know when to replace an existing set of orbital elements with a new one. It can't simply keep the elements with the latest epoch, because you may want to update the elements near the time of a close pass, which may be prior to the date of the elements that are already in then database. To solve this problem in SkyTools, there are now cases when a new set of elements will always overwrite the ones already stored for that epoch.

When you download the MPC NEA Today or MPC Daily Update from within SkyTools, the downloaded elements will always overwrite the current orbital elements in the current standard epoch. That way, you can always update your elements when a close pass is coming up (and the elements improve). These elements are updated daily, to the current epoch, and hopefully with the latest data, so they will often be the most accurate. Prior to a close pass you should download these elements. This is all most observers of close approaching asteroids need to do.

For Advanced Users
For those who want to enter elements from JPL's HORIZONS system, this is done by pasting the elements into a SkyTools dialog. When manually entering data, such as that from HORIZONS: if you edit an existing set of elements, this will always overwrite what was there before. If you create a new set of elements, be sure it has an epoch more recent than the one in the database. Otherwise it will not overwrite the one already there. Do not kludge the epoch. It must be accurate.

How do you tell if everything is OK with your orbital elements?

1. Open The Minor Planets Database from the Data menu
2. Enter the designation of the minor planet under Designation and press the Enter key.
3. When it finds the minor planet, it will list all of the orbital elements by epoch. Double-click on any one to see the full data.

Prior to observing a close pass, you want to see the top set of elements have an epoch very close to the current date. If you are planning to manually add new elements, ensure that there is no set of orbital elements for a date in the future, beyond the date of closest approach. If there is one, delete it, or replace it manually, by editing the data. To delete it, close the Osculating Elements dialog, right-click on the elements you wish to delete, and select Delete Element Set.

The MP 2022 AB is predicted to reach max brightness tonight ~3:30 EST in Gemini. The predicted path is shown here: [attachment=2186]

Closest approach doesn't occur until 2022 Jan 20, but it will be fainter than 17th magnitude then.

Good hunting,

Phil S.

I have released an update to version 4.0j R9. You should be prompted to update when you start SkyTools, but this may not happen immediately. To force the update, select "Updates, Registration & Feedback" from the top level Setup menu and click Check for Updates.

The primary reason for this release is to fix a rather perplexing issue that caused a range of apparently unrelated problems when connecting to mounts using ASCOM. This happened for all versions of SkyTools 4. Many had no trouble at all. But others had symptoms that ranged from not being able to connect, to crashes. The most common report was receiving a "missing property" error. This was caused by a call to ASCOM that found its way into a thread in SkyTools. ASCOM does not play well when being called from a different thread. If you were having any kind of problem connecting to your mount, this will likely fix it.

Additional fixes:

Visual & Imaging

• The Eyepiece/Camera Viewer for the Atlas now defaults to being locked to the telescope position if opened with a mount connected to SkyTools. This should help people find where the telescope is pointing on the atlas.
  
• Chart labels for some moving object trails had the hours for the time truncated such that the first digit was not visible.
  

• When printing logs using the Print/Copy logs for Observing Award feature: observing conditions text will now wrap when printed, and the text copied to the clipboard is better suited to pasting into Word or Wordpad.
  
• The Crab nebula was using the larger diameter of 8'x8' when estimating the visual difficulty. This outer diameter is mostly H-Alpha emission and not visible to the eye. The diameter was adjusted to a more appropriate 6'x'2 for the calculation, which now provides better results.
  

Attached is the stx file for the DSF forum object of the week 2021. This is in ST4 format so cannot be used with ST3. These are mostly challenging or very challenging objects for medium sized telescopes

Attached Files

  OOTW2021.stx (Size: 940 bytes / Downloads: 12)

The NEO 2022 AC4 is predicted to reach max brightness of 14.7 magnitude on 2022 Jan 10 ~2200 EST in Auriga. It will be slightly fainter, but closer & faster over the course of the next few hours reaching a speed of ~ 17"/sec! A real screamer.

The predicted path is shown here from Central Ohio (40°N):  [attachment=2183]

Parallax will affect all observations as this object is quite close. Also note that the time should read 20 - 23 hrs on 1/10 because the tens digit of the hours isn't displayed as BMD has noted in another post. I suspect that this is due to the length of the field allotted for the output character string being too short when seconds are part of the time output - an unusual occurrence.

Good hunting,

Phil S.

Hi Greg,

I've been creating observing logs to keep track of close approaching asteroids, but that's not an ideal solution. All the MP log entries really slow down the Restore operation. Can you suggest a better way to rank the quality of close approaches? I want to keep track of the ones that I've already evaluated. Perhaps the log entries can be deleted once the ratings have beeen applied. I do like the information that the logs allow me to add regarding maximum brightness & minimum earth distance though. Would Notes offer the seme options?

TIA,

Phil S.

As the Nexus DSC seems to be getting more popular it would be nice if ST4 could output the current comets list in a format that it could read. The Nexus DSC basically reads an MPC softCmt00.txt file that has to be copied onto a MicroSD and put in the device. Although one can of course edit the one from the MPC or Gideons site it would be nice for ST4 users to do it easily. Just to balance out all the requests from the MP users 

Hi All,

This big, bright NEA is currently in Puppis at -49° Dec moving north & brightening. Max brightness is predicted to reach 10.4 mag on Jan 18 @ 1900 EST when it will be in Pisces ~7° Dec. It should be visible from both northern & southern hemispheres, weather permitting. It's already 15th mag & should remain at least that bright until Jan 25.

Here's the predicted path: [attachment=2176]

Good hunting,

Phil S.

On Using the Eyepiece Viewer help page, what are the meanings of the Z and L arrows in the image?

Also, what determines the angle of the W arrow on the eyepiece FOV circle? For example, viewing 65 Psc on the Interactive Atlas has W to the right, but after selecting Eyepiece View, the W arrow points near upper left.