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How I set These Up - bigmasterdrago - 2021-07-09
I use https://cneos.jpl.nasa.gov/ca/ and https://spaceweather.com/ to watch for close passes.
2019 NB7 looks good but the time error window is huge. Most likely due to being lost after not many observations. I'm choosing 2021 NE because the error is small. Never mind that it's faint and going to be below our horizon as this is just an example of how to set one up.
Click the name and it will get it into Horizons where you can adjust location, Time Span, etc. From the previous table saw close approach at July 10 15:37UT. I'll let Horizons run a 48 hr ephem from July 9-11 00:00UT to see where it is in dark skies. See 4-9UT good window for two mornings. Use your IA to find when those positions are up - 9th transits 01:00CDT, 10th transits 02:35CDT.
Now go back and change ephemeris to elements and create an hourly elements set. I'll pick 07:00UT on 10th. Copy (Ctrl+C) one full hour of elements.
Now in SkyTools, choose "Data", Minor Planets, "Enter New Minor Planet", Paste. Add in the name & H from Horizons. Click OK.
Wait. Do not interfere with the process. My hourglass takes ~200 seconds to completely finish and clear. Wait!!
Now go back into ST Ephemeris (position) and do object search. Set up the Date to coincide with the time of observation, Period for 1 hour, Interval for 2 minutes. Be watchful of time (UT vs Local). Run. Times agree well with Horizons!
Now pick time and choose Interactive Atlas. Run some tracks there. Use your finder chart. If anyone can add ways to shorten this process, I will thank you now.
Kenneth Drake
RE: How I set These Up - PMSchu - 2021-07-09
BMD,
Thank you for this nice description of the process to choose a target & get ST4 set up to observe a close approach. Much appreciated!
Greg, it would be great if this procedure could be added to the ST4 Help system for documentation & reference by other users. Possibly a sticky post in the forum would work too, but not all ST4 users may be on the forum.
Phil S.
RE: How I set These Up - bigmasterdrago - 2021-07-09
Phil, I'll add that few probably try to chase down faint fast movers. I'm thinking the Title will bring those wanting to know to the page. It can be very frustrating and disappointing to spend a good bit of time setting up an observation(s) only to fail. Weather. Real magnitude. Weak details of orbit. Etc... I've reached a point in my amateur life since Jan '83 that I get great enjoyment out of dynamic observing. Thin crescent moons, Galilean Moon phenomena, grazing occultations, rare active visual comets & solar eclipses. I've finally become fluent enough in using the powers of ST. It's chart making is superb for us guys that still don't use devices at the scope or Go-To.
And Phil, just an FYI, my old I5 quad core takes ~2:30 to complete an MPC NEA Today only refresh. And for some reason it seems to not replace the set I got last night from Horizons. Which is good. I need to experiment with that.
RE: How I set These Up - PMSchu - 2021-07-09
Hi BMD,
I followed your directions & downloaded a set of osculating elements for 2019 NB7 that's supposed to have a close approach on 17 July. I used the 'Enter New MP' button to add the elements calculated for 2021 Jul 17.75 successfully as that's close to the close approach time. When I tried to add another element set at 2021 Jul 17.25, ST4 went through all the calculations, but the MP database still only has the elements for 2021 Jul 17.75. I retried to add 17.25 being careful to follow each step, but No Joy! Only the 2021 Jul 17.75 elements are present. Were you able to get the extra element sets into your MP database? From Greg's description of the operation of ST4, I expected to see a database entry for both 2021 Jul 17.25 and 2021 Jul 17.75. The DB has entries for 2021 Mar 11.00 and 2021 Jul 23.00 so multiple entries are allowed. Maybe I need to add elements for Jul 16 & 18 instead of multiple entries for Jul 17, like 17.25 & 17.75.
With 2.4x10^6 element sets in my database it takes a long time to update all the calculations after the addition of each new element set. I think the option to add multiple sets of elements before SkyTools does all of the calculations to speed up the plotting process would help. This is my first experience with adding elements to the MP database so I don't know if this is how it's supposed to work or not.
This is an interesting activity, but a challenging one. Success has eluded me so far. It has interesting possibilities for use of the iTelescope system which offers access to scopes in Australia, Chile, Spain & the western US.
Phil S.
RE: How I set These Up - bigmasterdrago - 2021-07-09
Don't add elements. Do an "Enter New MP".
RE: How I set These Up - PMSchu - 2021-07-09
I did use the 'Enter New MP' button, but I only got a single element set for 2021 Jul 17.75. Using the button again to add the element set for 2021 Jul 17.25 didn't add the new elements, as expected. I tried it twice.
Are you able to add multiple element sets for a single day? That's what I expected to happen.
Phil S.
RE: How I set These Up - bigmasterdrago - 2021-07-09
Yep, not working for me the way I said. I entered four new sets of elements as "Enter New Minor Planet". It seems to have rejected them as it only shows one epoch entry as July 9.0 and I had entered July 8, (8,9,10 &11UT) as separate new MP. They are not there. Only the July 9.00 which is the one that was updated this morning with the MPC NEA Today download.
Plus the ephem positions do not agree with Horizons for rock 2021 NG yesterday at 11UT
RE: How I set These Up - bigmasterdrago - 2021-07-13
(2021-07-09, 09:25 PM)PMSchu Wrote: Hi BMD,I was playing with 2019NB7 tonight and with the huge uncertainty (4d20h30m), the difference in position along the track looked like ~25° (MPC vs JPL elements). Man, how crazy is that. Horizons seems to agree with JPL but it appears the last observation was 2019 07 15.354328UT. Two years ago! If it gets near 19mag on this close approach, which I doubt, they might get another crack at it.
I followed your directions & downloaded a set of osculating elements for 2019 NB7 that's supposed to have a close approach on 17 July. I used the 'Enter New MP' button to add the elements calculated for 2021 Jul 17.75 successfully as that's close to the close approach time. When I tried to add another element set at 2021 Jul 17.25, ST4 went through all the calculations, but the MP database still only has the elements for 2021 Jul 17.75. I retried to add 17.25 being careful to follow each step, but No Joy! Only the 2021 Jul 17.75 elements are present. Were you able to get the extra element sets into your MP database? From Greg's description of the operation of ST4, I expected to see a database entry for both 2021 Jul 17.25 and 2021 Jul 17.75. The DB has entries for 2021 Mar 11.00 and 2021 Jul 23.00 so multiple entries are allowed. Maybe I need to add elements for Jul 16 & 18 instead of multiple entries for Jul 17, like 17.25 & 17.75.
With 2.4x10^6 element sets in my database it takes a long time to update all the calculations after the addition of each new element set. I think the option to add multiple sets of elements before SkyTools does all of the calculations to speed up the plotting process would help. This is my first experience with adding elements to the MP database so I don't know if this is how it's supposed to work or not.
This is an interesting activity, but a challenging one. Success has eluded me so far. It has interesting possibilities for use of the iTelescope system which offers access to scopes in Australia, Chile, Spain & the western US.
Phil S.
RE: How I set These Up - PMSchu - 2021-07-13
So that's what the "4_" meant in their table. Huge uncertainty for sure.
RE: How I set These Up - bigmasterdrago - 2021-07-13
four day uncertainty. have to be very cautious, and check positions from different sources in order to pick out 'rogue' figures.