Book Project: Discovering Asteroids

[Ags]

All asteroids are minor planets, and all minor planets are (eventually) assigned a number indicating order of discovery, like 1 Ceres or 4 Vesta. The numbers were introduced to replace unique planetary symbols that were initially assigned to the first minor planets to be discovered.

https://www.minorplanetcenter.net/db_search/show_object?utf8=✓&object_id=4

Only the first few asteroids to be discovered got planet symbols, and indeed they were recognized as planets. The symbol for the planet Ceres was:

These little planets were demoted to minor planets when the number of discovered asteroids became too large - exactly the same reason for demoting Pluto from planetary status 150 years later.

Of course, since 2006 we also have the category of dwarf planets (namely minor planets that are round due to hydrostatic equilibrium). Ceres is the only dwarf planet in the asteroids belt, but possibly Hygiea may yet be promoted to dwarf status (there is some dispute over why it is so round).

 

Edited March 7 by Ags

[Ags]

The print proof arrived today.

The cover is way too dark, but was just a quick placeholder so that Lulu would print it.

The family verdict on the milky way traces I added to the charts was "Is it a printing error?"

I am happy with the look of the individual asteroid pages.

The book includes some pretty pictures. Whoever sent the book to the printers with the green debug boxes switched on is FIRED!!!

[Ags]

I worked on reducing the graduated shading representing star density to sharp contour lines. Hopefully looks less like a printer's error now!

It was quite easy in the end, just little bit of integer division and remultiplication, plus a few cosmetic tweaks to reduce the number of dark countours and avoid very light contours.

[Ags]

This books coming along very slowly. My laptop has died last week, waiting to get it repaired before I can continue.

[Ags]

We have shifted forward to the 2025 book, we're a bit late for 2024! But once I have the 2025 version ready I will backport the code to 2024 to produce a PDF for the remainder of the year. 

I have been working on generating the calendar of events. So far I can detect planetary and asteroid conjunctions. I noticed this particularly close one:

50/125: 18 Melpomene | 287 Nephthys
2025-Sep-21 to 2025-Oct-11
Closest on 2025-Oct-01; separation 0.042°.

They might get closer than that, I am limited because I am sampling the orbits in 24-hour steps.

I have to figure out how to detect triple/quadruple conjunctions next (I can solve it by brute force, but I am hoping I will think of something elegant), and also detect lunar occultations. 

[Ags]

Added magnitude color coding to the annual highlights list. There's a a small bug in my book - magnitudes brighter than -10 lose their minus sign (an issue in parsing the data from the NASA Horizon database). It only affects the Moon in this book. I'll fix that tonight. 

[Ags]

I am wondering if I should enhance the 'close approach' algorithm for the annual highlights by adding a linear interpolation step to make a reasonably precise (give or take an arcminute) approximation of the true closest position. For objects approaching within 0.2 AU of the Earth I’ll clearly need Horizons to give true positions more frequently than daily, hourly or 30 minutes would do fine.

I also added labels on the week markers on the asteroid tracks to make the zoomed in charts more readable.

Edited June 8 by Ags

[Ags]

Well I finally sent the book to the printers for a final print proof (and forgot to remove the debug grid AGAIN).

Here is the 2025 PDF for your perusal. I'd be interested to hear any comments or suggestions

I'll run off a 2024 version tomorrow so you can look at current data too, but the charts will have very little editing, it will just be a data dump.

test.pdf

Edited yesterday at 15:17 by Ags

[Ags]

In other news, Google ate discovering-astronomy.eu. I use Firebase (a Google thing) to provide hosting for that domain, and my discovering-astronomy.eu project (and several others) has disappeared! Although the project has disappeared, pages are still being served for the domain...

But anyway, looking forward to any feedback on the long-delayed PDF  

Edited yesterday at 15:24 by Ags

[Ags]

To my great relief, I found the missing Firebase projects. I was being an idiot, and using the wrong login. 😱

Edited 21 hours ago by Ags

[Ags]

Some upcoming events in 2024 June:

....and I just noticed I forgot to fix the bug that drops the minus sign from the Moon's magnitude.

Edited 19 hours ago by Ags

[Stu]

9 hours ago, Ags said:

Some upcoming events in 2024 June:

....and I just noticed I forgot to fix the bug that drops the minus sign from the Moon's magnitude.

Just been reading through this thread, the book looks great!

One thing though, I checked some of the above against SkySafari and there are some quite big discrepancies. For instance closest approach of 21 Lutetia is on 23rd according to SS which is normally quite accurate. Is it just the SS data is wrong?

[Ags]

Thanks @Stu for having a look at the book, and taking the time to check the data.

What timezone is that? My times are calculated for zero hours UTC on each day, so the cusp of 23/24th for the Lutetia/Venus conjunction. Sky Safari is being a few hours more precise here. I have thought of being more precise by interpolating the data from NASA Horizons, but I am not convinced it would make much of a practical difference. 

I will try out an interpolation routine today, let's see if I can match Sky Safari. Why not be precise?

Did you see any bigger discrepancies? 

Edited 9 hours ago by Ags

[Xilman]

On 10/12/2023 at 18:13, Ags said:

I think it can be quite helpful to have an indication of how busy the star field is when chasing down  something faint and star-like like an asteroid. If I realised a faint asteroid was tracking through a crowded field, I'd devote my observing time to something else.

Thinking of making the fuzz red so it disappears with a red light torch. 

It can be extremely important in my experience, especially for fainter objects deep in the Milky Way.

See https://britastro.org/observations/observation.php?id=20230828_184842_42ee6a28ac144694 for an extreme example. OK, that is a TNO rather than an asteroid and markedly fainter than the ones in your list, but still.  If you want an even more extreme example, see https://britastro.org/observations/observation.php?id=20240613_175030_e5946be4b090d772  where the stars in a globular cluster are completely swamped by those in the MW. One comment on that image when I posted it was that it looks like solar granulation.

 

[Ags]

I agree, but those Milky Way traces don't come cheap. The added ink coverage adds 10-15 euros to the print costs, as it forces a switch to printing in premium color 🤨

[Ags]

35 minutes ago, Xilman said:

https://britastro.org/observations/observation.php?id=20240613_175030_e5946be4b090d772  where the stars in a globular cluster are completely swamped by those in the MW. One comment on that image when I posted it was that it looks like solar granulation

Definitely Solar granulation. Are you sure took that photo at night? 😃

[Ags]

1 hour ago, Ags said:

I will try out an interpolation routine today, let's see if I can match Sky Safari. Why not be precise?

@StuI figured out a simple way to do this by brute force, without requiring any heavy calculations but I will need 100 times the memory. What could go wrong?

Even so, I will only have a 15 minute (time) precision. If you need more precision, planetarium software that accounts for your geographic location is a better bet.

[Stu]

1 hour ago, Ags said:

@StuI figured out a simple way to do this by brute force, without requiring any heavy calculations but I will need 100 times the memory. What could go wrong?

Even so, I will only have a 15 minute (time) precision. If you need more precision, planetarium software that accounts for your geographic location is a better bet.

I checked two others, images here. I in the UK, BST currently. 52 Europa was close to a date change but the others not. It’s a tricky one because finding these things involves accuracy so location makes quite a big difference which can’t be accounted for in the book.

[Ags]

Yes, a planetarium app is going to give much more precise values taking into account your geographic location, precise time etc. The goal of the section is to provide an overview of such events through the year, but it will always be statically generated. I think however that changing to a granularity of 15 minutes (100 times the precision) has got to be close enough for most people. Surely? We'll be debating arcseconds at that point, and your geographic location is going to be the predominant uncertainty. Even if I generated finder charts for each conjunction, the difference would be less than the point size of the printing process.

[Ags]

@Stu not seeing an additional issue with Hermentaria - the distance in the book is measured at zero hours UTC and Safari is showing the position 6 hours later, by which time it had closed by another 7 arcminutes. so raising the precision of the process for the book to 15 minute snaps means the separation should be accurate to about 4 arcseconds, and the time accurate to 5 minutes.

As for Europa, I am not sure why I generate a closer approach than Safari. I assume Safari is taking your latitude into account - The parallax on the Moon is over a degree for different latitudes.

Edited 6 hours ago by Ags