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Book project: Discovering Deep Sky Objects


Ags

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I have found my previous project Discovering Double Stars to be tremendously helpful to me, so I have decided to roll out another one for deep sky objects. After including the Messier and Caldwell catalogs, and adding in some brighter galaxies, variables, carbon stars, globular and open clusters and planetary nebulae, the book covers 389 objects covering the northern and southern hemispheres. I am tempted to include a few classic doubles as well, but that would of course duplicate the earlier book. One lack is diffuse nebulae, but I find those completely inaccessible from Bortle 8 skies, so I have only included the ones in Caldwell and Messier.

I have refined the diagrams somewhat: the callouts on the left side cover less of the map, I added a border, and made most callout lines avoid crossing each other (some line crossing is insoluble however). As the targets can get quite crowded and there is a greater density of targets on many overview maps, I don't generate a finder circle per target but I do color code the target pointed by the brightness of the target (blue should be easy to spot, orange is somewhat fainter and red is difficult).

image.png.a4152d0d8291f6c3a87dcefbdd8f8c87.png 

Edited by Ags
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At the moment, I mark everything that is mag. 7 or brighter as blue, mag. 9 or fainter as red, and everything else orange. That's based on my personal experience with scopes of up to 150mm aperture with Bortle 8 skies, but I might want to tweak the rules based on objects (globulars cut through the light pollution more than galaxies, etc). Obviously, with a larger scope, you have more of a chance with red objects, while if I have my ZS66 out, I would tend to stick with the blue objects 😀

Edited by Ags
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I just bought a ZWO ASI485MC so I might have some distractions to contend with... 🤣

The book is 80% done, but the last 20% takes 80% of the effort. And then the next 20% you didn't count on takes 80% more effort!

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@PeterW Yes I have tested the colors under a red light. The same colors are used in the double star book in my signature. The charts should look a bit like this:

red_light.jpg

Detailed finder charts are provided per object, showing a five degree finder circle (total finder chart 10 degrees square).

Edited by Ags
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  • 4 weeks later...

I have been led astray for weeks by my new color camera, but thankfully thick cloud has driven me back to my literary endeavors. I finished documenting the Caldwells yesterday and if things go really well I hope to finish the Messiers early next week. It's a bit of a race as I have some new bits coming for my camera!

Having been through the whole Caldwell list and having written a potted description on each one I have to say - some of those Caldwells are insanely hard!

These are the pictures that ate a book:

M42-RGB-session_1-St-final.thumb.jpg.5cebf1d0272381d7d1ba5e5cbf3b975b.jpg

M45.thumb.jpg.fe6f315108b33070be80c54da71cf73d.jpg

Flame-RGB-session_1-lpc-cbg-011.thumb.jpg.b680b47c74372fc1ab3a3eae3ea6ee97.jpg

 

 

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  • 4 weeks later...

I am still plodding on with this book. I have covered the Caldwells and Messiers, and now I am working on the supplementary objects (variables, carbons and some more planetaries and clusters). I am enjoying the filler material more than the Caldwells and Messiers for some reason. They seem to be a bit more peculiar and unfamiliar. But I wonder, how many long-period pulsating variables is too many? I do like them for their disappearing act. 

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  • 1 month later...

Here are some sample pages from the book (I stress, it is still being edited and may contain typographical and astrographical inexactitudes). First up is the overview of DSOs by constellation (can you spot the glaring error on the page?):

dsos_first_edit_constellation.thumb.png.bae65b74ff852728acedd595cb9937d1.png

These are the overview pages:

dsos_first_edit_overviews.thumb.png.e42d500cc3d79618f4fbca63c68d58ca.png

And the detail pages:

dsos_first_edit_details.thumb.png.ffc97ce0edc6a790f7e028d200fb45e5.png

Finally I also include some Bortle estimator charts:

dsos_first_edit_bortle.thumb.png.49825581aca2468b416069c2934cca62.png

I don't include charts for Bortle 1 because Bortle 1 is just a myth, there's no such thing. 😀 Seriously, if an astronomer is in Bortle 1, they feel it in their bones.

I have a few things to take care of: some stars are classified as variables when they could be better categorized as carbon stars, I need to add a page describing the convoluted spectral types for carbon stars; maybe I need to indicate objects with more informative symbols (eg cluster/galaxy/variable/carbon/planetary/diffuse nebula); directions to objects are done by algorithm but I need to review these and write better ones for the more difficult cases; I also need to work on the introduction. But these are all small things.

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19 minutes ago, Ags said:

Here are some sample pages from the book (I stress, it is still being edited and may contain typographical and astrographical inexactitudes). First up is the overview of DSOs by constellation (can you spot the glaring error on the page?):

dsos_first_edit_constellation.thumb.png.bae65b74ff852728acedd595cb9937d1.png

These are the overview pages:

dsos_first_edit_overviews.thumb.png.e42d500cc3d79618f4fbca63c68d58ca.png

And the detail pages:

dsos_first_edit_details.thumb.png.ffc97ce0edc6a790f7e028d200fb45e5.png

Finally I also include some Bortle estimator charts:

dsos_first_edit_bortle.thumb.png.49825581aca2468b416069c2934cca62.png

I don't include charts for Bortle 1 because Bortle 1 is just a myth, there's no such thing. 😀 Seriously, if an astronomer is in Bortle 1, they feel it in their bones.

I have a few things to take care of: some stars are classified as variables when they could be better categorized as carbon stars, I need to add a page describing the convoluted spectral types for carbon stars; maybe I need to indicate objects with more informative symbols (eg cluster/galaxy/variable/carbon/planetary/diffuse nebula); directions to objects are done by algorithm but I need to review these and write better ones for the more difficult cases; I also need to work on the introduction. But these are all small things.

Great stuff! I look forward to browsing double deep sky objects (DDSOs?) by constellation! 😂

Seriously though I love the Bortle charts. This will help significantly when going from my current location to somewhere with less hideous LP. 

 

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  • 1 month later...

Looking at ways to indicate other objects in the finder charts without crowding them too much. My latest attempt is to use index numbers with a key at the bottom of the page.

ycvn.png.6392b5d96193b12af7d85d0e54b85788.png

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Agnes,

Another superb project!

I really like the Bortle charts. They give a far more realistic idea of what the sky looks like from a particular location. They will also give some illustrative ideas for those engaged in the Light Pollution campaign.

One question- would an acetate Telrad/ Rigel type overlay be a possible for the book or are the illustrations to differing scales?

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The diagrams are to different scales, but in any case I don't have access to the level of bespoke publishing needed for cutouts and overlays.

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Label positioning was highlighted as an area for improvement in the edit. I have been working the past couple of days to refine label positions. Rather than some fancy coding to automatically move labels to free areas, I am simply going through all the labels and shifting them to one of 12 standard positions manually - I think I will get better results this way, without the headaches of fighting a label-placing algorithm.

Before:

image.png.3a24895e2bbf8be388ad06643375e3e7.png

After:

image.png.229a5152b0aedec5c7a9d92ede28b644.png

 

Edited by Ags
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Getting close to the end now - wrote the acknowledgements section, and created an icon for the "related objects" paragraph.

Final edit tomorrow, and then some work on the website and I can share the PDF.

image.png.b936e0896e402cff779b7c9b9f1397d0.png

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