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Martin Meredith

Pretty Deep Maps v0.3 pre-release

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As a precursor to the full release of this PDF atlas of the deep sky, I've uploaded a sample (Cassiopeia) for anyone interested in trying them out -- and ideally helping me to iron out any problems before making the whole (large!) distribution available. Main features in v0.3:


1. Complete sky coverage with over 6700 charts. 


2. Detailed hyperlinked index of more than 100,000 items, organised by object type, constellation and catalogue. For example, you can find all open clusters in CAS and sort them by angular diameter, or look for the most distant quasar, or bright stars with a high colour index, and then go straight to the relevant chart. The index can also be used standalone to find 'interesting' objects. Each chart also contains back-links to the index via object types (all sky or just the current constellation), and via catalogues (e.g., Messier, Trumpler, Barnard). e.g. you can list all Hickson groups directly from any chart, or just those Hicksons in the currently-displayed constellation.


3. Dense star regions are now displayed using a shaded map. This has a nice side-effect of showing up the presence and even the shape of dark nebulae in some detail (easier to see than describe). As before, the default deepest stellar magnitude is 18 for non-dense regions (i.e. for stars displayed individually), with a gradual reduction for dense regions down to magnitude 12. However, even in dense maps, stars in open and globular clusters are displayed as individual stars, and in most cases the limiting stellar magnitude for OCs and GCs is 20 (e.g. see NGC 129 on the chart below).


4. Finder charts are now integrated with the deep charts, and their field of view has been increased. Clicking in the finder takes you to a deep map. 


Here's an example map page and index page to show what I mean. 




index: OCNameI.pdf


A quick note on PDF viewers. Many viewers (e.g., Preview on the Mac) don't deal with links properly, and can be slow at rendering the charts. For now I recommend using Acrobat Reader (nice in full screen mode). On an iPad I've used the Documents app and it is still my favoured solution, but across-document links are not quite right (*).  


Here's a zip file (170M) which contains all the Cassiopeia charts and the open cluster indices. Just unzip, click any of the PDFs, and explore. I'll post a help file shortly.




cheers


Martin


(*) They sometimes require clicking the left-pointing arrow at the top of the screen to fully realise the link. I'm working on a solution but I'd be interested in hearing any experiences with different tablets/apps. If you are using Documents then in Settings>PDF I suggest unsetting 'highlight links' and set 'scroll pages' to 'Horizontally'. 
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Hi Martin,

Very exciting to see round three of this amazing project emerging.  A quick question - I looked at the CAS zip you provided, and the charts themselves seem to include only starts and OC (and of course as you indicated the indices you provide are for OC).  In the future do you plan to plot all DSO on the same charts or will there be separate ones for GX, PN, etc?

Thanks, and please keep up the great work on this!

Alex

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Thanks Dave. It is due to incessant rain around here that I've had time to work on this...

Cheers Alex; the charts do plot all types of object, but it's just that there are fewer of the other types of object in Cassiopeia. However, you should be able to spot 31 PNs, 112 bright neb, 140 dark neb, 9 reflection nebs and 62 galaxies not to mention one Abell galaxy cluster (and that's just the ones in the index ;-). 

Martin

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Thanks Martin. An incredible amount of detail here (like the 18.2 mag galaxy in the ASCC2 field... would have never noticed it but will look for it next time). I think these maps will cover pretty much everything visible with amateur telescopes.

Will the ~22k  galaxy index be one file?

We give the CAS maps a go tonight let you know if I have any comments.

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Thanks Martin. An incredible amount of detail here (like the 18.2 mag galaxy in the ASCC2 field... would have never noticed it but will look for it next time). I think these maps will cover pretty much everything visible with amateur telescopes.

Will the ~22k  galaxy index be one file?

We give the CAS maps a go tonight let you know if I have any comments.

Thanks. That is exactly my aim, to cover everything. Not there yet, and there are some rewarding challenges (up to mag 24) too amongst the quasars for amateur scopes.

Yes, the galaxies will be one 4Meg file(*). But with the ability to filter by constellation and to sort on various criteria it should be relatively fast to find the things you need. By the way, you shouldn't necessarily trust all the galaxies. In dense fields there are some misidentifications in the LEDA catalogue (particularly in Cygnus). There's really little I can do about this except wait for better sky surveys. The same is true for some of the dense stellar regions where there is a clear blockiness, presumably resulting from survey sampling criteria. But I think we can live with it and await some of the forthcoming sky surveys which of course I will incorporate.

Martin

(*) Actually, due to my self-imposed limitations of using PDFs, there are two actually files for each sortable column. And all information is repeated twice, once for the 'all constellations' table and the rest distributed amongst the individual constellations. But disk space is cheap and getting cheaper… and this way it is fast. I just finished all the charts and indices and it comes to just under 9G, which seems like a lot but then I'm holding a 32G USB stick in my hand and backing up to a 2Terabyte drive and thinking maybe its not so much in this day and age!

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I've now uploaded the complete set of indices, covering 100k+ objects (bright stars, doubles, variables, open and globular clusters, planetary, reflection, bright and dark nebulae, galaxies, galaxy groups and clusters, quasars/active galactic nuclei). These, I hope, will a resource in their own right for session planning and just general interest, regardless of whether you eventually use the links to the charts.

The indices are context-sensitive; for instance, if you have selected to sort galaxies on angular size and then want to change to double stars, since the latter have no angular size you will need to select one of the common columns (Objects, Dec, Mag) before you can change to double stars. Similarly, if a given constellation has no exemplars of a particular object type, you won't be allowed to select it. Otherwise the indices should be straightforward to use. Angular size is always in arc minutes. For the meanings of the other columns feel free to ask (eventually they will be documented) but the information is also available in the cited catalogue links via the CDS VizieR service and for the more specialised fields such as variable star types you will need to consult the references therein. I particularly like the comments fields in the Arp-Madore catalogue and in the PHR planetary nebulae. The last observed data for certain bright double stars is also revealing. If the indices inspire anyone to contribute new observations I will be very happy!

Indices: https://www.dropbox.com/s/36yvi82py4006iz/index.zip?dl=0(339M)

And here are three more constellation chart sets to be exploring:
Martin

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I've made up 6 bundles of constellations covering

northern circumpolar

southern circumpolar

(N) winter, spring, summer, autumn

but each one is in the range 1-1.5 Gbytes. As before, I could also provide charts for each constellation independently.

I'm happy for these to go in my dropbox but if anyone has a better solution do let me know….

Martin

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Martin, download bundles by constellation may be easier to manage/download (just a suggestion... not sure how the hyperlinks work)

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Impressive.

Took me ~45 min last night to download them all, and I've been glancing at the content. It took me a few min to realise that all the .pdf files should be in one flat directory, and everything worked as expected after doing that.

One suggestion, but I'm unsure how to implement it: When selecting an item from the index, that the item is highlighted somehow on the map that is opened up. I can get in the approximate area by using the RA/Dec coordinates, but it's hard to locate faint items sometimes!

Overall, an amazing resource, and thank you for collating this. Looking forwards to any more versions!

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Thanks! 45 mins to download the lot seems pretty fast to me! 

I will look into your suggestion of homing in on the object. I'm not sure if it is possible the way I've implemented things. For chart composition I'm using Latex and hyperref and I'm just not sure if I can specify a coordinate as the target of the reference. The limitations of pdf as an output format… For the moment I just quickly memorise the RA/Dec and jump in, zoom and search. I quite enjoy the process of discovery and often get side-tracked by other interesting stuff.

Martin 

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