Atlas for faint stars (V=18 and below)

[naskies]

Does anyone know where I can find an atlas for faint stars?

The star catalogues that I've been using (in Stellarium, CdC, etc) run out pretty quickly around magnitude 18. I'm interested in correlating the faint dots in my stacked images with apparent magnitudes.

Thanks!

[mithrandir]

UCAC4? CdC, C2A and Hallo Northern Sky (and probably others) support it. It's available from USNO as a double sided DVD. An email to "brenda dot hicks at navy dot mil" should get you a copy. IIRC they are on Simbad now. There are patch files to fix known errors in it but I'd have to look up where to get them.

NOMAD if you've got a few hundred GB to spare. It works with CdC and C2A (and probably others).

[PeterM]

Dave,
I have ucac4 on disc from usno. I can bring to Leyburn next month.

[Merlin66]

UCAC4 catalogue with CdC is definately the way to go!
Printing out the result :eyepop: may be a bit problematic.....

[mithrandir]

I've got a copy too. I could make copies but I've only got single sided DVDs so they would have to be two disks.

I found the fixes. Look for "modifs_py3 patches for UCAC4". The canonical site is http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/ucac but I can't get that name to work. I suspect the US have decided that all 113.* IP addresses are in Asia and are blocking them.

[naskies]

Thanks for the suggestions, gentlemen! Lots of new acronyms to learn...

From my quick bit of online research, it looks like UCAC4 bottoms out at around V=16.

Support for NOMAD in CdC looks good - there's even a thread on IIS (http://www.iceinspace.com.au/forum/showthread.php?t=94258) about it. Here's the link in case anyone else is interested:

http://www.ap-i.net/skychart/en/news/nomad

The academic papers I've found, such as this one (http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA520456), suggest that NOMAD contains stars down to V=21. The catalogue is only a 30 GB download via BitTorrent, so it's happily downloading away now :thumbsup:

Interestingly, it looks like the Pan-STARRS survey (http://pan-starrs.ifa.hawaii.edu/public/design-features/wide-field.html) can capture mag 24 stars in a single 30 sec exposure, and with integration over several years the catalogue will reach mag 29.4 :eyepop:



Thanks for the offer, Peter. It looks like UCAC4 doesn't go quite as deep as I'm looking for. I'm not sure I'll be making it out to Leyburn again before Nov/Dec - studies are becoming far too busy. If you'd like a copy of NOMAD for CdC, I'll be happy to mail one out your way ;)

[PeterM]

Thanks for the offer, Peter. It looks like UCAC4 doesn't go quite as deep as I'm looking for. I'm not sure I'll be making it out to Leyburn again before Nov/Dec - studies are becoming far too busy. If you'd like a copy of NOMAD for CdC, I'll be happy to mail one out your way ;)[/QUOTE]


Thanks Dave,
I have the NOMAD data SkyX add on.
Didn't think about the mag limit on UCAC4.

[RickS]

Is Aladin going to be of any use, Dave? You can drop a plate solved image into it and then overlay with any of a bazillion catalogs including NOMAD. I find it useful for identifying very faint little galaxies.

Cheers,
Rick.

[mithrandir]

That's only step 1. If you follow all the instructions in the CdC page you need about 200GB temp space and the final catalog is 48GB. If you use Window's folder/file compression the final catalog only needs about 28GB.

You'll probably find if you try to go to mag beyond 18 you won't be able to use a FOV beyond a degree or maybe two. CdC seems to have a limit on how many stars it can label at once. When Patrick gets the 64bit Windows compile working again (the compiler has a bug) it might be able to show more.

[naskies]

Rick, you're a genius! :thanks: This is *exactly* what I was after - I didn't expect that there would be a free tool available that would work so well. All the faint dots and smudges in my long exposures are now clickable with magnitude data. Itch, scratched :lol:



Yep, not a worry. Luckily, disk space is probably the cheapest piece of astrophotography gear :rofl:




Shouldn't be a problem... my camera only has a FOV of 40' x 30'. Anyhow, I'll probably only use CdC + NOMAD while away from a fast/cheap internet connection. Thanks!