ASTAP & HNSKY forum

Jay,

PPMXL is included in version 4.0.0 RC3.

Clear skies, Han

After HNSKY 4.0.0 is stable in a few weeks I will have a look.

The Gaia catalog will have one billion ( 1000 million) stars and will be the first deep going catalog not extracted from the DSS (like USNO 1B) so completely clean of false detection's.

Hunting trans-neptunian objects must be a challenging hobby. The sky here is here too often cloudy, so for the moment I still enjoy imaging deepsky object rather then hunting minor planets.

I don't know anything about Gaia dr2, just from what you post. Doesn't look like they will support stars fainter than Mag 17.

The great thing with NOMAD, for me, is it goes down to like Mag 21 which I sometimes need the magnitudes from 17-21 for transneptunian objects like Eris, Sedna and Lempo to name a few. I don't use the automated software like astrometrica, that find the object for you against a back plate.

I like to trawl (look) against the HNSKY fov for that target, compare with my 'photo' and hunt down the target. It can take allot of time, especially if its faint, but in this age where everything is instant, I like it. Its part of the whole fun of astronomy for me ... I use the automated telescope to find, take the pix but I will hunt the object down myself among all the background stellar noise.

It is this reason, a good catalogue with access to faint magnitudes is essential.

Hi Han,

PPMXL is a catalogue of positions, proper motions, 2MASS- and optical photometry of 900 million stars and galaxies, aiming to be complete down to about V=20 full-sky. It is the result of a re-reduction of USNO-B1 together with 2MASS.

I like the NOMAD system, and use this with HNSKY, but would like the option of being able to choose PPMXL with HNSKY.

Don't want to be picky here. It seems that allot of other astro software's are now adding PPMXL to the catalogues they support. I have been told its more accurate, but in all honesty NOMAD is still pretty good. PPMXL just gives another string to the bow, so to speak.

If you could, perhaps add it to the current ones we have. For things like variable stars, and those who perform more detailed close-up work, it will come in handy.

That is possible. I don't want to add too many catalogs. Gaia second edition will probably replace all those catalogs very soon. It the PPMXL much better then Nomad? Nomad has at least the brighter stars from Tycho. If PPMXL is better, I like to drop the Nomad but we could also wait for Gaia. Do you have a good purpose for the PPMXL?

My guideline:
http://www.astrometrica.at/default.html?/catalogs.html

Gaia dr2 wll be released in april 2018 making all previous catalogs catalogs obsolete.
https://www.cosmos.esa.int/web/gaia/release

Hello Han,

Would it be possible to implement the PPMXL star catalog into the HNSKY software? it could be accessed online, like with the NOMAD catalogue.
The PPMXL is more accurate, and upto date.

Info on it http://dc.zah.uni-heidelberg.de/ppmxl/q/cone/info and perhaps VizieR could help http://vizier.u-strasbg.fr/viz-bin/Vizi ... e=%20PPMXL

Your doing a great job.