Newbie Question

"Damian Burrin" wrote:

Just got PocketStars on the PPC and am looking through the Messier and i've
noticed an odity in thr RA.

eg M57 according to my Starmap is DEC33 & RA 18h52 accoring to PocketStars
its Dec33 & RA 18.89 how can that be right, is there a conversion need to
get this .89 into minutes?

Hope someone can help.

0.89 degrees = 53.4 minutes (0.89 x 60). As for the remaining
difference, what epoch are the two sets of coordinates using? If they
aren't the same they will be, uh, different. I would guess one is
using J2000.0 and one is using the current epoch.


Tim
--
My last .sig was rubbish too.

Hi,

Hope someone can help what is probably a very simple lack of understanding
on my part.

Just got PocketStars on the PPC and am looking through the Messier and i've
noticed an odity in thr RA.

eg M57 according to my Starmap is DEC33 & RA 18h52 accoring to PocketStars
its Dec33 & RA 18.89 how can that be right, is there a conversion need to
get this .89 into minutes?

Hope someone can help.

Cheers

Damian

--
Damian Burrin
UKRA 1159 Level 2 RSO
EARS 1115
http://www.ukrocketry.com
http://www.larf-rocketry.co.uk

email
email
email

"Damian Burrin" wrote in message
...
Hi,

Hope someone can help what is probably a very simple lack of understanding
on my part.

Just got PocketStars on the PPC and am looking through the Messier and
i've
noticed an odity in thr RA.

eg M57 according to my Starmap is DEC33 & RA 18h52 accoring to
PocketStars
its Dec33 & RA 18.89 how can that be right, is there a conversion need to
get this .89 into minutes?

Hope someone can help.

Cheers

Damian

--

Hi Damian

0.89hr x 60 = 53.4min. http://www.seds.org/messier/m/m057.html gives
M57 RA as 18hr 53.6min so it looks like either Starmap is slightly out or
they are not using J2000 coordinates.

Robin

"Damian Burrin" wrote:

Hi,

Hope someone can help what is probably a very simple lack of understanding
on my part.

Just got PocketStars on the PPC and am looking through the Messier and i've
noticed an odity in thr RA.

eg M57 according to my Starmap is DEC33 & RA 18h52 accoring to PocketStars
its Dec33 & RA 18.89 how can that be right, is there a conversion need to
get this .89 into minutes?

Hope someone can help.

60 minutes in a degree so 0.89 degrees * 60 = 53.4 minutes

Not 52 but close enough for most purposes - the ring is about 1 minute
across anyway and it depends how up to date the figures (what epoch
they are fixed to) are as precession makes it different Starry night
offers a choice of epoch - corrected for now when the RA is 18 53.75
or for 2000 when it was 18 53.585. Your starmap may be an oldish one -
but, if you don't find the ring, it's not because the figures are
wrong - they're definitely close enough.

--
Martin Frey
http://www.hadastro.org.uk
N 51 02 E 0 47

Thanks everyone.

I've since found you can tell Pocket Stars to show Hrs:min:Sec in the star
map view and there's a concersion utility in the program to.

Case of RTFM i supose ;-)

Thanks

D

--
Damian Burrin
UKRA 1159 Level 2 RSO
EARS 1115
http://www.ukrocketry.com
http://www.larf-rocketry.co.uk

email
email
email
"Martin Frey" wrote in message
...
"Damian Burrin" wrote:

Hi,

Hope someone can help what is probably a very simple lack of
understanding
on my part.

Just got PocketStars on the PPC and am looking through the Messier and
i've
noticed an odity in thr RA.

eg M57 according to my Starmap is DEC33 & RA 18h52 accoring to
PocketStars
its Dec33 & RA 18.89 how can that be right, is there a conversion need to
get this .89 into minutes?

Hope someone can help.

60 minutes in a degree so 0.89 degrees * 60 = 53.4 minutes

Not 52 but close enough for most purposes - the ring is about 1 minute
across anyway and it depends how up to date the figures (what epoch
they are fixed to) are as precession makes it different Starry night
offers a choice of epoch - corrected for now when the RA is 18 53.75
or for 2000 when it was 18 53.585. Your starmap may be an oldish one -
but, if you don't find the ring, it's not because the figures are
wrong - they're definitely close enough.

--
Martin Frey
http://www.hadastro.org.uk
N 51 02 E 0 47