Polaris transit time. Help please!

[Specman]

Hi guys,

Just setting up my HEQ5 and struggling a bit with finding the polaris transit time.

My SynScan handset says that Polaris will transit again in just under 3 hours time, i.e 15:30 03/04/2011 at N58 50.7 W002 55.2

HA = 21:00 which I guess means that Polaris transited 21:00 hrs ago.

This is where I get confused. I used the following website:

http://www.usno.navy.mil/USNO/astronomical-applications/data-services/mrst-world

and get the following results:

Polaris

(no name given)

Location: W 2°55'02.0", N58°50'07.0", 100m

(Longitude referred to Greenwich meridian)

Time Zone: Greenwich

Date Rise Az. Transit Alt. Set Az. Lower Alt.

(Zone) Transit

h m ° h m ° h m ° h m °

2011 Apr 03 (Sun) ***** *** 14:10 60N ***** *** 02:12 58N

2011 Apr 04 (Mon) ***** *** 14:06 60N ***** *** 02:08 58N

2011 Apr 05 (Tue) ***** *** 14:02 60N ***** *** 02:04 58N

2011 Apr 06 (Wed) ***** *** 13:58 60N ***** *** 02:00 58N

2011 Apr 07 (Thu) ***** *** 13:54 60N ***** *** 01:56 58N

Can anybody help?

Kind Regards

Mark

[malc-c]

There is a program that might help you http://home.online.no/~arnholm/org/zip/polar202.zip

Here's how to use it Polar Alignment

hope that helps

[Specman]

Thanks for that Malc, much appreciated. However I now have a conflict

My handset says that Polaris will transit at around 15:00pm and the polar finder software says around 15:15

Can anybody advise on the discrepancy? Please advise.

Many Thanks

Mark

[msinclairinork]

Hi Mark,

Remember we are now GMT+1 for BST

So that would make the descrepancy 5min's which isn't somthing to be too worried about.

HTH

Michael

[zcapp96]

I use the us navy site too, it gives the value in GMT so you need to add one hour for BST. Using this I have got very accurate results, the other night I took about 30 lots of 30s subs of M13 and the stars only moved about 10 pixels the whole time! You don't have to work it out for that night either, you can pick any date at all. I always pick one that polaris transits on the hour as it is easier to line up. And also remember that once you have done it once it will work for anypoint in the year so you don't have to do it again!