Hi Ed here,

I'm creating a piece of art which based on a date in the past. ( 11th April 1609) and the moon is part of the piece.

I have been doing some on-line research and have come up with an Altitude and Azimuth readings for the moon on this date in 2009 and am wondering how accurate these readings would be for the same time in 1609.

The readings are based on my location being Lat 52.651864. Long. -7.250289

The site was www.dailymoonposition.com

If anyone could help me on this I would be really greatfull. I have a couple of projects in mind that will involve location and time specific astrnomic observations. after reading some of the form articles, I have alot to learn but am looking forward to making first step!

Hopefull

Ed

Below is data for the moon's position at 21:00 on April 11 1609 based on your decimal co-ordinates. Note that the equatorial co-ordinates are given for Epoch "now" and Epoch 2000 - I'm not sure if there would be a significant difference in the precise position of the moon back in 1609 by using current Epoch data...

Hope it helps

Dave


Object name: Moon
Equatorial: RA: 08h 08m 07s Dec: +19°22'28"(current)
Equatorial 2000: RA: 08h 30m 33s Dec: +18°07'54"
Horizon: Azim: 220°54'32" Alt: +51°09'54"
Visibility: Rise 11:01, Set 02:37
Transit time: 19:13
Phase (%): 57.25
RA rate (arcsecs/sec): 0.4269
Dec rate (arcsecs/sec): -0.0904
Ecliptic: l: 120°09'15"b: 00°12'55"r:
Moon parallax: 0.9419
Moon angular diameter: 00°30'48"
Moon distance (km): 388009.00
Moon true RA: 8.1529
Moon true Dec: 19.9062
Moon topocentric ang. diameter: 0.5199
Moon altitude w/refraction: 51.1782
Moon optical libration: l: 7.2925 b: 0.2657
Moon physical libration: l: -0.0162 b: -0.0128
Moon total libration: l: 7.2763 b: 0.2529
Moon position angle: 13.8094
Moon phase angle: 81.6587
Moon position angle of bright limb: 282.2381

Ed

If you download Stellarium. You can set your position and then set the time and date to any you wish. How precise it is in the past is not clear though.

Steve

Can we ask out of curiosity, what happened on Apr11 1609 ?

oh wait, is that when Galileo invented the astro telescope. ?

Hi.

Sorry I should have said.

Kilkenny was constituted as a City by a Royal Charter of James 1 on April 11 1609,

Ed

Hi Steve

Thanks for your suggestion

I'll have a look and get back to you on any progress

Ed

Hi Dave

Thanks for that, It will take me a while to get to gribs with all that data but I will definitely know alot more than I do at present by tyhe time I'm finished.

Really appreciate it

Ed

To OP,

Apart form Epoch,

as far as I know the calander used in 1609 in Ireland/Uk was the old Julian calandar, while Europe used had changed by that time to current Gregorian calandar. Think there was about 10 days difference in it at that time. AT a later stage UK/Ireland changed their calandar to match rest of Europe. You would need to know if the date quoted in 1609 was old vs new calandar as software today will run off new dates..

There may be a convention on how historians report dates between the time of adoption of calendars in UK and mainland Europe. Someone may be able to answer this ?

Woody

woody wrote:

To OP,

Apart form Epoch,

as far as I know the calander used in 1609 in Ireland/Uk was the old Julian calandar, while Europe used had changed by that time to current Gregorian calandar. Think there was about 10 days difference in it at that time. AT a later stage UK/Ireland changed their calandar to match rest of Europe. You would need to know if the date quoted in 1609 was old vs new calandar as software today will run off new dates..

There may be a convention on how historians report dates between the time of adoption of calendars in UK and mainland Europe. Someone may be able to answer this ?

Woody

the gregorian calender was adopted on oct 4th 1582 in catholic countries in which 10 days were dropped from the calender so october only had 21 days, some countries took it up immediately some took months or years to change. england did not adopt the calender for another 170 years.