Lat long question

[Marvin Jenkins]

I have had a couple of aborted sessions recently due to my neq5 mount not getting even remotely close to star targets whilst doing three star alignment. When I mean not close, I am talking a couple of constellations away.

To remove the idiot effect coupled with the obvious you dumb idiot aspect I went back to zero as many of these problems stem from simple stuff like not imputing the date American style etc.

I took the mount and OTA out in the day and set up the polar scope cross hairs on the center point of a very distant pylon. Added the OTA and aligned that to the same point and aligned the spotter scope for good measure.

Moved the mount to face north and levelled using the bubble. Waited for darkness. Identified Polaris and adjusted so it was in the cross hairs, then looked through the OTA to ensure the same and finally the spotter scope, all good.

Oriented the RA so the zero was TDC and looked at synscan app on my phone. Coordinates read 44, 14’ N 00, 58 E. I check that the read out for reticle position is northern hemisphere. 

Do polar alignment, power up synscan unit, I imput all data correctly. Start 3 star alignment. First star degrees off, second star same again, third star even farther away! Got me thinking about long lat....

I have a long long lat finder on my iPad which uses google earth. I can pinpoint a spot in my garden that I view from and the Lat is 44.2378 N Long 0.9689. W

My question is, why is there a big difference in longitude between google earth and the gps reading on my phone and is this causing the problem? Which one do I use?

If it’s the last one should it read 00’0968 ?

Any help much appreciated Marvin

[symmetal]

Both results are the same, just expressed in different units.

44.2378 N is in decimal degrees and is the same as 44 degrees 14minutes, 16 seconds N.

Likewise 0.9689 W is the same as 0 degrees, 58 minutes, 8 seconds W

Astro equipment usually use the deg, min, sec system so the synscan app reading is the one you want to use directly. If you want to use the Google Earth decimal reading you'll need to convert it first.

Here's an online calculator to do the conversion with an explanation.

Alan

Edited August 29, 2019 by symmetal

[Steve Clay]

Does your Ipad have a GPS chip or is it deriving position from the wifi location.

For my azgti I use synscan init app that gives all of the data in the correct format. I have it on my phone that has GPS.

Steve

[Marvin Jenkins]

Thanks both of you that has cleared up that conundrum. Thank you Alan for the online calculator.

Steve, I think the iPad is using the WiFi location, but I have the int app on my phone with gps like yours so I will go with that in the future.

Hopefully no more alignment issues. Marv

[old_eyes]

In the UK there are online resources that convert postal address into Lat/Long in both formats. That’s what I have used and it has been accurate enough for me. I would expect something similar in France,

[Vroobel]

Hi old_eyes, 

The Google Maps does it.  Simply type the address and press longer red drowing pin. I used my phone now, but PC version gives you more. 

Tomasz 

Edited August 30, 2019 by Vroobel

[jambouk]

At the end of the three star alignment, does it say alignment successful or alignment failed?

Inputting incorrect lat and long won’t cause this problem. 

James

[jambouk]

I did experiments with lay and long some years ago to prove they are in essence unimportant: