solar conjunction calculation discrepancy

[Jim S.]

Why is it that, with the solar outage period almost here, the outage times calculated at Sun Outage Calculator differ by about half an hour from the sun azimuth match times calculated at SatBeams - Satellite Coverage Maps - Sat Footprint ? I even tried advancing my computer's clock to the middle of the outage period and re-running the satbeams calculations, and the difference is still about half an hour. The satellite coordinates calculated by the two sites match, so I can't figure out why there's a difference in the calculated times that the sun is at those coordinates.

 

[AcWxRadar]

Jim S.

I am not sure how SatBeams is calculating this. But, I found an even greater discrepancy for my personal location. About an hour and twenty two minutes roughly.

I used: Sun Outage Calculator and compared the results with this: Sun Transit | Telesat.com The results agreed within +/- 2 minutes. The TeleSat calculator only shows a few satellites to select from (within their own fleet) so I checked 107.3 Anik F1R on both calculators.

I'd trust the Sun Outage Calculator.

RADAR

 

[Jim S.]

Thanks for the comparison.

 

[Pixl]

Using the Sun Outage Calculator I checked my fixed dish for Hipsat 30w. My location called for 8:50am, went out and found the lnb was casting a shadow exactly centered left/right on the bottom dish edge. I presume this is correct for an offset.

 

[Pixl]

OK, did a sun survey of my dish farm today, I can easly see why I can get 30w to 137w, but not 139w. It is behind the tree line across the street.

 

[ttalex]

We will look into the formulas and figure out why the results differ so much!

Why is it that, with the solar outage period almost here, the outage times calculated at Sun Outage Calculator differ by about half an hour from the sun azimuth match times calculated at SatBeams - Satellite Coverage Maps - Sat Footprint ? I even tried advancing my computer's clock to the middle of the outage period and re-running the satbeams calculations, and the difference is still about half an hour. The satellite coordinates calculated by the two sites match, so I can't figure out why there's a difference in the calculated times that the sun is at those coordinates.

 

[AcWxRadar]

We will look into the formulas and figure out why the results differ so much!

ttalex,

Are you involved with or are you in charge of the SatBeam site? Or another? I know that I have had dialog with someone from SatBeams in the past, but it's been a while and I have forgotten who I was conversing with, I apologize if it was you and I have forgotten. Too many other things going on for me, I guess, but I would like to here from you again if you are affiliated with SatBeams. Write me a PM.

RADAR

 

[Anole]

Maybe it's as simple a matter as the local time in different time zones.

The actual week for Daylight savings time changed here in the US a few years ago.
For years, it'd been a different week, but it's been altered for no good reason.

So, anyway, our time change happened here a few weeks ago.
Listening to the Formula One race coverage, I hear it's changing this weekend in Australia, but next week in the UK.
(I might have that backwards)

 

[Tron]

During my recording of the STS-133 shuttle mission landing, I lost signal for about 15 minutes. Fortunately, the LOS occurred well after the shuttle was on the ground, so I didn't miss anything important. I wasn't attending the recording, so I didn't know about the problem until I played back the video. I checked the time when the outage occurred, and it corresponded exactly to when the sun would have caused an outage on 87W for my location. I set up a recording the next day to prove it was the solar outage, and it happened on schedule again.

 

[ttalex]

Radar,

You are absolutely correct - I run Satbeams website and we exchanged some messages quite a while ago.
I have already asked our programmers to look into the issue!

ttalex,

Are you involved with or are you in charge of the SatBeam site?

RADAR