Sun pulls a complete 360 on it's axis.

An object doesn't just rotate 360 degree and stop in the middle of the space. Such motion is prevented by the laws of physics. Either it will keep rotating or just doesn't start to rotate at all.

You have to consider how much energy is needed to start spin an object of the mass and size of the Sun. It just doesn't happen. This is a misidentified observation. I'm 100 percent positive.

Originally posted by murfdog
I think the most logical explanation is that the camera lens has an outer lenses shield to protect it from space dust. The outer lens remains fixed while the inner lens is free to rotate and adjust independent of the outer lens. Mystery solved.

Can you name any cameras that has this outer solid cover and inner free moving lens apparatus?
Please?

Did anyone ask NASA?

Even though their answers can be less than fulfilling, it would be good to hear their input. After all they took the pictures, right?

Didn't read all the replies, if this has been posted, apologies.

Originally posted by Sly1one
...First, if the entire satellite moved how do you explain the sudden and precise STOP, with no drift?I realize it was over 12 hours time but still, as far as I know most all satellites in space tend to drift after axial rotation for a short period of time until they create their own type of tidal locking. So why does the rotation of the sun suddenly stop on a dime if it is indeed the entire craft rotating?...

The spin of the spacecraft is not due to drift, but is due to a regularly planned "spin maneuver" that is done for maintenance purposes (I used to know why they do this with the SOHO spacecraft, but I forgot).

As weedwhacker said above, this spin maneuver is achieved though thruster burns. Spacecraft are precisely-controlled objects, and have a reaction control system (RCS). This RCS are computer controlled thrusters, which can privide the proper amount of thrust and counter thrust that would allow the spacecraft to "stop on a dime" as you put it.

This could be done easily in space because of the "zero-g" environment, which means all the forces acting on the spacecraft can be more easily calculated by the RCS computers.

Originally posted by Soylent Green Is People

Originally posted by Sly1one
...First, if the entire satellite moved how do you explain the sudden and precise STOP, with no drift?I realize it was over 12 hours time but still, as far as I know most all satellites in space tend to drift after axial rotation for a short period of time until they create their own type of tidal locking. So why does the rotation of the sun suddenly stop on a dime if it is indeed the entire craft rotating?...

The spin is not due to drift, but is due to a regularly planned "spin maneuver" that is done for maintenance purposes (I used to know why they do this, but I forgot).

As weedwhacker said above, this spin maneuver is achieved though thruster burns. Spacecraft are precisely-controlled objects, and have a reaction control system (RCS). This RCS are computer controlled thrusters, which can privide the proper amount of thrust and counter thrust that would allow the spacecraft to "stop on a dime" as you put it.

This could be done easily in space because of the "zero-g" environment, which means all the forces acting on the spacecraft can be more easily calculated by the RCS computers.

Thanks for the info, Thanks to weedwhacker as well.

reply to post by NWOnoworldorder


I hope you are trying to be funny with this, Offence. Because if not I wouldn't comment on someones grammar if you cannot spell it right yourself. Offense is what you should have wrote.If you are just being funny then disregard this post.

Originally posted by tsurfer2000h
reply to post by NWOnoworldorder

 

I hope you are trying to be funny with this, Offence. Because if not I wouldn't comment on someones grammar if you cannot spell it right yourself. Offense is what you should have wrote.If you are just being funny then disregard this post.

Actually, the spelling could depend on where he lives (or grew up).

Once again, there is no lens involved here. The EVE MEGS-SAM uses a pinhole camera.

The spacecraft is rotated to calibrate the instruments. As the sun spins, one side is moving toward the craft and the other side is moving away. This causes a doppler shift in the electromagnetic radiation the spacecraft is observing. By rotating the spacecraft (a process that takes 7 hours, with 15-minute pauses every 22.5 degrees for imaging), they can observe how much of a doppler shift there is and determine the exact axis of rotation for the sun. They can then use this calibration to filter the doppler effects out of the data products.

Originally posted by nataylor
Once again, there is no lens involved here. The EVE MEGS-SAM uses a pinhole camera.

The spacecraft is rotated to calibrate the instruments. As the sun spins, one side is moving toward the craft and the other side is moving away. This causes a doppler shift in the electromagnetic radiation the spacecraft is observing. By rotating the spacecraft (a process that takes 7 hours, with 15-minute pauses every 22.5 degrees for imaging), they can observe how much of a doppler shift there is and determine the exact axis of rotation for the sun. They can then use this calibration to filter the doppler effects out of the data products.

Plain english please. And, does your expanation explain the black spot? Can't tell. thanks.

Originally posted by SunnyDee
Plain english please. And, does your expanation explain the black spot? Can't tell. thanks.

That is english. And yes, I've previously explained the black spot as a set of pixels with reduced sensitivity on the imager.

reply to post by nataylor

reply to post by SunnyDee


Thanks, often wondered what the sat. was doing during this spin operation. Knew it was something to do with camera or something. You would expect people would know all these anomalies from SOHO were some effect from the sat. and not U.F.O.s or weird stuff.
Cool!

reply to post by SunnyDee

Plain english please.

Had no difficulty understanding what nataylor wrote.

Here's a break-down. Based on that great detailed info.

Spacecraft is commanded to rotate, and each interval of rotation is 22.5 degrees. (Did the math....this means a total of 16 steps, to complete one 360-degree rotation). Yes?

Each time, the spacecraft stops for at least 15 minutes, in the new orientation, to calibrate, and take images.

So, 16 X 15 minutes = 240 minutes eaten up, (4 hours) just for the stops, during the rotation calibrations intervals.

As nataylor said, the total maneuver will last about seven hours. So, the other three hours of the total maneuver? That is the time it is actually rotating, those 22.5 degrees. Those three hours = 180 minutes. The spacecraft moves 16 times. Divide. 180 / 16 = 11.25 minutes.

This means, the spacecraft rotates those 22.5 degrees in about 11.25 minutes....gee, that's easy!! Two degrees/minute rotation speed. Think about it...very slow, steady, careful and extremely manageable...so as not to damage an expensive piece of equipment, that is out of reach for repairs.......

Putting this into another perspective...IF they wished to rotate the spacecraft at the same rate, but without the 15-minute calibration stops every 22.5 degrees....then one complete rotation wold take a total of 180 minutes, at 2 degrees/minute, right? (3 hours). THAT is how slowly it is moving. Perfectly understandable.

Now, with the mechanics of zero-g, and spacecraft maneuvering physics out of the way....the rest, I hope you got? Calibration because the Sun is not perfectly round, and "bulges" in and out as it rotates, which require adjustments, to accuratize (is that a word? Hope so...means "make more accurate", if I just made it up...) the data it receives, and sends to Earth.

My threads always create a lot of heat...

I didn't expect much out of this, but lol

This is from the SDO-EVE Science Operations Mission Log Summary


2010286-10/13 85850 16690 86240 85710 EVE_Normal_Ops HMI roll maneuver continues through 0:42
2010285-10/12 85849 15000 86239 85709 EVE_Normal_Ops HMI roll maneuver 18:00-end of day


It was a scheduled roll maneuver.

This may have been posted already, but if you look at the lower left of the sun there is a dark spot. When the sun flips, or rather the satellite flips, the dark spot remains stationary from our perspective.

reply to post by anonymousstranger


Does the person who captured the video work in the offices which deal with the uplink / downlink to said Sat.? If not I would just say the dark spot is some form of digital encoder "glitch" or phenomenon.

Ok so I'll ask again for someone to look at this. Go 5:20 into the video. Forget the dumbkoff talking, it's about the video, the black blob and what it did to the sun! Then explain what happened.