23.02.2011 Ha 太阳

[universe24]

Full disk: 38mm ERF + TOA150 + Daystar Ha + SBIG STL-4020M

Sunspot region: 150ERF + TOA150 + 1.6x extender + Daystar Ha + SKY-nyx 2-1M

[David]

The sun had become so quiet! But apparently there is some active region coming and the weather over here is improving.

I am curious how come the SBIG photos come out a bit blurry? The same also happens here:
viewtopic.php?f=15&t=765

[universe24]

I think it related to the exposure time.
The exposure time of the Ha full disk image is 0.15s.
While for visible light is 0.12s.

For solar imaging, the exposure actually should need shorter than 0.01s to freeze the moment.

Unfortunately the SBIG CCD I got has problem on the exposure time under 0.12s.
This is due to the exposure of shorter than 0.12s is controled by electronic shutter.
While exposure at 0.12s or longer controled by mechanical shutter.
I have told the problem to SBIG but there don't have solution for me.

[社長]

this is the reason I don't use SBIG for solar imaging - shortest exposure time is still too long to freeze the seeing, and not very convenient for stacking.

pixel size of ST8300M is 5.4um, better sampling rate than 4020 chip. You got a mono version ST4000, very nice....

[David]

I watched the sun yesterday and it was very boring. But just a few hours before I watched, this happened:
http://www.spaceweather.com/swpod2011/2 ... bjchql6hp6

I suppose I have had my luck a few weeks ago:
viewtopic.php?f=15&t=716#p7093