Registrax Questions

Post by **Airconvent** » Mon Dec 08, 2003 1:39 am

mm..I've noticed that the pics taken by weixing and euwen were bright after registrax but the raw photos are very dim. In euwen's case, I can barely make it out. Is this a requirement for the software? I normally adjust my camer's exp speed to get a bright image....will registrax turn a couple of these bright images into an overall over-exposed shot?
thanks

rich

Post by **weixing** » Mon Dec 08, 2003 2:15 am

Hi,
It is not the requirement of the RegiStax... For my case, it is the limitation of my equipment (my scope is only 5" lah)...

To get a decent size image, I need to take the image at high magnification. Also, my motor drive cannot track reliably, so I have to use a high shutter speed and use a lower ISO100 to avoid noise( I will try a higher ISO next time). As a result, the single shot image is very dim.

If you can take the image at slower shutter speed, it should be better. Also, the brightness of the image can be adjusted during processing.

Anyway, I think you need at least 20-30 images for RegiStax to stack in order to get a decent final image.

By the way, I'm still new in astrophotography, so I hope my information is correct...

dew · Post by **dew** » Tue Dec 09, 2003 6:22 pm

mm..I've noticed that the pics taken by weixing and euwen were bright after registrax but the raw photos are very dim. In euwen's case, I can barely make it out. Is this a requirement for the software? I normally adjust my camer's exp speed to get a bright image....will registrax turn a couple of these bright images into an overall over-exposed shot?
thanks

hmm i dont think its a requirement to use dimmer shots to stack, i just experimented with different shutter speeds and took the one which, to my eye, showed the most detail. but even for those dim raw photos that i used to stack, the final stacked image i got was very bright. had to reduce the brightness levels in registrax to make features appear more pleasing..
also, about using slower shutter speed, i foud that i had to use 1/2 sec for saturn to get a bright enough shot on camera. but back at the computer alot of the shots turned out blurry.. probably vibrations from me or the drive in the mount caused it.. so i think a faster shutter speed might actually be better. but this is just my results through experimentation, you might get different with other settings..

eu-wen

Grievous · Post by **Grievous** » Wed Dec 10, 2003 1:47 pm

hi all,
normally, i'll refrain from using long exposures and/or ISO settings higer than 200 on planets. This is because a longer exposure will put more noise into the frame, not to say poorer resolution due to misalignment during stacking or thru high magnification, which will also directly affect the frame. A higher ISO will result in grainer frames which we don't want in planetaries shots as it will affect the fine details.

i'll recommend exposures of 1/8 or 1/15 with ISO100 or 200. Take more shots, if possible. I usually take more than 300 shots and get like 30+ good ones. If in doubt, keep trying!

Clouds go away!!
Charlie