HorseHead in Ha only 4x 480s

[Daniel]

HI All, just thought i'd post this, I took this last night, unfortunately it's only 4x 480s, this was because soon after heading indoors, the mount went into meridian flip for over an hour, i should have noticed it would be happening soon when I saw the scope was almost at 90 degrees. A real shame because, im actually very suprised with what I got for my measily 4 subs. I'd done some colour subs earlier and admitedly i knew they'd be washed out by the moon, but they also lacked the definition I got in the Ha. So next time i've got a chance Im definitely going to do some long exposure Ha on this again, coupled with some decent colour, I think it could look pretty nice,

Anyway, it's not much since it was only 4 subs, but I can definitely see the potential once I get a good night on it.

oh, one other thing, I've left it in red since it's almost that colour anyway, and you'll notice alnitak has some diffraction spikes on it, this is because all 4 subs were taken through a dewed up lens too.

[JohnP]

Hi Daniel, That's pretty good for such short data - definitely worth a revisit... John

[Fay]

That is very promising, Daniel. I see you have those black bits again. Did you find ouit what they are.

I don't know if you know what this is. I get a black dot in the middle of the larger stars when using the Canon. Anyone else know why this could be?

Fay

[Daniel]

The black dots are as Chris mentioned on my M45 image, There the product of dark frame subtraction. I realise why im getting them now too, I only get them on images where I've started taking dark frames when the sun comes up, therefore the temperature has gone up and my darks now have more noise than the original subs, making it subtract where it's not needed.

Think i'll go buy that thermometer today so I can start building that library of darks.

The problem your mentioning with stars sounds like the camera is clipping off bright values, I know some video camera's do this if you point them towards the sun, but it's strange if it's happenning to a dslr and on something much duller.

[Rocket Pooch]

do a sigma combine the temperature will not matter then

[Daniel]

I'll have to try that, although Im prepaired tonight, I have thermometers out with the scope to record the temperatures, im going to make a start on my darks library. Hoping to get onto horsehead again tonight, going to try both colour and Ha