NGC 5128 between the clouds.

[tilbrook@rbe.ne (Justin Tilbrook)]

Well, the wet and cloudy weather has set in, and it took two hours to get 30 minutes of data last night. I'm pretty happy with the way this image of ngc 5128 has come up with limited data.

Hope to add to this once the sky clears.

Telescope 8” f/4 astrograph on a HEQ Pro 5 mount, orion mini guider.
Unmodded Canon 1100D at ISO 800.
6 x 300 sec subs ISO 800,
24 dark frames, 16 flat frames and 11 bias.
Stacked in DSS and post process in Phototshop.
Cheers,

Justin.

[strongmanmike (Michael)]

Hey for the amount of data that looks pretty alright Justin

Mike

[RickS (Rick)]

A great result considering the circumstances!

[jjjnettie (Jeanette)]

Very nice for the amount of data.

[TrevorW]

Justin why so many flats etc the rule of thumb should be about equal number based on lights as far as I'm aware

as a guide to DSLR imaging I used to follow most of this

http://www.saratogaskies.com/article...ook/index.html

Quiet a good image for 30 minutes of data

[RickS (Rick)]

Originally Posted by TrevorW

Justin why so many flats etc the rule of thumb should be about equal number based on lights as far as I'm aware

Flat frames, like all images, contain noise. The more you take the less noise you will be adding to your image from the master flat. There are diminishing returns, of course. I have seen recommendations anywhere from 10 to 100 flats. I like to take 25 or so...

Cheers,
Rick.

[TrevorW]

I was referring to the fact that only 6 lights where taken and I'd suspect that many darks, flats etc may have been overkill. With the QHY8 I don't use darks and flats you only need a few

[RickS (Rick)]

If it's a throw away image (or perhaps if you have a very low noise sensor) that's fair enough. If not, then it's not much harder to take 25 flats than 5 with most image capture software.

Cheers,
Rick.

[tilbrook@rbe.ne (Justin Tilbrook)]

Thanks everyone for the comments!

Originally Posted by TrevorW

Justin why so many flats etc the rule of thumb should be about equal number based on lights as far as I'm aware

as a guide to DSLR imaging I used to follow most of this

http://www.saratogaskies.com/article...ook/index.html

Quiet a good image for 30 minutes of data

Hi Trevor,

Rick has basically answered your question, so far using more flat frames seems to help.

Cheers,

Justin.

[tilbrook@rbe.ne (Justin Tilbrook)]

Hi,

I've done a bit more processing on NGC5128, and there was a little more to come out.

Cheers,

Justin.