Saturn 24 April

[EricB]

Hi there!

I had a small window of decent seeing last night before the clouds rolled in.

I had a quiick go at Saturn and the Moon. Here is Saturn.

and some of the specs:

Frames captured=1000
Camera=ASI120MM Camera (ZWO Design)
ROI=352x288
FPS=71
Shutter=14.28ms
Brightness=10
Gain=43
Gamma=51
Histogramm=43%

Cheers,

Eric

[Larryp]

Nice image, Eric. Very sharp:thumbsup:

[allan gould]

Nice catch Eric. I guess you love the camera. Are you using a Barlow?
Allan

[EricB]

Thanks Laurie and Allan.

Allan, yes, I love the camera. I am using a x2.5 Powemate.

Cheers,

Eric

[U.K.Cowboy]

Nice Saturn Eric. I'm correct in thinking the 2.5x powermate is parfocal therefore an extension tube wont work?

[EricB]

Thanks Stuart. As to your question, I am not quite sure as I have never tried to add an extension tube. Others will know, not doubt.

Cheers,

Eric

[Quark]

Nice crisp image there Eric, a bit more magnification would be good, might be worth having ago at using the 1.5 or 3x drizzle in AS.

Cheers
Trevor

[Troy]

Sharp little Saturn there, good image Eric

[EricB]

Thanks Troy and Trevor.

Trevor, I agree, but the seeing conditions haven't yet allowed me to use the x5 powermate. I have tried a quick 1.5 drizzle in AS, as you have suggested, but I lose detail in the belts (see picture).

Cheers,

Eric

[Shiraz]

very nice Eric - good detail and processing.

hope you don't mind me answering Stuart: the Powermate is telecentric, so magnification does not change appreciably with an extension tube. the optimum for the ASI120 in good seeing is f19 final focal ratio.

[EricB]

Thanks Ray. i was hoping someone would answer Stuart's question.

A quick (and probably silly question). Focal ratio is easily calculated, but what about when a camera is rigged? How is the camera taken into account in the focal ratio calculation?

Cheers,

Eric

[Shiraz]

turns out to be very straightforward for any system Eric.
http://www.iceinspace.com.au/forum/showthread.php?t=105057

regards Ray

[EricB]

Thanks Ray. Very interesting stuff.

In fact I meant focal length by the way, not focal ratio. For example, in my case here, with the AI120 I am imaging at a focal length of 1200 x 2.5 (powermate) = 3000. Is that correct?

Cheers,

Eric

[Shiraz]

yep.

However, the optimum FL will vary with aperture for a given camera, so it's best to use FNo.

[EricB]

Got it. Thanks Ray.:thumbsup:

Eric

[U.K.Cowboy]

The 2.5x powermate actually reduces slightly in magnification with an extension :
http://www.televue.com/engine/TV3b_page.asp?id=53&Tab=_app

[EricB]

Thanks Stuart.

eric