Ganymede, Io and the big one - 16/03/2014

[Barv]

I managed to get this this evening under good seeing conditions. Pushing the F ratio a bit I feel for the ZWO camera but it's the first reasonable image after experimenting with this f ratio for some time. It certainly shows Ganymede's detail well which is something.

Comments always welcome.

Thanks Harvey

[U Cyg]

Very nice Harvey!  Clouded out here.

Angie

[JamesF]

 Looks very nice.  I'd agree that f/38 is going a bit overboard, but sometimes that's the way it works out...

James

[SnakeyJ]

No shortage of detail there, despite pushing almost twice the optimal focal length for this sensor.   I've been struggling to get anything decent at F25!    The detail and colour on Io and Ganymede is very nice and they seem to respond quite well to the extra f/l.

The seeing was really nice down here last night, sadly tonight's not looking favourable, though Tuesday may hold some promise according to the Met and Unisys.

[Barv]

 Looks very nice.  I'd agree that f/38 is going a bit overboard, but sometimes that's the way it works out...

James

Thanks James, I am guessing the focal length as it was a barlow with a few extensions. I usually image at F25 and it was a lot bigger than that! I would guess around F35.

Regards

Harvey

[sologuitarist61]

That is a fine image and detail is brilliant!

[JamesF]

Thanks James, I am guessing the focal length as it was a barlow with a few extensions. I usually image at F25 and it was a lot bigger than that! I would guess around F35.

For Jupiter in its current position, if you multiply the number of pixels across the equator of the planet in the original image from the camera by 19.34 then you should get the effective focal length.  The numbers change as Jupiter moves closer or further away and for cameras with different size pixels, but I think that should work for your camera at the moment.

Getting the genuine f/ratio or focal length with an SCT (or Mak) is always a bit of a pain because it changes depending on where the focal plane is and no-one (that I'm aware of) actually tells you where the focal plane is when they quote the focal length.  My experience is that with a camera straight on the visual back, the focal length is shorter than that quoted.

James