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Saturn. First time in my 4" refractor

Posted: Sat Mar 24, 2012 8:49 am
by dazcaz
Friday night we went along to one of Cardiff astro society's regular observing sessions.
It was nice, for a change, not to be stood in the freezing cold :)

My main reason for going was to see how Saturn looked through my 2nd hand 4" refractor.

First light for the night was Venus, this was mainly to align my finder scope.

Then I moved to Jupiter. Great banding, but it was a bit like looking through a swimming pool. I guess that's the price we pay for not standing in the freezing cold :)
Jupiter was very low, but it was a nice view all the same.

Various other points of interest came along until about 10PM when the ringed one raised above the tree line.

At first, it was not a great sight, but within an hour, Saturn had moved out of the fudge and was in much clearer, and by now colder air.
My 4" handled it really well. Pin sharp at 100X. Definite banding and a glimpse of the Cassini division.
The sky, wasn't great, but the moments when the image snapped into sharpness were just great.

After a while, I was asked by a visitor if I could "zoom in" a bit more, so I inserted a 2X barlow.
At 200X the image was awful, but occasionally, it came quite nice. Banding was more obvious, but there was no sharpness, no definite edges.

200X is the very edge of the scope's abilities. For a 4" I'm quite happy with this. Given the poor sky, I'm very happy with this.

Going from 100X to 200X was a perfect demonstration to show that magnification isn't everything. Even on the club's 12" newt, 200X was appalling.

I really enjoy these observing sessions.
There were six scopes out in various sizes.
One couple had their new Skywatcher 130P newt, and they were overjoyed at their first ever view of Saturn.

Another great night. Looking forward to the next one.

Posted: Sat Mar 24, 2012 10:05 am
by David Frydman
Perhaps an eyepiece giving about 150x would be best with the 4 inch refractor on planets.
The jump from 100x to 200x is usually too severe unless the Seeing is excellent or better.

Regards, David

Posted: Sat Mar 24, 2012 1:13 pm
by Kevvek
Glad you enjoyed Saturn, I too have a 4" refractor, short tube and I find that 160x is the max useable, but enough to show detail on Jupiter (cloud bands, shadow transits) and detail on Saturn too. My first view of Saturn was May 2009, and was so excited couldn't sleep the rest of the night!
I looked at Saturn last night, couldn't make out the cassini division though due to the seeing, still a great view.

clear skies!

Kev

Posted: Sat Mar 24, 2012 3:36 pm
by dazcaz
Yes 200 was was a tad too much. I am looking for 6 or 7MM eyepiece. 150X would be the ideal for this 'scope.