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Observed Saturn but not the Cassini division


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Last night I managed to get some great views of Saturn, I could clearly see the rings, the shadow of the rings and even some faint banding on the surface (although I'm not sure if I was imagining that!). My view occasionally went blurry, it seemed to coincide with the wind (not vibrations but more like a momentary haze), when it died down for a bit, I got the best views.

What I was really hoping to see, was the Cassini division. But alas no matter how much I looked, the ring band looked solid. Was I expecting too much or should I be able to see it with my kit (SW 150P with the SW 10mm EP and 2x barlow)?

Mark

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you could try a 3x barlow perhaps. The blurring happens a lot too. One thing to note is that if you're using the eyepiece and barlow which came with the scope, that is likely to be the issue. The 25mm one is just about OK but the 10mm one is not good at all. I had the standard SW eyepieces and changed to BSTs and it made a hell of a difference on planets.

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I think you might be in need of an exceptional night to see Cassini's with the 150P. I found it difficult in the UK with an 8 inch SCT but moving to the 10 inch made it easier. It's largely down to the stability of the air at your site.

Olly

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Wind is often correlated with poor seeing. The blurring you were seeing isn't related to haze, but to atmospheric turbulence being worse during the windy periods. You need a night with little turbulence to see the division. Keep trying and you should get it!

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Mark I was out last night with my Skywatcher 150PDS so virtually the same scope. I used my Nagler zoom 3-6mm and had a good view of Saturn at 150x and 188x. The scope is collimated spot on and the EP speaks for itself.

Well I saw the odd surface marking but only got the odd fleeting glance of the cassini division.

Keep trying and as Olly states you need a good night of steady seeing but you will be successful in the end.

Mark

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I was looking at Saturn last night and it wasn't as clear as last week even though the conditions appeared very good. I think there was some atmospheric issues (noob technical term :clouds2: )

Sent from my GT-I8150 using Tapatalk 2

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Thanks for the tips guys, I think I'll upgrade the 10mm EP and keep trying. I was thinking of getting the SW 7.5mm plossl, would this be a good choice or should I go for something more expensive? Is it even worth replacing the 10mm with a 10mm plossl and not bother with the one that came with the scope at all?

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I've seen the division with my 6SE, so it's possible... it's all about the conditions. Try as I might, I couldn't see it last night with my bigger scope :clouds2: But the banding jumped out at me almost straight away.

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I have same scope and use a BSt Explorer 5mm for Saturn. Saw the same as you last night and havent ever seen the division. Wish I had more aperture sometimes but hey, the views of the planet and rings and a few of its moons were all very lovely and satisfied me :clouds2: new scope in a few months, maybe treat myself for xmas.

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Boltzy, I was out last night trying to do the same thing, but occasionally it went fuzzy, didn't see the Cassini Division, but did see some colour in the planet itself and two moons, Titan and Rhea, very clear pinpricks of light, my first ever viewing of Rhea in four years of astronomy, great!

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It is probably the seeing conditions, collimation and ultimately the resolving power of the 150mm aperture.

I have found that even with nice eyepieces and good collimation a sharper view is always (in my experience) possible with a larger instrument. I could see the Cassini division last night, when the seeing settled for short periods but that was with a 250PX at x171.

The stock 10mm and barlow are not that bad as a combination. Certainly no worse than the cheapo Celestron Plossl that I have for outreach events. I actually prefer the combination to the 10mm on its own.

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I had the same blurring last night with Saturn. Suprising as last time the weather was clear I had a crisp image. As for cassini not sure if I could see it ir not, in my 150 SW I thought I could see it on the left side of the rings but not the right! If that makes sense. Hoping for better luck tonight.

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I could resolve the Cassini Division last night with my 10" newtonian and similar quality eyepieces to Rik's. I also had my 4" ED refractor out to compare the views and the Division was only fleetingly seen, at best, with that scope. I'd say the seeing conditions were pretty variable last night - there were periods when the Division was very hard to pick out with even the 10" then short periods with even the Crepe ring was popping into view.

You have to grab the best moments with planetary viewing which it why it's worth spending some time at the eyepiece :clouds2:

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I could resolve the Cassini Division last night with my 10" newtonian and similar quality eyepieces to Rik's. I also had my 4" ED refractor out to compare the views and the Division was only fleetingly seen, at best, with that scope. I'd say the seeing conditions were pretty variable last night - there were periods when the Division was very hard to pick out with even the 10" then short periods with even the Crepe ring was popping into view.

You have to grab the best moments with planetary viewing which it why it's worth spending some time at the eyepiece :clouds2:

Yeah, I could just get odd glimpses of Cassini with my 4" 'frac too.

It was much better about a month ago when I last managed to look.

Mind you seeing something is better than seeing nothing:hello2:

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I can clearly see the Cassini Division through my 6SE with a TAL*2 and 12mm plossil (around x250 mag) without fail tonight.

So conditions are very good tonight, no wind at all (unlike last night).

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I was absolutely amazed as a real newbie, first good night since I got my 200P Dob scope and had a good look at Venus as dark fell, then shifted to Mars (nothing to write home about there it seemed) before swinging down and east to Saturn.

I started with the supplied 25mm EP and it looked good but no sign of Cassini. I then put on a 2x Barlow and instant improvement but still no division. Next stop was to put on my BST 8mm EP and wow, I think I saw a division. Nothing ventured, nothing gained as they say so I then refitted the Barlow and the BST into that and Cassini existed tonight for me - though keeping up with the panning at that magnification needs more practice. I bet it would be even better if the collimator we ordered had arrived but hey-ho, can't have everything at once, can we!

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Cassini was a permanent feature in my 16" dob (masked to 170mm) last night; it was never not visible. I find many people expect it to be less far out on the rings than it is. Higher powers might help. They blur the general detail but seem to make Cassini more obvious.

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