Viewing the Cassini division

[Imd]

I have never seen the Cassini, and after enviously looking at some of the posts on SGL of successful viewing, I am wondering whether I need a few more eyepieces to give more magnification options. I have a SW200P F5 and a SW102ST and use either a meade 4000 5.5mm or a Hyperion 10mm and can use either with a GSO (X2 / x1.5) Barlow. TBH, I dont recall ever using the barlow as a X1.5.

I have tried a webcam with the barlow too and no luck yet, see attached.

Perhaps all I need a lot more patience waiting for astro friendly weather and a darker sky for better contrast.

Do you think further reasonable investments eg new lenses or filters, could make a big difference?

Thanks

Ian

[jambouk]

Good image, but far too much gain.

If you take some videos with your webcam, get Saturn so it is quite dark, gain maybe at 50% or less, and take a few minutes worth. Then load that *.avi file into Registax and proces it there (lots of info on the net about that). Then tweek the filters (wavelets) in Registax and hey presto, you'll hopefully have Cassini Division.

I can send you screen shots of my videos if that helps, drop me a message.

James

[DirkSteele]

The Cassini division is typically not to challenging to see, though the visibility is influenced by the orientation of the rings from our perspective which can mean at times spotting all the way around can be hard. Based on the equipment you have and the EPs you have used, the Cassini is well within reach of your scopes. I have seen it all the way round with aperture of around 100mm and magnifications of 140-150x.

From a purely visual perspective, there are possibly two factors which may be contributing to your failure to see it. The first is the collimation of your scope. If it is way off, that can have a great impact on the ability to see finer details so it would be wise to check collimation. The second is unfortunately something we cannot do much about currently, which is its location in the sky. Saturn is currently in the constellation of Virgo and is struggling to even exceed 30 degrees above the horizon as viewed from the UK. This means we are having to view it through a thicker (and typically more turbulent) slice of atmosphere than we have in previous years, and the impact of this is to blur out much of the finer detail. As with all planetary observing, patience is the key, for that sudden moment of tranquillity when a vast amount of detail can suddenly be seen, however briefly it may last.

[michael.h.f.wilkinson]

I can see the Cassini division with my 8" SCT, so your 8" Newtonian is certainly sufficient (if properly collimated). You need decent seeing, and the Meade 5.5mm should give enough magnification (although a 4mm EP will give you better results if seeing is good). Using a webcam with just a2x barlow in an F/5 scope is a bit low in terms of magnification. Many webcams have pixel sizes in the order of 5 micron in size, and F/20 is a good focal ratio to aim for.

Hope this helps

[Imd]

Thanks everybody. More patience, check collmination, check again when saturn is at its highest and reduce the gain when using webcam. It's perverse but I'm disappointed that I don't have to buy something

[Imd]

I can see the Cassini division with my 8" SCT, so your 8" Newtonian is certainly sufficient (if properly collimated). You need decent seeing, and the Meade 5.5mm should give enough magnification (although a 4mm EP will give you better results if seeing is good). Using a webcam with just a2x barlow in an F/5 scope is a bit low in terms of magnification. Many webcams have pixel sizes in the order of 5 micron in size, and F/20 is a good focal ratio to aim for.

Hope this helps

[Imd]

Michael,

Please could you explain a little more about how I can aim for f20. The webcam is an spc900?

Are you saying that I would benefit from a x4 Barlow for my f5 scope and if so do you think the 8" aperture would cope with that level of magnification?

Cheers

Ian

[umadog]

Are you saying that I would benefit from a x4 Barlow for my f5 scope and if so do you think the 8" aperture would cope with that level of magnification?

Cheers

Ian

Sure it will cope. Maybe this thread will help: http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/2630247/Main/2628536

[Imd]

Thank you Umadog, I'll give it a go

[Northern Soul man]

HI Ian and welcome to the SGL, I would set the 200p up, forget the web cam for a bit, then visually put the 10mm Hyperion in and just see if you can just observe for a while, nothing else just spend a little time just looking at Saturn - to be honest the 10mm is still a little too much due to the height of Saturn above the horizon - its really low this time and your looking through alot of dirty, murky atmosphere - but if you keep looking - your looking for very short bits of "steady seeing" when the atmosphere settles for a second or two. your looking for a "line" in the ring system - that's it just a line - but with the atmosphere bubbling and moving, you may get a brief second or two of the steadying - the line comes into view - then "disappears". The more you just "look" at Saturn - the more you pick out when the steady moments allow you to.

Judging by the web cam image - the collimation looks to be ok - you can pick out the banding on the disk -its just over exposed - I just observe visually and the main thing you need is patience mate - if Saturn was a lot higher in the sky - you would see the Cassini division with ease - this apparition of Saturn is probably the lowest in the sky I have seen her for a few years - so just be patient - trust me - get comfortable on a chair and just "look" at Saturn, as time goes by - the more you see - Titan, Rhea, Dione, Tethys and maybe Enceladus appear with moments of steady seeing (remember if the moons are very close to the disk - they will probably be invisible due to the glare of Saturn).

As the time goes by you will be able to make a mental picture of the things that you see when the atmosphere steadies - just spend 30 minutes or so when your eyes have become dark adapted just looking - believe me it gets ADDICTIVE !! Paul.

[Imd]

Thanks Paul,

I will give it some staring time at the weekend.

I see that you have a MAK and would has probably 50% longer focal length. What magnification of barlow do you use when using a webcam, if any?

Ta

Ian

[Mattscar]

Hi Ian. I too have been trying to see/capture the Cassini Division for some time now. Only on the last couple of nights have I been able to start picking it out both observing and with imagining. Like alot of things up there sometimes you have to train your eyes to pick out details at first, then it can become alot easier to 'see' what you are looking at.

I have the 130 Skywatcher and this can pick out the cassini division if seeing is good enough and is just enough to image it with an xbox webcam and barlow

Saturn 640 20fps 02_06_2013 by A Drummers Space, on Flickr

This was my 3rd attempt at imaging Saturn, so don't be disheartened by attempts that don't work. See what you can learn from it and take that experience with you next time. Your kit is more than capable of doing what your asking, so couple that with patience and pretty soon you should start getting some great results

Matt

[Northern Soul man]

Hi Ian, just look at Matt's image - the Cassini division really stands out there. I have't used the Mak for a while, sorry don't do much imaging with my set ups, I've used quite a few scopes over the years and the Mak is a very good Planetary/Luna scope for its size, but sorry I can't help with the imaging side of things but there's a load on here that can help you in the imaging section. I took an image with the 11" scope a while ago on Jupiter with an old Toucam with a x2 Barlow (Meade shorty) and stacked it using Registax but can't access my flikr account so I can't post it (not sure if you can paste an image on here or not).

Keep at it ian, you'll get there mate - youve probably seen the Casssini division and not realised it. The larger the aperture scope you have means that you can increase the mag when the sky conditions allow - but too much mag just washes the image out and then starts to degrade it - what I do is stick with a 20mm ep when i begin a session giving a lovely bright image - as my eyes get "used" to the image I begin to pick out planetary detail, moon locations and banding, then i may increase a little for a short period to enhance contrast - but remember, doing this will darken the image, then dropping power again to see if I can tease a little more detail out - last night I was looking at Saturn and trying to tease a little more detail in the polar region - but with it being so low in the sky - not the best idea!!

The more you view the more you will get used to which ep works best for you - we're all different what works for 1 may not work for another, remember though that a stacked image is an image the eye will never see - so don't expect the detail you see in the images, to be there visually. I'll see if I can find out how to post the pic so that you can see the detail. Keep at it mate and clear skies to you Paul.

Edit.

Here's the pic - but its been stacked and processed and visually, this amount of detail can't be seen only hints of this detail you can make out when the atmosphere steadies. Paul.

[Naemeth]

I've caught it on my 130P. What I have noticed is that it required two things: Good quality eyepieces (LV 7mm and TV 8mm plossl both show it, other eyepieces don't), Good seeing. Use as little magnification as you can so you can get Saturn as sharp as possible.

I saw it as an absence of light, and it's very subtle.

[Mattscar]

Naemeth makes a point I forgot about. Not much hope of seeing it in the standard SW EP's, Iv not tried with my BST's but my Celestron is a beautiful piece of kit that helps alot more than I realise.

[Donkeiller]

Saturn has been very good this week. Looked at it with my 4" refractor, 6SE and 8SE.All gave great views of the Cassini Division. The 4" could show it from as little as x80 and best at about x180. The 6SE showed improvements up to x210 and the 8SE up to x230. I use a mix of BSTs and Xcel-LXs and an Astro Engineering x2 Barlow. The Barlow is a great bit of kit. (http://www.astro-engineering.com/prod/telescope-accessories/barlow/supreme/AC710.html)- recommended!

[Matt Scunthorpe]

I always find it just pops out every now and then, really clear and crisp and then loses it again. But like above, it all depends on conditions etc, and Saturn doesnt get too high in the sky at the moment either.

[jetstream]

As I've learned from other members and now experience there is a bunch of things that will add up & spoil image detail.Collimation has to be good,seeing conditions,scope cool down,clean lenses,object height in sky,sky background brightness and dew.Last night was my first experience with dew,a little embarrassing actually,but anyway.The Cassinni was great last evening,Saturn view was the best yet,even with a very bright half moon nearby.At first the Cassinni "tips" were seen,with almost full rings later.But a lot of times I just see the ends of the rings so that is what I try to pick up first,knowing what to look for helps a lot.My little refractor (3.5") needs quite a while to cool down-obviously dependent on temp difference.This makes a HUGE difference in everything,sometimes I still get caught assuming it is ready.You know the quality of eyepieces may make a difference,but as long as there of reasonable quality,I think the Cassinni should be viewable-compared TV's against a Stellarvue branded planetary eyepiece ($100.00) vs way more & it did very well.Funny I looked at Jupiter the other night in good conditions,but with it low in sky,scope not cooled down....it looked as if my equipment was wrecked or something,it was that bad,I mean bad.Same scope cooled down,cleaned,just as darkness approaches,with Jupiter high in sky-it can see many bands,some colour,GRS and even an asteroid impact spot once.My minimum to see it easily is 105x so far & conditions have to allow for that.Keep on lookin'!!

[jetstream]

I should add minimum to see CASSINNI easliy is 105x with proper conditions.

[Bart]

Thanks everybody. More patience, check collmination, check again when saturn is at its highest and reduce the gain when using webcam. It's perverse but I'm disappointed that I don't have to buy something

Lol

[planet15]

I was watching the Saturn last night with my SW200P and new 6.5mm EP. The image was clear and largest I have seen, but there was something like air turbulence in the sky everywhere, as if seeing the air in hot summer sunny day.

Although the ring was large, well separated and clear, I could not see the Casini Division.

[John]

I found the same viewing Saturn last night with my 12" dobsonian. Normally the Cassini Division is very clearly and crisply defined with that scope but I was struggling to do more than glimpse it last night due to the seeing conditions.

[Bart]

Same here, the seeing last night was the worst I've seen in a long time! The moon looked as if it was doing a belly dance.

Barry

[Matt Scunthorpe]

I didnt set up last night, but when i was glancing at the Moon i thought there seemed to be quite a haze.

[michael.h.f.wilkinson]

I didnt set up last night, but when i was glancing at the Moon i thought there seemed to be quite a haze.

Same here. I could not be bothered to set up the scope.