chiltonstar

With Saturn down at murky near-horizon levels, I found I got a better image a few nights ago taking out the 1.5x Barlow I normally use*, imaging at 30 fps with my AS1224. This is therefore at about f15 (probably more like f20 because of the flip mirror and connections), the actual f ratio of the 180 Mak. With more aperture, I would have thought you would have a brighter image than I was managing? Chris * Barlowed, I could barely manage 15 fps at near max gain.

Your clouds haven't reached here yet - the view of Saturn is glorious, with a very sharp view (x240) considering it's so low down, with lots of ring detail! I too have security light nearby and of course the nearly full Moon is a nuisance, but it hardly matters for Saturn. Chris

I bought one (ZWO) very recently and found it very easy to set up and use for both visual and imaging. The refs above or the online manual from ZWO were excellent - it is much easier to use than I had imagined, and certainly appears to improve images more than just rgb stacking in Autostakkert can do. Enjoy, and hopefully some clear nights before Jupiter and Saturn slide into the dusk.... Chris

I think the key word is "video". What you see through the eyepiece has been processed by a seriously good computer (the brain) so that you see the sharp detail that may only be fleeting in reality. To capture something like what your eye and brain see requires an avi with say 3000 frames and software to pick out the best frames and stack them. Only then do you get something more like what you see in good moments through the eyepiece. Two night ago, I got a half-decent image of Saturn even at 52 degrees north, and yet individual frames looked very similar to your images above. Persevere! Chris

....we all notice how often clear nights coincide with full moon! Chris

Last night's conditions here produced a clear sky and excellent seeing for an hour even at Jupiter and Saturn's low altitude. The Moon near to Jupiter seemed almost to enhance the seeing. A transit of Io was just beginning, and the small disk could be seen just beginning to touch Jupiter, and then moving across as a clearly-defined creamy-white disk across the North Equatorial Belt for some distance. Ganymede was clear as a slightly darker clear disk, with minimal flaring around it from the seeing. Both Jupiter's main belts were beautifully defined for 20 minutes or so. I never caught the shadow transit as cloud had descended by then...... Saturn was very well defined, with the view snapping in and out almost like a NASA image for the odd second or two, with a razor sharp Cassini visible all the way round and plenty of band detail on the disk itself. Scope: 180 Mak, x190 for Jupiter, x270 for Saturn, both with ADC. Chris

Sounds like an excellent session John. Saturn has to be the most glorious sight in the heavens, even when viewed through all the atmospheric mush this year! Chris

Fantastic scope Stu, and a good one for doubles - what does it weigh? Chris

Pretty good for this near to the North Pole! Chris

Thanks. On several of the AVIs, I can just see the "eye" of the GRS starting to appear - first time this season. Chris

It was pretty good last night for both Jupiter and Saturn, wasn't it. Jupiter was razor sharp for a while around 23:45 after the haze had reduced a bit, with the GRS nicely on show, and Saturn was as sharp as I've seen it this year (x270) with Cassini beautifully defined and banding visible on the disk. Unfortunately, cloud came up here about midnight! Chris

In recent tries, I have found it is easier using an ADC . The separation is quite a bit cleaner, at least with a 180 Mak. Chris

Very interesting Geoff! It is said that there is a lot of eyepiece snobbery about, and maybe it is true. I don't have a 4mm SLV, but I do have theVixen 15mm SLV which is now my main EP for Jupiter (x190). What I can say (cpd with an SW EP of similar fl and a BST one) is that the contrast is better in the central region of the field of view, the colours more natural and unlike the BST, it doesn't have an annoying reflection which skips around as the eye moves. It does have an area of CA though around the outer field of view. I wonder though how much of the benefit with an EP like the Vixen SLV is scope-dependant? Clearly fast scopes need better EPs than very slow ones. Chris

My eastern horizon, during a spectroscopy session.... Chris

Nice to get out on these glorious summer evenings! A nice selection Nick. Chris

Very nice - amazing detail for our latitude this year! Observing visually last night (180 Mak, ADC) the amount of detail was surprising, with sharp views up to x270 (10mm Baader Ortho) with Cassini, ring on disk, and disk on ring shadows easily visible. Maybe this Saturn season won't be such a write-off for imagers and observers alike after all! Chris

After three evenings assessing my newly-acquired atmospheric dispersion corrector (ADC - ZWO) visually, I had a 30 minute slot to test it out last night with an AS1224 camera attached to the 180 Mak. This is the best of three, and still not much compared to the experts with skill+location+aperture (skill being the most important factor I suspect) all three of which I lack!! Transparency was good/excellent, seeing about the same and the elevation above the horizon about 15 degrees. The ADC has apparently made the image slightly sharper than other recent attempts over the last two weeks I've made at Jupiter (I couldn't test with and without ADC last night because of the very limited time until Jupiter crashed into a tree). Subjectively, I would say the colours were much "cleaner", more like the silvery pearl we see when Jupiter is higher above the horizon, and this has confirmed visual observations in the last few days. Chris

There are quite a few image examples on the ZWO website and references given there. I am more of a visual observer so what I see is more important to me, and of course I can't mentally RGB align the way software does on a recorded AVI, so an ADC seems the obvious choice! Chris

I normally see it (visually) at say x175 and more, certainly reasonably obvious at x190. Looking at recorded AVIs of Jupiter with and without the RGB align function in Registax or Autostakkert shows the extent of the fringing very convincingly! Chris

I was surprised (shouldn't have been) by the increase in line detail, eg Cassini and J's belts -I suppose light is bleeding up and down into detail like this. I suppose the benefit may depend on scope type and fl. Chris

After a lot of thought, I bought an atmospheric dispersion corrector - as usual FLO were prompt and efficient! Fortunately, it came with a clear night or two, so I tried it out on Jupiter and Saturn two nights ago, and compared it to the view without the ADC in place using my 180 Mak. Set-Up: easier than I thought, a quick read of the online manual, and five minutes making sure it was aligned. Jupiter (14 degrees altitude): without the ADC, strongly chromatically fringed above and below, GRS visible just, banding not that clear and slightly chromatic. With the ADC, now perfectly fringe free, the banding much better contrast (refractor like), and the moons sharper and the true diameter of Ganymede visible. The GRS looked no different (but it is of course one colour only). Saturn (9 degrees altitude): without ADC, muddy, heavily fringed above and below, Cassini just visible at the extremities. With ADC, no false colour, Cassini visible much further round than before. The view a bit fainter though (ADC absorbs some light). So far, I'm impressed - next stop an image or two! Chris

What will the weight of this one be when finished Stu? (I'm thinking of your back, and more significantly mine as I'm wondering about a large truss tube Dob) Great project!! Chris

180 Mak, AS1224 camera. 1000/4000 frames at 40 per sec in Sharpcap. Autostakkert/PShop Elements. I've not corrected the over-yellow colour balance, which is a result of blue being filtered out by all the murk along the horizon. Chris

Perhaps an arrangement with ex-colleagues living in Oz and NZ is the answer! I do wonder about an ADC though, but I hear very mixed reports (best thing since sliced bread.....worst thing since sliced bread). Chris

Another avi of the transit on 21/06/2019 of Io, shadow and GRS. Now, all I need is an ADC, some clear sky and an airline ticket for the southern hemisphere! Chris