RobertI

Excellent, thanks Paul, will do (I take two sugars 🙂).

It’s definitely ET for me too, especially when he’s the right way round. I laughed out loud the first time I saw it. It always surprises me how big it is, especially when compared to some of the smaller clusters in Cassiopeia. I am really hoping to get to Kelling in the Spring, even if I just go for one evening. I went a long time ago and the skies were amazing. When I looked towards Andromeda through binoculars I thought a small cloud was passing - it was M33!!

Yes I actually really enjoyed sitting at my desk with a coffee and my copy of Interstellarum and working out what to view. The process of identifying them and drawing a diagram on paper really helped me to familiarise with the clusters in that area. Interstellarum is fun to use and always provides some additional insight. I have to say though, when I am out in the field, I always seem to end up using Sky Safari (iPad version of course 😉).

Ok, so you’ve really made me think here (I should never have claimed it’s the “twenty brightest”, just “twenty of the brightest”). I’ve created a list from Sky Safari of the actual twenty brightest which can be imported into Sky Safari. Naturally it bears little resemblance to my list. 😆 Twenty Brightest OCs In Cassiopeia .skylist

…but you’re making me think I should put together an accurate list of the top twenty in Cassiopeia for others to use ….. I’ll see what I can do. 🙂

To be honest Peter I can’t definitively say it’s the brightest twenty, but I think it comprises 90% of them. Here’s a little pic I drew to help keep me ‘focussed’ on the project. Also attached is a table from Norton’s sky atlas which may not include everything on my list. May not be exactly what you’re after……

Did a bit more observing with the Hyperion 21 last night, with the C8 and F6.3 reducer/corrector. The first thing to note is that the previous time out I was using the double cluster to do the testing - I realise now this was a poor choice as the two clusters are spread out over the FOV and exaggerates any problems and not typical of most clusters I look at where the object sits in the middle of the FOV. So when I observed some other clusters tonight the effects were not so obvious, and the experience was much better. So doing some closer examination this time, I found that the stars started losing definition from about 50% out from centre, but could be focussed with a small adjustment (implying field curvature?). When getting to the extreme outer edge, lots of seagulls appeared which changed shape when focussing (astigmatism?), but only at extreme edge and not noticeable in normal use. I think I could detect barrel distortion when panning, but not a problem for normal viewing of objects. I did try swapping from my 2" SCT diagonal to a 1.25" prism diagonal and if anything the issues were slightly worse, certainly no better. I changed the eyepiece to the 102ED F7, and the results were better, with the stars losing definition from further out from the centre (about 60-70%). Forgot to check the extreme edges. Will try with an F5 scope and see what happens. So it was interesting to do these tests in more depth, and armed with a bit more knowledge from this thread, to really understand what's going on. I now have a used ES68 24mm on the way hopefully, and will do a comparison with the Hyperion.

A lovely session last night starting my quest to observe the twenty brightest clusters in Cassiopeia. It’s nice to have a little project. 🙂 More details here .

Thanks, yes I agree, it’s very instructive to concentrate on a small area - Cassiopeia is a great constellation for doing this. When I zoomed right out out to 24mm I could JUST see all three clusters in the FOV. Very nice.

I decided on a whim last week to try and observe the twenty brightest clusters in Cassiopeia, so I spent one evening doing some desk research using my various atlases and compiled a little list - it was fun and I learned a lot, something to remember for a rainy night . Last night was clear so I started on my little challenge. I concentrated on a small group of clusters in the bottom of the 'W', namely NGCs 654, 659, 663 and nearby M103. Observing was primary through the 102ED with a Hyperion Zoom. NGC663 was the most spectacular, even more so than M103. It was prominent in the 10x60 finder and easy to find. Why it's not not Messiers list is a mystery! It was large with around 20 bright members and a similar number of fainter ones. Moving on to nearby NGC654, much smaller with two bright members and number of smaller ones. Then finally NGC659, fainter than the others, looking like a small haze with hints of stars visible with averted vision. Through the C8 it was possible to resolve many of the stars and I suspect if I zoomed in even more would have been visible. Nearby M103 was a disappointment considering it's a Messier object, fairly sparse with some bright members. Four down, sixteen to go. I shall continue my quest next time out

Great report Jeremy. Nice location to observe from, a great haul of targets. 👍 I need to try out some IS bins sometime!

Yes I have wondered whether something is going on, although my 50% figure is incredibly unscientific and probably exaggerated. Pretty sure collimation is good, out of focus stars are concentric and I was getting some really good detail in Jupiter the other day. The other thing was I was using a 2” SCT diagonal, which has a longer light path and might possibly make the issue worse with the corrector. I was thinking about trying with the 1.25” visual back and prism diagonal just to see if a noticeable difference. But I did read an old observing report where I noted it was not so good with the F6 72ED I used to have, so perhaps just not so good with faster scopes. I’ll also have a go with the F7 frac and F5 newt just to see.

Thanks, that's really useful, but also slightly annoying as I was erring toward the ES68! 😄 I also like large eye lenses - that is one thing I DO like about the Hyperion. I see that the Altair version of the UFF is quite a bit cheaper than the APM - assuming they are the same eyepiece (they seem to be - I think Celestron do a version too) can you think of a reason for this?

I can use 2" eyepieces in the C8 but I understood that you get vignetting due to the limited size of the internal baffle of SCTs, but I wonder if this would happen with a 2" eyepiece of only 20mm? An interesting proposition as this would give a similar field of view to the 24mm 68 degree eyepieces, but at a slightly higher magnification.

Thanks for taking the time to explain, that's a nice simple summary. I think I probably confused myself by reading a review comparing the two eyepieces, and then trying to interpret the conclusions of that review based on insufficient knowledge (and the consumption of two beers). Sounds like you have found the ES68 to be a decent eyepiece.

Having recently posted a topic describing how I have never really been that fussed about eyepieces, I recently tried some rare wide(ish) field viewing with my C8, and when I examined the field of view, I was pretty unimpressed. I was using my F6.3 reducer/corrector and my Hyperion 21mm. Hyperions aren’t famed for their edge correction (so I believe) and the star shapes started to become very distorted about 50% of the way to edge. Not particularly pleasant for viewing large clusters and Milky Way. I swapped with my William Optics 20mm SWA 66 degree eyepieces from my binoviewers, and they were even worse! So I’m wondering, how can I get a nice flat field low power view with my C8 @F6.3? So far I have narrowed the eyepiece choices down to the UFF 24mm 65 degrees (APM and Altair do these) at around £125 and the Explore Scientific 24mm 68 degree at around £175. My understanding is the UFF gives a flat field, which means no fishbowl effect or ‘field distortion’, but does produce less than pinpoint stars towards the edge. I believe the ES gives the reverse, some fishbowling, but pinpoint stars right to the edge. So assuming my understanding about these eyepieces is correct, what do people think is a better experience - no ‘fishbowling’ or pinpoint stars to the edge? I’m inclined to say the latter, but interested in people’s experiences. Also, are there other 24mm 68 degree eyepiece, or thereabouts, which would work well in fast scopes? I can’t afford a Panoptic btw! 🙂

Nice images Chris - the achro has done pretty well there. Conditions were pretty good on Thursday - I was out doing some sketching of Jupiter so interesting to compare with your image. What’s the GRB by the way? Great Red Blob? 😉

Yes I have thought about something to reduce the glare with the 8" - perhaps I'll try a yellow filter or moon filter.....

Superb. I wonder whether you were still reasonably dark adapted after a long sleep? Never done early morning observing, must give it a go….

I also have a blue filter (Wratten 80A). I ALMOST put it in but decided against it in the end - will give it a whirl next time out.

Thanks Malcolm. Yes at certain moments of clarity the detail became overwhelming - my sketching powers (and speed) were not up to the job!

It's great that you are studying astronomy, good luck with your journey. I have a "mini-mission" in life to increase people's awareness of the universe around us and 'show' them what's up there through a telescope. Might just give people a new perspective on life and trigger them to start asking some searching questions.

Very nice! I agree about a good observing chair being a game changer. The Berlebach is a quality piece of kit. I bought a Nadira observing chair after years of standing, and have never looked back. I think the Berlebach looks more stable and more comfortable with its padded seat - something I might have to add to the Nadira. I was also worried that the spaced slots would not give enough adjustment, but turned out to be just fine in the field.

Very enjoyable session on Jupiter last night with pretty good seeing. I used two scopes and got an interesting and surprising comparison between the two. Might even post a sketch later. Full report here.

Lovely dark transparent evening, had an hour or two on my hands, so planetary or deep sky? Well the seeing looked good so I thought I’d try Jupiter with the C8 and binoviewers and was not disappointed. The seeing got better and better and at 180x I was viewing some beautiful features, brown belts, grey streamers, white ovals and the beautiful Great Red Spot (now salmon pink!). I spent a good hour sketching and I may share later if I feel brave enough. I thought I’d switch to the 102ED with BVs just to compare and, oh my, was I surprised. At around 170x the view was so much more pleasing, and the white/light areas and white ovals much easier to see. The disc was sharper, the features richer and more contrasty, the sky was darker and the moons had become tiny little discs. The only real downside was that floaters were getting in the way every now and then which is a pain. I was expecting under these decent conditions that the C8 would pull away from the 102ED but I was surprised. I finished with a little deep sky - a view of the double double cluster. For fun I thought I would compare the view through the 102ED and binoviewers at x57 with the C8 and single Hyperion eyepiece at about x60 - again I was expecting the greater light gathering of the C8 to provide much the better views but I actually preferred the view through the 102ED with BVs - the stereo viewing, dark background, and pinpoint stars made for a really immersive experience. Need to work out how I can get more out of the C8 for lowish power viewing of open clusters and star fields. Edit: Sketch added, while trying to capture the detail I got the positioning a bit wrong, but hopefully of interest.