niallk

Great report @Captain Magenta! Those boots look the biz alright 👍 Nice one on the Pup - I've never had any success seeing it! One of these days I might take the plunge on a Hb and try for the HH, but I rarely see the Flame well - those really transparent nights are few and far between- but oh what a difference they do make when they do come along! Great read, -Niall

Fantastic image! Frame that on your wall 😉 One of my most memorable views from the 'gold tier' dark sky reserve in Ballinskellig, Kerry - swigging from a can of beer at 4am. The clouds cleared and wow: Andromeda naked eye was HUGE. Awe inspiring.

I bought a plossl set from Telescope Service when I got my 250px, and it included a 15mm 'super wide' EP (70° afov) which was a favourite. However: I eventually took the plunge on a TV N13T6- wow! Way better to view through, and was gobsmacked to see colour in the Orion nebula with this EP: grey always in the cheaper EPs. That EP set cost half the single 13mm, but the TV 13mm was by far way better value, and I got 2 more TV eps for that scope in due course. I didn't buy any other EPs for the 250px, so can only comment on cheap vs TV, with the TV being highly recommended. From what I read, there are "mid range cost" EPs available now which perform very well compared to TV, so several excellent value options out there nowadays for an f4.7 scope. Others will be able to talk more authoratively than me! My main recommendation is not to waste money on cheap sets. Buy good quality, and buy once 😉

I can't answer your question directly - but I did compare a 10" SW 250px vs a 15" Classic Obsession on Jupiter. It was a good night for seeing, but not excellent. The 250px held up pretty well vs the Obsession that night, as I remember. I think I binoviewed with the 250px, and mono with the Obsession. That said, the 15" has simply given me my best ever views of Jupiter, Saturn, Mars etc on nights of unusually good seeing (and of course, it's way better on DSOs, which is what I got it for). Better than I saw with years observing with my 250px. The question of whether going up in aperture is worth it would be an easier one for me to reply to! 😉 I think I was fortunate with my 250px in that it was a good example (in my limited experience!). I've only bought one so I can't comment on chances of good or bad. For planets the 250px has an advantage: cool down time, which is very important. 45mins for the 10" vs 2-3 hrs for the 15" (it has a 2" thick mirror). From what I've read on forums, it sounds like the secondary mirror can often be worth upgrading in 'mass produced' scopes - and much cheaper to do too! One can get pretty good primaries it would seem from what I read. Of course one reads of poor examples. When paying for a 'premium' mirror one pays to avoid that risk of a poor figure / poor polish (hopefully!!). The Obsession moves beautifully leading to a very different experience at the EP. The mechanics and well thought out no fuss ease of use makes a big difference, as @Louis D says. But the 250px was the best money I spent on astronomy- no question. You could spend as much on an EP as on a 250px. There are certainly higher spec scopes than an Obsession - and one can easily double the price for similar aperture! There seems to be no end to the 'upgrade' possibilities in this hobby like @johninderby mentions 😂

Nice report @Captain Magenta! I'm actually in Dublin at the moment, so missed the sorm / power outages!! One thing I noticed last night was just how bad the light pollution is in Dublin - no seeing Orion's Sword naked eye for sure. Nice to get to scratch that itch: Was hoping to get out over the Xmas hols, but it seemed like constant cloud cover 🙄

Pretty cool to be able to produce that from photos!!

I've often thought of getting one to act as a baseline comparison for my Astro Systems barlowed laser - and my quickie method in the dark. I've read some exceptionally detailed and authoritive threads from Jason and Vic over on CN. Expensive though.... but probably well worth it.

Congrats - would be interested to hear how you get on with the autocol, and how you find it in the dark. I've flirted with the idea of getting one many times! I use a barlowed laser.

Nice one. I think Jim Al-Khalilli makes great documentaries, and is a really engaging presenter! 👍

I remember being swept up in the first space shuttle landing in 1981 - I was 5. I also had two kids' space cartoony picture books: one on the viking landers and one on planets which I'm sure speculated about dinosaurs living on Venus! 😂 This also mentioned Pioneer and Voyager which captured my imagination. I did get taken by my Dad to see Halley's comet at Dunsink Observatory in '86... it was an underwhelming experience! I remember the Giotto mission, and the reports on the Voyagers as each gas giant was encountered. Then I fell out of a pub drunk aged 32 and saw an amazing super dark sky in Allihies: wow. I found the 'Pocket Universe' App for my Apple iPod Touch in 2008, and shortly afterwards found Stargazers Lounge... and read about these 'dob' things, and just had to try one - got my first telescope in about 2011!! 😂

My understanding is that RMS is computed from a grid of sampling points across the optic: I can't remember exactly, but I believe in OMI's test setup for example, 300 points or so are recorded, and they tested at 523nm. That's a good sample size for computing a 1-sigma estimate... the reported RMS number. However, it doesn't necessarily capture smoothness, due to the finite sampling grid. As you mention, it's comparing the shape at the sample points versus the theoretical. I'm not an expert and open to correction, but a test that is 'continuous' can show poor surface ripple eg knife edge, or also integrating scattered light.

For me, it's my 17-10-6 Ethos. The 10E is my most commonly used EP - just a beaut giving 200x in my 15" with a Paracorr 2 in place. The 17E is great as a starting point on a target - or for larger targets. Great for 'standing back' and seeing a glob or DSO in situ in a star field. The 6E is great for planetary nebs, and planets ~330x. I've a N31T5 for greater tfov, and an 8E between the 10E and 6E. It does get use, but it's a luxury tbh. I've a 2xPM for planetary nebs and nights of exceptional seeing. Rarely gets used!! 😂 If I had to give them up, I'd drop the 2xPM, then controversially the N31T5 and lastly the 8E. Subjective based on the targets I tend to chase! All the EPs I see as lifetime investments.

You could go into business... Maybe FLO would stock them? 😂

Totally agree 👍 I drive for 10 mins to a spot on the coast where a river meets the sea in a bay sheltered by a peninsula. There's a marsh, and you get the sounds of the birds throughout the night, as well as the waves lapping on the beach. Good for the soul 😉 A couple of times I've watched the arrival of dawn - magical to watch the colours spread across the sky, and the birds greeting it in the marsh.

Hi, I too have the Interstellarum Deep Sky Atlas, and did pick up a copy of the Deep Sky Guide companion. I do really like the combo, though some sketches are done with greater aperture than what I have (15"). I use the two together, and also Google sketches in a 16" too when planning a session, or reviewing after I've found a new target. The 2 book combo are great with Google for extra info. Best regards, -Niall

What I'd give to see a gravitationally lensed object!

The skies can be very variable where I am - perhaps moisture content in the atmosphere (?). When I go to the coast to be as far from light domes as I can get, there has only been 1 night I can remember when the Flame neb was in-your-face very detailed. A real treat! I had one outstandingly magnificent night on the Omega neb - wow the detail. And one really extra special night on the Orion neb where it was even way more detailed than usual offering a curiously 'scooped out' 3D appearance, and tinges of pink - I always see green. So I think transparency and reflection of light pollution is a big and variable factor for me locally. Some nights it can be moonless, no jetstream, etc - but still not as rewarding as you'd hope. I do always strive to allow the mirror cool for a few hrs for DSOs.

That's a very interestingly mounted 18" club scope, John. In terms of aperture fever, mine was cured when I watched a 20" Obsession Classic being wrestled out of the back of an estate car at a star party. The ramps slipped and it dropped 2.5 feet or so to a gravel drive 😳 thankfully no damage! I did get to see M13 through it... up a ladder in the dark 😬 After that I have realised that 15" suits me Yeah, a lighter mirror box and a thinner mirror made by Zambuto would always be nice 😀 I'm very curious to look through something like a SW120ED - I've literally never looked through a frac! (aside from a finder, or a Ha solar). But a run of great weather is the real dream - I read of super seeing conditions in the likes of Florida over on CN 😜 The other dream would be using a scope in the dark outback in Oz on southern sky DSOs... droooooooool 🤣

A great advertisement for dobs 🙃 Hope the lens caps are on... 🔥 Would love a look through it of course 😉

I don't hate Bortle - just frickin 'security' lights 😂

I pushed the boat out to get my Obsession 15" Classic. It was the scope I lusted over for a long time. What I really long for now is the chance to regularly use my scope in excellent seeing, with really dark, transparent skies 😃 I'd also love a large aperture double stacked Lunt 😉

Corner of the master bedroom? This is where mine lives 😂

Nice report John! I haven't observed Uranus this year, but was thrilled to also catch 4 moons before during a run of good seeing and dark transparent nights before (15", ~330x). Seeing Uranus as sharply defined disk was also fantastic- albeit featureless to my eyes. Any hint of a lighter polar region??

+2 for the Lacerta upgrade. I got this for my 250px, and it was wonderful. I have a Moonlight on my Lunt and a beautiful Feathertouch on my 15". While they are both far superior to the stock SW focuser, I have to say that on my 250px, the Lacerta mod made it a pleasure to focus, and together with the stock focuser, was perfectly functional and usable. I spent the money I saved on other accessories!! 😉

+1 I saw the Cassini division for the 1st time in my 10" dob with my Maxbrights and cheap plossls. Also great on Jupiter, Mars, and the Moon. I think that apparition coincided with the rings tilting and opening more - could see it mono afterwards too - always easier to see things again after you've seen them once! But the gain from using two eyes was really noticeable. They don't reach focus in my 15"... must see if I can try a different GPC.