Captain Scarlet

All other things being equal, esp Reynolds number, air drag increases in proportion to the velocity squared. Since power = force x velocity, power required therefore increases in proportion to velocity cubed. The cube root of 6 is 1.82 so that seemingly modest increase in speed for a 6x increase in power is more or less as expected

Yes like tonight. Arranged a get-together with neighbours. Pristine sky 😖. Was actually a nice evening though.

I don't believe this is true. The focus knob can be safely removed if the baffle-tube O-ring is in place (yellow added later). The baffle tubes and the primary mirror (which sits on the outer baffle tube) are supported and held in place by the three bolts whose heads appear on the back of the rear cell of the OTA, and are locked in place by the three smaller bolts also at the rear end of the tube. Undoing those three big ones is what will cause the primary to crash around inside the tube. See my link here for pictures (and lots and lots of words! sorry!) of how my skymax 180 works inside: the skymax 127 will be similar although the metal tube itself is attached in a slightly different way (127 tube threads on to the rear cell). Cheers, Magnus Edit: on thinking more about this, I see what you mean. You mean that the outer baffle tube )with the primary mirror on it) can slide down and off the inner baffle tube without the focus knob on the threaded rod to retain it. There should be an O-ring sitting in a recessed trench on the outer baffle tube preventing this. If that O-ring is missing, and it's likely rubber and may have perished, then yes you are right. So I agree, best keep the scope horizontal or corrector-plate up when removing the focus knob from the threaded rod. And beware the evil black grease that coats the rod!

I spent the early part of the evening with my Kowa 88mm spotting scope on M2 mount looking at a huge long-out-of-control gorse fire about 7-8 miles away. Lots of fire engines and at least 5 different sub fires. That’ll be in our news tomorrow. I hope nobody lost a home or was hurt. I decided to put my Intes M603 on instead for a 6” and higher mag (but uncooled at first) view and discovered the little mount was quite happy with it. DeLite 18.2 for just over 100x. Then the clouds parted and I had a pristine sky for an hour or so, so I quickly took on M51, M81/2, trapezium A-E, and, most pleasingly of all, sigma Orionis and the fourth star quite plain in view. Also Struve 761 just nearby. I spent most of the time on this system, it was fascinating to see the scope get better and better as it cooled. To start with I couldn't even split the closer double of Struve 761, then later it was refractor-like. Clouds back in again so a very quick but nice session. Magnus

Ooo look an Antares reducer has just come up on the for sale section too … it’s fate! 🤣🤣 M

... seriously though. My wife has extremely sharp vision, she can see stars naked eye well beyond me. And out birding, she notices "bird action" far more sensitively than I or any other birders we've been out with. But she cannot see any colour whatsoever in Betelguese or Aldebaran, naked eye or through any sort of optics.

Is that the mythical "double blind" test? ... I always have to stop and think really hard when presented with double-negatives

Another thing you need to consider is diffraction spikes. Maybe you don’t mind them, but all the open-tube options: Mewlon, CC, RC will show them. I’d have traded up my skymax 180 for a Mewlon otherwise. M

I have to say that is possibly the most pimped-up scope I've seen in my 4-5 years on SGL. Meant in an entirely good way! Every non-standard feature is something I noticed and thought "oo good idea!". There just seems to be one fly in the ointment. That yellow-handled screwdriver. It looks as though it's magnetically attached? I hope it didn't cause an injury when it flew across the patio towards the (neodymium?) magnet ? Seriously though, I'm impressed! Magnus

I don’t know I’m afraid. I do know though that its image circle diameter is about 37mm, IIRC, from having used a DSLR to measure its true focal length. I’m not sure if that’s useful info. M

Just to add something to the mix there is a Skymax 180 in the classifieds at the moment (not mine) though at f/15+ It might not be your cup of tea Magnus

Yup similar so far at the other end of the landmass! I set up early when it was nice and clear but now the scope’s cooled properly (and still dry!) the cloud cover has come in with a vengeance. Not giving up yet, it’s all still out there.

I did. It’s simply a single layer of emergency blanket cannibalized from a first aid kit, and applied using electrical tape for easy reversibility. It does seem to allow reasonable viewing not long after getting it out though I probably shall go the whole hog and use the radiator stuff. Quick viewing report before dinner: Jupiter now too low I think for even early evening sessions: lots of CA mostly from atmos but prob some from uncooled scope. Bring on next season when it’ll be even higher! I did a quick pre-dinner tour of doubles Rigel (easy), Meissa, Castor, Alnitak all resolved but scope by no means yet steady. Briefly lovely and dark with MW on view, but all about to get washed away by Luna, which I’ll be viewing later tonight, dew permitting.

Getting the skymax 180 ready rather earlier than usual in case tonight’s forecast is correct 🙄.

I set up my skymax180 and got about 5 minutes on 7 Taurii before my vista became this, contrary to forecast. … irritated, I packed up after sitting waiting for it all to clear for 15 minutes. By the time I was past the point of no return in packing up, it suddenly cleared and not a cloud was to be seen. I’ve just taken out my Kowa grab-n-go for a consolation. Grrrr. Magnus edit: I did a quick tour at 30x with the Kowa 30w eyepiece and took in the Mintaka S, M42 and the 4 trapezium stars I must say were exquisite little jewels sitting there in the middle. Sigma Orionis system also lovely. I took in Almach, just split at 30x, couldn’t split Rigel, Cor Caroli was easy and Polaris was split too, which I was quite pleased about: 88mm and 30x. Something salvaged at least.

You should christen that feature "The Great White Shark". It looks more like a shark than Thor's Hammer looks like his hammer. Amazing quality from a hand-held! M

It’ll be unlikely there won’t be ANY light-domes from towns nearby, so try to choose a spot with a hill of some sort or wooded area between the site and the light-dome. I live in a very dark place, and luckily Lough Hyne hill sits just between me and bright Skibbereen. Magnus

On the Steeltrak, the main focuser unit can be detached from the base-attachment-plate by means of 8 small recessed grub-screws. The base-plate can then be used as a template for easily marking the tube for drilling. The nature of the base-plate, essentially two "rails", means that it will automatically be square to the outside of the tube. Certainly a laser can be used to check the squareness, but the laser itself must be properly collimated, which only the fairly expensive reliably are. Also, the unit comes with shims to fit under the "rails" if necessary to lift it up for narrower tube diameters. Extra shims can be used on one side or the other to vary the direction but I've never found this necessary, and I've fitted this focuser to 4 different newts now.

Yes I’ve done this. You just need to drill 4 new holes. If you have the metal-tube newt, which I did, the main problem is making the pilot-indents good enough that the drill-bit doesn’t skitter away when you start: the tube paint is quite hard and shiny. Magnus

I go back in the morning to pick them up off the grass! M

Very nicely written. List totally stolen, for convenience when hopefully soon, I’m next out. Magnus

I have one of those revelation focusers going spare, but it would need to be collected from Sunbury on Thames as I am not in the UK to be able to post it. I got it intending precisely to put on my own skymax 180, where it works fine just as @chiltonstar says. But then a feathertouch cpc8 came up and I now use that. Incidentally there is also one of those apparently available on ABS but they are pricey https://www.astrobuysell.com/uk/propview.php?view=181010 Magnus

Merseyside looks to me very like where I used to live (Sunbury-on-Thames, Middlesex) LP-wise. IE max darkness 19.05. I have seen M51 from there, but I needed to know I was looking in exactly the right place, and it was very high up. Just a smudge to tell you it wasn't just orange soup, but definitely there. I can't remember what I was looking through. I think it was before I got my 8" newt, so it would have had to be my Skymax127, I think. I reckon you should make a project of it. April-May it'll be very high up giving the best chance. M

Yes I’d heard those eyepieces were vulnerable to kidney-beaning 😄

Off the top of my head… Meissa the head of Orion is a favourite of mine. Cor Caroli east of the south end of Ursa Major Algieba in Leo Sigma Orionis a lovely system Castor in Gemini … and look up any of @cloudsweeper’s recent reports. A trove of unusual and worthwhile doubles. Magnus