Captain Scarlet

I’m a big fan of APM based on my small sample of their products (an 8x50 finder - really superb) and an LZOS 4” refractor (also obviously superb). So I’m not at all surprised their branded eyepieces are also really good.

An unexpected patch of clearness in the right direction, so I grabbed my Kowa 88mm spotting scope and used it first-time-ever on a celestial object. I mounted it on my Stellarvue M2 alt-Az and I think I’ve found my “grab and go” set-up. Fully waterproof too which was just as well! Anyway, back to the point, the two planets were both on view at max zoom, 60x, and remarkably clear. All 4 Jovian moons unless there was an interloping star, two main equatorial belts, Saturn’s rings very clear. And just off stage right and down (this is a correct-image scope) a huge looming crescent New Moon. Im glad to be able to say at least I have seen the conjunction-ish now, hopefully I’ll get some gaps on 20-21-22. Magnus

Skywatcher 200p gets my recommendation. It's useable for any target, not too small (aperture) for dark sites, and not too big for light-pollluted sites. I myself have one. People refer to it as a "Goldilocks" scope. The eyepieces (lenses) that are supplied with it aren't very good but that's no different from almost any new scope, even some very expensive ones. It is likely to come with a 25mm and 10mm eyepiece. The 25mm is not too bad, the 10mm is poor. It would be worth improving those by getting BST Starguider eyepieces at similar focal lengths, at a modest extra cost but huge optical improvement. Good luck, Magnus

As a fairly recent newbie myself I can totally relate to your enthusiasm and relive the experiences. And the scope you have is very capable. I only recently used the same scope to see the Veil for the very first time, by all accounts a rather difficult target! But I was (am) at a dark site, in Ireland as it happens. Whereabouts in Ireland are you? I’m near Baltimore West Cork. If you say you’re 20 minutes from bortle 3 ... that’s a total luxury for most of Europe and UK! cheers, Magnus

No, no damage at all, just the figure changing in response to different cooling rates in different parts of the mirror. I was lucky to be able to observe two extremes on consecutive nights, first terrible, thinking I’d been supplied a dud; then with previous night still fresh-in-memory, a beautiful experience indicating a near-perfect mirror. Just another thing to add to the list of unlikely things that need to be “just right” all together to be able to take full advantage of a good mirror: good seeing, good transparency and now as I’ve discovered, stable temperature.

I believe @GavStar has a serious contender in this category ... ?

I’ve toyed with the idea of a cooling fan but don’t have one yet. The mirror was cooling naturally but I’d say the temperature had dropped from around 4-5 degs C to about -2 in the space of an hour. I’d heard of the cooling effect on mirrors by reading some of Mike Lockwood’s writings. M

That is actually a feature not a bug. That rubber ring allows you independently to focus the eyepiece onto the reticule, then adjust the focus of the objective until the stars are sharp. That way the stars and the reticule are at focus in the same focal plane. If the stars are sharp and the reticule fuzzy, they are in different focal planes and you’ll get parallax, ie the cross-hair point moves around the star-field as you move your eye. I have an APM finder/ eyepiece and it’s very good. The SW-style ones that come with many scopes don’t easily allow one to make those adjustments. Cheers Magnus

Well. Out again tonight and as forecast, the early part of the evening has been lovely and clear. Filled with anxiety, that after my Star Test of the scope last night I'd paid big money for a dog from OO, imagine my relief when tonight the scope delivered a text-book and identical inside- and outside-focus star test. Thanks be to. Last night was, incidentally, First Light for the outside 3/4 inch of this new mirror. The inside part of the mirror got its FL a few weeks ago when I just plonked it into the SW cell replacing the extant mirror without regard to the different focal length, which required some surgery to the tube to place the secondary further away. Unfortunately, as forecast, early cloud has now rolled in so the heavens are teasing me! "Yes you have a good mirror, we'll just about allow you enough time to discover that, but sorry no you can't play tonight." Anyway, I'm pretty relieved. I've learned something fascinating though: a rapidly-cooling mirror, losing heat from its periphery well before its middle, thereby changes its shape and becomes "over-corrected": thinner at the edges than it should be, but still fat in the middle. I saw this first hand last night with that appalling star test. Temperature tonight was stable, and no dew (frightened away by my hair dryer close at hand no doubt). Cheers, Magnus

Yes very good. Over here in the West of Ireland there are similarly dark skies to protect. Much of Kerry somehow has managed to make a Dark Sky reserve of itself, and now that I find myself with some time to spare I'll have to see how West Cork can be persuaded to do the same. Magnus

I had a disappointing night last night for by no means uncommon reasons. The night promised and in fact was beautifully clear. Beehive was naked eye even through Skibbereen’s light glow. The first problem was dew, and the second rapid temperature change. I’d brought my 12” newt out a couple of hours early from a 15-degree garage. When I got to it to observe, dew was already on the secondary and the paracorr. About an hour into the session to add insult, all the dew was frozen. I tried to persevere anyway but the stars too were terrible. I think the seeing was OK actually, but the rapidly still-cooling mirror may well have been changing shape dramatically, as it was showing signs of really terrible SA, which normally it shouldn’t considering it’s a brand new OO 1/10 mirror. M42 was amazing briefly, but only the 4 main A-D stars I’ve yet to see the E and F. oh well, tonight’s forecast clear again so I’ll get the hairdryer out this time... Magnus

I too had a disappointing night for slightly different but by no means uncommon reasons. I’ve started a separate thread rather than hijack John’s. My problems were dew, and rapid temperature change. tonight should be better though, hairdryer assisted... Magnus

Really? A 300mm f/4.0 is essentially a 75mm refractor, they don’t come much smaller than that. I’m surprised it overwhelms a star adventurer unless seriously unbalanced. I have one by the way, a lovely lens. M

I think thicker vanes won't affect the diffraction spikes, the spikes are all about the total length of edges in the light-path (including the edge of the aperture). Thicker vanes will just result in a little more total obstruction. But shiny surfaces parallel to the light-path, especially those actually inside the llght-path, my instinct tells me will result in disproportionate glare around bright objects. A reflective inside of the tube itself will also be glare-inducing-contrast-reducing, but because it's outside the main light-tube-cone its effect should be reduced. But then again the sheer area of the inside of the OTA will offset that (i.e. make it worse). I plan to test the vane-reflectivity effect by introducing a long wide shiny blade into the light-path when next observing. Actually flocking the vanes may be the next step. Such fascinating fun, these thoughts fill my mind when going to bed and send me to sleep!

... on reflection, pun intended, I decided to reorientate the side-support grubs in the mirror cell so there is no chance of the mirror getting “jammed” between two nylon tips at the bottom. Rather have it resting not-quite vertically on a single one. that involved rotating the whole tube in its cell by 60 degrees. while I was at it, and this is the reflection part, I removed the spider again and the secondary to paint the spider-vanes cardboard black. They were actually very reflective, and the last thing one wants is a parallel reflective surface in the light-path. Before and after pics...

Ive always plumped for Araldite, I’ll get some JB weld on your recommendation, thanks

Lightpollutionmap.info is a very good resource (how I hate that word apols). The way to use it is to set the overlay to Atlas 2015. It’s a simulation of how the darkness will appear at zenith at best to an observer on the ground. I’ve calibrated it to two very different places, one 19.0 and one 21.8, and they’re both spot on with that overlay. The other overlays are views of how bright it looks from the satellite, a different thing. Cheers Magnus

I too had reservations about how stable it would be, but after collimating it and trying to move it around in situ with laser etc still in the focuser I wasn’t shifting the spot even with a reasonable amount of “wrist-torque”. I was surprised. The carbon tube I ordered directly from klaushelmi.de, I think he supplies astroshop.de with their pre-specified carbon tube upgrades. Going direct to him makes a decent saving. On my 300p I’ve worked out it’ll save me 4-5 kg as well as making it very much stiffer. Magnus

Latest ... I made the mistake of drilling the central hole for the focuser first, then realizing that I had to sacrifice a bit of the calculated distance to the spider holes because of the presence of the inner flange of the end-ring of the tube. I thought there would be plenty enough leeway in the secondary holder to accommodate the shorter separation. There wasn’t. As the picture shows to the eagle-eyed, I’ve had to back the secondary-holder by one screw on the spider-vanes to give me an extra 10mm, allowing the secondary to catch the whole light-cone. New longer carbon tube now ordered so hopefully won’t have to live with this bodge for too long.

It's not. It's just a very big spacecraft.

The most important thing when using a laser for collimation is that the laser itself is collimated. With a glatter you can be sure that it is. With that settled, as you say, you can collimate the secondary by “hitting the centre of the primary”. you can then still use the same setup to collimate the primary by observing where the reflected laser-spot return hits the face of the laser, and adjusting the primary until that return dot is on top of the laser hole. But that only really gets you roughly there. a much better way, after doing the secondary, is to put a Barlow in front of the laser, observing where the SHADOW of the primary’s donut returns to the laser-face, and centring that. You may need to use a piece of paper to see where that shadow falls in front of the focuser tube, that’s what I use. so you can do it all with just the laser, reasonably accurately, and with a Barlow extremely accurately. the tublug basically combines the whole thing into one unit. cheers, Magnus

I had to look that breed up. Very nice!

Never saw those cats before, they just emerged from the box, I assumed @billhinge didn’t want them 😉😺

Courtesy of @billhinge, a berlebach Uni to replace a steel SW. Herewith pre- and post-assembly and placed in front of my Planet, even with the distance-perspective it’s still dwarfed by the Planet: Cheers, Magnus

Just had a quick thought to check and find out Uranus is only around 4 degrees from the Moon at the moment (28-Nov nearly midnight). So went outside with my Nikon 12x50s and found it immediately! Very chuffed, a first for me, a Gas Giant through bins. I intended to put this in the "who's playing tonight" thread, but it seems to have disappeared. Cheers, Magnus.