Captain Scarlet

Good quick guide. Some people suggest that for visual, the need for accurate collimation is exaggerated. I strongly disagree, and unwittingly demonstrated this to myself a couple of weeks ago. I collimated my 12” in my usual way (using a tublug rather than just a laser but that doesn’t alter my point). I got on with observing, and noticed that everything looked far worse than I’d been expecting. I put it down to poor seeing, but just in case I pointed to a bright star and immediately saw the classic “pointy stripy oval” shape indicating bad coma. Very odd. I put the tublug back in and it seemed ok. I then rotated the tublug in the holder and the shadow started to move in a circle across the angled tublug screen! Something wrong with the collimator! I actually have two tublugs, so I put my other smaller 1.25” in, and it showed collimation to be out, by half the width of the angled screen, i.e. seemingly not grossly. I centred this shadow, and it stayed put when I rotated it. Subsequent star test showed all good. Next day I inspected the errant 2” tublug and found the angled-face insert to be loose, so it had been at a random angle. Anyway, my point is that even with the return shadow/laser dot only halfway away from “disappearing down the hole”, the view produced was noticeably poor in an f/5.4 (6.2 with paracorr) Newtonian. Poor enough for me to have considered abandoning the session had I not fixed it. Magnus

Fantastic

You only use those crosshairs to aim the centreline of the Cheshire at the centre-spot of the mirror, I.e. collimating the eyepiece/focuser tube to the primary. Even if bent you should be able to estimate where the proper crosshair centre should be. For the primary, they don’t come into it: you use the reflection of the angled-illuminated face, which might have its own cross-etchings: you line that up also with the primary’s centre-spot using the primary’s adjustment screws. I’d still return it, though. Cheers, Magnus

I'm no expert, but when I open the larger version of the image and bring my eye close to the screen, I'm drawn in by the details and cannot stop staring. Seeming supernova remnants all over the place. Exquisite. Magnus

I too get similar white dots on mirrors that I keep in the only-slightly-heated utility room. They don’t come off with cleaning or any solvents I’ve used including acetone. But they do come off with a fingernail I’ve discovered. I too would like to know what it is. Can Lichen get started under such conditions I wonder? Spider excrement has also crossed my mind. As a result I keep my newts vertically mirror downwards-facing now. Magnus

Courtesy of @The60mmKid and my sister in law network, these finally arrived yesterday:

Keep the unused ones, you never know they might come in useful. For example I refurbished a friend’s 10 year old 130p recently, and it turned out it doesn’t have springs, only (useless) rubber washers, making collimation a real chore of “push-pull” adjusting. I still had my old SW 300p springs, so I cut them in half and installed three on his 130p. Worked like a dream. Cheers, Magnus

I put this to my cousin, and I’ve screenshotted her reply. I tried to copy/paste her response but the app went haywire. Any of her phrases/words ring a bell? (Bear in mind for pronunciation the letter “y” is pronounced like a short “oo”, it’s sort of a vowel.

Like you having lately moved to a dark but more weather-prone site, I find the biggest visual difference to be the naked eye views: they are the ones that blow me away, even now three years later. If I can get even a brief naked-eye view of the myriad of stars and MW that were impossible from SW London, like I did tonight in 30-40mph winds, I'm not too unhappy at not having the opportuntiy to get a scpe out. Just as well, as we (and you) are due a very stormy week ahead... M

This has reminded me of my own (non-) project. I have a 20” mirror-set sitting in a box taunting me about not having embarked on it yet. The beauty of designing a truss OTA is that if you get it wrong and cannot focus, it’s no disaster: you only need adjust or replace the poles. M

Your description of Rigel perfectly describes my own view of it last night.

Just in from a session with my 12”. Stunning transparency, pretty poor seeing. M42 nebulosity three-dimensional but Trapezium stars fuzzy. That said, E was visible and F came and went. Sigma Orionis C star I could see but all bright stars were disappointing. Jupiter had moments of amazing clarity, the reddest I’ve seen the GRS, but only moments. Definitely worth setting up and getting out but far from the best session I’ve had. A handful of meteors. Magnus

It’s never the right time when a rare opportunity arises. Do whatever you can to keep the 102 and most certainly get the FS128. It’ll hurt for now, but that will subside. M

Yes that weight sounds about right, it’s certainly no lightweight. I also had an APM 8x50 finder attached. It was on an EQM-35, without counterweight (which I forgot when loading the car). It was fine, actually.

Yes it is a Planet, and I’ve just checked the az pin is removable. I believe @Stu has an AZ100 on a Planet.

I quite happily mount my 12” Newtonian on an AZ-EQ6 in alt-az mode. Although mine is now lighter than it used to be at around 21kg, my much heavier 300p came in at 27kg with finders eyepiece etc, and that was ok too, for visual only I should add. The Rowan AZ100 would be fine too I think. Magnus

Last Thursday I brought my LZOS 105/650 to our local Astro meet, and when it came to mounting the scope onto the saddle, I had the devil of a job trying to extend the dewshield. It eventually succumbed to my fingertips but it was a worry. Today I took it apart to see what was wrong. It turns out the felt lining the inside ring of one end securing the dewshield had detached itself from the adhesive. The adhesive itself was still more or less on the metal ring, effectively gluing the dewshield in place! I removed the loose felt/flock, cleaned everything up and re-attached some new flock/felt. It now slides as it should. It was interesting to see how it all goes together and the Cell as a separate unit. Cheers, Magnus

Very interesting and useful too. Thanks M

As to what actually happened to fog up your primary: when, after an observing session say, you bring a cold scope or mirror into the warm house, the glass immediately fogs up of course. Here it’s the same but in different circumstance. By heating the secondary, you’ve added heat to the air inside your tube. So you’ve effectively brought warm somewhat humid air to a cold mirror and in just the same way the water vapor condenses onto your cold mirror. Cheers, Magnus

A few days ago @Chandra posted a very useful reference chart of the object-types for features of Jupiter, which I’ve taken the liberty of re-pasting here: I could guess all the abbreviations except SDER, which it turns out stands for something like Spot Dark [within] Extended Region. In finding that out, I came across this below, which is also useful, especially page 13. http://www.jupos.org/etc/JuposProjDoc_English.pdf It’s at a non-secure link (i.e. not https) so might not always be available. Key screengrab here: Page 16 also shows names and abbreviations for all the bands. Cheers, Magnus

I suggest Edison for John’s ED120 🙂

It is a good scope, all the more so because on my advice he upgraded his eyepieces to BST Starguiders. The mount he has with it is not good though, especially as he has wrestled it into as close to alt-az mode as he can by tilting the RA axis as far over as it will go. With the counterweights consequently tangled up in the tripod, he was changing azimuth for different targets by picking up the tripod and re-placing it! There was only so far I could go in giving there-and-then advice without becoming a bore. Herewith the perils of a beginner being given an eq mount. Luckily his enthusiasm remains undiminished and for now I’ll lend him my stellarvue M-2 mount, far more intuitive. Others were in fact impressed by the views of Jupiter through his scope. I was even more impressed when, after everyone else had been driven away by the cold, we discovered he had had his lens-cap aperture-mask on the whole time 🤣🤣. Again luckily, he saw the funny side to it. His wife, who was there with us for a time, apparently still hasn’t stopped laughing. Anyway, yes the scope is remarkably good, but it needs decent eyepieces and a more sturdy mount than the eq-2. Magnus

Tonight was Astronomy night for our fledging astro group. I took two scopes, my LZOS 105 on eqm-35, and my Skymax180 on skytee2. One other member brought his own scope, a 130p on eq3. About 8 turned up, but didn’t last long once outside as it was a bitter -2 and a 15mph unsheltered north-easterly. We all got to see Jupiter and Saturn through all 3 scopes though. It was the first time I’ve had the Skymax 180 out for more than a year, perhaps even two. But tonight on Jupiter it was tantalizingly very very good indeed, GRS clearly on show with its change of SEB shade fore and aft, sitting within what I too saw as a pale surrounding ring; but I could only sit and look for brief moments before guiding the rest of the group. Lovely scope, I’ve missed it.

I had my best-ever views of Jupiter a couple of nights ago with my 8” f/4.4. Mirror was filthy too. The fact you can get a used SW200p for £150 or so is amazing. It really is the Goldilocks scope both for its abilities and its £ outlay.

I was observing Jupiter last night with my 8" newtonian, and also particularly noticed that shade change either side of the GRS. Also that the coloue of the GRS was the best I've seen it. I thought it would have been a good evening for me to start sketching, there was plenty to sketch. Thanks for the drawing, Magnus