Pixies

Seeing OK here but not outstanding. At least unexpected clear skies! Looks like those down south had more stable conditions: Theta Aurigae was just split, the dim secondary popping in and out of view. Iota Cas was OK but not the usual 3 pin-pricks. Almach was as lovely as ever, though. I spent some time on the moon, after everyone had been raving. Tried for the rille in Vallis Alpes, but nothing. However, I think I found Danger Mouse in Mare Humorum! Quick phone snap at EP:

Almach (Gamma Andromedae) - Blue/yellow medium split Iota Cassiopeiae - white/yellow/blue triple, tighter split Theta Aurigae - double with a much dimmer secondary, harder still Not sure how the above will fare with the moon.

If you are seeing the shadow of the secondary - you are too far out-of-focus for a star-test. You can use this view to do a rough check that things are aligned, but a proper star test involves only adjusting things slightly off-focus to either side of focus. The 'rings' you see are pretty small and their diameter is not big. You will need high magnification. As for the test being different away from the centre - that's correct. You want to check for concentricity at the centre of the view. It changes as you move away, which is why it's important to do the test on Polaris (which will move very little) or with a driven scope. In fact - that's how you collimate with a star test: you find the location in the view where the rings are concentric - and if that is off-centre, you adjust the primary mirror to move the 'concentric' star back to the centre of the view. https://www.astroasheville.org/wp-content/uploads/2013/09/No-Tools-Collimation.pdf

I know what you mean, but for people new to collimation, the multitude of reflections can be a bit confusing.

This is where a long Cheshire (acting as a 'sight-tube') comes into action. You rotate the secondary after loosening the centre bolt and making sure it is under the focuser. Twist the loose secondary so that it appears as a perfect circle. You can do this with a collimation cap, but it's harder to be accurate. With the coloured paper trick: With a Cheshire: With a collimation cap: You want everything concentric:

From the reflection in the primary, you can see that the secondary is twisted away from the focuser. Red: secondary centre axis Green: focuser centre axis You'll need to twist the secondary back. What tool are you using to adjust the secondary, a Cheshire?

He used to be on here, wasn't he?

When you are watching the start of the programme and it comes up with "and with Pete Lawrence", does anyone else go: "Yay! Pete's on!"

For those with iPlayer access: https://www.bbc.co.uk/iplayer/episode/m0013c9c/the-sky-at-night-dark-skies That was the best one I've seen for ages. Actual astronomy content!

The JWST will actually be in a 'halo' orbit around the L2 point, so that it is not eclipsed from the sun by the earth's shadow. This orbit is about the same diameter as the moon's orbit! https://webb.nasa.gov/content/about/orbit.html

Thanks. Looking closely at some google images, it appears to originally have a long cap-headed bolt that passes through the hub, and a captive nut. As the holes in the hub are threaded for the bolt, this would mean as you turn the bolt, it will tighten both ends. If I used a captive bolt and tightened with a nut, only the nut-side would tighten. I'll get these parts when I order the hardware to replace the rusty parts on the mount. That's this weeks' job!

For months now, I've found the Met office app much more reliable than CO. However, since the new year, the latter has been winning hands-down.

Quick question for any owners of said tripod. The bolts that fix the legs: They're just plain bolts that hold the legs against the top plate, screwing into threaded holes in the plate itself. No washers were present on it originally. There is very little adjustment possible, other than loosening them enough for desired movement, but then there would be nothing to stop them loosening with use. Is this the way it was designed? I assume then they could be tightened when the tripod was set up to reduce wobble and loosened again when packing away? If that's the case I might see if I can get a through-bolt and large winged nut to make this a little simpler. Otherwise, is it just a case of living with a bit of wobble and occasionally tightening then up a wee bit? Perhaps felt washers would help.

This has all taken a bit of a back-seat since the summer, but the run of cloudy nights prompted me to sort out the tripod. It was a little rusty (very in some places) and some hardware was missing or broken. I managed to find modern marine A4 stainless steel replacements for all the nuts and bolts, etc. A replacement for a broken plastic spreader bracket was fabricated by a friend into 3D printing. The rusty spreader was sanded-down and repainted with Hammerite. The 'hinge' bolts cleaned up. I also re-painted the white parts with primer, top-coat and sealed. et voila (all scrubbed-up with 2 coats of Turtle Wax): I can source the old triangular spreader tray, that is fixed with wing-nuts. I just need to try and find the best-suited one so that I don't need to drill holes. Bresser UK are proving very helpful. Going to start on the mount next week. I might have a source from some SP spare parts.

Saw one around 11pm. I was out observing the Orion nebula with the scope and at one point when just looking up I saw a middling-bright meteor to the East of Orion heading South (down).

Was out last night. All apps said a clear night except Clear Outside - which said high clouds arriving at midnight. Started on M42. Lots of nebulosity visible (200mm dob and various EPs). Oiii filter showed wide circular arms but the unfiltered view appeared to show more 'texture' around the Trapezium. Speaking of which, I managed both E and F, the former steady but the latter was blinking in and out. Seeing was good but the view over a terrace of old Georgian houses and their poorly insulated roofs made for less-than-perfect views in that direction. Had a shot at M78 - which is another one off the list now. A pair of headlights in fog, as others have described it. Down to Rigel, which was easily split at x75. I then spent quite a bit of time on Sirius, looking for the pup. No luck though - it was dancing around in the heat distortions. I hoped it might settle down if I waited until the small hours. However, it turned out that Clear Outside was correct. High hazy clouds arrived and spoiled the party. I managed some time on NGC 2392 but that was it. I could have gone looking for double-stars, but had underestimated the cold and (as usual) not prepared for the first proper cold night of the season. Still, nice to be out under a decent sky for a change. Also saw the 5% waxing crescent Moon this evening. Got the kids off their electronic devices to come and look at it; standing on a table in the garden! Looks clear for a bit tonight, but I'm too tired and tomorrow looks good!

I don't know about GCSE now in England (I was O-level, too) but in Scotland my daughter has had lessons including the unreliabliity of internet-based information and how to fact-check from multiple sources. This was in the earlier secondary years and in the 'life-skills'-type lessons. Hopefully it will be covered again during the later exam years. Not sure whether Amazon reviews were included though!

All forecasts say clear tonight. Will get the scopes out later, as I don't normally start to 10:30pm at the earliest (once all my animal and childcare tasks are complete). But I'm taking no chances - so a quick bino-tour before dinner. M31, M36, M38, double-cluster, Pleiades, Alpha Persei Moving Group, Hyades, Jupiter and moons.

It's nice, isn't it. It's so light, too.

If you attach something long and thin perpendicular to the motor spindle (when off the mount), you can check that it's moving. Something like a straw, lollipop stick or wooden skewer. I was using a clothes peg to hold it in place and time a full revolution when I was working on a faulty stepper motor. You'll soon see if it's moving or not.

I think that transparency is better after rain has washed out any dust/particulates out of the air. If this is truly the case, the air above me must be VERY clean! Mind you, it looks promising for the next few nights. And I've got this week off work! 🥳 I have some winter Messier objects I still need to knock off my list. A few are too low to be able to be seen from my back garden, but I have hopes for M78 and around Monoceros.

Yep - double image normally means a collimation/alignment problem. As Geoff says - it's more obvious when looking at stars. Now - perhaps something has happened to your binos recently, to knock out the alignment. But here's a respectful thought.... Slight mis-collimation and double-images can be overcome by your eyes compensating, although it can cause eyestrain and headaches. As one ages, your ability to do this diminishes! You've had these binos for 30 years? you've had your eyes a bit longer, I guess!

It's the rotation that is causing it to look tilted: You need to get the secondary appearing perfectly circular under the focuser first - before worrying about the reflection of the primary in it. That's one of the hardest parts when first learning how to collimate. Once that's done, it very rarely needs adjusting. When the secondary is aligned under the focuser correctly, then you can start finely adjusting the tilt to get the image of the primary centred. Get the secondary at the correct distance from the end of the tube and rotated so that the outer edge of the mirror surface appears as close as circular as possible in the focuser. Before you do this, have a check on any tilt that has been set up on the secondary assembly. It should start parallel with the vanes - i.e. all 3 adjuster screws should be at the same length. You might find that with your work so far, it isn't very level. Best start with it as close to straight as possible. In @Spile's guide, this part here: This gap really needs to be parallel when you start. It makes this stage a lot easier and with your open-tube design, it should be easy to see. You will be slightly adjusting the tilt later. Does that make sense? Everyone describes this process in slightly different ways, but it's the same thing really. Once you get your head around what you're doing, it all fits into place. There are different tools to help - from the most basic collimation cap, sight-tube/Cheshire,Concenter - all the way up to systems costing far more than the scope! You can do it roughly just looking down the focuser, though.

That's a new one, to me. I'll have to check it out next time it's clear up here.. Tomorrow's looking promising!

For those of you using Twitter, here's an interesting thread from the Senior Advisor for Science & Exploration at the European Space Agency, about the need for the sunshield: https://twitter.com/markmccaughrean/status/1477213435087761409