John

When you have your primary mirror out for cleaning you can check that the centre spot really is in the centre. Sometimes they are not and that is another source of collimation error of course.

+2 for the AZ4. It handled my Vixen ED102SS F/6.5 very well 🙂 I'd like another one if I can find one. Another thing that I should not have sold 🙄

No, the laser collimator as a whole goes on the V-block, provided that it is a symmetrical unit such as the one I posted a link to earlier in this thread. @steppenwolf / Steve Richards shows a simple approach here:

Just had about 20 minutes or so with the 8 inch dob dodging clouds with enough gaps in them to make it worthwhile provided that I didn't mind a whistle stop tour. Saturn and Neptune looked nice plus brighter galaxies despite the moon. Best one was Mirach's Ghost, NGC 404 which was glowing quite strongly. Not really a session as such, more a reminder that there are still some very nice things up there, if only the clouds would clear 🙂

Just had a period of enough "sucker gaps" here to pop the scope out for 30 mins or so. Better than nowt 🙂

Great report Magnus - wish I had one that I could make tonight ! Triton is well worth looking out for - I have seen it a couple of times with my 130mm refractor. I'm hoping to get it with my 120 this season. If you can break mag 14 with your 140 then a the brightest of Uranus's moons (Titania and Oberon I think) might be "on" when they are well placed 🙂

I have an Orion (USA) branded 9x50 RACI on my Skywatcher 8 inch dob but it seems to be the same unit as the Skywatcher branded 8x50 RACI that I also own and has the same field of view.

I've just looked at mine - it turns out that it is an Altair ! Nothing more annoying than slightly narrower DT bars. William Optics did something similar a few years back for some reason best known to themselves

Mimas is placed well but the local clouds are badly positioned - between me and Saturn ! 😒

Early promise not fulfilled here ☁️☁️☁️😒

Not quite night yet and cloud may still spoil the fun but the simple 8 inch dob is out and waiting. If it stays clear the scope will get to use more of my Ethos eyepieces 😁

I'm watching the skies in that direction from here in Portishead 🙄 Thin clouds starting to spread from the west. Darn it.

I use one of those bolted straight onto the Tak clamp with M8 bolts. It's survived fine the past 7 years on a succession of mounts.

Well I've popped my dob out to cool so lets hope it stays reasonably clear for a while 🤞 It's been quite a while since I've had a proper observing session - which end do I look through ????? 🤔

I'd be looking for more precision than that which is why I suggested testing / adjusting the laser over a 20 feet+ range. For an F/4.5 newtonian the collimation "sweet spot" is just 2mm in diameter at the focal plane.

The Baader 10mm Classic ortho is probably one of the best eyepieces around for picking out faint point sources and nebulosity 🙂

I'm pleased that you saw Mimas with your 140 Magnus. I think I managed to see it a few weeks back with my ED120: I'm not sure that anyone believed me though 🙄

I can only agree with this. My FC100-DL is F/9 (so longer than the DZ) but the Tak tube clamp does an excellent job of holding the tube really securely. If folks prefer tube rings for other reasons then so be it but the Tak tube clamp is a very effective, reliable and robust item that has been proven over decades of Tak owners.

Here is a sketch of the Eagle Nebula as observed with a 200mm scope under a dark sky by an experienced observer. He used an eyepiece +barlow lens and a UHC filter combination which resulted in 80x with his scope. Messier 16 (Eagle Nebula) - Deep Sky Watch

Are you dead set on the ES dob ? I'm saying this because they are quite quirky in a number of aspects of their design. I've been reading up on them following a query on the 16 inch model by another person here and on the CN forum and it's seems that there can be quite a lot of issues with them that can cause some frustration. It's worth doing some searching on here and on the CN forum to see what has cropped up so at least you go in with your "eyes open" as it were.

Personally I use the V-block approach and a flat surface around 20 feet or more away with a "target" marked on paper stuck to the surface. If I can rotate the laser around 360 degrees without the dot wandering more than a mm or two, I'm happy. The process is described in the first section of this webpage: SCT Collimation (nightskyimages.co.uk)

Almost certainly slag I would think but this article might help: Meteorite Identification: Have you found a space rock? (geology.com)

It's not just about the glass used. The figuring, polishing, coatings and objective cell design all play important roles in how well the finished objective actually performs. The glass types are not the whole story.

If you want a laser that is reasonably straight forward to collimate, consider one like this: Astro Essentials 1.25" Laser Collimator | First Light Optics Not the most expensive by any means and it will probably need collimation but the 3 adjusting grub screws (you can see one in the picture) are readily accessible and the unit is symmetrical so that it will sit easily in a V-block to be rotation tested (at a distance of 20-30 feet ideally) and collimated. I've had the Baader and it's shape does not make it easy to collimate, IMHO. I also had a Hotech once and that was out of collimation as well ! Once you get these lower cost ones collimated, they tend to stay that way.

It can make a huge difference visually (I am visual only) so I guess it could also make a major difference in imaging. My best views of Saturn and Jupiter were many years back when they were really high in the sky. I've had some nice views occasionally recently but nothing to rival those views, despite my equipment and experience having moved forward someway in the meantime.