John

18 minutes ago, Franklin said:

You've probably already sorted it but the black rubber washer that is around the finder foot in your picture should be placed around the finder tube, it goes in the recess for fine adjustments when aligning.

Well worth mentioning this 👍

18 minutes ago, a6400 said:

That’s why I am going to use this:

https://www.firstlightoptics.com/adapters/william-optics-2-to-125-rotolock-visual-back-adapter.html
 

As for star collimation some people already told me you can’t fully trust it.

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.

15 minutes ago, Stu1smartcookie said:

+1 for the AZ4 ... its a straight forward solid mount . The only caveat is that it doesnt have slow motion controls 

 

+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 🙄

11 hours ago, Spile said:

V blocks mean that I’d need to remove the laser. The rotation method in situ means I don’t. That works for me.

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. 

14 minutes ago, mikeDnight said:

The Tak dovetail bar is slightly narrower than the standard Vixen/Skywatcher version, so if the locking screws are on the short side they may not securely hold the dovetail bar. I found the small secondary locking screw on my GP mount was too short to reach the bar, so I replaced it with a longer one. I'm sure some have used the Skywatcher or Vixen dovetail bars instead of the Tak Mewlon dovetail. They're much cheaper too!

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 

1 hour ago, Captain Scarlet said:

Mimas seems well-placed again tonight.

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 😁

15 minutes ago, Nugs said:

Judging by the downpour we've just had in Weston...... look through the end that the water is pouring out of. 😉

I'm watching the skies in that direction from here in Portishead 🙄

Thin clouds starting to spread from the west. Darn it.

7 minutes ago, johnturley said:

Would that be the case however, if the Tak was mounted on a Skywactcher AZ-EQ5 using the following:- 

https://www.firstlightoptics.com/takahashi-other-accessories/takahashi-tkp71423-dove-tail-male-for-mewlon-210.html

One review suggested that it wasn't an ideal solution, and works out more expensive than the StellasLyra tube rings when you add on the cost of the Takahashi clamshell

John 

 

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 ????? 🤔

9 hours ago, CraigT82 said:

You don’t need V blocks just to check the laser. With it in the focuser just unclamp the laser, turn it 180 degrees and reclamp it and see if the dot has moved which would tell you the laser collimation is out (or your focuser is rubbish).

 

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 🙂

3 minutes ago, Captain Scarlet said:

...... I wanted to get as many moons as possible and managed Titan, Dione, Rhea, Tethys, Enceladus, Mimas and Iapetus. I tried hard for Hyperion but no luck....

 

 

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 🙄

On 01/10/2023 at 17:04, mikeDnight said:

..... As far as the tube clamps are concerned, I have heard it implied that the Tak clamp isn't as rigid as rings, but it really is. So over all I wouldn't worry too much about either issue.

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.

7 minutes ago, Spile said:

If you want to check a laser is collimated and registered in the focus tube, rotate it and see if the dot “walks” around the donut. Basically it shouldn’t.

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)

3 minutes ago, GTom said:

I have that feeling too. Asked Altair, but they are NDA-bound to share specific details about the optical formula. IF identical to the TS (FPL53 + Lanthanum) then it is as good as a triplet and best-buy candidate. Unfortunately no glass or design CA-plot is available, someone has to try it with a wide-band L1 type luminosity filter.

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.