parallaxerr

Just managed about 15 minutes on the Moon before the cloud swept in. It would appear that the shorter pier has drastically improved the situation, any wobble/vibration is now very short lived and far less in magnitude than before. A sharp tap to the tube or mount results in one or two oscillations that dampen out in about a second. At X200 I could track in Az using the flexible slo-mo control whilst still being able to scrutinise fine detail, so I think the setup is good for some high mag action on Mars later in the year. I tried the mount with the tripod collapsed and raised up by about 50% on the legs, no difference. This tells me any remaining vibes are still in the shorter extension but I can't try without it because the tripod is an EQ5 fitting and the AZ100 is EQ6 - the extension is essentially an adapter between the two. I've also changed the knurled knobs back to the socket cap screws which can be tightened a bit better, removing any play. There's no need to break the mount down now as it's lost a fair bit of weight and can be carried relatively easily. All in all very happy, a success. Yes a Berlebach without the extension would probably perform better and is still desirable, but has dropped down the priority list a little now!

The shorter EQ6 extension arrived today. The mount looks far better proportioned now and giving it a tap results is significantly less vibration, dare I say close to none! Let's hope that's the case in practice.

Looking good Andrew, glad it's all sorted. That pier sure looks a beast!

I ordered from onbuy once. Waited a long time with no delivery before making enquiries. They said the item was posted but could not provide tracking. I requested a refund which was duly paid. Probably wouldn't bother again!

Andrew bought his from FLO, to whose website my comment applies. Glad he's getting it sorted now, that's what matters 🙂

I think I would have assumed the shelf came with the Nexus DSC too. Looking at the site it doesn't show the shelf under the "frequently bought with this product" section, so is easily missed. Shame about the bent altitude knob. I do think this mount needs more robust packaging. FLO did a good job with the amount of flo-pack they crammed in, but your experience goes to show that the mount is heavy enough to make contact with the outer packaging given enough of a thump. Moulded polystyrene would be the best bet I suppose, but acknowledge the fact that Rowan are only just getting going with this mount. Hopefully you get it all sorted asap and can start to enjoy your purchase

Hi rideway, The azimuth adjustment knobs should prevent the mount head rotating by being snug up against the North pin. I can't see how it can rotate if this is the case. Also, you don't want lot's of friction between the tripod and mount otherwise you won't be able to adjust the azimuth during polar alignment. Is the North pin fitted to the tripod?

There's definitely a pattern forming John. Any sort of piers or extensions are prime candidates for vibration issues apparently, that SW Pier being the longest of them all!

Pretty sure you should have the DSC mount plate @andrew s. Looks like you got a manual though, which I didn't. Maybe they haven't quite nailed the packing lists for the various combinations yet!

Exciting times.....Enjoy the flo-pack 🙄

Thanks John, shame I moved the old Celestron CG5 2" tripod on. I did so though because my setup all got too heavy, ironically here I am moving towards a heavier setup again but I accept it more now having realised that the smaller setup I went with didn't give me the views I wanted. Tripod clearance was always my reasoning behind using extensions, I think it's needed with the current refractor but the 8" should suffice, the 16" is a bit excessive. If the Uni 28 is as stable as the 2" steel, then I may go for that but use it collapsed with the 8" extension fitted.

That's exactly what I am using, a 16" Orion HEQ5/SVP extension with machined bottom adapter and a cast EQ6 adapter in the top (machined down and painted). I noticed some movement in the lower bolts and torqued them satisfactorily in the machined adapter, but you're right - I fear I may strip the cast threads up top so I'm using knurled knobs done up as tightly as I can by hand. There doesn't appear to be any movement there though. I hope the incoming 8" extension improves matters and if the tripod is then identified as the weak spot, a Berlebach with EQ6 fitting will be next. Uni or Planet is the question, but the picture you shared suggests even the Uni is significantly chunkier than the 1.75" steel SW tripod, at least in the collapsed position.

That's a very handy picture @Split Zygote2, it is the setup I envision - Uni 28 with short extension. It looks far sturdier than my current tripod and extension combination and your timing of 1 to 1 1/2 confirms it is better damped. Mine was taking several seconds after a lighter tap.

I looked up the Uni vs Planet specs. The Planet is the same collapsed height as my steel tripod, whereas the Uni 28 is taller. Infact the Uni 28 with 8" extension would be slightly taller than my steel tripod with 16" extension when both collapsed. The Planet would need the legs extending to a degree to reach the same height. Therefore it's a toss up between a Uni 28 with fully collapsed legs vs a Planet with partially extended legs......there may not be a lot in it and the lighter weight of the Uni would be appreciated 🤔 This would dictate seated observing as opposed to my usual standing though as the EP gets quite low......so if legs needed to be extended then the balance may shift to the Planet. I'll try the new 8" extension on the steel tripod and match the BB heights to get a feel for the options.

That would be much appreciated Stu. No doubt the Planet will be better, but by how much I wonder? In the grand scheme of things the Planet is not that much more than the Uni but I do like the look of the metal spreader for the uni that enables the legs to be "kicked out" as I read.

@johninderby how do you find the Uni copes with the AZ100 and big red? Do you extend the legs on the tripod when in use? The planet would be nice, but £££! Before trying a BB tripod I've ordered the somewhat cheaper Orion Atlas 8" pillar extension (same as EQ6 but black) which is half the length of my current one. I'll try that with the steel tripod in a lower position to start with to see if the situation improves. If not it will fit on the BB at a later date. I'm reasonably tall and had everything set up to reduce back bending as much as possible so the saddle was at head height, maybe just too much mass up high.

Can someone confirm the correct Berlebach tripod to fit the AZ100? I read it is the EQ6 version, closest I can find on FLO is "Uni-28 for NEQ-6, EQ6-R & AZ-EQ6", is that the right one? Unfortunately I found out tonight the 1.75" steel tripod and 16" pillar extension aren't really up to the job. There's a wobble (very low frequency vibration) due to the weight of it all up high, even using the slow mo's was causing a wobble

Definitely!

Agreed, I can make those more my primary considerations now. To be fair the scopes I am considering are not vastly different, F7-F8 mostly so my reasonable quality EP's should cope OK. It's the resultant tube length that makes a difference to me at 130-150mm objective diameter sizes.

What is becoming readily apparent is that different people have vastly differing views on the subject and we may have strayed a little! For me, it's simple now. When considering two scopes of equal aperture, in most cases the view at the eyepiece can be matched (notwithstanding minor optical differences) by the use of different focal length eyepieces, such that I can make a decision based on physical practicalities alone, i.e shorter faster scope is easier to handle and mount. Thanks everyone for your input, it has definitely helped!

Agreed, which is what I am comparing as per OP

Well that's what the FoV calculator screenshot in my original post kind of disagrees with. Same exit pupil, same mag....perhaps those two examples are too closely matched? Anyway, they are of the rough sizes I am considering so the difference appear to be negligible. Yes, fast-ness is definitely an imaging hot topic and I did wonder if I'd confused myself with that at first.

....OK...A little beyond the scope of my initial enquiry, but interesting information nonetheless. I guess the takeaway for me is that there are many factors to consider including variations in glass quality etc.....but most importantly my rationale behind same mag/exit pupil/FoV is sound and I'm not missing or misunderstanding something fundamental. I can now consider the practicalities of different focal length scopes of around the same aperture, without worrying that one will be more or less suited to the type of observing I do!

An interesting excerpt from an article I saved to disk some time ago... "The brightness of extended objects (galaxies and nebulas) is proportional to the square of the exit pupil. Therefore, a low power 4mm exit pupil (4 squared = 16) is four times as bright on galaxies and nebulas as a medium power 2mm exit pupil (2 squared = 4). To put it another way, twice the power results in one-fourth the brightness on the faint fuzzies outside our solar system. On the other hand, the brightness of a point of light (a star) is a function of the aperture of your scope – not the exit pupil. The bigger the aperture, the fainter the star you can see. Stars do not get dimmer as a scope’s power increases and the exit pupil gets smaller. Extended objects do, however, and the sky (the most extended object you’ll ever see through your scope) becomes progressively darker as the power goes up. The result is that faint stars are usually more visible at higher powers, as the contrast between the unchanging star brightness and the progressively darker sky background increases." It would suggest that equal magnification and exit pupil should provide much the same image between two scopes of equal objective diameter but differing focal length as sky brightness is a function of power, which by default is a function of EP focal length AND telescope focal length... I think this calls for a multi scope, exit pupil matched shoot out.

Maybe that's the bit I'm missing then John - that regardless of exit pupil, the sky background brightness is a function of the eyepiece focal length only?