John

I'm wondering if Bresser had a challenge with the 90mm. Produced to the same fittings and finish standard as the 102mm I reckon the production costs of the two scopes would have been very nearly the same. Bresser realised that pricing the 2 scopes close to each other would mean that most folks would go for the 102mm and the 90mm would stuggle to sell in any volume. So they had to reduce the production cost of the 90mm to get a more attractive price differential. Celestron faced the same problem with the C5 sct. Apparently it's production costs were pretty much the same as the C8 but the retail price had to be quite a bit less otherwise it would not sell so the margin in the C5 was very slim. Celestron stuck with the same production quality / fit and finish on both scopes and lived with the C5 not being a money spinner for them. Bresser wanted to avoid this, hence the differences between the 90mm and the 102mm.

FLO's message is a little "warmer" though

Do you recall seeing these scopes at the Stoneleigh show Mark ? They looked from a distance like two giant white chopsticks

I've seen both the 90mm and the 102mm and that was my conclusion as well.

Actually I don't think a 2 meter long scope could be at all stable on an EQ3-2 no matter how thin or light it is. The mount could carry the tube of course (ie: it would not collapse) but the scope would be virtually unseable because any movement in the tube is amplified by the length of the tube so the image through the eyepiece would shake and vibrate virtually all the time. I owned this scope for a while. It was well within the weight limit of the EQ6 mount and the tripod had 3" steel tubed legs but even so the long tube (around 2 metres) created too much vibration at the eyepiece: Anyway, I hope Chris sorts out an exchange or refund with Bresser quickly

"Dear Valued Customer" "This email will not be forwarded" A bit contradictory ? Not unusual though, sadly.

It's not the weight but the tube length that determines the mounting requirements with these long refractors. Both are lightweight scopes but the tube length puts them both in a much higher mount bracket than a short tube design of the same weight. A single plastic tube clamp is simply inadequate for a tube of the length of the 90mm / F/13.3 regardless of it's weight because of the moment arm forces that will be working on that clamp and through it to the mount and tripod head. Saving money is one thing but if the mounting arrangements are inadequate for the scope design then it's going to lead to nothing but frustration or additional outlay. It's a poor choice by Bresser if the scopes will be returned by dissatisfied buyers (as they are entitled to do). I have also seen both scopes at a show in the UK last October.

If it is of any consolation, that is the standard diagonal that used to be supplied with the larger ES refractors as well as the Meade AR5 and AR6. At one time the last scope cost £1K plus and it came with a £10 diagonal !

Good to hear some positive stuff on performance anyway Chris

Bit late for Chris I owned a Bresser 127L and that was a pretty good scope optically. The focuser was functional but did it's job. The objective counter cell was plastic but the cell that actually held the objective was metal. The quality was the same as the Meade AR5 / AR6 (very near identical in fact) so not bad but still room for improvement.

It might use ED glass but I don't think it's going to deliver what we would normally expect of an ED doublet in terms of CA correction. Bresser class it as an achromatic refractor and a rich field scope.

I'm surprised that the clamp is plastic as well as being rather short. I think a conventional tube ring / dovetail bar arrangement would have been more approprate. You would think that the dealers who saw the early examples back in the Autumn last year would have mentioned this to Bresser

At least bought new ........ it can always go back

Interesting to see that they have gone for a tube clamp on such a long tube. The coatings on my Vixen ED102SS are not that obvious either. It's going to look good when it's mounted up

My understaanding is that to remove all visible traces of the "amici spike" the optical tolerances of the prisms have to be exceptional. Maybe you have one that falls into that category and the others have been up to spec but no more than that ?

They really should not be able to mess up slow achromat doublets like this. The CA should be fine for the aperture / focal ratio. It's the figure, polish and coatings of the lens elements that will determine the other performance factors. My money would still be on an ED100 but they are quite a bit more expensive than the 102mm F/13 bresser. Probably less expensive to mount though. Here is a chart which indicates the CA levels that can be expected:

Sounds like diffraction from a prism edge Hope the next one is good

Yes, I very nearly went for a Vixen 90mm achromat as my 1st "proper" scope many years ago. I managed to find a used 102mm Vixen though and went for that instead.

That is the trick to using these RDF and illuminated reticule type finders - look at the background sky rather than into the finder. Also keep the dot / circles / cross at the lowest brightness setting that enables you to see them against the stars. Many of these finders have brightness settings which are just too bright for deep sky searching in my experience. The exceptions are the Telrad and the Rigel Quickfinder whose brightness levels seem to be much better optimised for astronomy.

These scopes look quite a bit longer in real life than the photos on the website I've linked to suggest. They are going to need a sturdy mount despite their modest tube weights.

It's been a while, but I've got to post a pic of some of John Pons magnificent fracs again

I saw these Bresser F/13 achromat refractors at the Stoneleigh show last year and thought they looked rather nice. The 90mm and 102mm are now available for what seem to be pretty interesting prices: https://www.bresser.de/en/Astronomy/Telescopes/BRESSER-Messier-AR-90L-1200-Optical-Tube-assembly.html https://www.bresser.de/en/Astronomy/Telescopes/BRESSER-Messier-AR-102-1000-Hexafoc-Optical-Tube-assembly-bresser.html Not sure that including a copy of Stellarium with them is a strong selling point though !

180 is a BIG frac

Talking of "cheap as chips" refractors, this 90mm F/11 Meade seems a reasonable buy (a bit undermounted though): http://www.ebay.co.uk/itm/Meade-Polaris-90-EQ-D-90mm-Reflecting-Telescope-with-extras/112359236735?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20131017132637%26meid%3D9ffe454f5d3b4a3c85321d12f4f1b320%26pid%3D100033%26rk%3D1%26rkt%3D1%26sd%3D112359236735 Not my ad I hasten to say. Decent eyepieces with it too - I'd have given a lot for 3 1/2 frac when I was starting out but I'd have had to pay a lot more than 70 quid !

You need a diagonal to turn the image through 90 degrees. The vast majority of folks using schmidt-cassegrains, refractors and similar scopes use these. A mirror diagonal for astro use will turn the image the right way up but left and right are still reversed. You can get them that will give you a fully corrected image but they use additional glass to do that and we try and minimise the amount of glass that we view astro objects through to keep abberations, light scatter and distortion to a minimum. Usually folks use 3-4 eyepieces to give a range of magnifications. In the case of the LX90 A 40mm or 32mm is used for the lowest power, then, say a 20mm and a 12.5mm and something like a 9mm for high power viewing (approx focal lengths - something close will do fine !). The moon should be very sharp when viewed at low to medium magnification. It may get less sharp over 150x - 200x if the seeing conditions are not great. Yous scope needs 30-40 minutes to cool down if bought from inside. Before that it will be difficult to get clear images of anything because of warm air currents in the tube.