John

1 minute ago, DRT said:

I've just had a look on the Bresser website and the 102L seems to be a completely different animal to the 90L. No plastic bits, a decent looking 2" R&P focuser (looks better than the one they supply on the 127 and 152 AR models) and a similar cradle to the one that was on my 127L AR. 

€259 doesn't feel like a lot of money for that, particularly if the lens is as good as the one they fit to the 127L.

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

1 hour ago, Rick_It said:

 

Just to make an extreme case, a 2mt thin stick could easily be carried by an EQ3.2; a C11, even if it is super-short, can't.

 

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"

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A bit contradictory ?

Not unusual though, sadly.

51 minutes ago, Rick_It said:

Hi, I had the opportunity to see both refractors in Paris last november.

There's a logic behind those scopes and I do not agree that Bresser has "compromised on quality". The 90mm is made to be as light as possible, to be used with EQ3.2 class mounts. The 102mm is the one with better mechanics (expecially the focuser), but you need a sturdier mounts (BARELY an EQ5). Just look at the weights: 2.8kg vs 5.3kg. The 102mm weights almost twice the 90mm!

Those are wise choices by Bresser because they differentiate the two scopes and they allow also people with cheap mount to use a long fl refractors. With metal clamps, hexafoc focuser and metal cell no way you could have used the 90mm on your mount. You would have ended up with a scope with a cost and a weight very similar to the 102, thus no reasons to buy it.

I also do not worry too much for the plastic lens cell: such long fl tollerates very well slightly miscollimation.

Then, it's up to you. Buy a new Exos 2 GOTO with the 102/1350 and you will definitely improve a lot. OR stick with the 90mm and save a lot of money!

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.

48 minutes ago, Chris Lock said:

Also I know the diagonal they include is only a starter diagonal, but Synta have them beat hands down on it! The Bresser diagonal has a chromed plastic nose piece and the mirror doesn't look that bright/reflective, and the thumb screw was difficult to turn like it was cutting a thread in the plastic.

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

11 minutes ago, Paul73 said:

Bresser do seem to ramp up the quality as soon as you hit the 100mm mark....

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.

46 minutes ago, alacant said:

..Edit: talking of sublime refractors, they've also just released a 102ed f4.5. Around €260.

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 ?

On 08/04/2017 at 15:42, Dave Lloyd said:

Should be reasonably controlled do you think? 

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:

29 minutes ago, iPeace said:

I like this diagonal so much that I got another one...but had to return it. When observing a bright object (Jupiter), a pale smudge of light could be seen running horizontally through the object from one side of the image to another. This is clearly not supposed to happen...

However, I've ordered another one to replace it, will give it a few more tries if necessary to get another good one. 

Sounds like diffraction from a prism edge

Hope the next one is good

17 minutes ago, Alien 13 said:

When I started out an 90 mm frac would have been bigger than anything available in the UK at least in the non professional market, still cant understand why anyone would want any more.

Alan

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.

2 hours ago, Geoff_L said:

That's certainly my experience with a Baader Skysurfer III RDF. I find that I can keep both eyes open and just look along the scope. The red dot appears on the star field and although the body of the RDF moves relative to the stars when I move my head, the red dot is stationary.

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 !

1 minute ago, Gavster said:

Now your just encouraging me, Mike ?

I think my partner would leave home if an even bigger frac arrived. Also having noticed a material difference between the 100mm and 140mm a few weeks ago I think a move to the right would need to be a 180mm. Having seen DirkSteele's photos of his fantastic 180mm the sheer size (not to mention the cost!!!) means it's not going to happen. I have reached my comfort limit. And I think you mentioned to me previously that the FS 152 you had was a little on the large size? ?

Interesting ideas re bino FC100s but one for another year I think...

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 !

15 minutes ago, Jimmystargazer said:

@Alan64 I have a 26mm straight eye piece that I insert and holds in place with a grommet screw. Just need advice on something that lets me view easier, rather than having to get on the floor to look through the eye piece and also turn everything the correct way up.. ?

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.

15 minutes ago, Starlight 1 said:

....  I like the old mounts over goto .

So do I - minimal setup time. Point the RA axis north and switch on

A few snaps of my TMB / LZOS 130mm F/9.2 triplet on the HEQ5 mount (thanks Chris ).

Certainly looks and feels right. Hope the clouds shove off later !

How far is the objective down the dew shield with the F/7.4 Tak FC100's ?

On my DL the the front surface of the objective is only about 4 inches down the shield. I've not had dewing issues so far with it but it has crossed my mind that it could happen.