Bresser Optik Orion Newtonian (Vixen R-200S) & Vixen Sensor Mount Renovation Project

[SnakeyJ]

Somewhat by chance I discovered a rather unusual advert in my local free ads for a rather solid looking 8" Newtonian on a pretty chunky equatorial pillar mount.    The item was listed as a Bresser Optik Reflektor 200/1000 Art No 48-4000, which turned up a blank through the normal search engines.     The telescope was being cleared as part of the estate of the late Douglas White who was a keen local photographer and amateur astronomer.

Although I already own a 200mm F5 Newtonian, there was something about the picture that drew me in and seemed to hint at quality:

After posting a quick thread to see if anyone could help identify it, I got some excellent pointers and advice from John who directed me along the rebadged Vixen route.

Acting on impulse I've now brought myself another 8" Newt - and it seems quite a restoration project.    Having spent a good part of the weekend browsing the internet I've been able to identify the mount, a Vixen Sensor (load capacity of 15+ kg) c/w the Vixen DD-1 dual axis drive and steel pillar.    

The scope, mount and all accessories appear to be straight out of the 1985 Vixen catalogue, though rebadged as Bresser Optik.

Here's the project (currently located in my office):

There's currently 18 images of the scope & mount in my Gallery:

[SnakeyJ]

Although the everything looks original and intact, the scope has suffered cosmetically over the last couple of years due to Doug's declining health.     This will require some re-painting, replacement of some rusty fixings and the big ticket item will be the re-coating of the optics which appear to be in poor order.   That said there is no evidence that these have previously been re-coated, so they are possibly about right for almost 30 years

Moment of truth - Mirrors Out:

Both would appear to require re-coating.   If I look through the back of the primary at a strong light I can see some obvious bright areas.    I haven't removed the secondary from it's neat holder, but this looks dire in the image though not so bad by direct vision.    There is a small clip at the rear top edge of the mirror, so I hope this will slide out neatly once this is removed.

The original Vixen spec states the mirrors are 1/8 wave, so my question now is whether to go for a standard aluminium/si02 coat via Oldham or Galvoptics, or push the boat out for hilux coatings via Orion Optics.      Information on the various company sites seems to differ quite a lot.   They all agree that enhanced coatings are brighter, but Galv Optics and Oldham suggest that enhanced coatings offer a very marginal improvement, do not last very long and may be more difficult for subsequent re-coating.    Orion Optics claim that there Hilux coating makes things appreciably brighter by up to 20% and last longer up to 25 years giving best value.    Given the reputation and undoubted quality of OO scopes, I'm inclined to go in that direction although the cost is around double the other providers.    John has also said that OO have a service/support link with Vixen.

I had a really useful chat with Roger Wale @ Galv Optics this morning, but this now puts me in a bit of a dilema and reading Crashtestdummy's poor experience of OO gives some pause for thought.

[SnakeyJ]

Quick screen dump from of the relevant page from the 1985 Vixen Catalogue:

Now I'm just going to have to find one of those Vixen 60M achro's to ride piggyback!

[Naemeth]

I love threads like this, although they do tempt me to start trawling through eBay for future projects, again .

[SnakeyJ]

I love threads like this, although they do tempt me to start trawling through eBay for future projects, again .

It is a dangerous game!   Lou will kill me when she finds out I've brought another scope, which is why it's staying at work for the time being

[Naemeth]

It is a dangerous game!   Lou will kill me when she finds out I've brought another scope, which is why it's staying at work for the time being

At least you don't have 6 . 

I don't have a wife though, so I can get away with it to a certain extent .

Are you planning on re-painting to white, or black, or even a different colour?

[SnakeyJ]

Well I suppose it's four and counting with the Travelscope 70 finder, but definitely going to have to loose one at some point.

I'll repaint the OTA in a flat matt black as this will match the original Bresser colour scheme and its an easy colour to spray.    I'm hoping I can carefully warm and lift the stickers so they can be replaced after the re-spray.    The aluminium tube ends and rings are a gloss black flake, similar to a hamerite finnish - and this matches the mount itself.    Probably difficult to achieve this with a spray and touch up painting would probably make it look worse, so currently undecided here.    Though I'm considering getting a small grit blaster attachment for the compressor at work to test on some of the smaller aluminium parts like the motor brackets.      The pillar mount is in pretty good order, but will replace the bolts and clean/paint the base.

All a little boring, but will try to keep it as original as possible - The Celestron badged version SPC-8N looked quite nice in a gloss black with Orange lables:

This also shows a couple of adaptors that I am missing (eyepiece projection and camera adaptors).

[John]

This is going to be an interesting project Jake but worthwhile I reckon. I'd treat OO's claim of +20% reflectivity on their coatings with a pinch of salt by the way although the Hilux overcoatings seem to help them last well so there may be a more moticable difference later in the life of the coatings. OO can be pretty offhand at times though but they do know their stuff.

[SnakeyJ]

Thanks John, I've just been perusing the OO site having been led there unintentionally via links from Peter Shah's astropix site!     The longevity of the Hilux coating is probably the deciding factor for me.   By my maths 97% of 97% = 94% transmission to the EP, which would be perhaps 6% better than standard aluminium coatings.   Though even in a side by side test I think I would struggle to discern this visually.

As the mirrors are in rather dirty/poor condition, I do want to speak with them before sending the mirrors, for an assurance that they will contact me if there are obvious problems after stripping.

[SnakeyJ]

I spoke to Orion Optics this afternoon, who were extremely helpful up until I mentioned the Vixen model number, R-200S - when they explained that they couldn't re-coat this mirror as it was figured by Vixen's unique differential coating process and would need to be returned to Japan for coating.     I then spent some time explaining that this was a 30 year old model, which I believed was a standard parabolic F5 with a 1/8 wave figure, rather than the newer R-200SS or VC-200L models which are known to have mirrors that are built up with differential coating.

Not totally convinced Orion Optics have said they will take it and examine after stripping the old primary coatings.     Total cost for strip, re-coat and return of both mirrors is £ 91.61 for standard or £ 153.98 including VAT.   I have asked for the Hilux coating, provided the mirrors look reasonable after stripping.

Both the mirrors came out easily and have been packaged ready for courier collection tomorrow.    I've done my best to make the package bomb proof, given my long standing distrust of baggage manglers.    I shall not be marking the package as 'Fragile' as in my experience this seems to be taken as a challenge, inviting special attention!

[SnakeyJ]

Mirrors collected and en route.   Feeling rather nervous, despite adding an extra 25mm thick layer of impact absorbing polystyrene  and bubble wrap around my already over wrapped parcel.    Wouldn't be surprised if OO add an additional unwrapping surcharge

With the mirrors safely away I've started on stripping the removing all the fixings from the OTA ready for surface prep and painting.     Have to see if I can find some tips for lifting the Bresser stickers intact, so they can be reinstated after painting.

[Gina]

Maybe a bit of warmth from a hair dryer would soften the glue

[SnakeyJ]

Maybe a bit of warmth from a hair dryer would soften the glue

This is what I'm hoping, have to be gentle as I don't want to bubble or shrink the lables.    I will take some decent photo's beforehand, then worst case I can re-print them.

I managed to gently buff the blue paint off of the Bresser logo. 

Although not strictly original, I might even add an old Vixen logo, like this one for an 80M previously posted by John in another thread

[SnakeyJ]

I was getting a little nervous about the mirrors as I'd hadn't heard back from Orion Optics.   Perhaps being a little paranoid, but have to admit I was not totally comfortable with sending the mirrors by courier, however well packaged.    However, after a quick phone call they were able to confirm safe receipt and put my mind at rest

[Naemeth]

I was getting a little nervous about the mirrors as I'd hadn't heard back from Orion Optics.   Perhaps being a little paranoid, but have to admit I was not totally comfortable with sending the mirrors by courier, however well packaged.    However, after a quick phone call they were able to confirm safe receipt and put my mind at rest

I'd be worried too about sending a mirror on it's own via courier. I'd probably rather drive it myself, despite the horrendous effective delivery cost.

[SnakeyJ]

I'd be worried too about sending a mirror on it's own via courier. I'd probably rather drive it myself, despite the horrendous effective delivery cost.

I would really love to do this, and when I've eventually saved up for my VX10L it will be a definite collection   Though there's a couple of miles water between me and the mainland, which puts another 2-3hrs on the journey time and an extra £60-70 for a day return on my car    That and the tank of fuel would end up doubling the cost of the mirror re-coat!

I'm not stressed - much 

[SnakeyJ]

Just stripped off the OTA down to the bare tube for sanding and priming.    It is surprisingly solid and heavy.   My office scales run out at 3kg, but I would guess at least 5kg - shame they didn't build these in carbon fibre!

[SnakeyJ]

Lou took some convincing to let me use her hair dryer, but once I promised to be careful she relented    The stickers / decals came off quite easily with a little heat, as Gina suggested.   I've placed these on a gloss card box to keep them clean and out of harms way:

The Aluminium metal tag left a fair bit of adhesive residue behind, though this came off nicely with some nail varnish remover - which I smuggled out of the bathroom on the QT

OTA is now completely stripped of accessories and stickers ready for surface prep and prime.    I'm not going to grit blast, but will use wet and dry paper, etch prime and then fill with car body filler.   Once its all cut back smooth I shall etch prime again then spray with a flat matt black.

Good news back from Orion Optics today. the mirrors look okay and they confirmed pricing as expected for the Hilux coating - looking forward to their safe return early next week, although I will leave them wrapped for 4 weeks while the Si02 over coat hardens.

[SnakeyJ]

Mirrors back today from Orion Optics - all nice and shiney, though no documentation on either test or coat hardening times.    Also no centre spot on the mirror - what was I thinking!     They also managed to send the wrong customer credit card receipt, which almost gave me a heart attack when I quickly read it - £ 698 ish.    My invoice was correct and agrees with the bank charge of £ 154.00

I shall leave the mirrors wrapped and boxed for 4 weeks to give the coatings some time to harden off.     

[SnakeyJ]

How quickly time flies - almost 6 weeks and I haven't got any further than priming the OTA.    The mirrors should have hardened off sufficiently now, so will dust this down and finish the painting over the w/end - hopefully I have sufficient DC-Fix velour to flock the OTA and can get it mounted and collimated for a first light next week assuming the weather clears up at some point - pictures to follow

[SnakeyJ]

Mirror now centre spotted with a Catseye Hotspot (courtesy of FLO for the template and spots).   I'm on about my third or fourth coat of etching primer, as every time I cut it back I discover another defect where the original coat has bubbled off the tube.     Wish now I'd had the whole tube bead blasted back to bare metal.       Hopefully this is it and I can start applying the satin matt black top coat tomorrow - hoping to get 3 coats applied by Monday as I've decided I'm going to trial this at the IOW Star Party for a first outing.

I shall be purely visual this year, taking the Bresser/Vixen Newt and my Bresser Frac (on the off chance someone is bored and can be persuaded to help with some frac collimation). 

[SnakeyJ]

The kids were most obliging after Saturday haircuts and football training, as was the weather - so managed to get the two of the top coats on outside in the garden this afternoon.   Nice doing it outside in the garden, though a light breeze was a little wasteful of the paint and suspect I will do the final coats in doors and put up with the fumes!

After the final priming last night and now with the first two top coats (Unipart Premier Satin Black @ £ 2.99 / 500ml from my local autofactors):

  

Not a great shot, but the finish looks quite good up close, given that I've sprayed it from a tin!

[SnakeyJ]

Mostly back together now, but left a number of bits back at the office by mistake - I'll leave the optics out until all the fittings have been bolted back on to the OTA.

[SnakeyJ]

Finally re-united the missing bits (finderscope bracket, axial scope mounts and handle), primary and secondary mirrors now installed.   I didn't get around to collimating last night as it was late and would have needed to wade through the Somme (back garden) to get the cheshire and laser from the observatory.

Should be able to get this done tonight - need to source a few more bolts and bits to get this all remounted properly.

[leelee970]

Looks great Jake - I'm feeling rather jealous.

 

Have you done anything to the inside of the tube?

 

And are you thinking of upgrading anything or is this going to be a total restoration with genuine parts?

Lee