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Intes M603 Tear-Down Refurb & Re-Collimation


Captain Scarlet

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I had a more extended session observing on Saturday night. Star testing showed vastly better patterns than before, and stars were more or less points, though there's plenty of room for final improvement.

To demonstrate how much better the first rough collimation was, I took a couple of terrestrial photos, "before" and "after" of a pipe about 50m away. The "before" pic is really the very best focus I could achieve at the time. The "after" pic is of the same pipe a few inches down.

 

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I decided to re-test the primary-mirror axis and Baffle/focus-tube collimation with the external focuser attached, as the external focuser likely has its own axis. Sure enough, it was slightly off (the laser in the focuser pointed at a point 2-3mm different from my artificial star and its coincident reflection from the primary). I shimmed the meeting-face of the Revelation focuser on its rotatable dovetail-ring, and established that there is one position where all three dots coincide. I set it there, and locked it down.

To do that, though, I had to remove again the secondary-mirror boss to create a hole for the laser to get through. In the process of doing that, THE SECONDARY MIRROR FELL OFF!!! Wow. As the picture shows, the glue was very old with almost no "stick" left. I'm glad it did, as it would otherwise likely have happened at night in the cold while the scope was pointed up. And would therefore have landed on the primary.

_DSF0595.thumb.jpg.e51f87da9b4aa4cc3865dcd7556d6a9d.jpg

I also removed the not-especially useful central pin the the middle of the secondary front-plate, and will keep it removed to allow a permanent hole for a laser to be able to shine through. I'll keep it covered with some sort of plug or tape though.

I re-glued the secondary to its plate, and it's now curing:

_DSF0600.thumb.jpg.5a376f1416d0676508eb58108743436f.jpg

I had planned to start fine-collimating the scope today with an artificial star at the bottom of my garden, but this episode put paid to that.

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2 hours ago, Captain Magenta said:

I decided to re-test the primary-mirror axis and Baffle/focus-tube collimation with the external focuser attached, as the external focuser likely has its own axis. Sure enough, it was slightly off (the laser in the focuser pointed at a point 2-3mm different from my artificial star and its coincident reflection from the primary). I shimmed the meeting-face of the Revelation focuser on its rotatable dovetail-ring, and established that there is one position where all three dots coincide. I set it there, and locked it down.

To do that, though, I had to remove again the secondary-mirror boss to create a hole for the laser to get through. In the process of doing that, THE SECONDARY MIRROR FELL OFF!!! Wow. As the picture shows, the glue was very old with almost no "stick" left. I'm glad it did, as it would otherwise likely have happened at night in the cold while the scope was pointed up. And would therefore have landed on the primary.

_DSF0595.thumb.jpg.e51f87da9b4aa4cc3865dcd7556d6a9d.jpg

I also removed the not-especially useful central pin the the middle of the secondary front-plate, and will keep it removed to allow a permanent hole for a laser to be able to shine through. I'll keep it covered with some sort of plug or tape though.

I re-glued the secondary to its plate, and it's now curing:

_DSF0600.thumb.jpg.5a376f1416d0676508eb58108743436f.jpg

I had planned to start fine-collimating the scope today with an artificial star at the bottom of my garden, but this episode put paid to that.

 

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52 minutes ago, stuy said:

Hows the collimation going ?? 😀

Having satisfied myself the primary is collimated properly, I worked out another way of achieving first-order collimation of the secondary indoors, without looking at difficult-to-compare concentric circles on a target through a collimation cap, or via the hall-of-mirrors from the front of the scope, which I have found to be a very rough guide. Rather, if I put a laser in the focuser eyepiece, and look through the front of the scope, I can see the reflection of the facing-plate of the laser, reflected in the secondary and the primary. Which means I can see both the laser source and its returning dot reflected off the secondary. I just need to adjust the secondary until that dot coincides with the source. I did that, and now await a clear night for some real stars. Or the delivery of my tactical high-intensity torch to shine at a ball-bearing.

Tonight is clear, tomorrow I'm WFH, so I'll have a go tonight...

Cheers, Magnus

 

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Having once again "indoor-collimated" using my new technique, Monday night was just too temptingly clear to resist using Polaris to try to fine-tune, in spite of being a School Night. I'm now WFH anyway for the foreseeable future, so an extra hour in the morning would compensate.

Using the indoor-collimated setup, stars were, as expected, more or less points (unlike my horrid smear from a week or so ago), but nonethelss even at 43x wide-field obviously highly aberrated diffracted-comet-shaped horrors. Confirmation that indoor collimation is really a very rough starting point.

The high-magnfication defocused diffraction ring for Polaris was, at 250x, a bright outer nearly-circle with a bright point and squashed rings bottom left. I worked out which of the three secondary collimation screws was appropriate for that position, and adjusted it a small amount in a random direction. The pattern seemed to get worse and it certainly was worse when I had a look at best focus. So I'd adjusted the wrong way. At least now I knew which way I needed to go.

After a very slow process of adjusting screws, re-locating and centering Polaris as it moved away due to the adjustments, sometimes out of field in which case I had to change "down" eyepiece to find it again and change magnifcation back up, I finally managed the spot into more or less centre of the now-circular rings. By now the direction of the much-reduced aberration was slightly different so I switched collimation screws, and suddenly, bang, I found myself looking at textbook defocused diffraction rings, or something very close.

With not a little trepidation, I moved the focus-knob to actual focus, and my goodness! Nice Airy disc around Polaris, and symmetrical.

I changed from 250x back to my Panoptic 35mm to get a wide-field 43x, and suddenly I seemed to be looking through a high-quality refractor, lovely sweet pinpoint stars everywhere, lots of different star colours, it reminded me of the view I'd had through @Stu's Tak a while ago. It was after 11pm by now, I needed to look at something definite before I went to bed so I eventually found Castor (no finder so was hunting around a bit) and beautifully evident pair even at 43x.

I went to bed well pleased I'd finally got this little Intes performing. I don't really count this as First Light, so I'll round off before long with a First Light and some pics of its restored state.

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  • 2 years later...

Greetings, sir!

My Alter M603 is apparently of a similar vintage to yours.  The number on the back of my mirror is 127, and my baffle tube is inscribed 21.  Cousins at least, if not brothers.

I’m taking mine apart to attempt to repair a frozen focuser, apparently caused by binding somewhere in the rear assembly.

I have two questions, if I may ask for your opinion and assistance:

(a) Say, how free should the white metal focusing ring be? (I’m referring to the toothed disk, prominent in the photo above the text “The mirror off, and the focusing mechanism was revealed:…”) In re-assembly, should that turn freely for (say) several revolutions?  Really, I’m asking:  How much does the mirror have to move to insure sufficient focus play?

(b) Would you be so kind to share your shopping list for the “50-odd miscellaneous new stainless screws, grubs and bolts from accu.co.uk.”

Thank you for any assistance you can provide...

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Hi

Very gratifying to see someone getting use out of stuff I did years ago, thank you.

I'll answer (b) first as all I have to do is search my emails for the order confirmation. The list was:

SHK-M3-10-A2 M3 x 10mm Torx Countersunk Screws (DIN 965) - A2 Stainless Steel £0.2200 qty:8 £1.76
SHK-M3-12-A2 M3 x 12mm Torx Countersunk Screws (DIN 965) - A2 Stainless Steel £0.2700 qty:4 £1.08
SSN-M5-7 M5 x 7mm Nylon Tip Set Screws / Grub Screws - Stainless Steel / Nylon Insert £1.0400 qty:4 £4.16
SHCL-M3-6-A2 M3 x 6mm Torx Low Cap Head Screws (ISO 14580) - A2 Stainless Steel £0.2200 qty:6 £1.32
SHB-M4-8-A2 M4 x 8mm Torx Button Screws (ISO 7380) - A2 Stainless Steel £0.2400 qty:4 £0.96
SHK-M3-6-A2 M3 x 6mm Torx Countersunk Screws (DIN 965) - A2 Stainless Steel £0.2000 qty:8 £1.60
SSU-M2.5-5-A2 M2.5 x 5mm Cup Point Set / Grub Screws (DIN 916) - A2 Stainless Steel £0.2900 qty:4 £1.16
SSB-M2.5-6-A2 M2.5 x 6mm Socket Button Screws (ISO 7380) - A2 Stainless Steel £0.4200 qty:4 £1.68
SSO-M2-4-A2 M2 x 4mm Cone Point Set / Grub Screws (DIN 914) - A2 Stainless Steel £0.3900 qty:5 £1.95

As for (a), let me re-read what I wrote, search my memory, and I'll try to respond tomorrow.

Cheers, Magnus

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Will do.  I'm very tempted to write this up, title it something like "The Unofficial Intes Manual" and (after I circulate it for comments) post it to various boards.      

The shop I bought mine from is closed, the owner retired and moved away.  I sent a number of emails to various shops that had sold this 'scope in the past, and none had any sort of manual or documentation.  The Intes.ru site  looks derelict -- last copyright date 2005 -- and doesn't have any useful information anyway.  The threads on discussion boards are all the documentation there is.  

 

 

 

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On 02/08/2022 at 15:57, Ted Cheerfully Retired said:

(a) Say, how free should the white metal focusing ring be? (I’m referring to the toothed disk, prominent in the photo above the text “The mirror off, and the focusing mechanism was revealed:…”) In re-assembly, should that turn freely for (say) several revolutions?  Really, I’m asking:  How much does the mirror have to move to insure sufficient focus play?

That large toothed disk ultimately turns a thread (two half-threads, the two white plastic halves) which drags the mirror-sledge along a groove in the outer baffle tube. At a guess that groove is 2 inches long from stop to stop, which means the primary mirror can move that whole distance. That’s a lot of turns of the focus knob. Once you’ve disassembled it, it should be clearer what’s going on. Very different from the, say, Skywatcher or Orion USA mechanisms, and the Intes method apparently eliminates the mirror-shift on focusing.

I hope that answered your question,

Cheers and good luck,

Magnus

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Thank you, that's helpful.  My first naive try as re-assembly failed, as the gear bound after about one full revolution.

There will be a pause in re-assembly as I await Torx screw delivery.  A few items are out of stock at Accu, likely September before shipment.  Oh, well.  The mosquitos here are pretty rough right now anyway.  

The discussion of lubricants in the thread "Intes Micro Alter M603 Dissection" on the Cloudy Nights board is very interesting.  I've procured a general purpose synthetic grease - "Super Lube-21030 Synthetic Multi-Purpose Grease, 3 Oz." from Amazon.  I read through the materials compatibility sheet quite carefully before placing the order, though -- the risk is that I have no idea what material comprises those cream-colored plastic blocks.  If I start to feel very risk averse, I could get another half-ounce of Krytox specifically for those pads.  

Thank you again for all of your assistance, I never would have tried this repair without your write up on this thread.  

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  • 1 year later...

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