So my TeleGizmo 365 cover has started to leak. I thought it was minor and just the lower seams. But it looks like moisture has gotten into the scope and caused some mould on the inside of the OTA and on the inside of the corrector plate of my C925. Just noticed it today, as I was doing a sensor analysis of my ASI 294 using SharpCap. The OTA has been outside in the tropics and under the cover for 3 years, without any sign of trouble.
Ive attached some pictures. Should I send it to Bintel for repair or attempt the fix? Im handy (but not foolish) so happy to have a go with some experienced guidance if that is a sensible option. That damn secondary housing spun again, so I presume I need to collimate the thing again, and try and tighten the secondary housing, it happened a while back but don't remember my solution
Try this webpage... it is good description of how to do it, it is easy.
You can wash corrector plate with mild dish washing detergent or Windex (use demineralized water for rinsind)
Doesn’t look that easy 😅
Any ideas what to use for the Mould, on the corrector and on the inside of the ota?
I’m a bit confused by the lack of responses. Maybe no one has been daft enough to leave their scope out like this and not seen it. Or is it an indication I should just send it back to bintel?
Windex rules :-)
Also, it is good idea to expose the internals to sunlight (or UV lamp) to kill the growth.
I assure you many people on this forum did this.. (lack of responses is not indicator of difficulty of the task) and saved quite a bit of money. Try to google a bit more to build the confidence.
But... if you are not comfortable with the idea of DIY, then don't do it.
I agree with Bojan. The corrector can be cleaned using the dab dab dab method in the link. I favoured the isopropyl alchohol and distilled water mix but the action is the same as long it all goes back in exactly the same tape marked location.
Looks to me like condensation inside is your problem. Does it get cold at night outside for your scope in Darwin and how does a secondary move around?
The mirror makers use the straight alchohol and folded wipe edge to edge technique but this can only be done on a new or perfectly clean mirror or corrector with a small accidental smudge. Most of the contaminants in cleaning seem to come from the air or the existing surfaces, ideally all should be blown clean.
SF: in the wet season, it rarely gets below 21 with a high dew point and high humidity, in the dry gets down to about 12, low due point and low humidity.
The entire Secondary housing rotates, so the orientation of the 3 collimating screws changes/rotates. Theres a lot of info and misinformation out there, and im not sure if this matters more than just having to recollimate. Some info out there suggests that the secondary must line up exactly as from factory for optimal performance, others say that this applies to the corrector only etc. Not sure where the truth in all this lies. Hence my post, enquiring about any actual experiences.
BJ: is windex available in Oz? Ive been using distilled water and isopropyl alcohol for the exterior of the corrector, but wasn't sure if it would get rid of mould/fungus.
Windex is available in Oz, but distilled water and isopropil should also do the job (try and see - if it doesn't work, try with dish washing detergent and water).
As to orientation of corrector plate - I do not know, and IMO it should not matter (but it also doesn't hurt to original position, if possible).
Secondary mirror holder should not rotate - it is supposed to have a pin that prevents rotation of secondary assembly in its seat (which is fixed to colimation plate). Perhaps you mistook the mirror holder with screw-on retaining ring that keeps secondary mirror holder (with colimation mechanism) in it's seat?
Perhaps it is the front cover that rotates. The secondary housing should not rotate and is fixed in most cases to the corrector.
The corrector must go back exactly as set up in the factory with its serial number and makers mark pointing to the three o clock screw with the same cork spacers in each position. The corrector is not perfectly cut round and centred in all cases and so the spacers are not equal.
The secondary often has a makers mark also , sometimes visible through the cover which also points horizontally to the three o’clock position and the whole assembly is matched and tested on the bench at manufacture, with matching numbers on corrector , secondary and mirror.
Anything else will not provide the best possible result and may be difficult to collimate.
Last edited by Sunfish; 17-05-2019 at 12:31 PM.
Reason: Corrected word
...The corrector must go back exactly as set up in the factory with its serial number and makers mark pointing to the three o clock screw with the same cork spacers in each position. The corrector is not perfectly cut round and centred in all cases and so the spacers are not equal.
The secondary often has a makers mark also , sometimes visible through the cover which also points horizontally to the three o’clock position and the whole assembly is matched and tested on the bench at manufacture, with matching numbers on corrector , secondary and mirror.
Anything else will not provide the best possible result and may be difficult to collimate.
So I spoke to Don at Bintel, who thinks its Oxidation/corrosion rather than mold. Someone suggested that on cloudy as well. In any case I have gathered all the required parts, looked at many videos and online blogs. And Don has sent me some instructions as well. He also suggested I flock the interior. Hopefully I will have the OTA up and running again, otherwise it will have to be the Frac until a replacement comes along in the classifieds! Pity I missed the 11edge HD!
Sorry I only just saw this post this evening; I live in Cairns & recently experienced what appeared to be small mould blooms on the inside of my Meade SCT Corrector Plate. I cleaned it myself after much research, thought & after two months of working up the courage... I'd not done anything like it before.
First thing to make sure of: Humidity level below 60%.. I know this is tough in the tropics but, if you don't wait for a day where humidity is low, you will just trap a bunch of warm, moist air in your OTA... & you'll be back with mould in no time...
I made up a cleaning solution from a recipe I found on about half a dozen professional observatory sites; the recipe is as follows:
45% demineralised water
45% Isopropyl Alcohol (99 - 100% pure)
10% Windex brand only window cleaner (available in supermarkets)
5 drops of organic, non scented washing up liquid
Then, mark where your corrector plate sits using masking tape so that is goes exactly back where it was, carefully remove retaining ring & then carefully remove corrector plate. Removing the corrector plate may not be as simple as it sounds; I ended up having to use a carefully padded allen key to break the seal that had formed between the glass & the foam like cushion the glass sits on.
I used a couple of folded up clean cloth nappies to place my corrector plate on so that it was sitting on something soft whilst I cleaned it.
To clean, wear either lint free cotton gloves or powder free latex gloves. First step, take a Lens blower (Puffer) & blow off any dust.
Next, get a brand new camel hair makeup brush & lightly brush your optics to remove any remaining dust.
Next using either kimtech wipes or (again from an observatory site) Plain White Kleenex brand tissues. Carefully fold the tissue into a triangle, dip one edge into the cleaning solution so that it is damp, not ringing wet & wipe a small area from centre to outer using the weight of the tissue only, no force, no pressing: dispose of tissue, select new one & repeat, working your way around the corrector plate carefully.
Next, using a mix of 50% distilled water & 50% Isopropyl alcohol, repeat the process using a clean tissue each time; this is the rinse cycle.
Then, using a dry tissue, carefully wipe in the same manner to dry any residual moisture. Same method of tissue use, no pressure is used throughout.
Finally, once dry, blow with lens puffer & then last go over with camel hair makeup brush...
Before reassembling, look for any major dirt on primary/secondary mirror, dust inside the OTA, etc... only clean if absolutely necessary but, definitely blow dust out of OTA.
Reassemble carefully ensuring that your corrector plate is correctly aligned with the marks you made before you removed it... Take outside, collimate as required....
With a couple of go overs, my mould blooms were gone.. mirrors were dusty so got blown & brushed lightly but, that was all. Tube of OTA was a little dirty so it got blown, brushed & some minor cleaning.
Amazingly, my scope was pretty damn close to collimation when I reassembled & star tested... despite putting a fair amount of pressure on the secondary assembly initially trying to remove the corrector plate... Couple of tweaks (1/16th of a turn on one screw) & it was back in collimation...
I am now about 8 months on, no mould has returned, optics are beautifully clean and the views are good when there is no cloud.
I don't store my scopes outside but, inside the house in a well ventilated room (fan going all the time)... I'm paranoid about mould & have been investigating potential prevention techniques but, found nothing practical & suitable as yet. I do not put covers, lens caps or close boxes after a nights viewing.. I open everything up, point my OTA down & allow everything to dry thoroughly before EP boxes, etc.. get closed..
I had never done or contemplated doing this to any of my scopes before but, I watched countless videos, read countless procedures, took a deep breath & gave it a crack... it worked & on reflection, wasn't that hard.. just be careful when screwing the retainer ring back on.. it just has to be lightly firm not done up hard tight...
Hope this helps, good luck with your mould or oxidisation issue, hope you are able to end up with the result I did..
Doesn’t look that easy ��
Any ideas what to use for the Mould, on the corrector and on the inside of the ota?
I’m a bit confused by the lack of responses. Maybe no one has been daft enough to leave their scope out like this and not seen it. Or is it an indication I should just send it back to bintel?
Cheers
H
"I’m a bit confused by the lack of responses."
you only posted a few hours ago
I know I may sound off but "leave it to the professionals, don't try to repair anything unless you can afford to lose it
Hi outcast, thanks for reading, and responding in such detail. What you’ve said is exactly the advice I’ve got from my reading and from a cloudy thread I started. Don at bintel also told me to have a go.
Hi Jeremy, I posted on the 16th of May, so yes 144 hrs ago.
I’m in Darwin, so sending stuff out or back is a bit of a pain.....after all the research I don’t want to let someone else have all the fun, especially on a cloudy night.
I have removed the corrector from my C925 twice to clean it. Mine seems occasionally to get a bloom from what I think is the grease on the baffle tube outgassing. It feels a bit daunting to remove the corrector but it is really not that bad. Maybe helped by mine being around ten years old now so I am not as precious about it as I used to be.
My secondary has rotated a couple of times too. There is a roll pin in the holder that indexes it in the housing that attaches to the corrector. On mine that points to what was the "top" of the OTA when it was horizontal in the old CPC mount. You can tweak the tension of the holder in the corrector while you have it apart but it is likely to be like most things optical, "Just tight enough" will be the aim to avoid pinching any glass. I am not sure if rotation of the secondary makes any difference in actual fact to optical performance, there seems to have been a lot of conjecture over the years as to if Celestron match them any more or just bang them together and if they test OK, send them in to the world.
Aligning the screws so that the apex of the triangle it pointed to the "Top" of the OTA is handy though for collimating with a camera, if the camera is oriented the right way as well it makes it easy to pick which screws to move. That may not apply to an Edge HD as the normal SCT coma at the edges is the telltale to collimate with in focus and the Edge HD having less curvature and tighter stars off axis might not display it as visibly.
The outcast recipe sounds good and fairly close to what I also have done twice.
It helps to have the OTA mounted so that it can be pointed downward when blowing the dust out of the mirror with a rocket blower just as you would with a camera, and pointed upward when replacing the corrector.
My c8 scope is older so the secondary is fixed and I have read that the secondary misalignment can be fixed in collimation .
I have also read that misalignment of the corrector itself leads to problems. I would imagine an Edge HD is tested as shown in this image of the Celestron final mirror polish and alignment set up from an older journal I came across. Not sure what model these are being figured by hand or if this represents standard practice.
So finally had some time to start the restoration.
I marked everything and photographed everything so I have some reference how it all goes back!
1. Took off all accessories inc dovetail
2. Took off corrector gasket with shims
3. Took off corrector with with secondary
4. Took off Feather touch focuser
5. Removed retaining clip on baffle/draw tube
6. Removed Primary mirror (slid off draw tube)
note: Don at Bintel was spot on, the secondary cell at the front of the OTA does not need to be removed, the primary can be tilted and rotated out of the tube. This is different to what ive read and watched online.
7. Once primary was out I started picking at the white spots: not fungus as far as I can tell. Its definitely oxidation/corrosion!
8. The entire tube is covered with the stuff, so to make restoration easier I decided to take the front and rear cells off.
9. This was straight forward: there are some nuts and bolts that need to be removed and voila the cells can be eased off.
OK now I have the scope in bits, the optics well protected and ready for cleaning after ive address the tube.
QUESTIONS
A. Any suggestions here would be good..... my current plan is to sand the oxidation away and then flock the tube with felt. Im not sure if this will fix this or just paper over it! Im told that painting it with anticorrosive treatment isn't a good idea due to out gassing.
B. is there anywhere I could get another tube fabricated? possibly in carbon fibre. Celestron don't sell the Tubes without the optics!
C. The corrector is off centre with some two plastic spacers (ive attached a photo of it) is this normal?
D. All the hardware is rusted, does any one know if these are standard sizes bolts etc that I could replace with marine grade hardware?
So the mirror and secondary are ok if you look closely with a loupe?
Just corrosion in the tube from differing metals used in construction and being left outside. ?
The tube I think is aluminium and can be cleaned and repainted. There are some Images on CN of this. The little bolts I know are very poor zinc coated and could be replaced with anything not too long.
My tube came a little loose and I reseated and tightened the bolts and that worked. Perhaps you could repaint the existing tube and reassemble without too much trouble but I would not touch the focus tubes except to clean it . And don’t clean the mirrors like I did. It is a pain. Don’t even touch them with anything other than puffer air.
The tube and base can not be parted I think except by those with optical instruments to realign.
Are you sure the focus tube is corroded metal?
Last edited by Sunfish; 27-05-2019 at 09:09 PM.
Reason: Spelling
The corrector can be cleaned easily using a mixture of isopropyl alchohol and distilled water in a very clean dustless room by dabbing with fresh saturated tissue, or Giotto lense cleaner. Do not rub and use up the whole packet , continually changing to a new tissue and fresh mixture for each small section.
Finish with distilled water , dragging the edge of a single dry tissue with no pressure.
Any fungus , sap or dew can be cleaned off first with pure isopropyl alchohol and a paper pure cotton wool swab with a rolling action, but avoid the makers marks if they are faint permanent marker lines on the edge of the corrector.
Wear dust free surgical gloves to avoid prints.
There is a link elsewhere here to a long post on CN and a youtube video showing how this is done.
Others have paint stripped the tube but I wonder if it can be lightly powder blasted inside by your local powder coater, and perhaps they can do the inside only , taping the outside. That would clean it up nicely for a good flat black spray paint.
I would wait until it outgassed and had no smell at all before putting the mirror back. I would only do the inside if possible so the outside can hold your alignment marks.
Others know more about flocking than I do so check the posts. The inside of my 35 yo c8 scope looks perfect , but perhaps it has been repainted inside.
QUOTE=Hemi;1430387]Hi SF,
The primary and secondary mirrors are fine, just a little dust.
The corrector has water marks and Mould.
The aluminum tube has massive amounts of oxidation. The baffle-draw tubes are dusty.
So I spoke to Don at Bintel, who thinks its Oxidation/corrosion rather than mold. Someone suggested that on cloudy as well. In any case I have gathered all the required parts, looked at many videos and online blogs. And Don has sent me some instructions as well. He also suggested I flock the interior. Hopefully I will have the OTA up and running again, otherwise it will have to be the Frac until a replacement comes along in the classifieds! Pity I missed the 11edge HD!
