Carbon Brush

Interesting to note. Looking when the OP last visited. There has been the opportunity to look at all of the questioning and helpful posts made earlier than this one. No photos or other scope/eyepiece information, or 'fixed now' thanks, reports have been forthcoming from the OP. I have noticed a lot of 'help' posts being made by new members, usually followed by lots of helpful advice from established members, sometimes with requests for further information. But all too often the new member does not respond. In this thread a great deal was made of @900SL response. Although some would not consider it to be the best worded response. It does comprise valid content. OK moan over.

Excellent advice from @Louis D. You are spending >£500 on the scope. Look around SGL Classifieds for a 2" diagonal. If it works out, great. If you prefer something a little different, sell it on for little loss.

Yes the meter is set to AC voltage. As an aside. When an AC range is selected and a DC supply is connected, many meters show zero volts. Basically telling you there isn't any AC! This meter displays about double the DC value leading to confusion. I won't go into the (mostly cost saving) reasons behind this strange response. V-straight line is DC. Batteries, mount power supply output, etc. V~ squggle is for alternating (AC) supplies. That is (dangerous) mains and transformers.

@AstroNebulee I couldn't have said it better!

I fully agree with the idea of off centre masking, if using a newt (or other large) scope. I also agree that a small refractor or mak, or similar, are a better choice for ease of use. However, we do not know if the OP has another scope & mount available, or if his budget will stretch to this. An A4 sheet of Baader film is £23. Other materials to make a safe filter holder are probably free from the shed/garage. The leftover film can be used later for a refractor, or convert binos for sunspot viewers, etc. HTH, David.

Well I wonder what the OP eventually did buy? Given the last site visit was Nov 2022, soon after the opening post...... Yet another case of SGL members trying to help by venturing their opinions and never finding out if they were considered valid.

Never had hold of this particular focusser. But I'm thinking along the lines of @saac. The blue & red screws keep the pinion in the correct place for mesh in the rack. The green screw presumably retains the right hand knob. The purple screws hold the main shaft (gently) pushed against the opposite side of the shaft bore. This could be proven (or disproved) by taking the mechanism off using the blue screws and looking inside. If I'm right IF IF. After reassembly, bit of screw locking on the purple screws might be called for. Not a 'hold for ever - drill out' loctite. Anything a bit sticky to stiffen the thread. Of coure I may completely wrong. Free advice is worth what you pay and all that. The definitive answer should of course come from the retailer after the long weekend.

Thank you for linking to this fascinating book.

Just seen your mention of silicon sealant. I assume this is the 'no smell' cure type? Standard sealant releases acetic acid (vinegar smell) during cure. The chemical release from 'smellicone' sealant can cause a lot of corrosion problems in electronics. As for leaving in a warm or cool place while the silica gel works its magic...difficult but I don't think there will be a big difference. If there are problems fitting big bags of silica gel into anything, there is another way. Calcium chloride absorbs a lot more moisture per Kg of product. It changes from flakes to a lump or gel. You would need to buy it already packaged in suitable bags. It is a single use method. No oven reset. A further thought is that calcium chloride is quite corrosive - if it gets out of the bag. I have encountered this compound in big applications - not in small applications. This stuff from amazon may be worth a look. https://www.amazon.co.uk/NATRUTH-Moisture-Absorber-Bags-Fgrance/dp/B0BHX32SN7/ref=sr_1_10?dib=eyJ2IjoiMSJ9.z7yKOZaItl_GYJbR8CsMEUKRrcPjXnItbLiAy9KimxmKfQ3vx20ZgZmLrsx9WZ0pnFpN3IYxiK4WWvB6IrftE1l7UMx4zcwapvFZbe4A7FnayMlKffZp8WEYIbOAlBL3Ll4v5OMEY8GRclSgni5jcTXfOgGlD6Sm0phE4kOE8MKm7_7UYSxTWrZ48LdfP7oQik3StPj956HcMRqZvvv6o8nY6VQNAtifCD-E1giX91o.GYATK0_cPTdaEDZ7TwCBgiuSxKM2eb9kWwY7hR_e1HM&dib_tag=se&keywords=calcium%2Bchloride%2Bdesiccant&qid=1711633995&sr=8-10&th=1

Silica gel absorption is a very slow process. Give it time. Sealing the housing on a cold dry day minimses moisture trapped, reducing the burden on the silica gel. Something else to consider. Do you know anyone who has a MIG welder? With a cylinder of argon based welding gas. Standard argon shielding gas for MIG welders is an argon & carbon dioxide mix. Importantly no water vapour. In some equipment I get involved with, the electronics (and more) enclosure is purged using either nitrogen or argon. High pressure cylinders contain dry gasses. Feed the gas in slowly at one side of the box, allowing it vent at the opposite side. OK not a 100% air purge but a big improvement. HTH, David.

A sealed camera case is a good solution. It is my preference. First check the state of all the weak points. Clear dome to box gasket. Box lid to body gasket. Lid screws are outside the gasket. Any PCB fixing screws that pass through the wall muct be sealed. Cable exit via well compressed glands - not connectors, etc, etc. If you reckon the box is well sealed, put a bit of tissue paper in there - not the camera. Give it a blast from a pressure washer. Not too close, but simulate a gale and intense rain day. This also simulates wet air being present at higher pressure than inside air. Dry off the outside. Open up and check the tissue paper is good as new. If not look for the leak. Silica gel absorbs only a small amount of water for it's mass. The amount of water held in air is temperature dependent and not a simple straight line. I read somewher that a 1C rise in temperature can allow 7% more water in air. Then how do you know it the silica gel is dry to start out? Are the bags new and from an assured source? Pop the bags (yes quite a few) into an oven at a little over 100C for several hours. Yes hours. That ensures all moisture is driven off. Unfortunately some bags melt their glue. But the product is cheap so don't worry. Immediately, while hot, put the bags into a biscuit tin or similar. For long term storage this way, add sellotape to seal the lid. Now take your camera outside, on a cold day. There won't be much moisture in the air - unlike your warm house with pans boiling on the stove, humans exhaling, shower running, etc. Stuff as much silica gel into the camera as you reasonably can and seal it. Lots silica gel ensures you can absorb a lot of water and leaves little space for moist air. I reckon that should do the trick. When diving and snorkelling in the sunny parts of the world, I avoided condensation by storing my cameras and open housings in the fridge. Immediately on removal from the fridge, the camera was sealed into the housing with of course little air space. This alone was a very good condensation preventor. HTH, David.

Yes the camera is much too far away from the scope. As a daylight test, point your scope at a distant object. Get rid of all the 2" & 1.25" stuff. Wave your camera (with live view) in mid air above the focusser. When you see a focussed image, you have a measure of how much/little adapter train is permissible. This will guide you on what components are allowed. I have used this technique on various scopes (newt, Mak Newt & frac) to get a feel for the size of the problem. In some cases it has meant rummaging in my bits box for the correct spacers/adapters. Hopefully this is the case for you. In one case it justified the purchase of a lower profile focusser! If you find you are only looking for a couple of millimetres, look at the main mirror fixings. Moving the mirror up the tube a little will push focus out. Depending on the scope, you have to go a long way to make the light spill over the secondary to any extent. HTH, David.

Doing a bit of aimless web wandering I came across this interesting (to me) article. https://www.atlasobscura.com/articles/why-clouds-vanish-during-solar-eclipses?utm_source=pocket-newtab-en-gb

Absolutely. All my threaded parts are bought outside of astro retailers. Right from replacing the SW alt bolts (remember when they used to be made from stale cheese) by decent stuff, to replacing rusty screws by bright and shiny. Springs and ball bearings on a flextube come to mind for affordable replacements. Being born in Yorkshire has helped with financial control. I'm not saying the few bits of bolts sold by astro retailers are a rip off price. The retailer has to either buy in the small packet of screws at a high price. Or buy a bucketful for a good price and hope he sells enough of them. He can easily spend the same time sorting out the right screws as advising on a ££££ scope package. However, we must remember that some people don't know about screw thread sizes and all that. They have to play safe.

I had other things conspire against me this year, so missed the show. Fingers crossed for next time. Thank to all who have made the show possible, and those who have posted reports to let me know what I missed. In partcicular I note the photo by @Gfamily showing the sensibly located Pulsar dome. I recall it being almost an obstacle near the entrance at one of the Kettering shows🤣

The '127 Mak is generally tolerant of eyepiece type. I think first thing is to establish that the eyepiece/diagonal adapter, which screws in, is still there. If you post a picture of the arrangement, that will guide your next move. HTH, David.

If you tell us what mains adapter you were using, that might give us a clue. Ref comment by @Elp Much easier than diving into all the other potetial problems.

A contrail comprises water, carbon dioxide and bits of soot. As the carbon residues are tiny particles how long is it before they fall to the ground? While carbon is in the sky, it will seed cloud formation.. I'm sure someone somewhere knows about this effect. I remember reading a long time ago about Australian farmers making daily reports on pan evaporation. This was on the orders of the government. Agriculuture department maybe? Something that started in the 19th century and continues today. Sorry I don't have all the details. The evaporation rate had gradually changed due to the sky being less transparent. I took a quick look to see if I could find the article. But no luck. Again someone may know more.

Thank you for posting the article link. It is a much debated subject. At home I have a good view of a major high altitude airway. On a good day I can see a contrail start west of Liverpool (over the sea) and follow it beyond my Nottinghamshire overhead. I know where I start viewing by timing to overhead and assuming cruising speed, or more accurately using Flightradar 24 to track. Most contrails dissipate in tens of seconds, maybe a minute or two. Though on a few days, they can persist much longer. Then there is the question of dissipating beyond unaided eye view, and dissipating beyond heat retention. Think back a few years to the aviation shutdown caused by the (very long unspellable name) volcano in Iceland. We had a period of no commercial flying. I remember looking at the sky on more than one day after flying resumed, seeing contrails that were all but games of noughts and crosses in the sky! It certainly made me think about how 'clear' our skies are.

The 12V to 11V 'step' indicates one cell (of six) has shutdown early. Equal performing cells would give a gradual voltage decay. A bit of unexpected bad luck if it was a known brand. Definitely battery to the bin. You should find the lithium battery is good for providing high current. The other good news (given UK weather) is lithium performance degrades gradually with charge/discharge cycles. not the calendar. In addition, the self discharge is far lower than lead acid. A good choice for the replacement.

Some years back I converted an old Prinz scope to take (modern) 1.25" eyepieces. The not quite 36mm thread and Vixen adapter ring a bell. If I can recall the details I will add them. I do recall that when the fit was not quite right (couple of tenths of millimetres on diameter) I used a screw thread gauge as a scraper on the female thread to make things fit.

Methods vary between scopes, but I think this generic explanation of why you have to buy an expensive scope for Ha viewing is reasonable. The Ha solar scopes initially filter out unwanted wavelengths. Starting at the objective and refining further down the scope. Rejecting unwanted energy prevents scope heating. They remove the IR, the UV and most visible, leaving a narrow red region. The narrow red is passed to the etalon. This is a really really narowband filter that is necessary to view the filaments. In addition, the actual wavelength has to be tunable/adjustable to get best views. Doppler shift - another word to introduce. Adjustment is by tilting the etalon, or by altering the air pressure inside, or by altering temperature. Tilt and pressure are immediate adjustments, temperature is slower. To get the etalon bandwidth into perspective, it is typically 0.1 nanometres (nM) pass. Double stacking reduces to typically 0.05nM. A visual Ha filter for night use has 50-100 times the pass bandwidth. So even if the energy rejection was done, it would not show the filament detail. All manufacturers have to select their etalons from a mixed materials bucket containing research grade, to landfill quality. It is the way the material turns out. This means if you get a report of first rate views from a scope type, if you go to buy another, it may be better or worse. In the early days of the PST, I read about someone going to a retailer and setting up on the pavement. Selecting from the 3 scopes in stock, and seeing very different results. In the early Quark days a lot of people returned poor quality product. At a show I asked how the complete Daystar Ha scope could sell for less than a Quark eyepiece. The retailer could not (or would not) provide an answer. HTH, David.

Alternatively set them up, widely spaced, in a field. Call it the (Astrosoc name) Very Large Telescope Arrary. Oops - has that term been used elsewhere😁

If you really want to spend on Ha, look at the Solar Observing section around Jan 2019. There are quite a few entries about when I was trying to upgrade from PST. Various discussions mentioned Quark, Lunt, Coronado, etc. Some of it is still relevant today. If you are happy to stick with white light, a Herschel wedge gives a lot of enjoyment for the ££ spent.

Bolting the Vixen to the Losmandy as described by @RT65CB-SWL would be my first choice. I have access to good drilling and tapping tools so it is easy. Not having sight of the Losmandy bar I don't know if there is drilling involved. The only contra indication is if your mount is on the weight limit. Option 2 (again drill/tap required) is a couple of short lengths of ali bar (1/2" sq?) on the old Losmandy fixings to space the Vixen bar off the OTA. HTH, David.