Jannis

I'm having some problems with my wheel not always detecting all 5 filters.This have now happened on 2 different computers, and i've tried both old and new drivers, as well as multiple capture programs. The wheel i have is a 5 filter wheel, and when it detects all 5 filters then it works, but when it only detects 3, it will naturally not let me select filter in 4th and 5th position. Does anyone else know how to fix this?

To me the first looks better then the 2nd, however, that might simply be cause it does not look like the Ha was aligned properly. At 100% scale you can easily see the channel being off by a few pixels. I'd give the 2nd version another go with more careful alignment and see how it turns out. v3 looks too soft. Your 4th version by following Olly's advice is without doubt best in my opinion, but for nebula with less stars maybe your v2 method would be better? It depends what one like i guess.

Well, i found out i unfortunately have the C mount 5L, not the CS - however i found a solution thanks to you guys! First of all, this worked fine with the C mount front in place even though this or 5mm longer then the CS mount front. I didn't find a T2 to 1.25" adapter, but i found an adapter from T2 to slightly smaller (yet larger then 1.25") thread that came with the lens lit from QHY that just happens to fit perfectly with a 1.25" adapter i had laying around when installed backwards! This is what was needed to connect the 5L to the wheel and reach inf focus (and way beyond).

Thanks guys! I didn't even know there was a C and CS option available for that camera, i assumed it was CS. I will double check. However, i did try with the Polemaster as well which i know is CS, and that didn't focus either - and a different solution then my current adapter will for sure be needed.

Thank you! Yes, it is indeed planned to upgrade the camera at a later point, but that will not be before earliest next season, and so i was hoping i could use the QHY5L-II for now. I already have the M54 to M42 T M-F adapter, it actually looks like it's identical to the one Bernard sent me. I just gave him a call now, and he have both the T2 to 1.25" that you linked to, and the standard length in stock. I will check which ones is best suited and make an order for it. The only risk i see by using this solution is the risk of the camera slipping and falling onto the filter, should i be un-careful in the middle of the night - but the 5L have a protection ring i can use if i go for the low-profile type so that shouldn't really be an issue.

The QHY5L-II-M. It appears i can grind it down a few millimeters, but i'm hoping to avoid that.

Just received my QHYCFW2-M Ultra slim wheel yesterday plus a set of Baader 2" LRGB filters and the Canon EF lens kit for the wheel. I put everything together and tested it OK, but i quickly run into a major problem... I can't focus beyond around 2 meters... To connect the CS mount camera i received two quite low profile adapters. One from M54 to T2, and then one from T2 to C mount. All in all this does not build up very much, but it appears it was still just not close enough to reach inf. focus. I don't know exactly how many mm closer i need, but it's not much. I tested by manually holding the camera closer without an adapter and it appears i can then reach focus and well beyond that without touching the filters. So in theory, this means i should be able to get it all working with an ultra low profile M54 to C mount adapter - but does anyone know where i could be able to find such an adapter? Bernard at modern astronomy unfortunately did not have any lower profile adapters then the ones he had already sendt be. Alternatively, if there exists a lower profile M54 to EF mount adapter that would work too, but I've been unable to find it.

I will receive my new QHYCFW2-M filter wheel with a set of Baader HaLRGB filters any day now, and i will most likely be starting my imaging season with camera lenses and the Polemaster as my main imaging camera. My two main lenses will likely be Canon 50mm F/1.4 and Olympus OM 135mm F/3.5. I might also be using an EF-S 55-250mm f/4-5.6, but i will have to see how it perform first... Naturally the most easy way is just to select a lower F step on the lens, but this causes unwanted star spikes (as well as it's not a manual setting on the Canon lenses, so changing it is not too easy). To prevent this i've seen some people use simple filter step-down rings to manually step down the lenses without getting any artifacts. This seems like a very simple and good solution to the problem as i will how have the filters behind the lens instead of in the front, however i'm not sure how to calculate what step-down ring size i will need to reach the different F ratios? Is it as simple as measuring the size of the opening of the step-down ring and the distance? Like, say i get a 58mm-25mm step down ring and attach this ot the 50mm lens. Will this then give me 50mm / 25mm = F/2 (roughly)? Also, is this a solution that causes any other known problems?

I dont think you read the entire thread... :-) The sensor is the same, and the lens is easily removed. I have used it even for narrowband with better success then the 5l due to no FPN removal, meaning my calibration frames actually works. its unfortunally limited to 120 sec exposures though..

I have not used the polemaster as an off axis guider, however, considering it's using a standard CS mount lens it should have the same back focus as the QHY5L-II i would guess? If so, I'd guess the back focus is 12.5mm. Or is this different when using an off axis guider? This is the lens type the Polemaster originally comes with: Specifications: Focal Length: 25mm Angle of View: 11° Distance of View: 70m Image Format: 1/3", 1/4" Mount: CS Aperture: F1.2 Suitable for cameras with either a 1/3" or a 1/4" sensor.

Indeed! There is no more risk of silicone grease spilling now and the metal appears to be clean, but i will give it one round of acetone just to make 100% sure. I don't yet know if condensation will be any issue, but i'll keep an eye on it. It may have enough friction as it is now after some slight modifications, but some more testing will be needed. It run fine for 4 hours last evening until i had to call it a night, and the rotation speed was only about 2-3% off (i will improve that later, but it's a great starting point i think).

You are correct there Peter, the nylon wheels are with just a center bolt. I have used silicone grease on them though, and i think that helped a bit. I agree ball bearings would help even more, but I'm not sure how i could attach it properly. I do have a set of brand new skateboard wheel bearings available though, maybe i can make them fit somehow. I'd need more bearings in the end though, but 4 wheels with bearings would help to start with. The bracket for the lateral support wheels are a bit flexible to compensate for any unevenness, but it's quite stiff. I will try to make it slightly less tight and see if that changes anything. A 2nd gear set, pulley belt, and motor driver have been ordered now anyway just in case, but what a joy the 15-45 day shipping from china is...

Thanks guys! Well, it appears i wasn't that lucky though. ~2:15 in it started slipping again... It's an improvement though, as with the 3 added support wheels pushing from the inside the nylon hose was unable to even run for a few minutes, and even started slipping at slewing speeds, where it would previously work for 30-60 min. I will start with a cleaning of the steel ring again and run a retest though, as i have been lubricating a bit with silicone grease, and i don't know if maybe there was some spilled.. I can still sand down a bit more to get more traction area, and i probably don't need the 3 support wheels pushing so hard on the ring. I will work more on it, but i think i will also order the gears for the 2nd motor just to be sure. If it could run for two hours with just 1 motor then it should probably not be any problems at all with two. More work and cost involved though, as well as waiting time for the parts.

Thank you for all the help so far guys, and also to Xplode for your PM with great info and tips! I have so far tried to use Plasti Dip to rubber coat a thinner rubber hose(real rubber this time, but too thin), and while it indeed had enough friction and didn't slip at all, it ripped apart at sidereal speed - even with ~10-12 thick layers. Because of that failed attempt I've been checking up options for having a custom made wheel with a U profile to match the steel tube and have it coated with high friction rubber designed for this use - but i have yet to get a response back from the company on the price and time needed to make it. In the meantime, i might have found a more usable option. I found a piece of solid rubber designed for resting for example engines on to absorb vibrations. This is seemingly very tough rubber and designed to not not let go of the metal. It also appear to have decent friction, and is just about soft enough to get a good grip without twisting and tearing. I sanded it down to a rough U profile so it now have 3-4x the gripping surface compared to a "flat" wheel. Since it only had a short M8 bolt i gave a flexible connector a go as i needed M12. I was skeptical at first with regards to how much torque this flexible joint would handle - and i guess i had reason to... Well, so, plan B... I sanded a bit of the M12 rod down to roughly 9mm and threaded it with M8 1.25 threads and used a bolt connector to solve the issue. To make sure it would stay put i also filled the connector with high strength epoxy glue before attaching it all. I run a test with slewing, and it did not slip even one bit. I'm currently running a sidereal test, but naturally it will take time before i know if it works or not - however it's been running for ~90 minutes apparently without slipping som far! I'm thinking that if this still slips at some point, but the rubber can withstand it, my easiest option would probably be to attach another motor on the opposite side so that it will rotate more easily.

Thank you very much for your advices guys! I have now removed the anti-slip tape again and will first of all try to get the nylon hose replaced by some real rubber and see if that alone works. The most easy option would be to use racer bike tubes as they might be small enough to just stretch over the current drive wheel - but are the bicycle tubes strong enough, and are they not made to have minimum friction for easy installation/replacement? I don't think there would be space to glue a racer bicycle tyre to the underside of the metal ring, but it should be space to glue on a bike hose to create that rubber<->rubber contact. I also thought about making the drive wheel U or V shaped to give larger traction area, but i'm not quite sure how to get that done, but i will look more into it. A spring loaded system won't be possible due to there is no space above the metal ring, however the drive wheel is intentionally slightly oversized for that spesific reason, so that it takes most of the weight off the 2 closest wheels. There is probably about 25-30KG resting on the drive wheel. I also learned it the hard way today that adding strong sandpaper to the metal ring and holding it in place with strips was not a good idea, as the roof actually got pushed off the wheels when it hit the strip. So i have now attached 3 extra guide wheels to make sure that sliding off simply will now be possible ever again. This howevere, made it even a bit heavier to rotate, but at least now i know the roof will stay on the wheels...