I recently ordered a Moonlite 2.5" focuser to replace the stock unit on my Skywatcher Black Diamond 120.
When I originally bought the telescope I was aware the supplied focuser was temperamental (thanks to a gentleman in Canberra who owns one, who turned out to be a member of this forum -- I've forgotten your name, sorry!) and even though I successfully resolved the problem of having the drawtube slide out under heavy load (a problem which is simply due to how to focusers are assembled and adjusted in the factory), I wanted something a bit more robust and decided to give the Moonlite a go.
After placing an order with Moonlite, it took just 4 business days for the unit to arrive in Melbourne from Pennsylvania, carefully wrapped and in pristine condition. Installing it was an absolute breeze and took about 2-3 minutes.
Aside from the blazingly fast delivery time and the excellent quality of the product itself, Moonlite have provided nothing less than Tier 1 service when it came to answering my questions about the purchase.
After I installed it I found that I was no longer able to achieve focus with my 4x barlow connected and that I needed a couple of millimeters of extra travel. I contacted Moonlite and enquired as to whether they could provide a 2.5" -> 2.0" compression ring that was deeper than the 10mm one supplied, so as to gain the extra travel needed to resolve this problem. Much to my surprise, Ron from Moonlite wrote back and said that they could manufacture the part for me during their next machining run. I mean, let's face it, most companies would just turn around and say, "Sorry, the one we supplied is the only one we do."
I am very happy with the Moonlite focuser. The 2.5" diameter drawtube appears to make everything brighter when compared to the one supplied by Skywatcher and I look forward to trying out the high-resolution stepper motor which I also ordered as part of the kit. Their gear is worth every cent you pay for it and their service is fantastic.
The bearings on my focuser broke (probably as a result of me tightening them to much). I contacted Ron and he sent me out a replacement set FOC!!! Even though my focuser was out of warranty.
I replaced the focuser on my 12" Skywatcher flextube with a 2" Moonlite and the difference over stock is incredible. Much easier to achieve sharp focus with the dual speed, smooth focuser.
I have just ordered the 2.5" focusers with motor for my RC8 and ED80. They are at the post office now. Delivery was quick, in fact it's spending more time in customs (over $1000) then it did to get here from the US. Ron's advice on what I needed was comprehensive with quick replies.
Do you have any pics of your shorter 2.5" to 2" adaptor Brett?
I had a 2inch and then upgraded to a 2.5inch and am happy as well. Ron's customer service is great.
Only minor issue I had was that the drawtube in both my 2inch and 2.5inch were very slightly tilted, possibly due to the pressure from the teflon pad.
you can see this when you draw it in completely and if you have the 3 bolt compression drawtube, one of them wont touch the body. Not sure if others have this issue.
I asked Ron about this and he said that can be adjusted with collimation or the base hex bolts. That's the only bit I wasn't too happy with but the 2.5inch seems to hold my load pretty easily. need to see if it works well in heavy dew.
Thanks for chiming in, guys -- I am glad that other people have found Moonlite to be similarly pleasing to deal with.
Alistair -- I believe I had the same issue with my 2" Skywatcher focuser, a slight tilt that became only worse after installing their focuser motor. Although there are a few hex screws that can be adjusted, it was asking too much from the Skywatcher focuser considering the load I was trying to have it bear.
I've attached an image of the compression ring you asked about. I notice you've got AO (I'm assuming it's AO and not just an OAG) and filter wheel happening there alongside your camera. I'm hoping the Moonlite has enough travel to allow me to add those to my own setup in the coming weeks.
A few people have questioned my motivations for wanting to do so on a low-end refractor such as this one, but I like it and I want to get the most out of it. I'm hoping AO will help at 1800mm and 3600mm focal lengths.
Yes it is an Orion steadystar AO with its built in OAG, SXUSB filter wheel and an rcc1 coma corrector. Still hasn't had first light.
I would suggest using spacers from the body such that the focus is 5 to 10 mm from fully racked in. Less flexure on the drawtube and in some cases less vignetting.
What is the height of the lip of that compression adaptor? You mentioned 10mm, I thought you were referring to the bit thats after the thread.
The lip (I'm assuming you mean the segment where the screws are) is 10mm and so when the focuser is fully racked in, it leaves a 10mm gap. The longer segment after the thread is 30mm.
I was looking at getting the SteadyStar but the large format version is no longer available and I am not sure that the 40mm optical window (38mm actual) of the standard version is sufficient. After factoring in CCD size it doesn't appear to leave much room for the OAG pick-off prism. Also seems a bit of a waste having a 40mm window when the drawtube has an extra 20mm or so to offer.
I'm not surprised your gear hasn't seen first light yet, the ongoing cloud in Melbourne can no doubt be attributed to a flurry of recent equipment purchases ;-)
Any idea where one can purchase large format (ie 2.5" and 3.0") accessories such as focal reducers, flatteners etc.
Not too sure about the large format stuff. Try teleskop express. I buy most of my stuff from there and their prices (minus vat) are really good. Ups delivers in 4 days flat.
Mine arrived today; man, this is some nice gear. As soon as you hold one of these in your hands you're left without doubt that it was money well spent. The stock focuser I took off my SW Black Diamond ED80 seems like a joke in comparison.
Combined with the arrival of my Telegizmos 365 covers, this means I can finally get out and do some imaging again! Better yet, I can now get things actually in focus, and leave it out so I don't have to set it all up again every day.
I have the 365 covers from telegizmos as well. Had my rig set up in the backyard for the last 18 months and the covers still look as new as when I bought them. Very well made covers.
Mine arrived today; man, this is some nice gear. As soon as you hold one of these in your hands you're left without doubt that it was money well spent. The stock focuser I took off my SW Black Diamond ED80 seems like a joke in comparison.
It's definitely a sturdy piece of kit. The stock focuser could have been so much better if SW made the effort to machine it properly at the factory but if you want motorized focus, the Moonlite or an equivalent is the only way to go. I looked at alternatives, but one particular brand had the drive belt for the focus motor mounted externally and that didn't appeal to me.
I received the controller for the stepper motor in the post the other day and it's great, extremely fine-grain... and I can finally achieve focus with a barlow connected, which was a real hassle with the old focuser.
The only issue I've had with it so far is that it needed to be collimated. You might want to check this, Lee. It wasn't the focuser at fault, since they center them before they ship them out, but the SW tube not fitting flush against the 3-bolt Synta flange Moonlite supplied with it. There are 3 hex screws to adjust and although it took a while I eventually managed to get it dead center -- according to the collimation laser anyway.
I think there built quality is superb. The only quirk I have found is operating their focuser from BackYardEOS via ASCOM - the software assumes the focuser is starting either fully in or out - and won't allow the focuser to move the other way.
Checked this with Guylain (who wrote the driver for Moonlite I believe). Solution is simple - start the focuser either fully in or out so the Zero position is the true starting position. In the past I always set focusers to half way out (at nearly focused) and fine tuned them from their. Other focusers travel in both +ve and -ve directions (in or out) the ASCOM driver or BYE itself stop all -ve direction travel when the focus position reports 0 (presumably to protect the gear).
Once you know this - its all smooth sailing from there!
Matthew -- assuming that BackyardEOS is not the problem, I might be able to help with this.
When you connect to the Moonlite ASCOM driver, you should see a Windows Form like the one I have attached to this post. For some reason it starts off minimized, so it will probably not be on the screen as such but rather down on the Windows task bar.
Here, you can set the focuser starting position. This is 0 by default; if you connect to the focuser with the draw tube extended halfway, the driver will not move the focuser in because it thinks there is no inward travel available, which would be the case if you were truly at 0 (fully racked in).
The solution is to either:
a) connect to the focuser with the draw tube fully racked in, in which case 0 is the correct starting point. You can also specify a maximum position of 30,000 if you want the full available range (for a 4.5" draw tube).
or
b) specify something like 15000 as your starting position in the ASCOM setup window and then connect to your focuser with the draw tube at your preferred starting position. This gives you 15,000 steps in either direction, which the BackyardEOS should honor if it's talking to the ASCOM driver correctly.
Thanks very much Eden, I will definitely try this! I note this behaviour should have been very clearly documented somewhere, and preferably the control software should have issued a warning or error message saying it wasn't going to rack the focuser in because it believed the focuser was already all the way in. Instead I had to ponder why focus wasn't at all improving until I switched on the lights and saw focuser wasn't moving in both direction; a heart stopping moment until I reasoned correctly what was causing this behaviour!
The only issue I've had with it so far is that it needed to be collimated. You might want to check this, Lee. It wasn't the focuser at fault, since they center them before they ship them out, but the SW tube not fitting flush against the 3-bolt Synta flange Moonlite supplied with it. There are 3 hex screws to adjust and although it took a while I eventually managed to get it dead center -- according to the collimation laser anyway.
Thanks for the tip!
Forgive my ignorance, as I'm new to all of this and I've only used a refractor which don't need collimation so I'm not 100% sure what all of this means. Is it correct to say that incorrect collimation will result in optical aberration known as coma? And if so, would I be correct in thinking that the attached image is demonstrative of this phenomenon?
If that's so, can you, or anyone else suggest a good / cheap way of resolving this... don't really want to spend a lot if it's a one-off event.
Matthew -- You're welcome, let us know how you go with that.
Lee -- Ignorance? Not at all. Generally speaking, refractors usually don't require collimation as far as adjusting the objective lens is concerned. In this case I'm referring to the focuser itself. For best results, you want the draw tube of the focuser to be aligned with the center of the telescopes objective lens. Mine was off by quite a bit after I installed it and some adjustments to the 3 collimation hex screws were required to get it centered.
Looking at the image you've attached, at first glance I would say it looks like drift... but having seen some of your recent images (O Cen for example, which is really good I might add), I'm guessing you would know if this was the case? If you did a relatively short exposure on a bright star, are the results the same?
