raanany

I’m thinking about using the Sky Watcher Quattro 200 f/4 for viewing. I am hoping to get 3 degrees of FOV with ES 25 (100 deg AFOV). I believe I need a coma corrector and would like one that doesn’t magnify (I wish to maximize FOV). Thought I could get the Aplanatic coma corrector from Sky Watcher (designed for the Quattro series) but from the looks of it, I don’t see how I could connect an eyepiece to it. Is there a way to mount an eyepiece on this coma corrector or is there another corrector with no magnification I should consider?

Been out with the scope lately and would like to share my updated findings with you guys. First I'm happy to report that the optics of this scope are pretty good. There was an Obsession 20" f/5 at the same location (albeit a week earlier when I didn't have my scope with me) that I could compare with and I was surprised to see that the views in my 18" Skywatcher were nothing to be shy about. Eyepieces: 31mm Nagler, 21mm Ethos, 10mm Ethos and 6mm ethos. All were coupled with Paracorr 2 and occasionally Orion's Ultrablock filter. Venue: Negev desert in south of Israel (Borot Lots). Supposedly, the darkest place you can find in Israel, around 900m high. Except for some annoying humidity after midnight and some annoying wind at sunset, the sky was amazing even without the telescope. Objects: M51 using 21mm and 10mm looked amazing! I didn't see more details with the 20" obsession so felt pleased with my scope. Veil nebula: Beautiful details on both scopes. 52 cygni looks like in pearl sitting inside lace. Just beautiful. 20" showed more details but the comparison is a bit unfair because it was equipped with a Lumicon UHC and a Lumicon OIII (too much contrast for me) and I was using Orion's Ultrablock. Also, the Obsession was coupled with a different eyepiece. I think it was a Panoptic 24mm. When I get to put the two scopes one next to the other and swap filters and eyepieces, I'll report again. I got to see the veil also with a DGM NPB using my scope and it was better than the Orion Ultrablock. Cat eye - Beautiful. Could see the star at the center clearly. Ring Nebula - beautiful view. Jupiter/Mars/Saturn - This scope is not built for planets. With such high brightness you'd want to use high magnification. The problem is that without tracking and with such lousy alt bearings, you can't even manually track :-( My 6mm eyepiece was sitting useless. The view however, was as good as with the 20" Obsession so I'm guessing that in terms of Mirror quality, the 18" Skywatcher isn't bad even at high magnification. I'll update when I get to use it in better seeing conditions. I felt the limiting factor wasn't the optics. Build quality / Usability Sorry to keep moaning about this but the following [removed word] me off: 1. The shroud is not so well designed. The fabric has these ribs (strips) of flexible material embedded into it to keep it rigid and out of the optical path and these can (and will) twist inside the fabric and make it hard to fold around the scope. The scope's design also doesn't let you keep the shroud away from the optical path and it keeps getting in the way even when there's no wind. 2. The alt bearings suck. Even with ample lubrication there's just too much static friction. This is very annoying when you're trying to track an object at high magnification. You keep losing it until you give up. One has to apply too much force to overcome the static friction and once you've won the fight against it, dynamic friction kicks in and is by far weaker so you end up overshooting EVERY time. The Obsession on the other hand was smooth and fun to operate. 3. The mirror cover is... well... I don't want to get banned for profanity so I'll just shut up. That's it for now. I'll update when I have some new findings.

I relaxed the three colimating screws of course. The center screw wasn't the only one BTW. All screws show signs of prone-to-get-stuck. The main screws that hold the side rail bearings were all squeaking and weren't smooth to get in and out right from the start which is why I keep them in a jar with a bit of oil. They feel like they would rust quite fast if I won't

Yes, exactly like this ugly blue stuff. Question about the fans: If I wait long enough, the mirror's temperature should get to the surrounding air temperature even without fans, right? I mean, the fans can only blow ambient temperature air on the mirror. They don't have any active air-condition effect. And another questions: Why do we consider the mirror to be hot to begin with? Is it the mirror's absolute temp that we care about or the delta to the ambient temp? The scope included a shroud. I took the pictures before putting it on. Raanan

Pretty much the first one, yes. I'm an "all or nothing" kind of guy. I had a toy telescope when I was a kid. A cheap 2" refractor with an internal (I found out when curiosity lead me to open it up...) 1" aperture limiter placed right next to the objective lens. As I said, a toy. But the dream stayed and I finally bought a real one. Sort of. I'm confident I've achieved pretty good collimation using a laser collimator. I couldn't get the secondary mirror main screw opened (screw was jammed as I mentioned above) so only near perfect. I know that because when I fitted a 6mm eyepiece the diffraction rings around stars were centered almost perfectly. As for cooling down, I still didn't fit fans to the scope. Does it really make that much difference? The mirror on my scope is the fused one with the ribs. Instead of taking a photo, I'm attaching one from an earlier post. Sorry about that... Note that mine doesn't look that clean and shiny. I've got some manufacturing residues between the ribs. A hazardous looking blue coloured powder. As for the eyepiece I used to try and watch M31 - it's the 31mm Nagler coupled with a Televue paracorr so I should be getting around 1 Deg FOV. I know that's not enough to see the whole object but thought the total 1.8Deg would mainly add light in frequencies I'm unable to see anyway. Thanks for all the feedback guys. I'll post more when I gain more mileage. Raanan

Hi folks. Some of you may remember my post from a few months ago where I asked for advice on eyepieces Well, the scope has finally arrived and I’ve been out with it twice. I’d like to share my impressions with you. Build quality While I wasn’t expecting iPhone quality fit and finish from an 18” telescope, I was hoping that for NIS 21000 (GBP 3500, USD 5335) I’d get something of higher quality. Materials are cheap and I was disappointed to find the following: The four base mounted brackets comprising the bearings on which the two arched rails rest, were not accurately spaced. The distance between the rear pair was about 3mm narrower compared to the front pair. The front pair was correctly spaced but the rear one was too narrow. This caused the arched rails to get stuck. Friction was too high and it made the scope jerky to maneuver despite ample application of the supplied lubricant (vaseline). After making some measurements I noticed I may be able to improve things by opening the screws that hold the brackets and moving them by as much as the frame will allow (very little). This didn’t eliminate the problem completely as I was only able to widen the spacing by less than a millimeter. However, it did change things from being marginally useable to just acceptable. I assume that with wear and tear the silicone pads on these brackets will slowly fit the metal arched rails better. The manual obviously doesn’t say anything about the need to do this and I assume it’s simply the result of poor manufacturing precision and even poorer quality assurance. The black plastic shield protecting the primary mirror is a joke. It’s made of the thinnest plastic you could think of and is flexible instead of being rigid and protective. Also, instead of hanging on to the mirror box it just rests there and can easily move or fall off. There’s a padded foam clumsily glued to its inside but it’s thin and I wouldn’t want to count on it for protection should the cover get pressed or moved. I was expecting a rigid cover that screws on to something and keeps a safe distance from the mirror it’s protecting rather than this sorry excuse. It will protect against a falling screw but don’t expect it to do much more. The Mirror with the metal part it’s mounted on are pretty heavy weighing around 22Kg and with its sharp edges should be handled with great care. If the plastic cover protecting the primary was as I expected, you could potentially hug the whole thing to your chest making it easier to carry but being so flimsy, you’d be smearing the “protective cover” all over the primary mirror if you did that. Instead you’re left with holding the mirror box like a huge and very heavy dinner plate projecting from your body. Not very easy. All metal parts are made of cheap low quality metal. You won't find any high quality steel screws. The screws tend to jam and require pre-emptive lubrication. They are of such low quality that when I tried to unlock the secondary mirror in order to collimate it, the main screw’s head couldn’t handle the torque the screwdriver stripped the screw's head. Keep your shirt on, I know how to handle a screwdriver. I ended up buying a kit to drill it out. Picture attached. Optics This is where my opinion should be taken with caution. I’ve never looked through a telescope for more than a minute and even that was on 8-10 inch looking at the moon at company events. With the StarGate, I had a look at the orion nebula, Andromeda Galaxy and of course, the moon. Andromeda looked like an elliptic cloud with a bright center. I couldn’t detect the spiral I was hoping to see. Could also be my eyes or lack of patience and experience. The orion nebula was quite beautiful.