Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

Search the Community

Showing results for tags 'dob'.

More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


  • Welcome
    • Welcome
  • Beginners
    • Getting Started General Help and Advice
    • Getting Started Equipment Help and Advice
    • Getting Started With Observing
    • Getting Started With Imaging
  • Community
    • Official SGL Announcements and Events
    • SGL Challenges and Competitions
    • SGL Star Parties
    • Star Parties & Astro Events
    • Celestial Events Heads Up
    • The Astro Lounge
  • Retailers
    • Sponsor Announcements and Offers
    • FLO Clearance Offers
    • IKI Observatory
    • Supplier Reviews
  • Astro Classifieds
    • For Sale / Swap
    • Wanted
  • Equipment
  • Observing
  • EEVA (Electronically Enhanced Visual Astronomy)
  • Imaging
  • Science
  • WADAS's WADAS Discussion Forum
  • Beaufort Club's Topics
  • Swindon Stargazers Club's Topics
  • East Midlands Stargazers''s Topics
  • Central Scotland Astro's Topics
  • SGL Cumbrian Skies's Topics
  • Herts, Beds and Bucks Group's Topics
  • SGL East Anglian Group's Topics
  • South Leicester Observers's Topics
  • South Wales Group's Topics
  • SGL Surrey Observers's Topics
  • South Yorkshire Stargazers's Topics
  • Yorkshire Astronomers's Topics
  • Devon and Cornwall's Topics
  • West Midlands's Topics
  • Essex Cloud Dodgers's Topics
  • Essex Cloud Dodgers's New equipment
  • NLO and Planetarium's Topics
  • Astronomical Society of Edinburgh's Discussion
  • Dorset Stargazers's Topics
  • Hairy Stars Club (Comets)'s Tutorials and Guides
  • Hairy Stars Club (Comets)'s General Discussion
  • Hairy Stars Club (Comets)'s Observing Campaigns
  • Hairy Stars Club (Comets)'s Analysis results
  • Hairy Stars Club (Comets)'s Useful Links
  • Pixinsight Users Club's Pixinsight Discussion Forum


  • Astro TV
  • Celestial Events
  • SGL Calendar
  • Astro Society Events
  • Star Parties
  • WADAS's Events
  • Beaufort Club's Events
  • Astronomical Society of Edinburgh's Events
  • Dorset Stargazers's Events


There are no results to display.

There are no results to display.

Find results in...

Find results that contain...

Date Created

  • Start


Last Updated

  • Start


Filter by number of...


  • Start





Website URL







Found 40 results

  1. Does anyone happen to know the size of the small, black, flat-tipped, philips head screws that hold the primary mirror cell in place. These are the screws on the outside of the OTA at the end, just above the black "collar" of the mirror cell. Thanks.
  2. Any suggestions on positing this to a better section then please let me know... I have been using a 200p Dob for over a year now. I have been impressed with it and managed to take some decent pictures and web cam videos whilst nudging it around. www.mauton.co.uk To add to the mix I have a modded XBOX webcam along with a Canon1100d DSLR. I have decided that I am interested in DSO and have been thinking about upgrading to a GOTO/Tacking mount such as the HEQ5 and/or 80ED. My options are as follows, with questions on each: 1. Buy a new mount HEQ5 (not sure on exact model yet) with a 80ED Refractor. This seems to be a good entry setup for DSO's from various posts on these forums. Q. Will I be able to use by DSLR 1100D fine? or will I need anything further Q. Except for the obvious improvement with a tracking mount, how will the 80ED improve the images I can take over that of the 200p ? How does the f7.5 as opposed to the f5.91 make that much difference? 2. Sell by 200p Dob and purchase a 200p on a EQ-5 mount. It would be the same scope however I get to have a mount which can then be motor driven. Q. Would it be worth it in any way keeping the 200p and going with option 1? 3. Has anyone mounted a 200p Dob on HEQ5 mount? Then all I have to buy is the mount.... Q. How would the image quality etc be improved if I purchased the ED80 ? Many questions I know !!! - But please any that you can. Thanks
  3. I threw an opinion into the mix in the beginners forum the other night and decided I should expand on my reasoning here. Even somewhere as benign as SGL, you still have to remember this IS the internet. That means opinions repeated enough by people with large post counts, gain credence as fact among the rest of the forum. It does not hurt to challenge that, if only to get people thinking, as long as you do it in a reasoned way. So..... What got me thinking was the humble 8" Dob. For instance, I've noticed that the most recommended scope for a beginner is an 8" Dob; 10" if there's a sniff of the OP having a bit more to spend. The thing is, a rake of this recommendation appears straight off the bat, without further quizzing of the OP, but for most newbies, I think it is wrong. True, a great many people started there and went on to bigger (some might say better) things, but a lot do not. You don't have to be Poirot to notice it's also the most sold scope on Ebay, along with the EPs it came with; reasons (excuses) of needing the space, etc, being given. The ratio of 8" Dobs for sale on Ebay is greater than on here. A lot of people don't stick with it long enough to achieve the fifty posts required for access to the classifieds. Why? Because if you don't know your way around the skies, you'll find it really hard to find stuff and you'll break your back grovelling around doing so. It is also a scope that will likely be way off the mark in collimation out of the box and be harsh on the rather basic EPs* it came with. When I started, my Explorer 200p only showed half the primary when looking down the focuser. They really can arrive that far out of whack and dealers these days are driven by price, so they are extremely unlikely to have seen more than the outside of the box you've been shipped. Few would actually check the scope and if they did, most people would whine they're too expensive. Service costs. So, if you do find something on your first light with your new scope and then pop in the 10mm MA it came with, it will look rubbish. De-collimate your scope with a half decent EP and have a crack at Jupiter. It's not impressive and that's as easy as it gets. For a n00b, it's confusion time. In other words, it's not the most intuitive scope, it has a built in steep learning curve just to get it to work and requires immediate upgrades just to get near what this, admittedly capable scope in the right hands, can deliver. The 8" Dob is best suited to someone who has at least used binos, or a friend's scope. That way, they'll have advice on hand. So my contention is that, in this push button, battery driven age, the ideal beginners scope is a 127mm AZ GOTO Mak. I can hear the hackles rising, so let me justify this. I'm not interested in the cries of 'It needs to be level, it needs to be pointed North!'. That involves a bubble level and the one star everybody knows. People who get the date format wrong should RTFM! Anyway, if this is tricky, how are they going to get along with a Planisphere? No, the learning curve is minimal and when the crisp little optics and it's long FL, which is easy on cheap EPs hits a target, it's going to be a sharp view. If it doesn't hit the target first time, the erstwhile n00b will slew around a bit and unless they're complete attention deficient, will hit the target. This is my point. Getting the first few targets a newcomer sees to be clear, is the hook that keeps them engaged. Jupiter will look good in a Mak. Saturn at any size when sharp is unforgettable. The moon will look amazing and M42, M57, globs, etc, will be good enough to show people there's a universe out there they hadn't even considered. I know an 8" Dob will do these subjects better, but it's not exactly Wow! territory. There are plenty of atmospheric UK nights and particularly from suburban locations, where a 5" Mak might actually do these subjects better. Now I know that hardly anybody reading this will still have their first scope, but if one of these had been, it would still be a great little grab 'n' go, plus a handy mount for an 80mm ED/Apo for the same purpose, plus white light solar, etc, etc. Nobody who starts in the hobby with an 8" Dob stays there. In the long run, rationally, the humble 5" Mak GOTO is a very handy little weapon on a number of levels and one that has uses further down the line. Russell * One of the scopes I bought at a time when my collimation learning curve had long since flattened off, came with the usual 10 & 25mm MAs. For a laugh, I thought I'd give them a go. You know what? In a 300mm F4.9 Dob, they weren't that bad. The deficiency I recalled, was in fact, mostly mine in terms of collimation - It was far easier to blame the EPs and post yet another 'What EP for a n00b' thread....
  4. Hope someone with more experience than I, which basically means anyone that has successfully collimated a Newtonian, can answer a couple of compound questions I have based on my first and only attempt at secondary collimation of my SkyWatcher Flextube 250. 1) All three of my secondary collimation screws were extremely snug before I did anything and I was only able to comfortably turn them counter-clockwise. Is this normal? Do I need to loosen all three screws first before I can properly start collimation? Should I be turning any screw beyond "snug"? 2) Before collimating, I placed a yellow sheet inside my OTA opposite my focuser tube and I placed a red sheet between my secondary and primary. The view this gave through my focuser tube was of a red circle surrounded by a partial yellow ring (the secondary mirror stalk blocking a portion of this yellow annulus). While independently turning each of the secondary collimation screws counter-clockwise I looked down the focuser tube (both with and without a sight tube installed) expecting to see some change in the shape of the red area (more or less circular) and/or the yellow area (less or more even thickness). I turned the screws no more that 2 complete revolutions. I did not perceive any appreciable difference in what I saw and I turned each screw back (clockwise) to their original tightness before working with another of the screws. Does it make sense that I didn't perceive any change? Should I have turned the screws more revolutions? Should I have loosened more than one at a time? Very confused and looking for your help. Thanks
  5. Hey all, I've been having a spot of trouble with my 7mm X-Cel EP, when I look through it, I see a lot of tiny black spots across the entire field of view, it's rendering the EP useless. I've checked to see if it's dirt but the EP looks spotless to me. My mirrors are about 18 months old and I haven't cleaned them myself, there's a bit of dust and dirt on them but nothing severe. When I use a 9mm EP I don't see the black grains at all, I suspected it maybe dirt on the primary/secondary which only becomes apparent at high mag. With that I mind I tried barlowing my 9mm last night to get a 4.5 mm EP, with that still I couldn't see any black grit or dirt marks. I believe it's the optical coating on the 7mm EP, I think it's degraded or maybe there's dirt inside the EP. I've since gone back and cleaned the 7mm methodically but no improvement at all with the view. When I was looking at the moon last night It was as if i could see 30 or so transits all at once moving across it!!! Does anyone have any experiences they could share? Any tips or potential solutions? Thanks for any replies.
  6. I wouldn't want to miss observing the Sun in a full-size 300mm filter, the detail compared to smaller instruments is such a joy to see. I do have an off-axis mask for my 300mm dob but not all the time. If daytime seeing is too bad for such a large scope, I'll switch to a smaller one, but the extra resolution and ease of spotting micro-detail thanks to the brightness is something I can't do without. A sheet of 500mm wide Baader fillm allowed me to craft this. I had enough left to cut several smaller filters. To protect it I made a storage box from cardboard of obvious origin. The box had to be custom-made to save space in my dwelling, and it also hosts a bahtinov mask for nighttime. At f/5 fine focus is not too hard with the smooth single-speed focuser, but in order to enjoy moments of clarity immediately at high power, I pre-focus with the bahtinov, which sees through turbulence, what a nice invention, and simply wait for calmer air. No need to rush to fine focus and waste precious moments. This mask needs to be copied in some sort of plastic, the cardboard trial proved the number and width of the slits are fine. The rear of the filter shows the four clips mating the four button screw heads outside the tube. And this lateral view shows the sandwiching. A rigid backing plus two layers of lightweight neoprene foam cut from a cheap mat in tiger-stripe deco, its poor taste matching its 7€ price. The bottom sheet used to be a shower booth panel, my neighbor had in its garage. Hey, do you need that? No? Okay, thanks! The Baader film is held between the neoprene sheets by staples and many strips of tape. The neoprene is held to the shower booth sheet by little collars, and its edges are sewn together for a finished look. Oversize 10mm stitches didn't take too long to do, and the foam layers can be separated for replacing the film, something glue would prevent. Holes in the neoprene allow to check that the clips' bolts are always tight. Close-up of a clip. They are made of a material whose name I forgot, I only remember it is made in the UK (thanks, guys!). This is a PVC foam that's much easier to cut, drill and sand than full-density PVC, and it's much lighter (thanks, air bubbles!), which is essential for an item that's at the front of a scope where leverage is maximal. My GSO dob has four of these screw heads, one for each spider vane. They proved very convenient for attaching the filter. The black knob is an add-on to move the scope without having to grab the large tube with both hands. Pretty obvious what we're seeing here. Note the clip is flush with the tube, and pressed hard against the scope's metal rim for a very secure and tight fit. Only four clips but eight attachment points, really. Building this with tight tolerances was more lengthy but more reassuring. It is impossible to disengage a clip by accident because tolerances are too narrow, and the shower booth plastic tough spring action doesn't allow it. But should it happen three clips would hold the filter safely. All three layers of frame material are flexible, so, to remove the filter from the tube you just bend it at a corner while you lift the clip, and the clip disengages. I already rebalanced the dob by pulling the 7-kilo mirror to the rear thanks to shorter and tougher cell springs but I'm working on a sliding counterweight made of pliable steel ribbon. Adhesive felt pads protect the paint. Thanks to the large hole the 300mm filter is not too heavy (and it's used without the finder) but the off-axis mask has only a 115mm hole, so it's heavier and may require this. While I study the combinations of heavy or lightweight eyepieces, finder/no finder, mask, filter, I can change the experimental counterweight by cutting off or adding pieces of steel ribbon. Little mounting nuts and bolts through the many holes, there's always one at the right place. Ever hated to feel the Sun while loving to watch it? If you have no sunshield you did. Heat is a discomfort on the head, and light kills off contrast. So I cut a plastic folder in this weird pattern to allow sliding it between the shower booth plastic and the neoprene mat. When it's stuck there it makes quite a large area of shadow, that's such a relief. But that's also only a prototype that wants to be made again with a better material. Has to be opaque, quite thin, very lightweight, but rigid enough. I'll stumble upon the right material sooner or later.
  7. Hi all, I want to share with you my so far best image of Saturn, taken using: 305/1500 goto dob Skywatcher QHY-5 mono IR-UV block filter Baader barlow 2.25 Registax, stack of 40 images, postprocessing
  8. I am about to buy a high quality 250mm F/6 (or longer) dob. I will invite Orion UK to tender, but who else would you go to?
  9. I have a Skywatcher 200p Solid tube dob. I was curious if it is possible to fit the synscan system onto it like their truss tube dobs. Anyone have any insight on this one? It would just be nice to have since I live in the middle of downtown so finding some things isn't always as easy as it should be. Jon
  10. Thanks to those who contributed to my choice ITS HERE.... Woopeee. Of course it arrived yesterday just in time for the last bit of clearish skies... minus the box with the base in. That arrived today. Purchased from Amazon by OPTICRON TECHNOLOGIES who sell for Orion (US) and distribute from Holland so no nasty import surprises. The BIG box with the scope had been a bit through the mill being transported by FedEx with a few holes punched through the outer box but the inner box and scope were fine..well packaged. Waiting for the base gave me the chance to set the scope up on the table sitting in its foam cradles and check the collimation . It had been through the wars so not surprisingly it needed a quick tweek . Nice big knobs to do the job...I think its OK but star test will tell at first light. My first play at this being an ex SCT man. The second box arrived today... the build and installation of the push to bits was easy IF you followed the videos on the Orion Website. Don't try with just the literature. Its the right choice for me. I can only just carry it assembled from my garage to the deck about 15 meters. Just the right size to break down and fit my Ford Focus. I will do a First Light post but for now I must apologize for the poor weather for the foreseeable future.... new scope you see
  11. I picked up my new (and first ever) dob from Nottingham yesterday. Its a 20" f3.6 Lukehurst dobsonian. It has a 1/10 wave mirror. David Lukehurst gave a quick demo of the scopes features and answered my questions on collimation. Then it was time to dismantle and put all the pieces into my car. I had taken some duvets and pilllows to allow me to get everything packed in and there wasn't much room to spare... Everything was unloaded into my garage just before dark. Today I have been making up some wiring to connect the various "enhancements" that will increase my use of the scope. David had fitted the powered ground board, 10K encoders and Nexus controller plus UTA dew controller unit (he cleverly wired the dew controlled up through one of the hollow trusses which is a neat solution) & secondary heater. He has added a few pass through holes in the corners that made it easier to get the cables out to the mirror box to connect up the fan & UTA dew system. Once that was complete, I got my neighbour to help me carry the mirror box from the garage down to my shed (obsy). Assembly was a breeze as David numbers each side and each of the trusses so you get them on the correct side (easy). I added the shroud then attempted collimation using the Howie Glatter laser & tublug. The secondary was almost spot on and the primary took a half turn before the triangle shaped centre spot appeared in the tublug display. I gave the Nexus a test with a false alignment on the sun and practised some push pull to find the imaginary mercury and mars. All seemed to be working fine. Just had time to fit my astro systems scope coat and see how much spare material there was as the coat is for an f5 longer scope. Anyway, too much cover seems to make the job of putting it on much easier Now, I just need a clear spell to get out and align the finder then we should be away! Alan
  12. Skywatcher 250PX Dob modded with Wixey alt/az encoders Well loved in excellent condition, stored in house. Mirrors light dust never cleaned (scared to :-) apart from rocket blower and MC Donald straws ) Secondary has steel washer mod, Base has lazy Susan mod, also levelling feet and wheels. Focuser is standard but will include self centring adaptor. Also included 50mm illuminated RACI finder. Also Baader laser collimator. Obviously due to size, collection only or can meet if local ish. Selling as going solar ... Any questions feel free to ask. ***photos tonight*** Also on UK Astro buy and sell
  13. This is the first mod to my newly acquired 250px. The teflon pad bearings on the mount are quite simply atrocious for a scope that costs over £400.00 new. Simple solutions are on hand though. Enter the B-Tech BT540 Television Turntable. These were available on Astroboot for a while and Amazon UK but they are currently out of stock. I am sure other brands of a very similar nature are available. This is a 16" bearing with a 75KG load bearing capacity. 1. Remove the dob mount pivot bolt and remove the teflon pads. 2. Remove the sticker centre from the turntable and push out the 2 part fixing so it comes apart. On checking the innards it is quite well made with steel bearings running in 3 channels. The centre hole is the same diameter as the pivot bolt so no machining is necessary. Put the unit back together, you can apply a little contact adhesive to the outer edge, this will aid assembly later. 3. Cut in half the dob mount centre bush. For ease of assembly I glued each half back into the woodwork with some contact adhesive. 4. Obtain a replacement centre pivot bolt that is 30mm longer than the original. Should anyone need one to try this mod let me have your address and I will pop one in the post to you. I only have 3 so it is on a first come basis. 5. Line everything up and reassemble with the new pivot bolt. Total build time about 20 minutes including waiting for the glue to dry and a 10 minute trip to my local nut and bolt shop. Mount is totally transformed, smooth and stable. No machining required whatsoever ..... simples
  14. Good Morning, Does any of the guiding softwares out there auto-correct a sync scan auto dob, with the use of a guide scope? The main use would be to to keep Planets in view so several runs of imaging them can be done in a session. I notice my XT8G does drift out of view ever 10mins at 250x. If I wanted to take gifs or many shots of something I'd need it to stay more dead on for longer than that. I have gotten as close to perfect gps coordinates, time to the second etc. Thanks Enrico
  15. Hey guys A guy in my area is selling a 13.1" Coulter Odyssey, the 2 mirrors. I'd want to get an idea on the optical quality of them. He bought the many many years ago, and they still in the original package, hasn't been used. 1. Would the optics degrade over time if they were wrapped up? 2. What is the general quality of the mirrors. I have heard the optics can vary alot, and they generally not that great for planetary views. 3. He is selling them (and he mentioned the Rocker once) for around $350, is this good for a un-used mirror. I'd like to build a really nice DSO / Planetary Dob, and this gives me hope if the optics are really good. Any advice, tips etc would be greatly appreciated. Tx guys
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.