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Showing results for tags 'dob'.
Found 37 results
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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 -
Hello folks, for long I have been browsing the internet to find a suitable 10in dob and despite lack of reviews, I have decided to take the plunge with the Bresser Messier 10in Dobsonian. There was some doubt at first, especially when considering the popularity of similar scopes from Skywatcher, Meade and GSO. Even though Bresser is relatively new to the market, it has some clever features: 1. The massive 2.5in hexagonal rack and pinion focuser is very solid and the movement is smooth. Despite being only single speed, Bresser sells an a dual speed 10:1 extension. However, I find the movement precise enough and do not need the extension at the moment. 2. Optical finder scope feels a bit cheap but it is a nice upgrade over the red dot finder I had on my previous scope. 3. Rocker box style base allows disassembling the scope into two pieces (OTA and base). 4. Tube rings allows the scope to be easily balanced when adding weight + after adding a suitable dovetail plate, the OTA can be used on an equatorial mount (if you plan to upgrade to an eq mount, I would consider the 8in model, as an eq mount for the 10in would be expensive). The only negative comments I can give about the scope is the production process. There were some minor issues with the assembly with the scope as parts did not fit properly. First problem was with one hole drilled deeper (loosening the particular screw fixed the issue). Another problem was with the altitude wheel as it made the OTA to pop out from the rocker box. (A loose screw on one of the plastic pads between the box and altitude wheels was causing this. Make sure all these screws are tightened and below the surface of the pads). Lastly, I assume there must have been a mistake in the quantity of items included (I got twice as many screws for the rockerbox and 2 eyepieces instead of one, both were 25mm super plossl but the standard was a 1.25in advertised on the bresser webpage, while the other was a 2in wide angle) I did not have the opportunity to test the scope outside properly due to clouds. Update: 01.06.2017 Had the chance to try it out on the moon and jupiter to a max magnification of around 160x. The results were very sharp and detailed views. Unfortunately, clouds rolled in before it got dark enough to observe DSO's. I am waiting for clouds to clear and a package with a 42mm wide angle eyepiece and a 2in GSO 2x ED barlow to arrive next week.
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Hello guys,my 8" dob is arriving soon. I have trouble setting my expectations Since i have looked through my 3 " dob its hard picturing what i could see with an 8" one.i live in a light polluted city. Can i look at any dsos directly? How will they look like using adverted vision? What can i expect to see? Also which all around filter should i buy (2") to look at dsos and maybe some planets? Thanks Kronos
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After adding several large two-inch eyepieces and an Explore Scientific illuminated finder scope, my dob was quite top heavy. To remedy this, I added two 18” bar magnets to the bottom portion of the scope. Balance now seems nearly perfect! Got this idea from another post I read a while back on SGL!
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This is probably my options as of now:I will definetly buy a 12mm BST Starguider A 2X BST Barlow( So thats 100x and 200x magnification) AND Either: 15MM BST STARGUIDER VS 25MM STARGUIDER My dobsonian telescope will include:A 25mm and 10mm Eyepiece . So the obvious awnser is to go for the 15mm BUT i ve read in reviews that the bst s have are noticabely better than the eyepieces that come with my telescope.So i am wondering, should i buy the 25mm or the 15mm BST? Also is it worth to barlow either 25mm eyepiece to make 12.5mm and ditch the 12mm i am definetly buying for a 6mm one? i am thinking not because if i barlow the 6 mm it will give me 400x and i think that is too much magnification for the image to appear clear , plus i will also barlow the 10 mm to give me a 240x the acceptable limit for good clarity / magnification ratio (i ve read that and not sure if its true or not). Thanks again for your time and help! This forum has been very polite, welcoming and kind to noobs like me just getting into the hobby XD I hope i can one day look back at myself and laugh at my ignorance! This site has been truly amazing and i hope i can stay a member for a long time to come! Thanks as always Clear skies everyone Kronos -
In preparation for the upcoming "galaxy season", I have been busy re-organising my eyepieces across my eyepiece boxes. I am expecting to be using a mix of traditional and a-focal night vision observing. Therefore, I have put together a "mixed" case of eyepieces. There is a little space remaining just in case I need to swap in a couple more (but I don't tend to go outside will all my eyepieces in one go as they only get cold and unuseable, I prefer to leave a couple inside for a mid-session warm eyepiece swap-in! I have also created a new Sky Safari "brightest galaxies" observing list so I can target these larger/brighter galaxies with the night vision to hopefully tease out some views of unseen spiral arms? (most likely with the 55mm TeleVus Plossl) as focal speed is key to getting the arms. I may need to swap in the TeleVue Panoptic 27mm for more scale (but we will see)... [Here is the Sky Safari Observing List that I will be using Galaxy High Brightness.skylist should you wish to try it too…(you can import it into your Sky Safari - just email it to yourself then when you try to open the file in the email app it should offer you the chance to "open with Sky Safari") ] Having learned last year that night vision is not much help on the smaller galaxies (they just get overpowered by the super bright galaxy cores), I have the TeleVue Ethos 21, 13, 10 ready for some "traditional viewing" (with the option of swapping in the Ethos 8 as needed) on the smaller galaxies. I am eagerly awaiting the heavenly widefield views of endless galaxies as seen in Leo with the Ethos21 and the big dob! Last year turned out to be a "Supernova Marathon" with seemingly weekly supernovas occuring over the UK (and I managed to bag EIGHT of them with the Big Dob). NGC 3941 - SN2018pv UGC 5049 - SN2018pc NGC2746 - SN2018iq NGC3367 - SN2018kp NGC6217 - SN2018gj NGC3158 - SN2018aaz NGC2146 - SN2018zd NGC4151 - SN2018aoq I can't see that happening two years running but I did bag SN AT2018ivc (in M77) on December 1st. Tonight I will be targeting SN2019np in NGC3254 so here's hoping... Either way, I will need a good supply of clear sky, so lets hope our luck is in. Wishing you the best for Galaxy season, Alan
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Hi everyone, I was lucky enough to get a 12" Skywatcher Dobsonian (305mm/1500mm) for Christmas. It shipped with a 10mm Plossl and a 25mm Plossl, both 52° AFOV. Finally had a clear enough night to try it out and I absolutely loved it. I researched a bunch over the last year so I knew this was the scope I wanted should someone want to get me a really sweet gift before I grabbed it myself. What I didn't research at the time was accessories and equipment, something I've been doing relentlessly over the past few days. I'll primarily be viewing in the backyard until I find a great viewing spot (and a good way to safely transport). Light pollution isn't terrible but I haven't fully gauged its impact on seeing fainter objects. I'm not interested in imagery/photography at the moment. Not foreclosing on the idea by any means but everything I'm looking to add is purely for visual gratification at this point. Hoping the experts out there can lead me in the right direction. Here's what I'm trying to figure out: 1. What eyepieces should I pick up? I've read that, generally speaking, you want 2-3 premium pieces in over to cover low, medium, and high magnification. I'm currently looking at the following "sets": 5mm Nagler, 13mm Ethos, 35mm Panoptic or 6mm Ethos, 13mm Ethos, 21mm Ethos. I'm not overly concerned about price. I recognize that there's going to be a premium associated with a brand like TeleVue and with squeezing out that last drop of performance; however, I don't want to throw away money unnecessarily if I'm not going to see a benefit from pulling out the stops. I'm not beholden to TV by any stretch but everyone says they're the gold standard so I figured I'd look there first. I'm not looking to grab everything at once either. Was thinking of starting with the 13mm Ethos since it would fill the mid-range gap between my 10mm and 25mm. 2. Should I grab a Paracorr? I've read many comments that go back and forth on this but the consensus seems to be that, while it's not crucial at f/4.9 like it would be with a faster scope, it's something I should probably have in the arsenal if I'm using wide field eyepieces, which the ones I'm contemplating are. I couldn't detect any coma with the two eyepieces I currently have but I suspect I probably wouldn't given the FOV and my beginner status. I also think that once I see it I'm not going to be able to unsee it. 3. Should I pick up a Barlow? This question assumes I'm not getting a Paracorr. I like the idea of essentially doubling the number of eyepieces I have but I'm not too sure of the ultimate utility/necessity of it. 4. Any other crucial accessories I should have? I'm looking at a Cheshire collimator for when the time comes. Aside from that, is there anything else I should absolutely have? 5. Finally, any suggestions on transporting? It goes without saying but this baby is heavy. I don't have a garage, and I'm hesitant to store it in the shed, so what I've been doing is removing the OTA from the base and transporting them separately to the backyard for setup. It's not bad but I can see it getting old after awhile, especially with numerous viewing sessions in a row. After all, I didn't get this scope so it could collect dust; I want to use it as often as the weather lets me. I do plan on replacing the feet with wheels so I can at least roll it, but I'm trying to figure out a good solution to getting it in and out of the house (down 3 small steps) to the backyard without damaging it or breaking my back. I think that's all I have for now. I appreciate any help you all can provide. I'm just trying to learn as much as I can so I can have a great experience and eventually show my little guy all about the joys of astronomy. Thanks everyone! -
Hi, I have a skywatcher 200p dob and was hoping someone would be able to recommend an eyepiece with a wide field of view that would help finding objects and observing larger objects like the Pleiades. I have had a look at an explore scientific 30mm with 82° FOV, but was unsure if it would be good with my scope. Thanks Katie
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After opinions please ... I have a C8 that I use for planetary imaging / visual and a 250 px Dob for DSO visual . I haven't touched the Dob for what seems like forever and keep using the C8 more and more . I have about £300 Christmas / birthday money and keep thinking about selling the Dob to maybe fund something like a Lunt 35 or 60 second hand to throw on the AVX ? Have any of you been through this process and were you happy ? Cheers for reading
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Hi, I have bought a new meade 8" dob (as in the pic ) and i have the skywatcher 130P goto scope. I was wondering what you pro's think of either of these 2 scopes and also give me an idea of how much better my results will be when using the bigger scope? my guess is that the bigger scope lets in more light and therefore I will get a clearer brighter image with more colour? note that I have to wait for delivery of the dob and i am very exited about it, also at christmas I am going to get some 20x80 bins (celestron sky master) and im looking forward to that to (this is because i found andromeda galaxy in a cheap pair if 10x50 bins and i was a bit disappointed with the result, I dont have a decent pair of bins yet). so, what do you thing of the 8" dob? thanks in advance.
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The Newtonian telescope design is both simple and remarkable. It is capable of producing a perfect image on axis, but off axis, the image quality degrades mainly due to an optical aberration called coma. Modern fast Newtonians and Donsonians of F/5 and below have a surprisingly small diffraction limited spot (just 2mm across in an F/4.5), where the image is not disturbed by coma. The Astro-Tech (also sold under the Altair Astro and GSO brand labels) coma corrector has been designed to cancel out this aberration to give a flat, wide field with high resolution from edge to edge. It is manufactured by Guan Sheng Optical (GSO) and was developed by Astro-Tech from a high quality, modern optical design by Roger Ceragioli My corrector came in a nice box and consists of two parts, the coma corrector itself and a 2" eyepiece adaptor which screw together with a 48mm (2" filter) thread. The eyepiece adaptor has two screws and a brass compression ring and is marked ALTAIR ASTRO 2", Coma Corrector, Made in Taiwan. At least I knew I had the right part, but no other documentation was supplied and I had to search the web for information on how to use it. Unfortunately the corrector is not ready for visual use as supplied, because of inadequate eyepiece spacing. The proper spacing is not critical and a compromise spacing to cover your eyepieces can made up with 2" extender tubes, such Hyperion fine tuning rings or empty 2" filters. You do not need a turntable like that of the Tele Vue Paracorr. With the spacers installed, the assembly which is now about 70mm long just slides into the focuser tube like a barlow. In this arrangement the focal point is moved in by a small distance of about 10mm (see photographs below). The corrector acts as a very slight barlow, enlarging the image by just about 10%. The lenses are nicely coated and reflect pale green. The aluminium housing is cleanly finished in satin black and the combined unit weighs about 350 grams. Once set up properly in a collimated telescope, the corrector works just as you would expect to give a clean, flat image. The view feels quite different, much more like a refractor, with pin point stars from edge to edge, but no chromatic aberration. Objects can be allowed to drift across the view of wide angle eyepieces with little or no visible loss of sharpness. The removal of coma can be clearly demonstrated by doing a star test on and off axis without the corrector installed and then with it. Any loss of contrast due to the extra corrector glass (two doublet lenses) in the light path is undetectable, I think. The coma corrector is now a permanent fixture in my focuser except on occasion when viewing planets with my 200mm Newtonian which now has a motor drive. It seems to me that a coma corrector should be a standard accessory for all fast Newtonian telescopes and particularly for larger Dobsonians with no tracking. This model is an effective, affordable example and I strongly recommend it. The first issue is actually finding one in stock. Supply has been patchy over the years and at the time of writing, it is listed by Astronomics (Astro-Tech brand at $135, including T-mount, but out of stock), Agena (GSO brand at $130, including T-mount, but out of stock), Ian King (Altair Astro brand at £88) and Telescope Service (GSO brand without visual adaptor at 61 Euro). There is then the issue of setting it up properly and most of the remainder of this review is devoted to showing how this can be done, but first there is a little information about Newtonian telescopes and coma. Newtonian telescopes are all designed with a single figured mirror in the shape of a parabola rotated on its axis, a paraboloid. All mirrors of a given focal length are the same shape. If you have a fast mirror, it is easy to to create a slow one of the same focal length, just by blanking off the outer part of the mirror. It is the outer part of the mirror that generates coma, which is zero on axis but which increases linearly the further from the axis you get. At the focal surface, the amount of coma is independent of the mirror focal length so a single corrector will work for any Newtonian. In practice, a perfect corrector is not attainable so the designer will aim to produce the best result he can for a specific F/ ratio, F/4.5 for this model I understand. However, the corrector will give good results for mirrors that are somewhat faster than this and for all slower mirrors. Coma correctors would actually be better called Newtonian correctors, because the designer is looking to produce the smallest attainable spot size for a point source, so will also be looking to reduce the other lesser Newtonian aberrations, field curvature and astigmatism. To do this, he will have in mind a particular focal length, around the longest that is commonly used (so about 2000mm or slightly less), because these aberrations are less in longer telescopes and it is wise not to over correct significantly. Newtonian telescopes are perfect on axis, but coma damages image quality at even a modest distance off axis. At the focal plane, about 1mm off axis, in an uncorrected F/4.5 Newtonian, the image is just at the diffraction limit and the strehl of even a perfect mirror has fallen to 0.8. In a 250mm scope, this gives a coma free, sharp field of about 6 arc minutes across, about 1/5 of the apparent diameter of the moon. For comparison, the field stop of a 9mm orthoscopic eyepiece is about 6mm so only the central 1/3 (1/9 of the area) of the view is free of coma in an F/4.5 scope. Coma increases sharply with the speed of the telescope, at the focal surface inversely with the cube of the F ratio. Collimation is the business of lining up the coma free sweet spot with the centre of the eyepiece axis. The tolerance for collimation is perhaps 1/4 (though some would say 1/6) the size of the sweet spot so that it covers the centre of the eyepiece. So far as I can tell, this tolerance also looks good for a telescope fitted with a coma corrector. To set up the GSO coma corrector properly, the total back focus (distance from the last lens to the focal plane) has to be about 75mm. The designer says that it is not critical and from 65mm to 85mm will produce a good spot size. This distance will be made up somthing like mine below, added to the height of the eyepiece focal point height above the eyepiece shoulder (or subtracting the height below the shoulder). 1.25" My 2" 2mm 2mm Spacing from last coma corrector lens to the shoulder 45mm 45mm 2" adaptor spacing 11mm .... 2" to 1.25" adaptor (if any) 19mm 19mm Spacers (Hyperion 14mm ring + empty 2" filter) 77mm 66mm Total (excluding eyepiece distance) My one 2" eyepiece has a focal point above the shoulder, and my 1.25" eyepieces are all within -12mm/+8mm of nominal, so are all fine. Tele Vue is unique in publishing the height below the shoulder of the focal point for all their eyepieces. For other users, you are going to have assume the focal point is close to the shoulder or measure the position. First, locate the prime focus by taping a piece of tracing paper to the top of the focuser and focusing on something. This does not have to be at night and can anything sufficiently distant so that it comes into focus, such as a church spire or distant tree. It does not depend on the telescope so using a refractor with a graduated focus scale is very convenient. You then measure how far in (plus) or out (minus) you have to move the focuser for each of your eyepieces in turn. For users only intending to use 2" eyepieces, a single 28mm Hyperion tuning ring might be fine. If you do not like the idea of finding empty filter rings, or more likely buying cheap ones on eBay and removing the glass, some suppliers (in particular Telescope Service) have spacing rings with the right 48mm thread, in a few sizes such as 10mm and 20mm, but these are generally expensive. Variable spacers are also available but these are not going to sink into your focuser tube. When I first set this up I had to remove a 2" to 2" adapter to allow the unit to go all the way into the focus tube. This left too little out focus so I made a plastic washer (from a yoghurt tub, see photo below) to prevent the corrector slipping all the way into the focuser and providing the necesssary out focus. One correspondent who uses only 2" eyepieces has done away with the eyepiece adaptor and has simply added enough extender rings to screw the corrector to each eyepiece as he uses it. I hope that this will is enough information to set up this corrector properly but I would welcome questions, and of course comments and correction. -
From the album: Pappy Nick
It's finally been done !!!!! -
Hi, I have a Sky-Watcher Skyliner 300P FlexTube GOTO which I am enjoying however after a period of no use the base has become very stiff. My fault, as it became wet not realising that the cover I had bought for it was not waterproof. Looking through the threads in here I found one which I followed to try to strip down the base however I have become stuck at the point of trying to remove the motor housing from the base after removing the 4 machine screws. I suspect that it is a combination of corrosion and the base material swelling which is preventing me from removing the motor from the base. When I release the worm gear from the static gear using the release lever the motor turns easily which is what is fuelling my suspicion. Any advice or suggestions would be useful as I've come to a halt in my investigation for the moment. It looks to me like I'm going to need a new base which may be a better bet anyway as the original supplied is heavy and definitely not good in the damp. Dom
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ok ,after some research and deliberation it seems the explore scientific range are highly regarded ,and read "near nagler performance" in some threads. so im pretty much sold on getting these. which focal length would be your first purchase (assuming you have no eyepieces ) also , has anyone any issues regarding viewing with wide angle eyepieces . I previously owned a maxvision 24mm 68* albeit briefly . I disliked the flat top design and prefer angled cup designs. Oh, and they would be initially used in a 250px f/4.7
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Hi all, I am thinking of upgrading from my TAL-1M 4.5" reflector but I am not sure what to go for. My budget is around £500 and I am after something with some more photography capability. I know proper astrophotography demands 4-figure sums just for the mount so I am not expecting greatness but the disadvantages the TAL has as I see it and what I want to improve on are these: No polar scope so polar allignment is hit and miss (though I have got better gradually)It's only 4.5" so lots of objects are two faintI can only focus through the 3x Barlow so I can't do any deep-sky through the scope.I am hoping I can get something ok second hand around the 8" mark but I suspect it would have to be a Dob, otherwise the mount alone would use up all my budget. But does that then mean I can't take long exposures and am restricted to manually tracking Jupiter, Saturn, Mars and the moon? I don't need intricate detail, I 'just' want to be able to capture things like the Cassini Division, the GRS, the Plieades and the brighter galaxies, nebulae and clusters, so I need to be able to focus both with and without a Barlow. If I can get something to which I can add tracking later, that would be fine. Am I being hopelessly optimistic? If not, can someone suggest the kind of kit I should be going for? Many thanks for any suggestions, --- Alistair
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I'm scared I have attained the debilitating Collimation Syndrome ( HClV-1a : Human Collimation Virus strain 1a. - mild/severe). Was out with Calpernia yesterday (ehm..my scope's second name..) and I decided to correct her eyesight..again.. (She's now 11 month's old...her first name is Sky, her surname Watcher, 10" of joy..) I followed my baby's collimation guide (I mean Astrobaby..sorry..) And to my surprise the collicap worked (which I have never tried before) very well... I could see all the six mirror clips on my primary mirror..but it seemed like the clips were not evenly spaced with reference to the side of the secondary mirror's edge. As explained in AstroBaby's guide.. "The photograph to the left shows what the actual view should be like at this stage of the process. Note the three mirror clips are all visible and are all equally close to the edge of the secondary mirror and the secondary is showing round and centred to the focuser tube ( the dark area at the edges of the picture)." (Astrobaby, 19..) source: http://www.astro-baby.com/astro_baby_telescope_help_and_advice.htm. Collimation Guide for Newtonian Reflector Telescopes. I checked with my Cheshire...it showed that (according to the Cheshire) the secondary didn't appear quite cylindrical in the tube. So now I recollimated the whole thing...using my trusted Cheshire...and everything is bang on.. When I insert the colli cap thereafter I can see all the clips, almost all the same size, but still with a slight miscorrection of spacing around the secondary's edge.. Maybe I'm just getting old, and my eyes are tired.. -
Hello stargazers, I've been stalking this forum for a good couple months now in my search for a telescope. My main focus will be the visual observing of planets and DSOs. I like photography might plan that later if possible (i'd like it to be). The skies where i live is somewhat polluted but not so much. I can easily spot most constellations with the naked eye if my drive my car on a hill outside the city. I was thinking about one of the models below. I'd like the get the best bang for the buck and minimize the risk of being disappointed and then wanting a more expensive tube later on. I'd like to learn the sky by heart thus steering clear of a GOTO for now. I'm not going to buy anything right now because I'm putting some hard earned cash in a pair of binos first. My options: (but I'm open to any and all suggestions!) Skywatcher Skymax 150 PRO €569.37 + Skywatcher EQ5 Deluxe €269.02 Objective Lens Diameter: 150mm Telescope Focal Length: 1800mm (f/12) EQ5 because it's a good stable mount that I basically can keep using if I ever upgrade the OTA Skywatcher Skyliner 250PX Dobsonian €463.49 Diameter of Primary Mirror: 254mm Telescope Focal Length: 1200mm (f/4.7) Celestron Omni XLT 127 €647.16 Objective Lens Diameter: 127mm Telescope Focal Length: 1250 mm (f/10) Skywatcher Skymax 127 OTA €274.42 + Skywatcher EQ5 Deluxe €269.02 (Or EQ3-2 for €442.96) Diameter of Primary Mirror: 127mm Telescope Focal Length: 1500mm (f/11.81) I might also get the less stable EQ3-2 for a 100 euros less. But again, the EQ5 is a good investment I believe Skywatcher Explorer 200P EQ5 €504.55 Diameter of Primary Mirror: 200mm Telescope Focal Length: 1000mm (f/5) I got all the prices from FLO. Some questions that I still have: (thanks for staying with me so long) - Would you be able to see some DSOs with anything up from f/10? - Is a dew shield necessary if i live in the Netherlands? - I know its been asked a lot but what eyepieces would you recommend? FLO recommend BSTs. Then again which lengths? I thinks thats all for now:) Thanks so much for checking this post out. Clear skies to you all!
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Hi All, My Skyliner 200p OTA will fit in my car, but the Skywatcher mount that came with it will not. Are there any foldaway Dob mounts out there? Or any diy projects? Ta, Neil.
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The coming wet weather is the perfect opportunity to treat my baby to some upgrades and mods. My XT10i is to be pampered with: Telrad finder on a 4" riser Primary mirror cooling fan Protostar flocking Bob's Knobs on secondary Moonlite CR2 focuser Fingers crossed it all goes well and my baby will be even more wonderful. :-) -
Hi all not very good at gramma so stick with me ,Well I got the 16" reflector nearly a month ago and tonight was the first real night after the group meet the other night we spotted the primary with the , Catseye Hotspot & 4"-32" Centring Template (thanks FLO ) and set the secondary and job done . This dob sits at just over 6' 9" tall ,man handling it is a dream with the fear of god in me I took it all down the garden around 17:00 and checked colamination . I got out around 20:00 after a bit of family time and it being clear as a bell M42 This was a dream I first had a look with a 32mm plossl and it was just about all in very clear and the detail was unreal even a hint of greyish green and that's no joke theta 1s all 4 easily seen and sharp the nebula it's self was very nice the arms as I call them left and right were like a pair of wings ,the hook on the right of the neb was very prominent I switched to the 18mm celestron x cell lx the detail just got better and this ep gave me more detail and structure in the nebula NGC1980 This was great to view easily seen and just south of the main neb am sure I see a fuzzy patch of neb around this all star bright and sharp. M35 This again 25mm celestron e lux plossl and 25mm celestron x cel lx gave me a mind boggling view of this cluster I love it one of my faves I could see orange blue -ish ,white ,orange stars,very rich and deep diamonds do not describe this it was like seeing it for the first time again spent around ten mins looking at this , Orion's Belt Just panning around with the 25mm was great very rich in stars in the field of view M1 Very easy to find 25mm again a nice fuzzy shape very clearly a stretched oval shape and not much else to say M94 The Rigel finder made this usually faint fuzzy easy tonight no structure as it was low and around 21:30 by this time a small round fuzzy did not tale power well 25mm was the best view M82 Bodes This was the best I have ever seen and there was structure this time 18mm xcell lx the cigar shape had me screaming nearly the left side had a faint star in it ,I convinced my self it was the sn but new it could not be .faint detail in the centre and almost lines cutting through the whole of it M81 also,looked like a swirl a centre fuzzy with what looked like faint swirls just around it outstanding again I saw lots more stuff as well but do not want to drone on as you have seen them all before I had a few niggles,about dew ?,none at all ,not a bit at all .which was a relief as I have no idea how I would get rid of it. Home made shroud worked a treat made out of two camping matts and flocked at the bottom I brought two meters of spandex which a neighbours got busy with her sewing machine and made it a double piece with Velcro I may upgrade the whole scope with this .the campo,BG matts did not effect balance. The Rigel finder took a bit of getting used to and finding the right angle was hit and miss to start with but soon got the hang of it .its small and compact size is just right. Over all I am truly blessed to have purchased this scope and many of my fears of it's size and big mirror are gone I hope it stays clear every night as it's got so more to give . Has I said excuse my gramma and thanks for reading Pat
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Hi all Well my scope has been sitting in my front room since last winter , i have moved to a new area and 2 weeks after moving in they put new street lighting in the street and they are like flood lights so thats the the easy stargazing gone, i went camping on the last bank holiday to selsey with the scope to see why patrick moore loves it down there so much and it was a total wash out and never got to use the scope at all. So im looking forward to winter and the cold nights and getting to see orion, also i miss looking at the planets , is there any good planets this year?. i have also noticed on my skywatcher dob that one of the white rollers that the scope moves up and down on is missing and i need to replace it even though the scope is still useable, has anyone lost one of these before?. looking forward to spending more time on the site again and its changed a whole heap since i was last on it. cheers...rich -
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.
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We decided to build a shed to house our Dob, which was taking up way too much house space. As to design, @ollypenrice suggested that we build a large 'skateboard' upon which we should sit our shed. The board is made from a sheet of plywood onto which the wheels are mounted. The wheels we chose were the ones used for sliding gates (we have something similar on our roll-off-roof shed. Here is the shed on the rails. The rails themselves were mounted onto concrete, steel reinforced lintels which were concreted into the ground: A slot is cut into the skateboard to allow it to fit around the base of the Dob: It seemed sensible to put down some sort of circular patio, and we discovered that you can buy kits. It was a little awkward cutting the slabs around the tracks, but I am happy with the final result: Before After And finally, the completed project with Dob in situ. We used a green strap - the thing you use to keep your suitcase closed - to stop the Dob from rising up in the shed (without an eyepiece it is a bit rear heavy): We chose materials for the shed that would match those of our existing ROR observatory (from Home Observatory UK - https://stargazerslounge.com/topic/245177-home-observatory-uk/):
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I think I have just purchased a bargain. £550 for a Orion SkyQuest XT12i IntelliScope Dobsonian Telescope The product was used only for advertising purposes in my store, and the price is so low because has been unpacked-,full warranty, full accessories New,never,used- . To good to be true... I hope not I just snapped it up on AMAZON so at least not going to be a ripoff. Was looking for a 10" as thats how much I could afford but with a bit of luck it will arrive. Will be a bit of a change from my previous 8" SCT. Weather forecast over East Markham for the next 3 months Cloudy with rain..... -
Established wisdom, or opinion parroted as fact?
russ.will posted a blog entry in Musings from The Fen Edge
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....- 6 comments
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