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.

sgl_imaging_challenge_banner_solar_25.thumb.jpg.f1d5d01d306644f613efd90ef96b314c.jpg

Search the Community

Showing results for tags 'refractor'.



More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


Forums

  • 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
    • 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

Calendars

  • 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

Blogs

There are no results to display.

There are no results to display.


Find results in...

Find results that contain...


Date Created

  • Start

    End


Last Updated

  • Start

    End


Filter by number of...

Joined

  • Start

    End


Group


AIM


MSN


Website URL


ICQ


Yahoo


Jabber


Skype


Interests


Location

Found 82 results

  1. Hi Guys, I thought I would share with you my first hand experience of the Skywatcher ED100 Pro Esprit Telescope, I have only had it a few months, but so far I am extremely happy with the results, it is so sharp and the contrast is very high. I live in a small town, Stowmarket, Suffolk, UK, where the light pollution is not to bad, but still I have to be cautious with the direction I choose to point the telescope. All my astrophotography is done from the back garden on my patio. I have had a few different telescopes over the years, but I always found myself moving more and more into astrophotography, so after some research I selected the Skywatcher ED100 Pro Esprit, as many of the other users had commented on the sharpness and contrast. As I wanted to focus on more wide field astrophotography the F5.5 speed giving 550mm seemed the right choice, I also use an ED50 Skywatcher Guide Scope with an Altair Astro ASI130mm camera for the guiding and of course PHD2 software, all mounted on my Skywatcher HEQ6 mount. Here is a shot of the Andromeda Galaxy, 20 x 30s stills at ISO 800 on my Sony A7Rii, no filters just RAW images processed with Photoshop, Stacked Mean option. I used the Trevor Jones video on his BackyardAstro You Tube page for processing DSO's and it seems to work very well. What you will see from the image is just how sharp it is, something that really surprised me when I processed the images. This has inspired me to spend more time outside in the garden to photograph more objects, plus I have recently purchased an Astronomic CLS Filter for my Sony A7Rii, so I am looking forward to using this to see if it improve the contrast. I will keep you informed. Also I am looking forwarded to trying my Olympus EM1 MK2 camera, yes I know it does not have the capabilities of the Sony A7Rii for light gathering, but it does have a really clever mode where it can stack the images in camera to reduce noise, so I will also let you know how this went as well. Best Regards Jamie
  2. lets imagine I wasn't to see a nice DSO about 15' size and I think it should look good nicely framed with a 1 deg field of view in the EP.. Which would give the better (or higher probability of seeing anything at all ) view from a semi urban light polluted home site (e.g Bortle 6)? a) an 100mm f/6 refractor (fl 600mm) and a 10mm EP (60 deg afov, gain 60x = fov pf 1 deg) (and exit pupil of 100mm / 60 = 1.6mm) or b) a 200mm SCT with focal reducer to give f/6 (fl 1200mm) and a 20mm EP (60 deg afov, gain 60x = fov of 1 deg) (and exit pupil of 200 / 60 = 3.3mm) My gut feeling is that the SCT should give a better view just based upon its 2xaperture - but Im not sure I understand fully the maths why. Is the larger exit pupil going to result in a better / brighter / more successful view? Or will the view be 'roughly' the same ? Or have I got it all wrong..... Thanks.
  3. You're out with two APO refractors 65/420 and 70/478. Which one you would use DSO imaging and which of them left for visual observing meanwhile you're shooting? Why?
  4. https://www.astroshop.eu/telescopes/tecnosky-apochromatic-refractor-ap-70-478-quadruplet-flat-field-ota/p,57327 How to know this? I have read that with 65/420 scopes you cannot use 2" diagonals because there isn't enough backfocus.
  5. Hello all! I have been using my Skywatcher 8” Dobsonian for some time now, and decided I wanted a good refractor with an EQ mount as my next scope. I chose the Skywatcher Evostar Pro 80mm with an LX70 EQ5 mount. This seems to be a great scope to compliment my Dob, but I'm still getting used to the EQ mount! Found some good Youtube videos and am hoping for a clear night soon to really give it a workout! Any advice is appreciated!
  6. Hello all! I just picked up a Skywatcher Evostar 80mm Doublett and LX70 (EQ5) mount. This is my first refractor and EQ mount so it took me a while to put it together (if you all notice anything out of place please tell me!). I still enjoy my 8” dob but wanted to learn. This type of scope. It had good reviews for general viewing, but I'm not sure what to expect. The EQ mount took quite some time to figure out and one of my questions is do I operate the scope with the counterweight horizontal to the ground? I noticed that in that position I can use the control cables to move up and down and left and right. Any advice is appreciated!
  7. Hi Guys, any one had any use of a Technosky Apo or know anything about them. I am looking at getting my first apo as usually I am Astrograph man and seen this 70/478 mm quadruplet flatfield for £482. It seems a good deal but was just wondering about the build quality? As this seems cheap for a quadruplet!!! https://www.astroshop.eu/telescopes/tecnosky-telescope-ap-70-478-quadruplet-flatfield-ota/p,57327#tab_bar_1_select
  8. I bought this second hand, but it was almost untouched, and a relative bargain to boot. New it costs 1199 EUR from TS (approx. £1035 as of 08/03/2019 but who has any idea how this might fluctuate). Highlights: Apo air-spaced triplet with FPL53 Multiple focus positions thanks to removable tube segments 2.5” rack and pinion focuser, rotatable, dual speed controls, 6kg payload, with printed scale CNC tube rings and dovetail supplied Retractable dew shield First impressions: It’s a really nice box. Whilst it’s described as a ‘transport case’ the supplied storage box is sturdy and well made. Inside, the foam fit is precise bordering on tight. It’s actually mildly difficult to get the scope out of the box. Things get a little easier if you loosen the tube rights slightly, allowing for some tube rotation, and a longer term fix will be some straps to aid lifting the scope out vertically. The scope itself feels very well made, and is what I’m choosing to refer to as ‘reassuringly weighty’. At just over 4kg (without diagonal, eyepiece, or finder) there are definitely lighter options available, but it’s hardly a heavyweight. The finish is powered coat white, which looks and feels very nice. The focuser is very smooth (compared to my SW ED80) and feels pleasingly solid. I’m not going to be testing the stated 6kg payload any time soon, but I can easily believe it will be able to handle it. The dew shield is held in position with a single thumbscrew, and whilst it’s retractable credentials are clearly warranted, it only seems to extend a couple of centimetres. As it happens, this takes the overall length down to 450mm which was the very top end of my acceptable range in order to meet my ‘travel’ requirement. The focuser body also incorporates a finder shoe, but if you wanna finder then you have to supply your own as there’s nothing included. The idea of having additional tube segments is that you don’t have to rack out the focuser so far, and so improves stability. This also allows for multiple reducer/flattener options for imaging use. The TS website details the specific configurations using their recommended equipment which provide a faster f/4.9 option for sensors up to 36mm, or a full frame flat image at the standard f/6.6. I might be exploring these options later, but for now, this is going to be for visual use. First light: OK - this barely counts, but I was impatient. Predictably enough, first evening with a new telescope and it’s raining. But I did manage a pretty decent look at my neighbours TV aerial and chimney stack. They need some re-pointing. … The following evening (9th March 2019) was less rainy, but much the same for cloud, all but for about 30 minutes of relatively clear sky, interrupted regularly by patchy cloud. So still not great. However, my ambitious setup to allow for cooling paid off and I did manage a few minutes of actual use with a SW 28mm eyepiece. The Baader Zoom I also treated myself to for my travel use is frustratingly still not dispatched. And when I say set-up, I mean just carrying everything outside. I’m using this on the SW AZ-Gti mount, and a Manfrotto tripod I had already, so it’s very easy to pick up and take outside. I was using the scope with one of the two removable sections in place (this is how it is stored in the supplied case) and was able to achieve focus with a 2" diagonal without having to rack out excessively. Sirius was an obvious target to the south, and an easy hit. Brilliantly bright, as expected, and a blue-ish white colour. The upper half (the rest was below my sightline from home) of Canis Major was easy to see, with several of the background stars also visible. Despite the less than great seeing, the view was impressive. Stars were tight and there was no obvious chromatic aberration. Moving up to Betelgeuse, it’s orange-red brilliance was very pleasing, and again I was able to make out some of the fainter surrounding stars. Overall the view was very impressive, and bright. My only real comparison is with my SW80, and of course I now have over 25% more light, so that’s to be expected. But still, it makes an obvious difference. I wasn’t able to note any CA or distortion, and a quick full visible spectrum (no filters) star test reflected spot on collimation and no apparent astigmatism. Alas, the break in the patchy clouds did not last long, and I was soon packing up for the night and heading out for a beer. I’m looking forward to getting some more quality time with this kit, and who knows, I might even align the AZ-Gti next time and write a brief review for that too.
  9. I am thinking about a second scope to accompany my 8” dob! I would like a doublet with an EQ mount. I want it for planetary observation. I will also have to choose a reasonably priced EQ mount. I also want to be able to use my 2” eyepieces. Is that even possible? I thought maybe an 80-100 but the price really jumps as you go bigger! Any advice would be appreciated!
  10. For sale a skywatcher startravel 4 inch scope, has end caps and dovetail bar/rings. Would make a great guidescope, retail is £165, asking £100 with postage (ono), excellent condition throughout. Message me if interested...……..
  11. Another day another Takahashi ......... when will I ever escape this vicious circle ??? Just when I had resolved not to buy any more astro gear, someone advertised this scope at a very, very tempting price.... here we go again, my dear wife just shook her head when I told her I would be away for a couple of days picking up another telescope. Enter the Takahashi FSQ106ED build # 89 of 2014, in immaculate condition with a genuine Takahashi FSQ case, Extender-Q 1.6X, Clamshell and a pair of LE eyepieces. How could I say no? To say that I was happy driving the 700 alms back home would be an understatement ..... Thanks for viewing
  12. Patbloke

    IMAG1343

    From the album: The Great White

    This is a Skywatcher 150mm Frac that I bought slightly battered and bruised... she was old school blue but she's had a make over and is now the pride of my fleet :-)
  13. Hi all. Considering a new scope, and specifically a new refractor scope specifically for lunar and planetary work. Seen the Altair Starwave F11 102mm achromatic OTA which doesn't break the bank too much. With the longer focul length CA shouldn't be too noticible, and as I have no intention of doing any imaging with it then an APO scope seems a little expensive just for visual use. Anyone have one of these for visual use at all? Any feedback (good/bad) would be welcome. http://www.rothervalleyoptics.co.uk/altair-starwave-102mm-f11-achromat-refractor-telescope-with-2-crayford-focuser.html
  14. I'm considering to build a nice all-round wide field 150mm binoscope, mainly to observe DSOs and, why not, some planet observations. The priority is wide field observation with good contrast at 5 pupil exit, and also good contrast on smaller DSOs at 2-3 exit pupil, so I guess the focal length should be 900mm at maximum. I don't mind too much some chromatic aberration observing the moon and planets at 100 X, I'm not aiming higher than 100-150 X for planets. I want this binoscope to be a keeper for life. I'm considering these refractors, and I would like to hear your suggestions and recommendations based on your expertise: (1) TS 152mm F5.9 http://www.teleskop-express.de/shop/product_info.php/language/en/info/p2229_TS-152mm-f-5-9-Gro-feld-Refraktor-mit-3--Crayford-Auszug.html (2) iStar WFX 150mm F5 http://www.istar-optical.com/refractors-ii.html (3) Celestron Omni 150mm F5 http://www.teleskop-express.de/shop/product_info.php/info/p4010_Celestron-Omni-XLT-1590R-Rich-field-Refractor---Optical-Tube-Assembly.html I plan to use high end 2" barrel eyepieces, like Ethos 13 for the 2-3 exit pupil views, and other eyepieces suited for binoscopes (less that 6.2 cm diameter) for the 5 exit pupil range. Which pair of refractors do you think will do the job better and more cost-effectively? I'll consider other refractors you may suggest. Thanks in advance
  15. I just bought an Istar 150mm F12 lens and cell and will be building the telescope to hold it. The guy I bought it from has generously given me some excellent advice, so I know where I will get the aluminium tube and how I will cut it, how I will plan the light path and baffles, and how I will flock it internally. He also suggested a couple of focusers that he has used and likes. I think I will probably go for a Moonlite focuser as I have one on a newtonian and I really like the smoothness and precision of it, but I am also considering a couple of others. Do any of you have either the TS Monorail or the Baader Steeltrack? What do you like and dislike about them? I will be using the scope for visual observing only and the heaviest eyepiece I will use on it will be my Explore Scientific 30mm 82° at 1.4kg. Thanks.
  16. Hi all, not sure if this is the right place for this, but cannot decide which is the better one.. Here is my problem; I have an old Telephoto lens that is an 86mm achromatic and has a variable focal length of 600 to 1300mm. I have had this years and don't really use it anymore, it's no good for astrophotography as it stands but after some experimenting with various eyepieces jerry rigged in the end of the lens I have found it makes a very good and effective refractor telescope...and as I want a larger finder/secondary scope on my LX90 this would seem to be a good use for old equipment. The lens has a 42mmx0.75mm male thread on the end for the attachment of camera adapters. I have had a look for a female threaded adapter that would allow the use of either a single or interchangeable eyepieces on the lens. Does anyone know of any such adapter, or perhaps a couple of adapters that would allow the end game I want... Thanks everyone. Jim
  17. Hi all, I am thinking of adding one of these to my Christmas list. I want it primarily for astrophotography with my aps-c Canon on the Star adventurer mount, with a sturdy photo tripod (I have all of those already). For £399 it seems like the best combination of value and performance to me, but what's your opinion? https://www.altairastro.com/starwave-70ed-f6-travel-refractor-telescope-with-2-crayford-focuser-finder-diagonal-eyepiece.html thanks Mike
  18. found a $40 refractor at a goodwill today. will include some pictures, is it worth the money? has a EQ mount included, and for just 40 I'm seriously considering it. tips? it has no eyepeices included, but the mount looks sturdy and the i don't yet have a refractor so i really want it.. if its worth it. pretty sure its worth over $200 but idk 4 sure. remember that i know so little about refractors that i had to google how they worked.. again. but that mount alone would be worth it, even if the optical tube isn't. please feel free to tell me its not worth it, i don NOT want to waste money on this.
  19. Hey everyone ! I am new to this site , don't know how to properly use it , but hope someone will help me As the topic says , I am trying to buy my first telescope , and am quite excited for it. I have been reading wuite a lot about astronomy , so I know most of the basics , but have many many unanswered questions ... xD I was originally looking for a scope for viewing the planets , but well , after learning more , I thought that maybe a scope that can show only planets will eventually get a BIT boring , and will not be used much (although I still admire the planets and still will want to observe them). Just a quick info on me : I live in a city , have no place to go / or car to transport my scope to a darker place , live in a building , hope to observe from the rooftop. My ONLY CONCERN about this is that from my balcony I can see Vega at night , and as depressing as it may sound , nothing more .It may be because there are buildings covering my view (I at least hope so that's the case) or light pollution , although the place I live is in the orange to red zone in many light pollution maps. So originally I stumbled upon the Orion Starseeker IV 80mm GoTo refractor. http://www.telescope.com/Telescopes/GoTo-Computerized-Telescopes/Orion-StarSeeker-IV-80mm-GoTo-Refractor-Telescope/c/1/sc/15/p/113919.uts Thought it was good for the GoTo and stuff , but after doing some research , got concerned about the sturdyness of the mount.Some said it was too shaky (I have almost constant winds of about 10mph at night here) . Plus after some while I discovered DeepSpace and got even more interested in it than the planets . So I started to seek for reflectors. After a while I discarded Dobsonians as an option , cause I do want to do astrophotography ( just amateur , not gonna spend money on expensive DSLR s or sth) . And maybe in the future I will want to do some more serious astrophotography , so it will be very sad , if I have to change the scope later , if I want to... So after doing some research I am currently watching these scopes . 1. Orion 9827 AstroView 6 Equatorial Reflector Telescope . https://www.amazon.com/dp/B0000XMSR0/ref=psdc_499154_t1_B01N2HJBQC 2. SkyWatcher Explorer-150P EQ3-2 Reflector. https://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-eq3-2.html The only downside of these is that they're not GoTo (The second one has an option , but it's out of my price range) , but I think an additional RA motor drive will do the thing. At lease if I will be able to find anything in my sky ... That's it ! If you own/have used any of these scopes tell me more about them ! What you like/dont like etc. ANY GENERAL ADVICE IS APPERCIATED . Thanks !
  20. Hello guys, I may have found exactly the forum I need here I would be really glad if you could help me a bit please : I love stargazing on the mountain next to home (low light pollution), but now I want to level up. I mean, I'd like to use a device that is better than my eye to see the night sky. The problem is I am quite lost between telescopes, lenses, reflectors, refractors, and hybrids devices etc. So here I am, coming for your advice that will be, I am sure, of great help. Here's my question : what device is best suited for my use ? I'd like to see constellations and close deep sky like big galaxies (andromeda M31 for example). I am aware that refractor lenses are less bright than reflexion telescopes but I'm not certain which one to buy. > The main purpose would be a looking through device, but ideally if I can plug my Canon DSLR it would be fantastic. What are best brands for an amateur ? I prefer to pay more but once than cheap but twice and have a budget of around 250-300 € (if one is a bit above but really effective I can go a higher). Thank you a lot in advance for your time and advice ! Golfox2
  21. A new (old) 'frac added to my wee family of scopes. From an Astromedia kit of a slightly smaller copy of one of Galileo's refractors. Not had a chance to view the night sky yet, but get a 12x magnification, so should be able to see the moon in a little more detail. Field of view is small, but as one of the first kind of telescopes made this was cutting edge back in the day I guess! Hope for a chance tonight to observe something if the clouds permit!
  22. I do a lot of travelling and would like something properly portable. Obviously I would not get the performance that I get with my 6SE, but that would be an acceptable compromise. I have been looking at two posibilities, the Celestron Travel scope 70mm, 400mm/f5.7 or the Meade EXT80 with backpack which is 80mm 400mm/f5 Has anyone used these and what are their opinions?
  23. Do these lens edges look black to you? Uuh, yeah, sure! But now? Oooh! That was the blackening applied to my new Astro-Professional doublet. Bear in mind that the light exiting at the front first had to pierce the layer of blackening on the other side, but it remained pretty intense, right? Good commendable will on the scope maker's part, and job done, but a second layer of felt marker paint was in order. Yes, paint, felt markers actually apply a kind of paint mixed with a solvent that evaporates very quick. Thus it's quite natural that a second layer is needed for opacity. Stray light will take any path that's open, and bounce off the rough side of glass that has the ideal texture to spread it in every direction, so I also treat bevels. Look at the previous pics, they were not covered at all. The real black distinguishes itself strongly from the mere factory gray. If you knew the lens' specs, and the angle of vision, you could reconstruct an image of that room with a specialized software, but that's another story. While I had the lenses out of the cell, I made permanent rotation marks. A ghost of the factory inverted "V" is visible, I made scratches with a needle the first time I opened the cell, but during the first reassembly I suspect the lenses have rotated because a miniscule amount of paint at the wrong place made the rings sticky. Turning them made the lenses turn, I suppose, based on some loss of snap at the eyepiece, while the star test seemed similar. For future maintenance I dug two notches with the edge of a diamond-coated knife sharpener. Thanks to diamond hardness the job was done in seconds. But what happened to those unblack edges, you ask? That compact led flashlight is viciously powerful but not enough for two layers of black paint at entry and two at the exit. An optician wrote that paint (or ink?) hardens and shrinks enough to compress a lens out of ideal shape, that could be detectable in sensitive tests. Maybe, because the tolerances are only several dozens or hundreds of molecules; 500 nanometers in wavelength of light divided by a good lamba/20 wavefront would amount to only 25 nanometers, we're talking layers of molecules, here. But I still don't figure if the claim is far-fetched or not. The two rear rings have been painted with ordinary blackboard paint. It can chip, I know, however unlike lacquer it dries fast enough to not interrupt the work session, and it's so easy to reapply. The black lens edges coupled to the matte rings produce this effect: the lenses seem to vanish. Direct light from two lamps, a white ring under the cell reflects light at the same angles as intrusive light during real-world observation, but only an extremely faint ghosting occurs. Do you see it? Why two locking rings, by the way? Because a single one could make the lens it touches turn, and ruin the critical rotation alignment. The second buffer ring prevents that. A little not-yet-dry paint that bleeded between them may have caused the problem for a while. Of course, at shallow angles the lenses reflect some light, but the rings behind them remain discreet. It took a white ceiling and a white column (plus a Strat) to make these reflections. Some blackboard paint bled inside the cell scribing, which is not bright ink but an actual etching done into the aluminum with an interesting pointy tool, that's why it's shiny gray. Instead of spending time trying to scrape it, I filled all the letters and numbers; it created a nice, unique variant. Turns out, I always wanted a cell with dark engraving, and it's not lazyness talking. The bevel and the inside of the outer cell is matted-painted, too. If you own an Hyperion eyepiece, the hard, dull black finish in the barrel is the ideal finish but I don't konw how to do it, unaware if it's a paint (doubt it) or some chemical process. I often stargaze from my city, lamps everywhere, so I don't want any shiny areas. Everything but the optical surfaces should be dull black. This will also be useful if I do astrophoto one day - uh, one night - because cameras are so sensitive, and exposures so long, any stray light could damage contrast. But, Ben, but Ben! What are those white dots on the outside of the cell? I never liked the velours that barely puts the brakes on the dewshield's motion, and lets it wobble. The solution is those simple foamy rubber adhesive pads. Trial and error determined the right number was eight. A ring of pads at the very rear of the cell, and another at the very front suppress wobble completely, and they keep the dewshield in place even with a 700 gram tilt-lock (my invention so I get to name it) counterweight attached to it, with the scope pointing vertically. A strip of tape takes marks at the screws' location. I remove the strip, measure the separation of the marks while it's on a flat surface, put it back on the cell, and voilà! Perfect centerline for the rubber pads. Removing lenses means recentering them but their screws are not standard, so I recut a damaged mini screwdriver... ...and quickly glued pieces of any tubing I had to repair the handle and make it more ergonomic. The two notches in different shapes at the screwsdriver's collar help me keep track of turns and half-turns. This slot shape is not standard, a non-matching driver would damage the plastic: The tolerance between cell and lenses was nicely tight, but thanks to the extra thickness of paint, they almost self-align. After inserting them, and driving the screws at the same depth, I did an artificial star-test, found only one screw needed 1/8th turn to get near-perfect centering. The lenses require a gentle push on the side with a toothpick in order to be seated in the cell. They just slide against the cell walls without rubbing, and exit the same without catching. If they were too close to the walls, centering screws would be disabled, and thermal pinching could occur. It seems to have turned out pretty okay. The semi-apo quality shows in the very pale lime, almost white disk, and the purple ring. Intrafocal thru Explore 4.7mm eyepiece (120x). The Explore 4.7 increases chromatism in this refractor and in my achro, but the Myriad 9 reduces it, however it does not magnify enough for star-testing. That rounds up my first line of defense against stray light. How does it perform? Well, with the dewshield retracted, and two lamps shining into the cell from less than two meters: The glass edge and its retaining rings don't shine, and they cast a nice black shadow. The two baffles down the tube are not enough, though, I need to add a couple more, that will be for a later date.
  24. I recently posted about my first successful collimation experience (an SCT). I'm sure we all have our stories, of those moments when we perceived optical clarity. Come on everyone tell us of those collimation 'eureka' moments and your experience of your first observing session immediately following. Paul.
×
×
  • Create New...

Important Information

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