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Recommended focal reducer for WO Z61
Elp posted a topic in Getting Started Equipment Help and Advice
Anyone have any recommendations/results of using a focal reducer with the William Optics Z61? Asking as I tried capturing the heart nebula the other day and it just about squeezes into the field of view via the standard 61 flattener and a 183 camera. For my own personal preference I would like to have the option to increase the field of view but still keep the starfield flat which I believe the WO 61R does. -
Hi, I have been getting a lot of questions regarding what components my "optical test rig" has, and how to clamp the camera/laser with. I found some new bits and pieces which makes it very simple to build your own rig -
The Jewel Box ( NGC 4755 ) is an open cluster of mostly hot young blue-white stars that appears to the unaided eye as a bright 4th magnitude star close to the Southern Cross. Only visible from southern latitudes, the Jewel Box was first recorded by Nicolas Louis de Lacaille during his visit to South Africa in 1751 and was later described by Sir John Herschel as "a casket of variously coloured precious stones" - hence the name "Jewel Box". The Jewel Box open star cluster ( ngc 4755 ) in Curx ( please click / tap on image to see larger and sharper ) Please see here for image details. -
Also known as the Theta Carinae Cluster, The Southen Pleiades is a very bright open cluster in the Carina constellation. It was discovered by Abbe Lacaille during his visit to South Africa in 1752. Containing around 60 stars, IC 2602 shines with an overall magnitude of 1.9 and its brightest member is Theta Carinae with a visual magnitude of 2.7. This cluster of young blue stars is relatively close to us at "only" 479 light years. 5 May 2018 The Southern Pleiades open star cluster ( IC 2602 ) in Carina ( please click / tap on image to see larger and sharper ) Image details can be found here.
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Hi - I just wanna share my latest build - based on Starlight Express optical rig in which they align their camerachip / housings before the ship them out - And i was inspired to build my own. I am very keen to be able to do so much adjustments and tuning to my gear during the day as possible - and this is another method of doing just that, and in this case the aligning of camera tilt which can be a royal PITA during the dark and -20 degree C. So, here is the SX article on what i was going to build: SX Article Note: I haven't reciieved my new camera yet so the video does not contain the actual adjustment, but as soon as i get my new camera - I will show just how it works! /Daniel
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Greetings from cloudy and cold NJ! I recently had a lens replaced on a 102mm refractor, 1000mm FL, f/9.8, due to undercorrection of something more than 1/3 λ. The Ronchi lines seen in the double pass autocollimation test with an oil flat were significantly curved. The test is, of course, quite sensitive and allows one to see spherical aberration very easily. The new replacement lens is far better in that respect and a definite improvement over the original. It also shows a measure of undercorrection and I'm wondering if anyone familiar with the test and reading the images would hazard a guess as to the approximate wavefront quality of the lens. Nothing precise, just an estimate would be very much appreciated. Here are the specifics: Lens: 102mm, 1000mm FL, f/9.8 achromat. Ronchi grating: 150 lines per inch or 5.9 lines per mm. Oil flat, Double Pass Autocollimation. The distortions in the shape of the images are due to imprecise alignment and the variations in the line thickness from uneven illumination and slight oil movement. Of course, the 3 image diffraction overlap of the test gives a false impression of the poor edge quality. As I say, anyone who may have a knowledge and experience with the test and an idea as to what these results might translate to would offer an opinion as the the wavefront quality, or a range of same, I would greatly appreciate the information, for nothing else than curiosity about the new lens and a feel for the test. I'm quite happy to have received a much improved lens and I am sure it will be very satisfactory for use. Thanks very, very much! Joe. -
Hello! So I have been an amateur astronomer since last few years and now I see that so many people have asking me about general telescope suggestions. (Guess the next step will be helping to set up small observatories...Ah dreams!) We don't have many telescope brands available. The major brands that are available here are Meade, orion, celestron and skywatcher. The confusion starts to rise when the other party is interested in little larger scopes like 8 inch sct or 12 inch reflector with eq mount or dobsonian mount. Would like to know overall experience that you guys have had with these brands like optical tubes, mount, eyepiece etc. Sort of like "this is good, this is not so good" type. For e.g. I have used celestron 6 inch sct, 12 inch (sort of) sct and 102mm short tube refractor. Although I love their optics, I haven't had good experience with their mounts. Meade : Used their 8 inch sct with fork mount (and liked it). Used their 90 mm refractor and didn't like it much. Skywatcher has given balanced performance overall. Decent mount, decent optics, decent supplied eyepiece etc. Also, on the same topic, I am quite confused with how much importance does having a good telescope dealer has. As in we do have many dealers here, but many times I have experienced things like overpriced scopes, no decent guidance etc. If I suggest just one dealer with whom I hadam good experience then it looks like biased opinion. -
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
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Hi, I spend a day here to analyze my master flats and what vignetting I have on my lenses and telescopes. It's very simple done but still interesting to set figures on it. It's done on a full frame camera and I use the values from the center and the corner of the sensor. The corner is 22 mm of from the center on a full frame sensor. I never liked to have strong vignetting in my optics, and in the future I want to go for bigger size than full frame. I have put together a page over the vignetting I got: http://www.astrofriend.eu/astronomy/projects/project-different-lenses-vignetting/01-different-lenses-vignetting.html Maybe interesting for some of you to have a look at. My telescope shall handle a medium format sensor of the size 48 x 36 mm with the setup I have now. My medium format optics already do it. Just missing the medium format camera. /Lars -
Hi there, in packing away my scope the other evening I was shocked to see the state of the mirror in my star diagonal, at first I thought there were scratches on the reflective surface and couldn't fathom how this could have come about as the click-stop is normally permanently attached to the focuser on my SCT with a cap on the eyepiece end. On closer inspection it looks more like the marks may be detritus on the surface, though I am still not sure on this score. This being the case, I am looking for advice on how to go about cleaning the mirror, has anybody ever taken one of these units apart to clean the mirror? If dismantling the unit is not feasible how best to clean the surface in situ? Kind Regards Paul J.
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Have you ever thought about where all photons go when they enter your telescope? I have done a rough calculation of how they dissapear on the way through the telescope and in to the sensor, in this case it's for a rgb filtered mono camera. The result? You detect about 12% of the incoming photons through a refractor or 9% through a reflector! I have the calculation on my homepage here: http://astrofriend.eu/astronomy/tutorials/tutorial-transmission/tutorial-transmission.html For those who are curious as I'm ! /Lars
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So, I have been testing three different kind of lasers, each one is supposed to be the "best" in each category or what you want to call it, the hotech and HG is almost the same, but whit the difference in how you lock it down. The Catseye is very different in how it works. I made a Youtube video of my thoughts https://youtu.be/ERF33hNVieQ What do you think? which one do you use? Regards, Daniel
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Hey everyone! I made it out for some stargazing early this morning. I had a really fun morning of viewing doing not only my normal wanderings about the sky, but also watching Venus, Regulus, Mars, and Mercury rise. This was my first time viewing Mercury and it did not disappoint. Anyway, I quickly learned a hard lesson. Though I had stuck my dew shield in, I forgot to put it on the scope. Soon not only was my scope dewed-over, but it froze into frost and there was no way for me to clean my lens. I used a lens cloth to gently try to clear things up, but to no avail. Anyway, I had binoculars and a spotting scope along as well and still had a great time, but I as I got home a question came to mind: There is some minor smudging on my front lens now from the attempted frost clean-up. How often do you all clean your optics? Are you super anal about keeping everything spot free, or do you use things for a little while before giving them a thorough cleaning? Do minor smudges and spots have a noticeable effect on viewing?
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Baader optical wonder solution is practically Isopropyl alcohol. Instead of £12 for a 70mL of it, buy a 1000 mL of Isopropyl alcohol for £22 (before pandemic it was only £5). They have also smaller bottles which will be cheaper of course. The Baader solution and Isopropyl alcohol don’t remove the toughest of fungi on optics, only a few of the less deep set ones can be treated with them. I have used both for cleaning eyepieces and on certain stage of cleaning several 8 to 12 inch mirrors. They both worked identical. When applied through an optical cleaning fabric, they remove ( dissolve) fatty oils and fingerprints on optical surfaces. I had cleaned a 12 inch mirror once which for some unknown reason had ice cream stain on it (cleaning followed standard operation procedure for cleaning coated aluminised mirrors). -
Hi, I've got a Skywatcher Heritage 130p reflector, and if i insert anything less than 10mm eyepiece, the image won't get crisp. I guess it's normal, but as I'm very new to astronomy, I'd like to know what the sharpness depends on exactly. Is that the focal length (how fast the telescope is? ) or the size of the mirror and how much light it gathers? Or both affect it the same way? Are things the same with refractors in this regard? Thanks. -
The Rosette Nebula and Cluster ( NGC 2237 and 2244 ) in the constellation Monoceros edit: updated 30th Dec with improved colour balance and slightly increased brightness ... ...... original: ( please click / tap on image to see larger and sharper ) Still a work-in-progress really... with only 10 x 4min exposures for the main 'lights' before the clouds came over. I will try to add some more data when the moon has gone I am still experimenting with how to get the best out of the D7500. With the very warm nights ( low to mid 20s all night ) the 'warm pixels' are very noticeable so I reverted to my old practice of in-camera dark subtraction. This worked quite well and produced a nice smooth noise floor in the integrated images - albeit at the expense of more exposures. ................. Identification: The Rosette Nebula ( NGC 2237 ) is a large, circular emission nebula in the constellation Monoceros. It surrounds a cluster of hot, young stars known as the Rosette Cluster ( NGC 2244 ). ( SkySafari ) NGC 2237, 2244 Caldwell 49, 50 North is up. .................. Capture Details: Telescope: Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 ). Corrector: ASA 2" Coma Corrector Quattro 1.175x. Effective Focal Length / Aperture : 1400mm f4.7 Mount: Skywatcher EQ8 Guiding: TSOAG9 Off-Axis-Guider, Starlight Xpress Lodestar X2, PHD2 Camera: Nikon D7500 (unmodified) (sensor 23.5 x 15.7mm, 5568x3712 @ 4.196um pixels) Location: Blue Mountains, Australia Moderate light pollution ( pale green zone on darksitefinder.com map ) Capture ( 23 Dec 2017 ) 9 sets of sub-images with exposure duration for each set doubling ( 1s to 240s ) all at ISO400. 10 x 240s + 5 each @ 1s to 120s imaged ~ +/- 1.5hrs either side of meridian maximum altitude ~ 51.3 deg above north horizon Processing ( Pixinsight ) Calibration: master bias, master flat and in-camera dark subtraction Integration in 9 sets HDR combination Image Plate Solution =================================== Resolution ........ 0.633 arcsec/px ( full size image ) Rotation .......... 0.181 deg Focal ............. 1367.90 mm Pixel size ........ 4.20 um Field of view ..... 58' 59.4" x 39' 15.0" Image center ...... RA: 06 31 55.638 Dec: +04 56 30.84 ===================================
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Spiral Galaxy NGC 6744 in Pavo NGC 6744 is a Milky Way like barred spiral galaxy in the constellation Pavo. Visible only from lower latitudes, the light we see now left this galaxy around 25 million years ago. NGC 6744 in Pavo ( please click / tap on image to see larger and sharper ) Capture Details: North is up. Telescope: Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 ). Corrector: ASA 2" Coma Corrector Quattro 1.175x. Effective Focal Length / Aperture : 1400mm f4.7. Mount: Skywatcher EQ8. Guiding: TSOAG9 Off-Axis-Guider, Starlight Xpress Lodestar X2, PHD2 . Camera: Nikon D5300 (unmodified) (sensor 23.5 x 15.6mm, 6016x4016 3.9um pixels). Location: Blue Mountains, Australia Moderate light pollution ( pale green zone on darksitefinder.com map ). Capture ( 16, 17, 19 Sept. 2017 ). 9 sets of sub-images with exposure duration for each set doubling ( 1s to 240s ) all at ISO800. 85 x 240s + 5 each @ 1s to 120s. Processing ( Pixinsight - 5-17 Nov 2017 ). Calibration: master bias, master flat and no darks. Integration in 9 sets. HDR combination PhotometricColorCalibration Arcsinh stretch ( function written by Mark Shelley ) Image Plate Solver - NGC 6744 - Sept 17, 2017 =================================== Resolution ........ 0.586 arcsec/px ( full size image ) Rotation ............ 0.001 deg. Focal ................. 1372.24 mm. Pixel size ........ ..3.90 um. Field of view ..... 58' 30.3" x 38' 59.0". Image center ...... RA: 19 09 46.591 Dec: -63 51 13.44 ==================================
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Help with optics in new equipment
Troady posted a topic in Getting Started Equipment Help and Advice
Hi there guys, i see a ton of knowledge in this forum (after been observing others forums too) and good tips, nobody shy of helping a newbie and that`s what i need. i am a over the road interstate trucker, meaning being for months at a time away from home (don`t matter, got wife and dog with me). Have been interested in the sky for a long time, but just recently decided that its the right time to begin watching the sky by myself and not only watching hubble`s pictures on the net. Alone the road in places like Arizona, New Mexico, Nevada and others places in the west of the USA, i have observed very nice spots with very little or none light pollution, observing the skies from there at night should be a stargazer dream. I have been considering a 8" dobsonian, but seeing that it have to go in the truck (space and weight matters, the tube it`s almost 3ft in length and the total weight is close to 50 pounds), i have choose to go down a little and go with a 6", my election is the one you see in my signature, a Orion StarBlast 6i IntelliScope Reflector Telescope. Being a novice , i assume it will make my life easier having some help finding objects in the sky. The similar model w/o intelliscope it`s $130 cheaper, what do you think about the intelliscope? Any experiences with it?, it`s worth it? It does have a tabletop mount, making it smaller than the ones on a tripod and a lot less heavier too, just 23.5 lbs. Will have to go in and out of the truck (lorry) every time i will want to watch the sky. For the reviews that i have seen in Amazon and other places, it`s looks like a good telescope, but i have noticed some complaints about the optics, what kind of optics do you recommend to go with it? it come with a 1.25 10 and a 25 mm Sirius Plossl, are they any good? It will need to have a Barlow too, which one do you guys recommend? 2X or 3x? brand? Filters, other that the moon filter, what are the useful ones to watch planets and deep space? any filter collection you know off with everything included? How can i take pictures with my phone from it? Thanks in advance for your help. Any useful tips, are welcome and really appreciated, thanks. -
omega centauri A deeper look at Omega Centauri ( NGC 5139 )
MikeODay posted a topic in Imaging - Deep Sky
Update 16th June: I could not wait to tell people that I was just notified that my image of Omega Centauri will be published as a future NASA's Astronomy Picture of the Day ( APOD ) - my first ever I will update the thread when they publish. ................................. A deep look at Omega Centauri ( NGC 5139 ) This image is an attempt to look deeply into the the Omega Centauri globular cluster by using HDR techniques to record as many faint stars as I can whilst retaining colour and detail in the bright stars, including at the core ... ............. Reprocessed to bring out more faint stars and to produce a smother transition between brightness levels. New version ( 12 June 2017 ): Omega Centauri ( NGC 5129 ) ( please click / tap on image to see lager and sharper ) .......... Old version: Omega Centauri ( NGC 5129 ) ( please click / tap on image to see full size and sharper ) Image details: from www.nova.astrometry.net: Size: 58.6 x 39 arcmins, Centre: 13h 26 min 50.4 sec, -47deg 28' 39.1''. Orientation: up is -89.9 East of North ( ie. E^ N> ). Telescope: Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 ). Corrector: ASA 2" Coma Corrector Quattro 1.175x. Effective Focal Length / Aperture : 1410mm f4.7. Mount: Skywatcher AZ Eq6 GT. Guiding: TSOAG9 Off-Axis-Guider, Starlight Xpress Lodestar X2, PHD2 . Camera: Nikon D5300 (unmodified) (sensor 23.5 x 15.6mm, 6016x4016 3.9um pixels). No filter Long Exposure noise reduction off Location:. Blue Mountains, Australia. Moderate light pollution ( pale green zone on darksitefinder.com map ). Capture: 9 sets of sub-images with exposure duration for each set doubling ( 1s to 240s ) all at ISO800. Processing:. Calibration: master bias, master flat and no darks. Integration in 9 sets. HDR combination. Pixinsight May 2017- 40 replies
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( Edit 20 Aug: adjusted to increase brightness ) ... The Fighting Dragons of Ara ( NGC 6188 ) ( please click/tap on image to see larger and sharper ) ...................... Original: The Fighting Dragons of Ara ( NGC 6188 ) ( please click/tap on image to see larger and sharper ) Bright Nebula NGC 6188 and open cluster NGC 6193 are embedded 4,300 light years away in the Sagittarius arm of our Milky Way galaxy and can be seen with the naked eye south of Scorpius in the constellation of Ara. With powerful stellar winds and energetic ultra-violet radiation, massive stars sculpt the interstellar gas and dust of the nebula into wonderful shapes and cause the interstellar gas to brightly fluoresce. Closer to the hot young stars of the cluster, bright blue “sunlight” reflects off the clouds of gas and dust to produce the blue reflection nebulae seenin the image. Magnitude +5.19, RA 16h 41m 42s, Dec -48deg 48' 46". Approx. 3800 light years away. Image details: Plate Solution: Resolution .......0.586 arcsec/px ( original full size image ). Rotation .......... 89.764 deg. Pixel size ........ 3.90 um. Field of view ..... 58' 41.6" x 39' 9.5". Image center ...... RA: 16 40 09.856 Dec: -48 41 22.50. Image bounds:. top-left ....... RA: 16 42 10.059 Dec: -49 10 30.54. top-right ...... RA: 16 42 06.489 Dec: -48 11 57.14. bottom-left .... RA: 16 38 11.010 Dec: -49 10 39.74. bottom-right ... RA: 16 38 11.897 Dec: -48 12 05.58. Telescope: Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 ). Corrector: ASA 2" Coma Corrector Quattro 1.175x. Effective Focal Length / Aperture : 1410mm f4.7. Mount: Skywatcher AZ Eq6 GT. Guiding: TSOAG9 Off-Axis-Guider, Starlight Xpress Lodestar X2, PHD2 . Camera: Nikon D5300 (unmodified) (sensor 23.5 x 15.6mm, 6016x4016 3.9um pixels). Location: Blue Mountains, Australia Moderate light pollution ( pale green zone on darksitefinder.com map ). Capture ( 24 June 2017 ). 12 sets of sub-images with exposure duration for each set doubling ( 1/8s to 240s ) all at ISO800. 34 x 240s + 10 each @ 1/8s to 120s. Processing ( Pixinsight - 19 Aug 2017 ). Calibration: master bias, master flat and no darks. Integration in 12 sets. HDR combination PhotometricColorCalibration.
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NGC 2014 and Dragon's Head nebula in the Magellanic Cloud ( LMC ) not far from the Tarantula Nebula by Mike O'Day ( 500px.com/MikeODay ). This image shows multiple bright nebula and star clusters in an area adjacent to the The Tarantula Nebula ( NGC 2070 ) in the nearby irregular galaxy, the Large Magellanic Cloud ( LMC ). The largest of these are the bright pink nebula in the mid-right part of the image ( NGC 2014 ) and the blue nebula in the lower middle ( NGC 2030 ). ..... Updated image - reprocessed to impove colour balance ( April 15th ) ( please click / tap on image to see it larger and sharper ) .... Original: ( click on image to see larger and clearer ( grrr... image compression in version above )) ---------- This is the first image captured as part of a new image capture and processing workflow I am trying out... Roger Clark ( http://www.clarkvision.com/articles/index.html ) has a number of articles addressing colour processing and the performance of modern DSLR sensors. The "take homes" for me have been: 1. With a modern sensor ( one with on-sensor dark current suppression technology ) one may not need to capture dark frames ( in order to remove the now non-significant pattern noise ). 2. "Correct" white balance processing should start by using "daylight" RBG channel multipliers ( to get the star colour 'right') and any histogram adjustment to improve white balance of darker parts of the image should involve aligning the left side of histogram curves ( ie. not the peaks ) So, the workflow to produce the image above involves calibraiton with Superbias & Master Flat but no dark frame subtraction (neither post nor in-camera). Roger Clark speaks of using a "bad pixel map" as the basis of reducing hot pixels. I have not figured out how to produce one yet. However, with a little bit of dithering during guiding ( and the very busy image ) the hot pixels that are in the image below are not too overwhelming. With regard to colour balance; I tried using the "daylight" factors reported by the camera but these resulted in an image and stars that were quite blue. This image was based on the factors reported by DXOMark for the Nikon D5300 ( R x 2.12, G x 1, B x 1.49 ( D50 standard )). This was better but I still felt the need for a final tweak in Photoshop ( colourBalance Highlights +15 Cyan/Red, -5 Magenta/Green ) to improve the colour in the stars and mid-tones. { DXOMark "white balance scales" for D5300 found at: https://www.dxomark.com/Cameras/Nikon/D5300---Measurements on the "color response" tab } --------- Details: Bright Nebulae: NGC 2014 ( upper right, pink) size 30 x 20 arcmin Mag +8 NGC 2020 size 2.0 arcmin ( small blue-green oval nebula ) NGC 2030 NGC 2032 ( Dragon's Head nebula - blue, central bottom of image ) NGC 2035 size 3.0 x 3.0 arcmin NGC 2040 size 3.0 x 3.0 arcmin Open clusters: NGC 2004 size 2.7 arcmin Mag +9.6 NGC 2011 size 1 arcmin Mag +10.6 NGC 2021 size 0.9 arcmin Mag +12.1 Annotated : Image centre RA 05h 33m 32.362s, Dec -67° 32' 18.145" (nova.astrometry.net) Orientation: up is west, right is South Field of view (arcmin): 58.8 x 39.2 Scale (full size image) 0.585 arcsec/pixel Telescope: Orion Optics CT12 Newtonian ( mirror 300mm, fl 120mm, f4 ). Corrector: ASA 2" Coma Corrector Quattro 1.175x. Effective Focal Length / Aperture : 1410mm f4.7 Mount: Skywatcher AZ Eq6 GT Guiding: TSOAG9 Off-Axis-Guider, Starlight Xpress Lodestar X2, PHD2 Camera: Nikon D5300 (unmodified) (sensor 23.5 x 15.6mm, 6016x4016 3.9um pixels) Format: 14bit NEF Noise reduction: off Filter: none HDR combination of seven sets of exposures (20 & 22 Feb 2017): 58 x 240 sec ISO 800 8 x 120 sec ISO 800 8 x 60 sec ISO 800 8 x 30 sec ISO 800 8 x 14 sec ISO 800 8 x 7 sec ISO 800 8 x 3 sec ISO 800 Pixinsight: 26 Feb 2017 Links: 500px.com/MikeODay photo.net/photos/MikeODay
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Orion ST80 optics problem, please help
ebeygin posted a topic in Discussions - Scopes / Whole setups
Hey guysIm really struggling with an issue. Recently purchased an Orion ST80. At 20x to 44x using stock 20mm/9mm eyepieces stars look pretty good. But if I test it at 175x using 2.3mm eyepiece and point to bright star I get the pattern like in the images below.Will unscrewing the ring and tapping on the side of the tube resettle the lenses? Or is this an alignment/collimation issue that isnt fixed easily? Defocused, the center circle isn't too off the centre..but focused in, it looks like a cone. Really annoying. If I send this back, no guarantees that the next one will be any better. Or is this typical for type of scopeThanks in advance!- 32 replies
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