Review of the TPO/GSO/etc 6" f/6 Newtonian OTA telescope

A fantastic bargain of a telescope optical tube at around ~$200 USD (price varies depending on where you buy it and what accessories the seller includes). You get everything you need except an eyepiece, a mount, and (sometimes) the required extension tube for the focuser. Update, Jan 2022: Prices have gone up! It's still a bargain, if you can manage to find one in stock.
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Thanks for watching!
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[@tjzambonischwartz]

As a nearly 20 year reader, I'm overjoyed you're doing KZbin reviews now.

[@edting]

Ha, thanks TJ! Things certainly have changed in these past 20 years, haven't they? A generation ago it was the coolest thing to have a web site. Today nobody cares!

[@tjzambonischwartz]

Ed Ting Hey, I still care. At least about THAT website!

[@pivottech8881]

@@edting I only just started watching but in my opinion I feel I understand more hearing someone speak about someone face to face (like video or proper in person). Of course I know authors take time to write what they say but I just take more knowledge in from video.

[@marcomeiling9313]

So cool, to finally get a voice to a familiar face, reading since 1998

[@therainmakerusa5829]

Yes Ed, please keep the videos coming, and thanks for all your insight and detailed reviews on your website. Such and wealth of knowledge, thank you for being you!

[@anthonymistrulli5774]

Ed. You addressed the tightness of the tube rings. Agena addressed that problem saying this. Please note: The tube rings included with GSO's 6" scopes are a bit smaller than they ideally should be. Hence, do not attempt to rotate the tube within loosened rings unless you completely open them or you will scratch the tube finish. Some customers resort to removing the felt lining and replacing it with a thinner alternative to allow the tube to rotate within the rings.

[@edting]

That was obviously written by someone who does not use telescopes.

[@brentjablonski3730]

Great video, Ed. I've been a reader of your reviews going back nearly twenty years. You set a high-standard with your written reviews, and you've hit the mark with video, too.Thanks!

[@rhyndman]

This video is a gem. Thank you! Found it just *after* I bought the GSO version!

[@MrAstrojensen]

I've been reading your reviews since getting an internet connection in 2000 and only yesterday found out you're also doing videos now. I must say your videos look very good, are just as informative as your articles, being kept in much the same style, and you've got a voice that is pleasant to listen to (which is by no means a given, these days, when everyone and his dog is on KZbin!). Keep up the great work!

[@douglasmcdougall7054]

I purchased one of these some months ago. Also had a very good star test, showing near identical extra focal star patterns. Excellent value scope.

[@TheUrbanAstronomer]

Love your videos. I have the F5 from GSO, it came with the extension tube by default... It has been a joy to use till now.

[@bawattsyl]

It's interesting because I just got this telescope recently (within the last year) [mines the GSO Model] and it came with a dual speed 2" crayford focuser, and the extension tube.. along with all the other accessories you mentioned here.. it's been wonderful, and I've never had any issues viewing or with taking pics, achieving focus etc... Great bang for the buck. Especially with the dual speed 2" crayford.. this scope cost me about 260$ I looked up the cost of the the included GSO dual speed 2" focuser, and that by itself sells for $179... so really for getting that plus everything else for the price; is an amazing deal.. imo highly recommend for anyone. I got mine at agena, and like I said it comes with the extension tube, and pre check for collmination etc.. as for the rings, mine are fine, I can adjust and move the tube without any real trouble.. so that could be particular to the branding but🤷‍♂️ Really an unreal deal!

[@NGC6144]

I have had this OTA(TPO 6" f/6) for maybe almost around two years and it's quite good. I mainly bought it intending to image but I was also was quite pleased visually. Excellent views of the moon with a high power eyepiece(Orion 3.8mm Lanthanum, 241x). Excellent review.

[@gothicm3rcy426]

recently purchased a tpo 8in f/4, extremely pleased with it

[@alphalyrae4491]

The best telescocpe reviewer on the internet now does videos? Subscribed!

[@edting]

Thanks to all of you for your kind comments!

[@ripcat12]

Great video ED thanks for recording it. I have the f/5 version (from High Point Scientific) but it is the same as the scope from Agenaastro. I too had an issue w/ the rings being too tight and I replaced them w/ a pair from Agena. It's a fine scope and holds collimation better than any of my other Newtonians. I can't think of a better value for a beginner than this scope. I use mine on a Explore Scientific Twilight 2 mount and being an manual Az-Alt mount it's fun to scan the sky. Thanks again for a great video!

[@jeff7731]

excellent review. subbed

[@francois05]

Hello, Mr Ting, I remember you did a review on Scope Reviews a few years back on Orion's 150mm Newtonian Astrograph. You remarked on how nice the focuser was. Well, I have the Orion scope and I have the GSO 150mm f/5 bought through Agena with the upgraded focuser. Very nice focusers. The Guan Sheng manufacturing origin of both OTAs is evident.

[@dw6528]

Love your review videos!!!! Please don't stop doing them! Do you compare different Newtonian products to each other?

[@sold9603]

What a freaking awesome video. Thanks for sharing .......👍

[@nocturnalmayhem0]

i have this scope its decent for 200 the fix for the rotating is put wax paper on the inside of the rings then it will rotate like butter without undoin the clamps too much. overall my most used scope

[@davidmuth4571]

I got one like this a week ago. It's from the late 80s. It came on a Vixen Super Polaris, but it's going on a CG5. The model is Celestron SP-C6 150mm f/5 with a sliding door focuser, but I wasn't able to find a manual for it. Good to know info and I appreciate the tip about using a barlow as an extension.

[@astrophotonics9470]

Recognized the early 90's Meade 8" f/6 Newtonian still have it too, nice entry level newt .

[@andreguimaraes96]

I really like yours videos 🖖🏼

[@jeffblazey612]

Actually ED, the issue of the tight rings is not nit-picking. That is a practical issue which can impact the ease of use of the scope and, as you said, the mounting's alignment. But the scope does appear to be an excellent value. Well done review sir and thanks.

[@donaldkasper8346]

I don't see how tight rings exist since you control the tension. For a long OTA, you want them to be tight.

[@spacemanschannel6380]

I have a Skywatcher 150PDS which looks very similar. It is comforting to see a positive review about a simple 6" Newtonian when the internet is full of reviews about SCT's that cost 10x as much!

[@stretchedcheese]

Do you face any proble with the 150pds?

[@cattaraugustonawanda4426]

Just received my GSO 6"f6 today. $289 on sale 8/2022. Disappointed in the folded seam tube rather than seamless or welded seam but otherwise very nice and reasonably priced . Planning to make my own mount. EDIT 8 mo later - after a bunch of sanding and filing I was able to enlarge the ring holes and apply some thin cloth which makes it possible to rotate the tube. I had problems with collimation and this winter disassembled the mirror cell only to find one of the three springs in the wrong place. Reassembly with all springs correct it was easy to collimate and performs better. I have used this OTA on both a homemade Dobsonian mount and a CG-4 GEM. Now ready to see how it does on an HEQ5 mount. As a beginner the focuser was easy to understand but the collimation issue wasn't easily diagnosed. Lack of exploded view and instructions is an issue with most astronomy products. KZbin has been a lot of help for this beginner.

[@k.h.1587]

I got an early TPO version around black Friday 2017, the only logo was on the focuser, nothing was on the tube back then. They are GSO but the Orion and skywatcher versions are likely synta made, where the TPO, agena, astrotech and high point are GSO. I was a salesman at OPT from 2006-2011 so naturally I just drove down to get mine, but under new ownership I only got the normal black Friday $169 sale price, no more ex employee discount. The 35mm extension tube was not in the box but they threw one in from store stock My reasoning for getting one was that I was living on a boat, all my big and expensive stuff was in storage and my main instrument I was keeping on the boat and using was a C4R refractor with my SV M3 alt az mount, and I wanted more aperture that was low cost enough to risk staying on the boat or in the car. And I had plans to try and get one of the f8 spiders and secondaries to make it a mars killer for the 2018 opposition, since the stock secondary was a bit oversized, I think it was the same size as the f5 version. On the M3 it was the perfect equivalent to a premium dob and a joy to use. As a deep space scope it was very fun, but I noticed it started to break up after 100x and there was a stig flip in the star test. Loosened the mirror clips and that did not fix it, so further troubleshooting rotating the primary isolated that the secondary was the culprit, which surprised me because the secondary was glued on to the stalk unlike earlier GSO designs with the plastic shroud which was known to pinch the secondary. I contacted opt about a replacement secondary and they were more apt to just exchange the whole scope. Due to distance and other things going on I never got around to it before things went awry and I got kicked out of the marina and had to rough it for a while, during which time my storage (which now had everything in it) was ransacked several times and eventually they got all the telescopes. So if you bought a used 6f6 with a losmandy old gm8 style dovetail and astigmatism, it is mine. That also goes for a TV101, pronto, Meade 8" lx200R tube, c4r, all with the old narrower GM8 plates, and a cg5 and sv M3 all with GM8 saddles, as well as a dark grey c11 with black d plate and adm mini on top (the 8r also had and mini on top) and a celestron G11 with Gemini 1 missing tripod and counterweights, it is mine and I would like to catch the guys. The scopes were taken over the late 2018- mid 2019 period (the big cats taken last), the pronto taken out of car in salvage yard may-June 2018 in a doskocil case loaded with Pentax/televue/Meade etc eps and barlows, lumicon astronomik, Orion OPT filters and an astrozap etx90 solar filter, a sol searcher and vixen finder shoe were mounted as well. And back in2013 my solarmax60 with gm8 plate in a WO case was also stolen. Many years of bad luck

[@lornaz1975]

You should show us that big beautiful old Newt behind you!

[@anthonymistrulli5774]

Agena sells this. GSO 8" f/5 Newtonian Reflector Telescope with a dual speed crayford focuser. Comes with rings, mounting bar, 8x50 finder, 35mm extension tube to achieve focus in visual. I bought it for $529.00. Really good optics. I installed bob’s knobs. to replace the secondary screws. Much easier to align. Great telescope.

[@grandmasteryoda9893]

looks like a great deal for takeing photos

[@divye.ruhela]

Very accurate review! I have a GSO 6" F5 in one of these configs, and as a beginner who bought this a year back as the first scope, I have faced all the issues that he mentioned. I use a 32 mm extension tube with it (for my 1.25" eyepieces). Also, the rings are super tight, and I've scratched/ pinched my OTA's paint trying to rotate it around, so that is another thing to watch out for. Another thing he gets correct is that these scopes are sold as DSO imaging Newtonians (with extra large secondary), but the issue is that they are a bit on the heavier side, and with the autoguiding and main imaging camera, you'll need to invest in at least an intermediate level Go-To mount for AP (a beginner level, starter Go-To mount will fall short in terms of recommended payload; and you'll need autoguiding for the DSOs). So the money you save on the OTA is actually spent on the mount. Another issue that I've faced with the larger secondary mirror is trying to collimate using a standard size sight tube! The secondary is too large to fit, so I had to cut the sight tube to center the secondary.

[@donaldkasper8346]

You loosen the rings to slide the OTA up or down or rotate, then retighten.

[@divye.ruhela]

@@donaldkasper8346 You actually need to re-felt/ add free-to-move extra felt to the exposed metal where the pin/ screw that holds the ring together is at. The stock rings can be tight and can scratch the tube even when the whole ring is loosened & tube moved around. I'm still working on this OTA, added a dovetail to create a cage and two extra rings to be used as Wilcox-style inspired rotating rings.

[@donaldkasper8346]

@@divye.ruhela By definition, the tube felt has to be interior to exposed metal surfaces. For my Zhumell Z8 I had to add a set of 6 strips of felt because it was too loose. It was a generic ring clamp pair as the Z8 is made for a Dobsonian mount.

[@edufau815]

I wonder why there are relatively few manufacturers of Newt 6" at F/6..., many jump from F/5 to F/8, however F/6 seems to be an excellent compromise between the tube for imaging (short, light , manageable) and the one specially intended for visual (a tube already somewhat heavier and more than 1 meter long)...

[@lornaz1975]

I have the 8in F5 version of this from Agena Astro. I agree with the tube rings. They are tight and the knobs seem cheap. Otherwise it is a good scope so far.

[@JamesAdams-ev6fc]

Nicely done as always, but with a voice and a face. I'm a subscriber. And incidentally, you helped me to decide on a refractor a few years ago. I've been meaning to say thanks.

[@henribuhagiar9445]

I bought a 12 inch GSO Dob ( here in Australia). Found optics and views excellent. Even comes with a cooling fan, which for $900 was a bargain. Focuser is butter smooth ( comes with a dual speed focuser). Just upgraded to a skywatcher 12 goto dob and the focuser pales in comparison to the GSO

[@nikpan9744]

I‘m glad to hear that! I‘m thinking of getting a 16“ Dob from GSO and wasn‘t sure if they‘re telescopes are good quality.

[@Astronurd]

I recently bought a GSO 8”Dobsonian and it had the 35mm extension piece provided with the scope

[@edting]

That's good to hear. It seems the accessories you get depend on the supplier's mood that day...

[@Mr1945pete]

Hello Ed, Love your reviews! Though I disagree with you on the AT6IN f4 (I have the Apertura version of this Newt). I know you really felt is was compromised for visual use, but I feel the opposite. Like you say in your review it’s about things meshing with your priorities of what you want out of a telescope. And of course everyone has different priorities. Mine is I want the most compact, short tube Newtonian possible. Mostly for portability issues. As you say multiple times, the tube is really short! What’s a bonus for me is that it has a decent 2” two speed focuser, mirrors, rings (Though too tight, maybe they’ll get better with breaking in?). Also, my collimation is buttery smooth and holds really well. There is another member on the Cloudy nights forum who uses his mostly for visual use as well. A decent Coma Corrector does clean up the views. Again for me because of it’s size, it truly is a grab and go Newt. I have mine on a Starblast 6i mount. You can throw it in a bag and you also have the push-to capabilities. I like the Starblast 6 as well but it’s much longer and most disappointing to me there is no 2” focuser. Plus Orion only provides a cheap plastic one. The short tube 6” f4 feels a lot more rugged all around. As things start to get really cold it will be nice to just grab a Newt that has some punch and do some short observations in Dark Skies! There are a lot of similarities with the review of the TPO/GSO 6” f6. Both are cheap, come with good optics, overly tight rings. Lastly, I don’t have to lug around the much larger Dobsonian’s I have!! Keep up the good work, look forward to future reviews!

[@puuxexil]

Ed, long-time reader of your website and articles. I have the very same scope, and your review is spot on. I can attest to the two issues you highlighted (focus, tube rings) which I found troublesome. I know you mentioned spherical aberrations, but how good would you say this mirror was?

[@lphilpot01]

I bought the GSO f/6 version (with the two speed Crayford focuser) from Agena recently to replace a Sky-Watcher 4" f/9 ED refractor on my iOptron AZ Mount Pro. It came with a finder shoe but no finder and a 35mm GSO extension tube. I used an existing Stellarvue F001 RDF, which is all I need on the AZMP. As it turned out, all my eyepieces focus without the extension tube. The only semi-exception is my original 9mm Nagler (with the hybrid barrel). I have to use it with a 1.25" adapter but it works fine -- Otherwise it needs the extension. But my two old Meade UWAs, 15/22/27 Pans, 12mm dual ED and all the others focus without the extension. Since the AZMP requires the north-pointing OTA to be on the east side of the mount (facing north), I rotated the focuser 180 degrees and moved the finder shoe to above it. So far, I can't be more pleased with it, but in all fairness it's summer in the deep south US (HEAT, humidity, haze, bugs) and additionally the New Scope Curse is in rare form, so I've not been able to use it much. But from what I've seen it's a tremendous value for the money, not to mention kinda being one of the sweet spots in terms of telescope size. Excellent review!

[@edting]

Thanks for the update. Hope you got yours before the prices went up!

[@lphilpot01]

@@edting $340. Not sure if that's before or after. I've not checked lately.

[@k.h.1587]

​@@lphilpot01after

[@KingLoopie1]

I can't believe the prices of today as opposed to even just 20 years ago, never mind longer ago...! So much bang for the buck!

[@jeffblazey612]

Thanks for the review Ed and I'm glad you mentioned the optical quality. Also, IMO, your comments relative to the need for an extension tube and stiff rings are NOT nit picking. Without the extension tube, a buyer simply cannot get to a visual focus, making the scope unusable. Regarding the rings, the last thing you want to do in the middle of the night is fight with the scope to get the eyepiece into a comfortable position, especially with an aligned goto mount. Both of the issues you flagged need to be addressed by the vendors. One question did the scope arrive well collimated and if not, how easy was it to collimate?

[@donaldkasper8346]

Yeah, keep the rings looser.

[@Larpy1933]

Even w/o a photo of NGC 891 (or NGC 4631), I love this review. No interest in such a scope. Thx!!!

[@MountainFisher]

It is February 8, 2023 and Agena is out of stock on most of the Guan Sheng Optics or GSO except the f5 8" with a standard Crayford focuser. Also had a RC 12" Richey Chretien carbon truss tube telescope with 95% reflectivity quartz mirrors astrograph in stock. They are out of stock on their truss tube RCs to 16" even. $7700 sounds expensive, but not for a 16" RC it isn't. They are made in Taiwan and I looked at an 8" a guy in my club bought and it seemed quite good. He was stoked that it arrived collimated by Agena. It didn't have the quartz mirrors and 95% reflectivity like the RC scopes do, but its single speed focuser was smooth.

[@billiechiu2857]

Very informative video! tight rings are a no-go for mounting newt on equatorial mount. unfortunately, in my experience the taiwan specd GSO冠昇 guan sheng newt scopes all have this problem. strangely, the PRC specd synta newts use rings that allow one to loosen and easily rotate scopes. i need to test putting gso newt onto synta rings. cant wait for your vids on tak stuff. cheers!

[@bawattsyl]

I have the GSO version of this. Apparently the upgraded version, as it has a 2" Dual speed crayford. Mine was purchased this year , and the rings were a little snug but not too bad, however, i have a set of rings from an older orion 6" scope that fit this great, and I just like them better so I used those instead.. I think most of orion stuff is made by the company you mentioned. But I could be wrong. I don't know a whole lot about the various manufacturers.. Just thought I'd mention i was able to use other rings on my GSO version of the one he's reviewing here.. it's also worth noting, mine came with the extension tube, so focusing hasn't been an issue. Really a great overall value!

[@chrisstrobel3439]

Nah your not nitpicking those rings at all, in my book rotating rings are a must on equatorial mounted Newts, I have em on my 10” f/5 Parks, and probably will be ordering some Parallax rings for my GSO 8” f/5 after I get rid of the steel tube. Great channel btw, been in the hobby myself close to 50 years and still learn stuff here .. like unscrewing a Barlow to make an extension tube (it’s like dohh why didn’t I think of that 🙄 lol) Thanks

[@donaldkasper8346]

One manufacturer states "Counterweight at end of rod causes vibrations. Use a heavier counterweight or extra weight closer to the pivot point". Second, the Atlas mount might be rated for 40 lbs, but it uses a 0.75in (20mm) diameter counterweight shaft. They do have a one inch diameter upgrade but this is pointless as the breaking point is the thread into the mount head, which remains at 16 mm. The jump is CG-4 for $400 and Atlas for $3000, so one would presume it better show something more for that kind of money than just tracking.

[@IanSRutter]

GSO Newtonian that you have actually make the optics and mirrors, so which ever name you get they have the same optics/mirrors. GSO is a Taiwanese company and the f4 comes in 6", 8', 10' and 12". They make really good mirrors/optics and better than their Chinese counterparts. Really nice telescope and typically from 6' to 12' the do come with the extension tubes. They do sell out really quick.

[@greg4318]

Awesome review Ed as always…….but is not a Dob still a better choice…..(visual guy here)!

[@user-mk9yi1wi2g]

Hi Ed, Your review are spot on and well detailed. Pleasure to see tour dedication. Will need your feedback on Explore Scientific 150/750 EQ-3 Reflector Telescope Not getting much details on es website also for this. Is this a good telescope to buy for intermediate user? Thanks

[@OlDuckOffroad]

Great content, am glad I found your channel. have you done any reviews on the Celestron Omni XLT series? I am looking at the XLT 150 with the CG-4 mount as my first telescope.

[@edting]

That scope is OK. Those generic 6" f/5 Chinese-sourced mirrors have a lot of variability but at that price they are an OK value.

[@curronhill2744]

Quick question Ed, by having the focus point so far out of the focuser, does than means the secondary is oversized to reflect a wider light path at that point in the tube? If it is oversized doesn’t it then block incoming light? If it is not oversized does it pass all the light from the primary? Either way this looks like a potential loss of light. I have the GSO version and am really surprised what I can see with this scope. I’m even getting M74 glimpses at my Bortel 4 location. Thanks and I enjoy your channel.

[@edting]

The inter relationship between diagonal size, placement, and focuser height is complex to the point where it makes my head hurt thinking about it. The odd thing is even when you get it wrong the images often still look fine.

[@MrKA1961]

f/8 version is far better for visual observation.

[@Balajik80]

Hi Ed. Great review.. I have the GSO F5 version. Can you suggest a good alt az mount? Can skywatcher az4 work well with this OTA?

[@edting]

I have a 6" f/5 Orion (similar to your GSO) on a Vixen Porta (similar to the AZ4). I would rate the combination as "fair". If you are set on doing this, get the upgraded steel legs on the AZ4 if you can. If you are looking to make your own Dob mount, the classic texts on this topic are "Build Your Own Telescope" by Richard Berry, and "The Dobsonian Telescope" by Dave Kriege and Berry. Keep in mind a 6" f/5 tube is short; calculate the height of the rocker box so the eyepiece is high enough for an adult. Hope this helps.

[@Balajik80]

@@edting Thanks a lot. Will check

[@TripleXmodder]

Noob here.. actually trying to get my 17 yr old daughter her first telescope. I don’t know what I’m getting. Do you have links for what extender and base I need to order with this? THANKS!!

[@user-gs5pe8iq9m]

Hi I have a question about this scope the gso version I found it on cloudy nights classified for sale for $300 but it is on a dobsonian mount should I be concerned about the focal extension?

[@user-gs5pe8iq9m]

And is it worth the price?

[@atulnanal3889]

Does this achieve prime focus with standard canon dslr ? Is the focal plane too inside the focusser to achieve prime focus with dslr ?

[@k.h.1587]

Yes it is designed to reach focus with a dslr. But you will want to use a coma corrector, for 2 reasons, obviously coma correction, but also, you don't want your camera sensor exposed to the air for long periods of time and if you don't have glass in front of it, it will be exposed. Another option, which I used because originally I didn't have a coma corrector (back then there were no cheap ones, just the vixen, baader mpcc, and televue paracorr (which I eventually got), I used a lumicon 2" t adapter that was threaded for filters, and used a uv filter to protect the sensor.

[@charlessands6933]

Mr. Ting: Between THIS scope or an 8" f/5, which one would you recommend to use on my Orion Skyview Pro mount?

[@edting]

Hi, thanks for watching. If you have an SVP, I'd get the 6". The 8" will be pushing mid-20s for weight and it might be too much.

[@k.h.1587]

I used to use an older 8"f4 gso (hardin) on a Skyview pro, but I eventually bought a 2" steel cg5 tripod, since the 1.75" svp tripod is a tad too small and the legs only extend about halfway. And the top portions of the legs are longer than the 2" version. With that tripod I could go both lower and higher, and gained more stability. The SVP head has a little more mass than a cg5, and I think it will handle the 8" fine for visual, but you might want to try and source a used cg5 tripod, usually around $100 when they pop up. I had a Hardin star-hoc mount which was the same as the older Skyview deluxe mount, which was kinda between a cg4/astroview and a cg5, but essentially an ever so slightly bigger cg4, but on the same light aluminum tripod. I did a slight mod to the mount so I could put it on the 1.75" SVP tripod, and it handled the 8" nicely as a visual rig. I loaded the SVP/2" combo to the max or more, with the 8"f4, a piggybacked 80mm f11 refractor, 3 11lb counterweights, a 35mm SLR and actually did manual guiding with the dual axis drives on film. I wouldn't recommend it. But for visual work, the 8" is fine. Get the f4 if you can since it is a little shorter and lighter, but 8"f5 newts on cg5 mounts have been acceptable visual scopes for decades, which many push to the limit and do astrophotography with, before ultimately upgrading to eq6 or losmandy mounts. If you want something that is not likely to make you want to eventually get a bigger mount, than the 6" is better, or even better, an old used c8, which is actually lighter than the 6" newt (shorter tubes, thinner conical primary with the center removed, and a thin Schmidt corrector plate make for a very light 8" tube) A used C8 can be less than a new 8" newt and on par with a new 6" newt or just slightly more ($300-500 range)

[@niallchurch2679]

Why can't manufacturers put astop at the end of the tube to stop the tube from slipping further down if you have to adjust the tube dhile rings are loosened?

[@michaelyoung7908]

Agena astro has an GSO 6 inch F/6 with a upgraded focuser 2 speed crayford load bearing for $70.00 more, is this a useful upgrade?

[@edting]

Hi Michael, that upgraded focuser is mainly for astrophotographers who put heavy cameras in their telescopes. It may also be useful if you use a lot of heavy eyepieces like the 31 Nagler. Otherwise, their standard focuser should be just fine.

[@pasky7777]

I am new to these telescopes and a friend gifted me one with a 10inch mirror; weighs about 20 plus lbs. I am at a loss for which mount to buy for it. Thanks for your help.

[@edting]

I have a review of the Astro-Tech 10" f/4 on Scopereviews. I used it on a Losmandy G11, which wasn't quite strong enough.

[@pasky7777]

@@edting thanks. Will check it out now.

[@rubenmborgesmusic]

I was looking for a review of the apertura 6" f4 imaging reflector. Is it realy much better to buy an apo refractor vs one of these reflectors.

[@edting]

I have reviews of the 8" f/4 and the 10" f/4 on Scopereviews. Use the Master List. YT frowns on links in these comments. They are OK budget scopes. The best part is the focuser. They are however nowhere near the quality of a nice refractor.

[@rubenmborgesmusic]

@@edting I see. I'll check out your videos. I guess for tracked astrophotography the aperture size isn't that crucial since you can compensate with exposure? I've been looking online and refractor are definitely recommended for astrophotography over reflectors. I will tend towards your advice, you're credible as far as I'm concerned. Thank you for your reply.

[@davidbrandenburg8029]

or do what most people do and thats to buy the correct scope, so you dont need to mess with extensions!.

[@StargazerFS128]

Ed, love your videos but you have to give that old 8" meade (i believe) behind you a paint job, all those scratches break my heart lol.

[@edting]

Agreed! But I can't seem to get a reasonable quote for paint jobs around here. The best estimate I got to repaint the 4" Unitron for example is $550.

[@StargazerFS128]

@@edting Ohhh that’s steep, understandable, I was wondering where you reside, I am Canadian, are you in Canada or US? anyway, love the quality of your vids and, I play them as I’m cooking and such, I live just outside Toronto Canada. Pleasure to meet you! even if it is through KZbin, lol.

[@charlessands6933]

Just got mine from Agena, with the extention tube. The rings are tight on mine too.

[@Mr1945pete]

Mine too, I am finding others on forums are rubbing soap on the felt on the interior of the rim, or using dry silicone. Seems to work. Good luck!

[@charlessands6933]

@@Mr1945pete: Where do you get dry silicone and in what form is it?

[@Mr1945pete]

​@@charlessands6933 Here is what i'm getting and others have got. Dupont Non-Stick Teflon Dry. It goes on wet and drys to a microfilm of white teflon. It's ten bucks on Amazon. I'll try it out and give you an update. Thanks

[@Mr1945pete]

@@charlessands6933 I tried the Teflon spray dry. Absolutely no luck. Issue is the half of the ring is pinching the OTA. I can actually undo the rings completely and one half of the ring will hold the OTA in place without falling out! The rings are out of round.

[@charlessands6933]

@@Mr1945pete: it is most likely that they are simply too small for the OTA or they weren't made for it to be rotated within the rings which is what the retailer told me. If they were truly out of round it would be likely that they would be one or the other but not all of them would be that way. So what are you saying that the Teflon did not allow you to rotate the ring even if you loosened the rings? When my tube gets wet with dew, it provides enough friction for me to rotate it with some difficulty, even with the rings closed. The Teflon should provide enough of a reduction in friction to allow me to rotate it I'm since the dew does the same thing effectively.

[@clayc124]

Is coma reduced very much in an f/6 versus an f/5?

[@rodsmolter5046]

Yes significantly. f/5 is where a lot of people start using a coma corrector. I don't think anyone uses one at f/6, unless for photography.

[@k.h.1587]

Unless you are really picky, I could see coma in many widefield well corrected eyepieces such as 31 nagler, 20mm es100, and 34 and 40mm meade 5k SWAs (ES68, a copy of panoptic). The coma is only in the outer part of the field, and definitely not as bad as f5, you gotta be picky to really care. That is why 8"f6 dobs are so popular, most people can't see the coma, or they just don't own any eyepieces wide enough, that aren't chock full of astigmatism which tends to mask the coma, and make you want to ignore the outer field. Once you get that 31 nagler in there, you might want to invest in a coma corrector, a modest one like a gso is probably fine for visual at f6, but I only had experience with paracorrs, which I had sold off by the time I bought one of these for a specific reason (I was newt free at the time, and needed a cheap scope with decent aperture since I was living on a boat and all my big scts, eq mounts and apo refractors were in storage, and I was just using a 4" f10 acrhomat on a stellarvue AZ mount, and wanted something low value that I could keep in the car or on the boat, with more aperture than the refractor, and also was planning on trying to get a smaller secondary to turn it into a planet killer for an upcoming mars opposition. It turned out that mine had an astigmatic secondary limiting power to about 100x, but I didn't notice at first because I was hunting galaxies. Life got in the way, I got kicked out of the marina, forced down to van life, and in the process lost everything to tweaker storage theives, before even getting to have the 6" scope replaced.

[@ratnamaravind]

I bought one and replaced the primary with a Mike Spooner mirror. Pleasure to use

[@edting]

Oooh, a Stealth Machine - I like it! I know people who have replaced their stock XT8 mirrors with Zambutos too.

[@ratnamaravind]

You are an inspiration, Ed, and you have cost me thousands of dollars ever since I read your first FC100 review 8 years ago. I finally bought mine straight from Japan. Yes. The 6" f/6 is the my usual local outreach scope since it is a good tradeoff between my FC100 (my backyard only...no kids with greasy fingers) and my 11" f/5.1 Teeter STS with a conical RF Royce primary (dark skies). Mike Spooner delivered a wonderful mirror with lovely contrast and my views of Saturn at 300x last year with the Nagler 3-6 were memorable. Your reviews are wonderful. The only point that I would disagree with you on is the Mewlon 180c which is my backyard scope in good seeing. My sample is wonderful and holds collimation beautifully. It is a spanking deal for a Takahashi and rides comfortably on lightweight mounts.like the iOptron ZEQ25/CEM25

[@PopeAstro]

What will happen if I throw my 6" Meade 762mm focal length F/5 primary in this??

[@ratnamaravind]

@@PopeAstro eyepieces won't focus

[@PopeAstro]

@@ratnamaravind how about my dlsr?

[@han-shan]

hi there , thinking to buy 8inch SW / 1000 Newton or ts achro 152 f6 mostly for clusters and brighter galaxies. any advice here ? price gap doesn't matter

[@edting]

Don't get the refractor. You didn't specify which mounts you would be using. The 8" f/5 will be questionable on a midsize mount. I'd still recommend you stick with the standard recommendations, like the 8" Dob.

[@han-shan]

@@edting Thank you for your response . my mount is eq5. I think that the refractor will have a sharper image than the Newtonian, but I am afraid that it will not have such a good range for galaxies since it has a smaller aperture

[@k.h.1587]

​​@@han-shanthe refractor will be a little sharper at low powers for dso, but will have really bad false color fringes on bright objects. A 6" refractor will actually have improved contrast on galaxies if you don't mind your brighter stars in the field being purple. Both the 6" refractor and 8" newtonian are at the high end of the mount capacity, OK for visual without a bunch of heavy astrophotography accessories, guiders and cameras. Don't expect an easy ride for astrophotography with a tube that large on a cg5, and regardless of mount, an AR152 will perform horribly, with purple stars throughout the field. A newtonian with a coma corrector is a much better imaging tube, but you will want to upgrade to an eq6 class mount if you want to do deep sky images. But for visual, an 8"f5 is passable on a cg5. A used older C8 would be all around better though, and in the same or lower price range than a new 8" newt (but don't expect the latest high transmission coatings or coma free optics in that price range, but old c8s with the original starbright coatings or even the older "special coatings" versions still perform nicely, and tend to have very sharp optics.

[@han-shan]

@k.h.1587 thanks , already bought 6" sw ed

[@eagleeyetorr3244]

SOLOMARK 130eq is the same ?

[@edting]

No, not even close.

[@ultrametric9317]

So optics were good? An f/6 parabola is not easy to make! I agree, Newtonians should not need an extension tube, instead, there should be a closer set of holes to move the mirror cell forward in the tube if you are going to concentrate on imaging.

[@charlessands6933]

Mr. Ting. Since my Agena 6" f/6 OTA came with super tight rings too, I contacted Agena to see if I had the wrong rings. They said No. They said it is made to be rotated only after you remove the tube from the rings. Ridiculous. They offered me a refund or a $15 store credit. I said No to both. I have since ordered rings from Orion to fit it better.

[@divye.ruhela]

I scratched my OTA's paint at many places trying to rotate this in the dark. How are the Orion rings working for you?

[@charlessands6933]

@@divye.ruhela: They didn't. Even with added felt, they were too loose, so I returned them. My solution was to put the OTA in the rings with the focuser facing up.Most of the time, I csn reach the focuser with my eye. For the times I can't, where the focus her is out of eye reach, I made a long, wide bench about 14" (36cm) high to stand on.

[@k.h.1587]

​@@charlessands6933Too bad I saw this 3y too late to help, but to anyone else, orion and gso tubes are different diameters. I had this problem 20 years ago with a gso made 8"f4 that came with rings with no top holes to mount a piggybacked scope. So I bought orion rings, 3mm too big. A trip to home depot for a strip of neoprene, some epoxy, and carefully peeling back the orion rings thin felt, epoxying the neoprene to the rings, and then sticking the felt on the neoprene. Worked like a charm, and rotated REAL nicely. When I bought one of these 6"s in 2017, I was using it on an AZ mount and never had to rotate the tube, so I didn't notice the issue

[@donaldkasper8346]

You called it a crayford focuser, but I see a rack-and-pinion focuser.

[@edting]

It's a Crayford style focuser. There is no rack on the drawtube.

[@donaldkasper8346]

@@edting Okay, to me a Crayford is a 10:1 dial in a dial rig. For a large telescope you need fine adjustment.

[@rodsmolter5046]

@@donaldkasper8346 The scope is available with a 2-speed focuser. It's an extra $50. Well worth it when you consider that the focuser bought separately is $200. The GSO single speeds are quite good though, much better than the Synta singles speeds on the Orion and Skywatchers.

[@ufonaughts8814]

please can you just give dimensions! okay 6inch app but whats the focal length? and whats f6?

[@lphilpot01]

Aperture is 150mm, not quite 6" and f/6 focal length is 900mm.

[@k.h.1587]

F6 means focal ratio, or f stop, is is 1:6 meaning the focal length is 6x the aperture.

[@southbronxny5727]

No astro photography?....that's the real test.

[@peter7624]

Penny pinching by the manufacturers.