PLANET IN A 6" REFRACTOR v. 12" SCHMIDT-CASSEGRAIN TELESCOPE

[@Hitzaponylife]

Those comparisons are very useful so people can see which telescope they should buy.

[@tsulasbigadventures]

Yes, I agree.

[@supermario8416]

Excellent comparison, would be nice to see some more videos like this one :)

[@tsulasbigadventures]

Thank you. I will make some more! Viewers love comparison videos.

[@3dfxvoodoocards6]

Comparison videos with telescopes are the best. Big LIKE !

[@tsulasbigadventures]

Thanks! Everyone loves a comparison video. I'll try to make more.

[@HanYou2]

the thing is when looking with the naked eye you see a lot more detail on planets, way more color and subtle nuances that the camera doesn't have enough dynamic range to capture

[@tsulasbigadventures]

@@HanYou2 I agree with you. It's very difficult to show the viewer what I see through the eyepiece. What I see always looks better than what I can show with the camera. That's why I like to try to show my sketches of deep sky objects but I don't think I am skilled enough to make a presentable sketch of a planet.

[@HanYou2]

@@tsulasbigadventures your explanation and reactions to what you just saw are very good indicators of how good what you saw was! This was your first video that I have watched and it was very enjoyable! Don't be afraid to share the sketches as well, that adds a lot to the authenticity in my opinion. A lot of people take photos but I have never seen sketches. Maybe you can do a live sketch and explanation of what you saw!

[@tsulasbigadventures]

@@HanYou2 Thanks. I often include sketches. Explaining will help too.

[@steveengleman9257]

Great comparison and excellent video! I had the opportunity to view Jupiter through a 6 inch f/10 refractor and was blown away! Sharp image, and I could see a lot of detail.

[@tsulasbigadventures]

Thank you so much! I bet. I've never looked through an f/10 refractor. That thing must be very long.

[@thompsjm]

Hi, that was a very good video. The best view of Jupiter I ever had was with a 10" f/10.3 Newtonian reflector (homemade) I had on a permanent pier in my backyard. I had to use a stepladder to reach the eyepiece for most parts of the sky!

[@tsulasbigadventures]

@@thompsjm That telescope must have been huge! Did you build it?

[@zeitgeist8167]

Wow you have a lot of energy to be handling those behemoths

[@nodrogawson963]

Very surprising and interesting to see your results with the 2 scopes. Thank you for sharing,

[@lindafinch8983]

Hi Tsula, this was really interesting and so helpful, especially to have the comparison between the two types of telescopes and their strengths and weaknesses. I’m happy the refractor did so well, as I use that model, but secretly thrilled that you speak so highly of Artemis, as I have just bought a 12” SCT and now can’t wait to hunt for deep sky objects! Dark Skies forever 🤗🌙✨

[@tsulasbigadventures]

Thanks, Lynn. Congratulations on your 12" SCT! You're going to love it.

[@annikasoraya4322]

Congratulations! An exceptional video presentation - I thoroughly enjoyed your insights and comparisons. Weldone mate . . . . Sending you blessings and eternal light from Newcastle in Australia. Best wishes, Annika 🔮🍹🔭

[@tsulasbigadventures]

Thank you so much. I really appreciate your nice comments. Blessings and dark skies forever to Newcastle, Australia!

[@annikasoraya4322]

@@tsulasbigadventures Cheers Tsula!

[@waltergold3457]

Is this simply a case of the refractor's inherent clarity trumping the reflector's light-gathering power when it comes to the planets, which are already bright enough to see clearly, even in a small telescope?

[@tsulasbigadventures]

Yes, you could say that. The planets are so bright that the greater light gathering capability of the SCT could not overcome the sharper contrast you get on a refractor and that when the seeing is so good I was able to achieve a very high magnification on the refractor allowing me to see finer detail.

[@waltergold3457]

@@tsulasbigadventures I tried to find information on why lenses are better than mirrors for clarity but was stymied at every turn by the search engines, which provided endless advertisements for telescopes and repetitious and often erroneous articles, on the general subject of reflectors and refractors, apparently written by AI. And when I finally came across the precise question, asked by someone in Reddit, the answers were more of the same - in fact, the original poster complained that nobody had answered his question specifically. I imagine the answer has something to do with the light rays passing through glass rather bouncing from metal, surely with the involvement of quantum mechanics, but that's as far as I got.

[@tsulasbigadventures]

@@waltergold3457 I thought it was because with a reflector there is a certain amount of obstruction whether spider veins holding the secondary mirror or the central obstruction on a SCT caused by the placement of the secondary mirror and because you have multiple mirrors but just one lens but that would explain why an apo is still sharper.

[@waltergold3457]

@@tsulasbigadventures It's a plausible explanation and the one most often offered by the sources, one of which adds that mirrors have a longstanding reputation for inferiority simply because manufacturers, seeking a wide market through cheap pricing of a design most appealing to casual amateurs, chose to create an inferior product.

[@collegedad8656]

This video gave me eyepiece envy 🤣 Nicely done👍

[@tsulasbigadventures]

Thank you. I was shocked when I went to look up the prices to see what some of them cost!

[@paulcontursi5982]

Love your work. Another great video!

[@tsulasbigadventures]

Thank you!

[@wdavis6814]

It's always a wonderful moment when you check the weather and see clear skies all night:)

[@tsulasbigadventures]

Indeed!

[@OlliesSpace]

Hey Tsula - I've finally got a clear day today, so Im gonna try this test with my Mak 127 and Skywatcher 80. Refractors always give that nice sharp view, even if the image is smaller. Love your work. Ollie

[@tsulasbigadventures]

Thanks, Ollie. Looking forward to the results of your test.

[@KevinMurphy0403]

Great video Tsula, Thank you

[@tsulasbigadventures]

Thanks!

[@zulgadams5837]

Very nice, thank you for the video!

[@iamjessieray]

Another great video Tsula. I do love these telescope comparison videos. It is very interesting that the refractor would have a sharper view at a higher magnification than a large SCT like that. I suppose there would be many factors there though, different eyepiece, maybe the seeing was slightly different between when you were using the telescopes, and the fact that there is no central obstruction in a refractor. However, I would almost be that on a night of average seeing the SCT is going to beat the refractor every time, and I am personally more interested in faint deep sky objects anyway. I would love to see a comparison between different designs of telescopes at the same aperture though, I think that would be very interesting! Say a 6" SCT, Mak, refractor, and newtonian. Not sure how many telescope you own or could borrow but there is my idea!

[@tsulasbigadventures]

That is a good point about the seeing changing when going to the other telescope because the seeing does vary over the course of a night. It makes comparing two telescopes very hard to do. I would love to make a comparison video like you suggested but I already compared the 6" refractor to my 6" Mak in an earlier video about three years ago, and the only other telescopes I have that are the same aperture are a 10" Dob and 10" SCT and I am planning a video about that soon.

[@terrycooper4149]

Larger aperture magnify 17:04 zones of interference/turbulance, too.

[@tsulasbigadventures]

Even when the seeing is good there are periods of turbulence you have to look out for. That's why I stare as long as I can waiting for the optimal view.

[@JoeJaguar]

Hey, thanks for making the video and I appreciate you calling out my name I actually had butterflies in my stomach waiting for your outcome, but I’m glad you had fun with it Comparison on my channel is something that I do a lot of because you never know what the outcome is going to be This year, I’m a bit disappointed in Saturns view just because of the edge on of the rings. It’s really hard to seek the Cassini division, and I also like to look at the gap between the ring and the planet to see how the edges look. Jupiter is also a nice test I know when I’ve done my testing of refractors versus other telescopes, of course the larger telescope collects more light and the overall brightness for instance, Jupiters two main bands definitely looks brighter in a bigger telescope, but I see finer detail in my refractors Actually, let me just correct that I see or smaller detail in the refractor versus the others However, saying that like you, I also like my 12 inch especially for deep sky objects My 12 inch is the one that I bring more often than any other telescope when I go to a zone 2 In this case, I don’t think I would ever bring a refractor to my zone 2 because I want to see more of the objects and as you said the 6 inch wouldn’t be enough I guess that’s why all of us have a few or several different telescopes one for each different type of scenario that we want to do I know matching powers is kind of hard to do what I’ve done is I currently haveA svbony 3 to 8 zoom to get the powers more matching as I do a lot of comparisons so I need to have that power matching within a few power of each other Anyway, again, thanks for the great video. Glad you had fun.

[@tsulasbigadventures]

Thanks, Joe. It was very hard to see the Cassini Division on Saturn with the rings nearly edge on but also sometimes the seeing is just so awful that I can barely see any detail. I don't own any zoom eyepieces. Maybe I should look into that. Anyway, thanks for the suggestion and thanks for watching.

[@JoeJaguar]

@@tsulasbigadventures you’re welcome the reason why I got the zoom which goes from 3 mm to 8 mm is because I’m always doing comparisons and I need to have every millimetre specially when it comes to the higher powers so I can match it as best as I can For me being 30 or 40 power is just too big of a difference and then it wouldn’t be fair for the other one to compete so it’s something that you don’t have to do if you don’t do comparisons that often but for me, I found it very handy Cheers I’ll see you in the next video

[@ACAJUJU]

Interesting comparison

[@tsulasbigadventures]

Thank you.

[@Sk240DC]

Great video! The photo from the 12" looks more detailed than the one from the 6", perhaps this is due to the 12" having more focal length so Saturn looks bigger and captured more detail. Not sure how you processed the planetary images, but I've learned that stacking and wavelet post processing will typically enhance the planetary images quite a bit.

[@tsulasbigadventures]

I used Registax and Autostakkert to process the photos. I used a planetary camera on the 12" SCT and a Sony Mirrorless camera on the refractor because I've never used that planetary camera on the refractor before and I wasn't sure if it was the right pixel size for that telescope. The planetary camera is probably superior on the planets than a Mirrorless camera and that's why Saturn looked bigger and more detailed in the photo.

[@Johnnybox81]

Lovely report - Saturn looked great when I viewed it on the 14th Sept through my 127mm Mak-Cass from the UK. We were blessed with a good few days of clears sky and good seeing around that time. What's your 12'' SCT like vs your Dob?

[@tsulasbigadventures]

Glad you had clear skies for a change. I am working on a video on this very issue! Coming soon.

[@3dfxvoodoocards6]

I expected the 6 inch ED Skywatcher refractor to be on the planets as good as maybe a 10 inch reflector, but I was surprised to see it’s even better than the 12 inch SCT. On DSO on the other hand I guess the 6 inch refractor has to perform similar to an 8 inch reflector, way worse than the 12 inch SCT. The 12 inch SCT practically (not theoretically) gathers around 3x more light than the 6 inch refractor.

[@BurningFlame1999]

Very interesting, like!

[@SurfingFLA]

I'm thinking of getting a refractor for using while traveling. Way easier to stash in our camper van than our Meade Schmidt-Cassegrain type.

[@tsulasbigadventures]

Yes, you need something smaller for travelling. The SCT is way too big and heavy for me to travel with. But I did enjoy taking a little 6" Mak-Cass to travel with a couple of years ago.

[@terryhenderson3959]

Hi, love your videos... I have to mention something though... You are doing the comparison but you have not let us see everything you are seeing. You only showed a couple but I would like to have seen everything you were talking about, so we can all learn. Please show everything when you change your eyepieces. I have wanted a big telescope for ever but they never come down in price (and all the pieces, so its great to see what you see, so if i do get one I will have a better idea what to check out). Thanks

[@tsulasbigadventures]

Thanks! OK. It's very difficult to show everything I'm mentioning but I'll try.

[@aaronciviris]

awesome video. 👌👌🌹

[@tsulasbigadventures]

Thank you!

[@Easybreazygaming]

Nice video

[@markihde4381]

I always enjoy your videos. The great advantage of long focal length is the ability to use longer focal length eyepieces to achieve a given magnification. This generally results in a larger exit pupil and greater eye relief. With my 6" f/12 ISTAR refractor, I can achieve 300X magnification using a 6mm eyepiece, although I generally don't like to go above 150X. (Lunar observations being the exception.) The scope mounts on a Losmandy G-11T, which I find necessary, not for the 40+ pound telescope weight but because of the tube length of over 6'. (Lever moment.)

[@tsulasbigadventures]

Thank you. Wow, your 6" refractor weighs over 40 pounds? That's a lot. My 6" refractor weighs 27.5 pounds with the diagonal and eyepiece etc but because the weight is distributed across the long tube I find it much easier to get it into the saddle than a 30 pound SCT (my 10" SCT) I own where all the weight is on the end with the primary mirror. That makes it very difficult to install except with the use of a table.

[@peterberbee]

Thanks for the reviews. I’m thinking resolving power may be more important than light gathering when looking at bright things like Saturn. Resolving power is proportional to aperture, 12 inch having twice that of the 6 inch. 6 inch has more than enough for most seeing conditions. The 12 inch may by better in truly outstanding seeing conditions in the hands on an expert planet imager (I am not one). At any rate, it sounds like the 6 inch was the ideal instrument for the night!

[@tsulasbigadventures]

Thank you. Yes, the light gathering wasn't really an issue and the conditions favored the refractor on the night of my test.

[@catkitten-ss9fl]

Refractors perform very well on the planets

[@Starman2440]

Well done! I have a 11" SCT and a 6" APO. Viewing the planets, the APO always wins. The issue is the seeing. It has to be very good to excellent to see planets well in the SCT; something that is very rare in the upper midwest. Imagers do well with large SCTs as they photo shop the images to enhance them.

[@tsulasbigadventures]

Sometimes the seeing is so bad in Montana that I just give up on trying to see the planets because it looks bad in both telescopes.

[@curly_bill1629]

I'd be curious how a 6" Stellarvue or an older 6" Astro-Physics would perform.

[@3dfxvoodoocards6]

Probably very similar to the Skywatcher 150 mm ED/APO

[@tsulasbigadventures]

I would too. Where would one store three six inch refractors? Those things are huge.

[@peterfassler9856]

One critical point hasn’t been mentioned and that is the collimation of your Meade telescope. I’m sure it would outperform the 6” if it is critically well collimated, not just eyeballing it but with a software program like Metaguide. If the collimation is just a bit off the 12” won’t show its full potential. I can tell because I have a 160mm APO refractor (same quality as AP) side by side with a Celestron 14”. Also try to use binos. It makes a huge difference.

[@tsulasbigadventures]

I checked the collimation before I started and it looked to my eye to be perfect. The telescope lives on my JMI Wheeley Bar and gets very little jostling around. But that is a good point.

[@SoulCitySawdog]

Nice video, thanks for your time and analysis! Do a collab video with Ed Ting sometime, that would be fun!

[@tsulasbigadventures]

Thank you. If Ed Ting ever contacts me I will be glad to make a collab video with him.

[@radioparisment628]

Hi Tsula. Thank you for the video. The refractor has no central obstruction and so, is less affected by the seeing ( the light in the first ring of the Airy disc is only 7% of the total light in the disc ). At high magnification, it's necessary to observe in good seeing conditions with SCT and his central obstruction that increases the % of light in the first ring. Sometimes, there will be a merging between the first ring and the central disc. Perhaps, refractor could be better according to these considerations. Clear skies.

[@tsulasbigadventures]

Thanks. Yes, those are good points.

[@patricj951]

Very interesting video! I was thinking about that higher light gathering power does not only helps to see fainter objects, or using higher magnification. But also that if you have a larger exit pupil at a given magnification there is a light margin for using some filter. Which helps to see details despite it takes a bit of brightness. Am I right here?

[@tsulasbigadventures]

Thank you. Absolutely.

[@Hanejejrjxn]

Wow the 6 inch refractor beat the 12 inch reflector on Saturn... I didn't expect that.

[@tsulasbigadventures]

Neither did I.

[@terrycooper4149]

Glad I have both SCTs and refractors

[@tsulasbigadventures]

Yes, and this is why if you can afford it, you should get two telescopes (or more!).

[@Astronurd]

It's a no brainer, the 12" every time if the seeing supports it

[@cbf63]

I've been experimenting with masking down the aperture of refractors, since you have a lot of glass with the 6 inch you should mask it down to like 5 inch or even 4 and increase the focal ratio. I have a 90 mm refractor I Masked it down to 70 mm, that makes it a f-14 and the views are quite nice. Maybe you could do a video about that if you haven't already? Nice comparison video! thanks.

[@tsulasbigadventures]

I've read about that but never tried it myself. I will give it a try. Thanks for the suggestion.

[@sharonbryant7094]

Hi Tsula. Thanks for this video. Are you still recommending the HAZ31 mount? I want to get it to use with a AT102EDL and while I love the weight, convenience, and practical simplicity of the mount and tripod, I need it to work! And do you use a finder scope with any of your telescopes when using this mount? Thanks again!

[@tsulasbigadventures]

Oh, here is your earlier comment. Yes, I use a finder scope to center the alignment stars. You'll need one. I recommend either a red dot finder or a reflex finder scope. You could use a telrad but they are a little big for a 102mm telescope.

[@eviled2006]

Great vid....thank you.

[@tsulasbigadventures]

Thank you!

[@jackfrost4033]

hello thank you for this unique report As the years go by and as they get older, do 12 dobson owners abandon their large telescope for another much lighter one like an 8 dobson or SCT that is even more manageable?

[@715outdoors2]

What is "CN"??? I'm getting my first Dobson 8" and I can't wait to see these things more clearly!

[@tsulasbigadventures]

Congratulations on the 8" Dob! I don't remember referring to it in this video but I think it stands for Cloudy Nights.

[@perry92964]

i think with anything below 6mm you need to have a fine focus or electronic focus i have neither so the smallest i go is 10 mm, i bought a cheap 4mm to try out and holy cow is it hard to focus, i have to get lucky. im glad i didnt spend a lot for it cause i m probably never gonna use it again. i cant even imagine trying to focus a 3mm. is there a difference in the 2 inch and the 1.25?

[@tsulasbigadventures]

It isn't hard to focus the 3mm as long as the seeing is good. I wish I had brought the 6mm Ortho to see if I could focus it on the SCT. I forgot I own a 25 year old Orion Sirius 6mm plossl. I could have tried that. Oh well, next time. I only own two 2 inch eyepieces and they are both long focal length, 40 and 56mm.

[@stefanschneider3681]

Yeah, seeing is key for the planets. My best picture of Jupiter is just a well processed single image in a night that was simply PERFECT!

[@tsulasbigadventures]

Isn't it great to look at the planets when the conditions are superb?!

[@fastbow9]

COOL !

[@robocar-vf7hw]

Well the SCT has two mirrors with just 90% reflectivity and also a central obstruction that lowers the contrast and brightness.

[@radioparisment628]

And increases the first ring in the Airy disc, that reduces the resolution according to the seeing.

[@MatthieusStuff]

Thanks for the video. It’s a very interesting comparison. I’m very surprised at the outcome as I’ve been comparing my 4” f/7 ED refractor to my Celestron C5 SCT at 143x and 139x respectively. They were very close but I felt going back and forth that the C5 gave me a very slight edge seeing detail on Saturn. The same applied to the globular cluster 47 Tucanae. The moon was a tie as I couldn’t decide. M7 and splitting alpha centauri were the opposite as they were both slightly sharper in the refractor. It makes me think I should rerun the test on a night that allows for 200-250x to see if the refractor then pulls ahead.

[@tsulasbigadventures]

I was surprised as well. I wonder if the outcome would have been the same if the seeing had been suboptimal. There is no question the refractor would not perform as well on deep sky objects just because of the lower light gathering capability. In your comparison the light gathering was much closer in the two telescopes you used. But it would be interesting to see how your two telescopes compare at higher magnifications as you suggested. Let me know if you do another test.

[@kevanhubbard9673]

They use to say a refractor was equal to a reflector twice the size but I think that it would depend on the quality of both telescopes plus it's like comparing apples and oranges.... different fruit.

[@tsulasbigadventures]

Each telescope has strengths and weaknesses.

[@Naughtydogadventures]

Interesting

[@rodrigomm_astronomo]

Very good vídeo! I prefer refractor.

[@tsulasbigadventures]

Thank you.

[@KJRitch]

Did the Losmandy able to track on Saturn to keep it centered? Did the SCT need periodic adjustments since it's an ALT/AZ mount? For the final assessment, Saturn appeared to be the same size for each scope? Thanks

[@tsulasbigadventures]

The Losmandy is the best mount I own and it tracked perfectly. The alt az had to be adjusted at that high magnification to keep Saturn centered.

[@BrotherMichaeloftheCross]

Without my glasses, I have a certain amound of magnification from tmy eyes themselves. Don'tr know if that has any beraing. I used to have an 8inch Celestron

[@tsulasbigadventures]

Your eyesight definitely impacts what you see in a telescope.

[@barrycraig1549]

In the late '90s I was at a star party in Kankakee, Illinois. It was a particular ly. Excellent night of seeing and everyone who was observing had mentioned how good of seeing so was it just my experience. It was an excellent time to go around and check out different types of Scopes and look at the planets. Saturn was high and bright. A friend of mine and I went over to the astrophysics booth area and looked through their premium 7-in refractor. After getting a good look we decided to Take a look through a 10-in F5 starmaster dubsonian reflector with A go to drive drive. The 10-in smoked the 7 in. The powers were the same and the eyepieces were naglers. We went back and forth a couple times to verify and we are both convinced the 10-in with A zambuto mirror won the comparison. We also had an opportunity to look through some other Scopes. As a whole, the lower cost reflectors get a better job. It is hard to beat a reflector. I have looked through some excellent Celestron Schmidt's c5, c8, and c9.25. Good collmination was really important

[@tsulasbigadventures]

Interesting because the other night I was comparing Saturn in my 10" Dob and then in a 10" SCT and Saturn looked better in the Dobsonian. I still cannot understand why but it's what I saw.

[@johnathanedwards8706]

I see you have the Feather Touch microfocuser on the LX90. I am thinking about getting the same for my identical telescope. Was it difficult to switch out the original with the new? Anything I should watch out for? Thank you.

[@tsulasbigadventures]

It's very easy and I made a video explaining it: kzbin.info/www/bejne/oJy6XqZth6x9gc0

[@JamesAdams-ev6fc]

One explanation for the slightly disappointing performance of the 12" Schmidt-Cassegrain is that on the night you taped this, the instability of the air was a bigger problem for the larger diameter instrument than for the 6" refractor. If the air were more stable, I think the Schmidt-Cassegrain would win.

[@DomZ83]

I'd wager it also had to do with the inability of a large SCT to properly cool down to match ambient air. Untill I installed fans into my 8, I had issues with getting good images. Thermal stability in an SCT is critical imho

[@tsulasbigadventures]

@@DomZ83 I felt it was adequately cooled down since it was out there for so long. But I suppose that could be a contributing factor.

[@DomZ83]

@tsulasbigadventures it depends on the temperature delta for sure. My conditions tend to have higher fluctuations, and it's rare that I don't need to precool without using the fans.

[@JamesAdams-ev6fc]

@@tsulasbigadventures Very nice video Tsula. I thought that this was a near experiment. Somewhere I read that diameter of the instrument can become a problem, because as diameter increases towards the 10-12 inch range, the volume of air that has to be steady increases as the square of the radius. I don't remember where I read this, but it might explain the problem with seeing clearly through the Meade 12". Here in Florida the air is usually steady, but the TRANSPARENCY is very low. The air is so opaque that summer viewing, from about May 15 to September 15 is impossible. Then there's the light pollution problem. The number of people who care about that is probably less than the number of people who speak gaelic.

[@AstroDavey]

I have a 115 EDT APO, and a 16" Teeter Dobsonian. Its hard to compete with premium Dob aperture at that scale, but the sharpness of the refractor on planets and the Moon are hard to compete with. If conditions are good, the Teeter is king, but in average conditions the view on planetary objects is outstanding with the refractor.

[@tsulasbigadventures]

Yes, that sounds about right. And that's why if you can afford it, the perfect combination is a big Dob and little to medium refractor.

[@craiglowery4427]

Nice video. I use a 14" on planets. I think SCTs also have a cost advantage.

[@tsulasbigadventures]

Definitely when compared to a refractor.

[@mikemurphy7711]

Inch per inch a high end refractor will resolve better than most SCTs. Refractors have no obstruction, they usually need no collimating after their first time from factory, but an SCT usually needs constant collimating especially when they are used in planetary use. Unlike faint deep sky objects, planets reflect plenty of light for any telescope to magnify which is why a refractor can do just as well. It is critical that an SCT's collimation be as best as can be for planetary detail to pop, and to never use it's primary focuser knob as the main focusing (at least if you plan to capture your images). If one uses the mirror focuser knob on SCT for primary focusing, then most surely collimation will be off enough that planet detail will be lacking. I have a 5" triplet refractor which gives my 16" Meade SCT a run for it's money when in planetary mode, and often I like the refractor's final results better even though a smaller image. But when it comes to deep sky, yes, the SCT rules.

[@tsulasbigadventures]

Well said.

[@lornaz1975]

I once heard of an article in 1985 Sky and Telescope by Roland Christen where he compared a 5 inch non-apo triplet refractor with several mirrored scopes including a 20 inch dob. He looked at a moon transient of Jupiter. He said that when the moon reached the lim of the planet it became lost in all of the mirrored scopes including the 20 inch but in the refractor it was clearly visible. The article ( or I should say Roland) said that the mirrored scopes do not have the contrast that the refractor does. I thought this was very interesting but could not find the article to read it myself. Also, the other day I had my TSA 120 out at 300X and thought I could see the Cassini division but it was so faint I am just not sure.

[@tsulasbigadventures]

That's interesting. I'm going to try to find it. I have never looked through a 20" Dob but it seems like the transit would have looked awesome in that telescope. It is very hard to see the Cassini division right now because of the rings being nearly edge on but I am pretty sure I saw it when the seeing was excellent. If the seeing isn't excellent forget it.

[@lornaz1975]

@@tsulasbigadventures If you find the article let me know!

[@anata5127]

What about Artemis and refractor versus 20” dob. At excellent seeing, you will see disks of Jupiter satellites in 20” dob.

[@tsulasbigadventures]

Please send me a 20" Dobsonian because I would love to see that!

[@TransformersHoarder]

Did you collimate the 12” the night of this recording.

[@tsulasbigadventures]

No. I checked it before starting and it was perfectly collimated.

[@TransformersHoarder]

@@tsulasbigadventures awesome

[@TransformersHoarder]

Off topic, have you ever seen more than four of Jupiter’s moons with your 12”?

[@tsulasbigadventures]

@@TransformersHoarder Yes, I have seen more than four with the 12" but I would have to go back to my notes to see which ones they were.

[@bmwm530jahreedition8]

Lets hope your LX90 12" meade never gets broken. meade and orion are dead!

[@tsulasbigadventures]

I had a bad dream about that last night and wondered what I would do. But you can send your Meade telescope to a telescope repair shop. I researched and there are a couple of them. It's just that the shipping would be astronomical.

[@bmwm530jahreedition8]

That would be wonderful. I am just wondering how do those repair shops get the right parts for your telescope when they stop making these parts/ equipment?

[@OllieCat125]

Can you share what models Refractor you are using?

[@3dfxvoodoocards6]

It’s a Skywatcher 150/1200 mm ED/APO.

[@tsulasbigadventures]

@@3dfxvoodoocards6 Evostar

[@MacM545]

It was a great comparison, one I've been looking for, but the main channels aren't covering. I've noticed that refractors are in a different price range, more expensive. Does anyone know what refractor is needed as equivalent to an 8 inch SCT?

[@tsulasbigadventures]

Thank you. I have an 8" SCT and a 102mm refractor. I could try a comparison of those to see how they compare. I think it would be similar to comparing a 12" SCT to a 6" refractor as I did here.

[@jeffrystehle3960]

It seems that the planets are inherently bright to begin with so small aperture refracting telescopes with no central obstruction does well. Agggh makes me think I need more than one kind of scope:)

[@tsulasbigadventures]

If the budget supports it you should definitely have two telescopes of different kinds.

[@Ajajambo]

Frac is definitely sharp, but an SCT with double the aperture needs to be collimated to perfection, and the 6-inch would struggle. Trust me, I had my 9.25" Celestron versus a 6" frac, and my SCT was as sharp as the frac. The frac was perhaps a hair sharper due to the fixed mirror cell, as there is no slack. I can for certain, say the frac has better contrast but the SCT is a little brighter and this where filter comes in to eek out those details with the SCT.

[@johnrobison1413]

Just looking at your video samples I thought gee wiz, my cheap as chips Omni 102 achromat at 220x does pretty well after all.

[@tsulasbigadventures]

I think unless the refractor has some kind of defect in the optics like astigmatism or chromatic aberrations that you should get a sharp image on planets as long as the seeing is good.

[@davidaaaa4611]

I had a 6 inch refractor, it was great on planets. Wish I had kept it. It was a Celestron. I would think the 12 would out do it easy.

[@tsulasbigadventures]

Usually it does.

[@Vrenn_soK]

Nice video. I'd like to add that even though the Skywatcher is a big refractor, it is still an "average" refractor. You can get better / sharper images from higher-end triplets or doublets with better glass (FPL-53 etc.), and they do not have to be even so big (5", 4.5" or 4"). These scopes can handle "more than 2x aperture in mm" magnifications much better. Cheaper scopes like this SW tend to get softer if you push them so much. Simple physics... worse glass. Don't get me wrong on the price.. it is possible to get awesome 4" APO for the price of this 6". It will be sharper and lighter. Eyepieces + diagonals count as well (there are better choices like Baader BBHS prisms, something like Takahashi TOE or Vixen HR eyepieces etc... Just remember that the output of any optical chain strictly equals to it's weakest member).

[@tsulasbigadventures]

Thanks. I searched and searched but Skywatcher is very secretive about what kind of glass they used in the Evostar. I think it's a decent refractor but I don't think I've ever looked through a higher end refractor of this same aperture to compare it to. I own a very high end 90mm Stellarvue that is very sharp but it's hard to compare a 90mm with a 150mm refractor.

[@3dfxvoodoocards6]

​@@tsulasbigadventures the Skywatcher 150ED most probably uses high-quality FPL53 glass.

[@tsulasbigadventures]

@@3dfxvoodoocards6 If so, then why do they keep it a secret?

[@3dfxvoodoocards6]

@@tsulasbigadventures from the reviews I saw, it's optical performance is too good to be just FPL51. Of course I can only guess, but I would bet its FPL53.

[@BurningFlame1999]

And now the same test on DSO - galaxies and nebulas… The 12 inch SCT would easily win.

[@tsulasbigadventures]

Oh, yes, Definitely.

[@kevyjo]

6" is generally viewed as the largest apeture that isn't "fussy" about seeing conditions...12" is going to be very "fussy"...Id guess at least 80% of the time the refractor would win. Im suprised that so many were suprised by this.

[@bowrudder899]

The smaller aperture won't get the same resolution either.

[@tsulasbigadventures]

I would like to perform this same comparison on tight double stars. The resolving power on the refractor is .76 arc seconds I think. So theoretically the SCT should be able to split some stars that the refractor would not but when you get down to under one are second I don't believe I have ever split any double star. So, it's hard to say.

[@bowrudder899]

What you called "sharp/sharper" I think is resolution -- the degree to which we can see detail. I think that is supposed to be a function of aperture.

[@australien6611]

Now do the comparison on a faint object like orion. The 10" will beat the 6" everytime

[@tsulasbigadventures]

I agree. The 12" would slaughter the 6" on DSOs.

[@DavidBridges-i1q]

Hi, it should be noted that planets are very bright compared to most other celestial objects. That being the case, the larger scope's greater light grasp is somewhat negated. Also the smaller aperture refractor actually has a built in advantage in cutting through atmospheric turbulence. The smaller the aperture of a scope, the less it's likely to be effected by bad seeing conditions. Of course, where smaller scopes faulter, is when your viewing dimmer celestial objects. Say M 51 , looks great in scopes 12 inches or greater, but in smaller scopes 6 inches or less, pretty disappointing 🥴.

[@tsulasbigadventures]

All true. That's why I think if amateur astronomers can afford it, it really helps to have two telescopes a big aperture one and a smaller refractor.

[@joseborges8479]

It has also been my experience refractors are sharper. All that mirror bouncing takes away sharpness.

[@tsulasbigadventures]

True but you would need a very large observatory and lots of money to own a 12" refractor.

[@bowrudder899]

You need a step ladder!

[@tsulasbigadventures]

I have one but I hate standing on it.

[@misaelescobarruiz1193]

Fantástico Saturno la astronomia es bella

[@stadtchronistjennersdorf6351]

Hi Tsula! I can confirm your results with my equipment - SW ESPRIT 150ED APO vs. C14 Edge HD SCT: On planets the 6inch APO not only shows a more contrasty but a more clear and sharper view than the SCT. Of course the 14inches do give a brighter view of DSOs due to its far bigger aperture.

[@tsulasbigadventures]

You own some nice telescopes.

[@stadtchronistjennersdorf6351]

@@tsulasbigadventures Hi Tsula! Thx, indeed, "problem" is that I don't have as nice skies as you have, having Bortle 4 to 5 and just 243m above sealevel.

[@matttrowsdale2804]

12" looked better to me. 🤷 (Though a bit it difficult to tell with what has been presented - guess you had to be there?).

[@tsulasbigadventures]

One of the hardest things about making a video like this is trying to portray what I actually saw in the eyepiece. It's so hard. Also the seeing changes over the course of an evening and could even change in the time it takes me to get from one telescope to the other. So, that might explain why you thought the 12" looked better.

[@astroashruff]

Before clicking this video I guess the schmidt-cassegrain would win due to aperture and mirror type, and it's true like you expected

[@australien6611]

Bigger aperture isnt really needed for the planets only for faint objects that need a big light collector

[@4280blkpowder]

SCT’s are softer than refractors viewing wise and imaging wise, besides comparing with a Meade which is known to be inferior to Celestron

[@tsulasbigadventures]

Known by whom? I don't agree.

[@cyndimorgan9792]

Wow ! With 900 times magnitude you could probably read the book the man on the moon is reading! Sorry! You had me laughing there for a while..

[@tsulasbigadventures]

I know it was ridiculous but I couldn't resist. That 3mm eyepiece was so much better than the one I was using on the SCT.

[@dn1927-b7c]

Get a Binoviewer, seriously.

[@tsulasbigadventures]

I bought a binoviewer but I had to sell it due to a tragedy involving my 12" telescope where the corrector plate broke. I had to sell a bunch of stuff in order to look for a suitable replacement for my beloved 12" SCT.

[@Miraculouslife-bj7bx]

Interesting comparison