Comparing a 6" Reflector to a 4.75" Achromat Refractor 

Yes! :) I was screwing the semi-Apo filter onto the camera nosepiece when the clouds rolled in, otherwise this video would have had a little bonus chapter featuring the Evo120 with filter.

Thanks! I sometimes use the Baader Semi-Apo which does a pretty good job reducing CA. it's not quite as effective as the fringe killer but that one imparts quite a strong colour cast. I did prefer the results from my Takahashi FC100dc when I compared that to the budget C6-N, but you would probably hope so considering the price difference: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-l7h27agtCMc.html

Well! It just so happens I was thinking of testing the StellaMira ED125 against the 200p Newt for my next comparison video :)

​@@Astrolavista that would be great, I would love to see that :)

I have a 6" Skywatcher BD f/8 newtonian with a premium mirror. That beats the shit out from any 125 mm Stellamira, it performs excellently on planets even at 375x on good nights. Aperture always wins if optics are ok and the weather's fine. Its basic physics.

@@MrKA1961a 6 inch newtonian has no chance again a 5 inch APO. The 6 inch newtonian has a central obstruction and also 2 mirrors with just 88-92% reflectivity. The light gathering capacity of the 6 inch reflector is the same as that of a 5 inch refractor. But the 5 inch APO will have a significantly better, sharper, higher contrast image than the 6 inch reflector.

@@3dfxvoodoocards6 An air spaced apo triplet has 6 surfaces only at the objective, then there's the diagonal mirror, just do the math... With a field flattener you or a barlow you have +4 surfaces! If the central obstruction is less then 25% then it's almost unperceivable. Then the Newtonian is 6" which in ideal conditions has a 20%+ resolving power. It's basic physics. What's a disatvabntage the spiders at the newtonian can throw up 4 spikes, but still, the newtonian is the clear winner.

Hey many thanks! Yeah the reflector definitely seemed to respond better to the pre saved wavelet pattern applied to both images.

The larger the aperture, all else being equal, the more precise the image seen in the eyepiece will be.

Only if you put up more security lights than there already are in my street :D

Cheers Ron :)

I took a look at the description for that video as it's been some time. Looks like I used the Semi-Apo filter with the Evostar to give it a fighting chance against the 8". I had planned to do a with and without semi-apo filter test for this video but the clouds rolled in off course lol Maybe next time.

Oh yes that ones happening :) I plan on doing a StellaMira 125 vs Sky-Watcher 200p f5 Newtonian side by side video soon : )

It's a good idea, I just don't have those telescopes at the moment. I will try and do more budget comparisons though :)

Similar to what you suggest, I had hoped to test the C6-N vs the Evostar 120 both with and without my Semi Apo filter, but the clouds had other ideas lol oh well maybe next time : )

I'm a bit gutted I was clouded out before I could add the semi-apo filter. It was supposed to be a C6-N verses Evostar 120 (with and without Semi-Apo filter video). I do have another Jupiter comparison between the Evostar120 (with Semi-Apo filter) and my 8" Newt if you want to check it out. The only thing I'm not keen on is the purple weather belts which the Evostar seems to show for some reason: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-4ATO07PFSpc.html

Nope.

The 6" f/5 Newtonian would win hands down when it comes to deep sky imaging. The f/ratio of the achromat is on the slow side for capturing faint deep sky objects plus stars look big and blobby when imaged through an achromat. The Newtonian would show pin sharp stars by comparison albeit with diffraction spikes on the brighter stars. I'll be honest, it wouldn't be at the top of my list when it comes to video ideas, sorry about that.

@@Astrolavista no problem. For visual observations would it be the same ? Would the 150mm newtonian be better for DSO than a 120 mm F8 achromat?

@@Astrolavista the light gathering capacity of the 6 inch newtonian is practically the same as that of a 5 inch refractor. On DSO galaxies and nebulas the 120 mm F8.3 will show excellent images, only on the Moon and planets will it show chromatic aberrations / washed out image.

Was the refractor second and therefore Jupiter was lower and setting? If so, that could degrade the seeing.

Nice! I'll check it out

Cheers Tony! Yeah the C6-N definitely gave a more natural result (I'm not keen on the Evo 120's purple weather belts).

Hey many thanks! : ) It was very nearly a three way test between the C6-N, and the Evo120 with and without my Semi-Apo filter, but the clouds rolled in from the South before I could make that happen. I'm not sure if the colour fringing is also responsible for the the pink/purple equatorial cloud belts on the Evo120 image?

Hi thanks! I'm using a Sky-Watcher EQ5 with dual axis motor drives, and the C6-N optical tube, rings, dovetail, Barlow, finder, and ZWO planetary camera comes to around 6kg. I also use a Sky-Watcher 200p f/5 Newtonian with the EQ5 and that weighs nearly 9kg.

@@Astrolavista Thanks for replying. That 6" is truly a match for EQ5 or AZ-EQ5. My Explore Scientific 210mm f/3.9 - PN210 weighs 22lbs/≈10kgs + 0.45 kg of HRCC-02 coma corrector, two cameras ASI533MM (or ASI224MC)+ASI120MM mini(imaging and guiding), and accessories (filters, heaters, e-focuser) brings it to between 13-14kg! It does track and image well as long as there is no wind, else, it will cause steaks in the image. BTW, do you use any coma corrector while imaging?

Thank you and I agree! I wish I had time to show an image from Evo120 with my Sem-Apo filter as it does seem to help. Even so I'm still not keen on the un natural looking result from the Achromat. I should make an aperture mask to stop it down to around 80mm f/12 and see how that effects things. Clear Skies!

@@Astrolavista that would be a very interesting video

Hey thanks! I've been using AVI for so many years now I forget to experiment with other options. I tend to stick to RGB24 8 bit too so I can share colour live footage even though RAW would yield better final results. It would be good to experiment and compare AVI to SER as part of a video so I appreciate the nudge : )

🙂

Maybe it was on those recent clear nights we've been having that have really bad seeing, like I could see the brightest stars in Orion twinkling so violently you couldn't see them one second and they'd be shining brightly another

Although you can't see jupiter twinkling in the video

They both definitely could but the Reflector will always produce higher detail images due to having 1.25" more aperture. It can resolve smaller details than the Refractor ever could.

​@@alinaqirizvi1441I couldn't agree more the last couple of weeks UK has some very strong Jetstream that was playing havoc with that seeing. Eveytime clear night was possibly the worst seeing I have seen for years. 3/10

​@@alinaqirizvi1441 Is it a plane? Is it a flying ambulance? No! It's just Sirius with exceptionally bad seeing!

The Celestron 102T has a F9.8 ratio, higher than the F8.3 of the 120mm Evostar so the image quality on the planets would be very similar. From the Celestron 102T to a 6 inch newtonian the difference would be very small especially on the planets. A better upgrade would be a 8 inch newtonian.

If its a 6" f/8 Dob. Get the Dob!

@@Astroturf100 Yes! The 6" f/8 Dobs are proper planet killers. I had the Sky-Watcher 6" f/8 at one stage and I made my neighbours jaw drop showing him a shadow transit of Jupiter. Tiny secondary mirror so great contrast, and likely high Strehl mirror because f/8 is easier to grind and polish to a high accuracy :)

I already have a 12, but it doesn't see much action because of seeing conditions.@@3dfxvoodoocards6

Looks like an HEQ5

Hi, I'm using the Sky-Watcher EQ5 plus dual motor drive kit: www.firstlightoptics.com/skywatcher-mounts/skywatcher-eq5-deluxe/ref/astrolavista/ www.firstlightoptics.com/astronomy-mount-upgrade-kits/enhanced-dual-axis-dc-motor-drives-for-eq-5/ref/astrolavista/

The C6-N is f/5, I have one, but had the mirror refigured. Jupiter is like a much bigger scope when done with a better mirror than stock.

@@MountainFisher as far as I know the reflecrivity of most newtonians main mirror is at around 88-94%.

I'm tempted to do a video where I test the Evo120 using various size stop down rings to simulate different apertures and f/ratios. F8.3 doesn't quite cut it for planetary unfortunately. It's better with the Semi-Apo filter I think.

@@supermario8416 I know, but I bought mine from a Pawn shop where the owner cleaned the mirrors with paper towels and Windex. Most paper towels are abrasive, why they take the reflective coating off sunglasses, imagine the SiO2 coating on a mirror? Mine was refigured to 1/12th wave and .98 Strehl and then recoated to 96% reflectivity. It will image Jupiter like a 10" mirror would if conditions are decent and surpasses most telescopes except maybe a Takahashi reflector. My friend uses it for DSO imaging and it takes a lot less exposure time. It is very difficult to polish out a refractor lens to that high of optical quality as it has two sides and at least one more lens with two inverted sides. When you see a 102mm refractor pushing $3000 to $4000 you now know why it costs that much. It isn't just a really good focuser, which I replaced on mine asap.

@@Astrolavista that would be very interesting. Also with the semi-apo filter it surely would have been on the level of the 6 inch reflector

Just an IR cut filter which I keep on the camera to sharpen the images and remove the pink cast caused by IR wavelengths. This was used for both images. The reflector certainly gives a more natural result I feel.

@@Astrolavista Definitely the Newtonian is more natural. Well collimated reflector really can produce pleasant image. What are they like visually looking at Jupiter wide bby side? Does the Frac edge it in sharpness?

@@Ajajambo The Evo does a little better for observing than imaging (image processing seems to bring out the worst in the Evo120). The image is more contrasty in the Evo but the CA can be off putting. The Newtonian seems sharper and the tone more clinical neutral if that makes sense. I've only really glanced through both whilst setting up for imaging through, so please take the above with a slight pinch of salt until I can do a side by side observing video and try to describe what I'm observing between the two in real time.

@@Astrolavista Have you tried a baader contrast booster with the Evo?

lol I would love to know exactly why the Evo120 shows pink bands; maybe a combo of the glass imparting a hue as well as CA I'm not sure? I much prefer the red-brown hues from the reflector.

​@@AstrolavistaI had the same issue with mine. 🙄

The 4 inch Takahashi APO destroyed the 6 inch newtonian on Jupiter. Look at the video. The 4 inch Takahashi APO was almost as good as a 8 inch newtonian.

@@3dfxvoodoocards6 He hasnt specified seeing conditions at all. Also, compare the prices for a Tak FC100DC and literally any 6/8 inch Reflector. Refractors for visual, no matter if Achro or Apo, are a supreme waste of money. Youre comparing a high end APO to a budget 6/8 inch Newt. You completely missed the point.

@@Sharpless2reflectors clearly have the best price/performance ratio but the refractors also have many advantages over reflectors. The Takahashi is very expensive but there are many cheaper alternatives, like the 122mm APO triplet from Svbony for 1399$.

@@3dfxvoodoocards6 Which is still far more expensive than an 8 or even 10 inch reflector that will still deliver better views.

@@Sharpless2 yes but with the refractor you don't need to colimate it, it's much smaller, lighter and more easely to transport, is has a much shorter cool down time.