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Equipment Discussions >> Refractors

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Asbytec
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Reged: 08/08/07

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Re: Another Jupiter comparison...food for thought new [Re: Eddgie]
      #5565883 - 12/11/12 12:42 PM

Eddgie, yea the human eye...and magnification. Another day...whew! But, time to jump in the fire.

Quote:

The right side picture is very typical to what I see in my 4.7" apo on a decent night when the atmosphere steadies.




I agree with Steve (and Sasa) on this one, in 8/10 seeing or better. I see pretty much the same thing as the ED100 image at 150mm obstructed, but with much less (obvious) color saturation and less distinct detail in the EB.

The dark oval and the white ovals are almost perfect, except they are held steady in the image. The dark oval is easier that the white ones. I do get more contrast visually, however, with the interplay of gray and white in the south and with the NNTB. The tawny and white hues are about right, as is the festoon blue. Maybe Steve would agree.

Other than that, the image is pretty much the same, including the gray clouds in the NEBn.

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5562818/page...

Personally, I think this validates everything Eddgie says. And he is right, a casual look will never show that level of detail, an hour or more of study can, if the conditions are nearly perfect.

I could not comment on whether a C14 could visually replicate the C11 image. Maybe, as Gord mentioned. That's an enormous amount of detail. If so, I gotta get me one.

An after thought: Maybe it's image scale. I'm at f/13 and 30x per inch, not sure how that compares to the ED100 at f/36. But if it's a larger image, especially for 100mm aperture, then that additional processing power will bring out detail that wash out visually at those scales in larger aperture. Dunno.

Edited by Asbytec (12/11/12 01:32 PM)


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seafury
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Reged: 01/18/12

Re: Another Jupiter comparison...food for thought new [Re: Eddgie]
      #5565981 - 12/11/12 01:46 PM

Hi guys looks like I will have to make do with an image the size of a pea with a couple of faint dirty smudges on it does that sound about right?

Gordon


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EddWen
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Re: Another Jupiter comparison...food for thought new [Re: BKBrown]
      #5566017 - 12/11/12 02:07 PM

Lookin' good with the C11.

As you probobly know, the prolific Christopher Go has recently upped his game from his faithful C11 to a C14. And he is using a newframe-by-frame de-rotator which provides a 'crisper' stack.

The result is more than I've ever seen visually with my 16" Rumack on good nights at 6,650' in central Arizona.

http://astro.christone.net/jupiter/

He certainly puts up high quality images worth trying to emulate.


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mikey cee
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Re: Another Jupiter comparison...food for thought new [Re: EddWen]
      #5566815 - 12/11/12 11:53 PM

That's why when I compared my 10" refractor's view with the two images above I picked the 100mm one. I knew better than to try and BS my way with the C11 shot! I've got too much visual experience to get painted into a corner with that. Just sharpen the picture way up and cut the color intensity back say 40% and add a touch of blue halo not much but just a hint. Mike

Edited by mikey cee (12/11/12 11:59 PM)


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Asbytec
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Re: Another Jupiter comparison...food for thought new [Re: mikey cee]
      #5566838 - 12/12/12 12:24 AM

Quote:

That's why when I compared my 10" refractor's view with the two images above I picked the 100mm one.




Mike, I would have thought you'd painted yourself into a corner saying it was not as good as it probably is. I was taken aback by your modesty.

When you said it resembled the ED100 image, something was amiss. I can see it not being as good as the C11 image, but it's has to be better than the ED100. Surely your IStar knocks the socks of my view that approximates the ED100 image.

Anyway, they are both killer images for the aperture. I think that was the point.


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mikey cee
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Re: Another Jupiter comparison...food for thought new [Re: Asbytec]
      #5566915 - 12/12/12 01:57 AM

Give me a break Norme we're not talking about a 100mmED image here. It's a processed pic. That pic isn't close to what a 100mmED will show you visually. Mike

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Asbytec
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Reged: 08/08/07

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Re: Another Jupiter comparison...food for thought new [Re: mikey cee]
      #5566936 - 12/12/12 02:39 AM

Well, at least I have a story to tell about accidentally stepping into the refractor forum.

Regards, Mike.


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Gord
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Re: Another Jupiter comparison...food for thought new [Re: mikey cee]
      #5567222 - 12/12/12 09:36 AM

Quote:

Give me a break Norme we're not talking about a 100mmED image here. It's a processed pic. That pic isn't close to what a 100mmED will show you visually. Mike



Mike, I can't tell if you are being serious or not...

The 100ED image is processed and has a lot of detail in it. But, I know I can see quite a bit of that in my 4" achro. As you say, dial the color way back (almost grey-scale), and take out some of the very fine features, and sharpen it up some, but that's in the range of what I see. Of course there is a purple halo and if compared directly against a true apochromat, you can see this causes a little bit of a veil across the whole face of the target, but there's still a lot of detail in the image.

Are you sure you aren't seeing more?

I wonder if this could be that thing that Valery was mentioning in the other thread about the objectives that have been shifted to reduce the visible CA (I believe that is what the IStar "R" series are doing)? It comes at the expense of losing detail in other color bands according to his explanation.

Of course it can be observer to observer, seeing, etc. differences as well.

Clear skies,


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Gord
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Re: Another Jupiter comparison...food for thought new [Re: Gord]
      #5567230 - 12/12/12 09:41 AM

Oh and forgot to add, I agree with Eddgie's and some other comments that the ultimate, fine details are not something that "leap" out at you with the view showing just as it does in the pictures above showing all at once. It's something that takes minutes or hours of observing in a session to pick it all out. Teasing and waiting for the perfect moment to pick out a small detail and building up a mental image over time.

I've found this comes with experience too. I know I can see more now in my 4" achro then I could initially with my 8" newtonian. But again, a lot of the time when I was inexperienced, I would not spend enough time.

Clear skies,


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mikey cee
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Re: Another Jupiter comparison...food for thought new [Re: Gord]
      #5567296 - 12/12/12 10:31 AM

Gord....I've yet to experience a super good night here. I'm lucky to get past a 7-8/10 around here. When I do get a 8+ it never seems to last long enough to let me study everything I'd like to. I tend to agree that the abilities of the 10" are awaiting to happen. In the past my Brandt 8" f/13.3 showed detail that dropped my jaw. Mike

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azure1961p
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Re: Another Jupiter comparison...food for thought new [Re: mikey cee]
      #5567661 - 12/12/12 02:07 PM

At least with my 8" reflector on a rare 9/10 night maybe a good 8/10 night the image trounces the 4" refractor view. Yes the contrast is electronically enhanced and exaggerated but in sheer micro details the 4" image is club fistedly smooth and ho hum. What's misleading here again is the saturation in color and contrast of the processed image. I d strongly believe unless your scope was faulty your 10" would show a staggering amount of intricate even woven details that's hard to comprehend. If it happens (rarely) with my 8 when I finally get 9/10 seeing Id have to believe your scope would beat it processed or not. On those nights the 100mm would make a fine finder scope maybe.

Pete


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Asbytec
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Re: Another Jupiter comparison...food for thought new [Re: azure1961p]
      #5567999 - 12/12/12 05:34 PM

Well, seeing is a huge factor visually. With imaging, I suspect, seeing is some what mitigated due to the image scale. The pixel is pretty large compared to point sources and can absorb a lot of distortion, the eye is less forgiving in that sense.

Some have mentioned a 10" is optimal on planets, apparently it hits a sweet spot with resolution tuned to the best seeing we can expect on earth. So, seeing really has to cooperate at it's level of resolution. Another whammy is larger aperture is generally more susceptible to seeing. (We hear that in the reflector forum all the time. )

Anyway, folks are doing some killer small bore work on Jupiter, and not just in this forum. In fact, one local imager put up an image that first opened my eyes to the Mak. Wow, it was amazing for it's aperture.


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dag55
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Re: Another Jupiter comparison...food for thought new [Re: Eddgie]
      #5568008 - 12/12/12 05:44 PM

I enjoyed your pics. very interesting and the Skywatcher faired very well especially for the very modest price. I have the 120 Pro ED Skywatcher and am very impressed with it, I sold my Tak. 128fs because I couldn't justify the investment over the preformance difference. I don't know if all the examples of the SW OTA's perform as well but for the money and the light weight tube allowing the use of a much smaller and affordable EQ mount they are hard to beat.
Dane


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smee
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Reged: 10/19/10

Re: Another Jupiter comparison...food for thought new [Re: BKBrown]
      #5569557 - 12/13/12 04:38 PM

Quote:

Hi folks, been a while since I posted here...it's been an amazing and busy Jupiter imaging season. While the bulk of my work leading up to opposition was done with my C11 Edge HD, I also did some small bore imaging with my SW100ED. Again the results were highly gratifying, it's amazing how much detail that four incher can pull in. And while the Skywatcher image sits next to a very nice shot from the C11, this is not about comparing the two since the big SCT is clearly in another weight class. I thought you might find it informative to see how much detail the smaller scope can pick up. Check out the GRS w/ interior detail, the Oval BA "doughnut", the strange dark small spot chasing the Oval BA, several of the light tone south polar ovals, and details in the equatorial belt including one of the long, whispy blue streamers. All-in-all a terrific amount of detail. I hope you enjoy these shots, and hope that anyone thinking they have to have a big OTA to do planetary imaging will think otherwise after checking out these images. Thanks for dropping by!

Clear Skies,
Brian




Can you explain something to me please?

I know about Focal Ratio and what the native of each telescope is. However, I don't understand what is meant or what was done acquiring the images to make you say on the attachment - " at f/25 at f/36..." for each scope.


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Samir Kharusi
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Re: Another Jupiter comparison...food for thought new [Re: smee]
      #5570227 - 12/14/12 01:00 AM

Perhaps this might explain focal ratio choice in a simplistic fashion, comparing two "APOs" for planetary imaging; a camera lens (Canon 600mm f4; 150mm aperture) vs a more traditional APO (TeleView 140mm aperture f5). The camera lens had a 1.4x Canon tele-extender + a 5X Powermate, yielding f4*1.4*5 = f28, roughly. The TV scope had a 5X Powermate, yielding f5*5 = f25. Detailed spacing of the components does make a difference, but, roughly, it is that simple. Photos of the set ups:


and



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buaku
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Reged: 02/24/12

Re: Another Jupiter comparison...food for thought new [Re: Samir Kharusi]
      #5571685 - 12/14/12 10:20 PM

I've always wondered if you could somehow use a Canon Lens as a makeshift telescope...I gotta try that one day.
Thanks for putting instructions on your site!


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ValeryD
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Re: Another Jupiter comparison...food for thought new [Re: mikey cee]
      #5571944 - 12/15/12 02:24 AM

Quote:

..with my 10" Istar I can actually obtain a view very similar to the 100mm's pic. That was with about a 8-9/10 seeing. Only difference was the slight CA at the 515x with my binos with a pair of 20mm 66° plossls. Of course I failed to mention the image was very sharp, not blurred as in the pic. The spot between GRS and BA oval was like a moon shadow. The actual color intensity was just a tad less because of the pic processing. ;Mike




With high quality 10" aperture (10" Mak 22% c.o.) and with bino, at 8-9 seeing, I routinely can see Jupiter with details level as on the picture with C11. A bit less details and a bit less colors fidelity. But FAR superior to 100mm picture.


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BKBrown
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Re: Another Jupiter comparison...food for thought new [Re: smee]
      #5572138 - 12/15/12 08:14 AM

Quote:

Quote:

Hi folks, been a while since I posted here...it's been an amazing and busy Jupiter imaging season. While the bulk of my work leading up to opposition was done with my C11 Edge HD, I also did some small bore imaging with my SW100ED. Again the results were highly gratifying, it's amazing how much detail that four incher can pull in. And while the Skywatcher image sits next to a very nice shot from the C11, this is not about comparing the two since the big SCT is clearly in another weight class. I thought you might find it informative to see how much detail the smaller scope can pick up. Check out the GRS w/ interior detail, the Oval BA "doughnut", the strange dark small spot chasing the Oval BA, several of the light tone south polar ovals, and details in the equatorial belt including one of the long, whispy blue streamers. All-in-all a terrific amount of detail. I hope you enjoy these shots, and hope that anyone thinking they have to have a big OTA to do planetary imaging will think otherwise after checking out these images. Thanks for dropping by!

Clear Skies,
Brian




Can you explain something to me please?

I know about Focal Ratio and what the native of each telescope is. However, I don't understand what is meant or what was done acquiring the images to make you say on the attachment - " at f/25 at f/36..." for each scope.




Samir provided good pictures and a detailed explanation, I will break it down further. If you multiply the native focal ratio by the magnifying factor of the Barlow or Powermate, you get the operational focal ratio of the imaging system, for instance: the SW100ED is f/9 X 4x Siebert Barlow for f/36. This can also be expressed as a focal length by multiplying the native focal length in millimeters by the magnifying factor of the Barlow or Powermate (or combination of same): the same SW100ED with a focal length of 900mm X 4x Siebert Barlow has an operational focal length of 3600mm. Hope this helps...

Clear Skies,
Brian


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smee
super member


Reged: 10/19/10

Re: Another Jupiter comparison...food for thought new [Re: BKBrown]
      #5577070 - 12/18/12 10:31 AM

Brian and Samir,

getting a late thankyou to you.

Probably some texts and tutorials "out there" may contain the information about imaging natively or with a barlow/powermate and the result affecting the focal ratio giving the wherefor/whyfors.

Perhaps if I had searched more comprehensively...!

And looking at your other comp threads, superb images. cheers!


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