Request pleasant discussion of med/large CATs for visual use.
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Request pleasant discussion of med/large CATs for visual use.
* Celestron C6 SCT on a Twilight 1 Alt-Az mount
Prof. Barnhardt to Klaatu in The Day the Earth Stood Still: "There are several thousand questions I'd like to ask you.”
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Re: Request pleasant discussion of med/large CATs for visual use.
Unfortunate that the Vixen sale has just ended.
APM has a nice custom 275mm Mak-
See Far Sticks: Elita 103/1575, AOM FLT 105/1000, Bresser 127/1200 BV, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS 100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, SXP2, AXJ, AXD
Az/Alt: AYO Digi II, Stellarvue M2C, Argo Navis encoders on both
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Tak prism, TAL, Vixen
Eyepieces: Antares to Zeiss (1000101)
The only culture I have is from yogurt
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Re: Request pleasant discussion of med/large CATs for visual use.
Some eyes (like mine) can't cope with the level of residual field curvature and astigmatism of a plain vanilla
Where controversy and acrimony develop it is usually on the part of folks who are perfectly happy with the images provided by a non aplanat
The discussion gets focused on the hardware which is futile since the difference lies more in the physiology of the individual's eye than in the aberrations of the
I intend to start a separate thread detailing how the differences in use of nonaplanat versus aplanat CATs depends critically on the eye in a way that is too complex for simple radius of curvature measures for
So let's keep that discussion for another thread where I will try to explain it more clearly than in the thread that was blown away. For your thread and to help with your decision two important questions for you to answer are:
1) Do you require an aplanat?
2) Have you made observations that lead you to believe that you do?
If the answer is 1) yes and 2) yes then let that be your requirement for the thread. If you've observed with an aplanat and find the experience clearer, sharper, more contrasty than with a nonaplanat then that is all that needs to be said about it. This thread can then proceed serenely (I hope) with that as a staled requirement by you. Hopefully civil discussion of the optics and physiology, aplanats versus nonaplanats, can be contained in the thread I'll start leaving yours in tranquility.
Does that work for you? Do you need an aplanat and is this based on your own observations?
BTW I took delivery today of a VMC200L as part of my risk reduction looking at an eventual VMC260L or 11" Edge.
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Re: Request pleasant discussion of med/large CATs for visual use.
Here it is: viewtopic.php?f=71&t=9552Lady Fraktor wrote: ↑Sat May 02, 2020 4:00 am The Celestron/ Meade Aplanatics are better than the standards, Vixen has probably the quickest equalization and for the price of a top of line Tak or Vixen you could buy a small vehicle to drive to darker skies
Unfortunate that the Vixen sale has just ended.
APM has a nice custom 275mm Mak-Cass from Intes Micro for sale right now at 17.000€
If I could I would but.... :shrug:
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Re: Request pleasant discussion of med/large CATs for visual use.
* Celestron C6 SCT on a Twilight 1 Alt-Az mount
Prof. Barnhardt to Klaatu in The Day the Earth Stood Still: "There are several thousand questions I'd like to ask you.”
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Re: Request pleasant discussion of med/large CATs for visual use.
notFritzArgelander wrote: ↑Sat May 02, 2020 4:28 amHere it is: viewtopic.php?f=71&t=9552Lady Fraktor wrote: ↑Sat May 02, 2020 4:00 am The Celestron/ Meade Aplanatics are better than the standards, Vixen has probably the quickest equalization and for the price of a top of line Tak or Vixen you could buy a small vehicle to drive to darker skies
Unfortunate that the Vixen sale has just ended.
APM has a nice custom 275mm Mak-Cass from Intes Micro for sale right now at 17.000€
If I could I would but.... :shrug:
I realize that that may be a great scope, but it's rare, I'm not ready to buy yet, it's expensive (17,000 EU = $18.7k), and frankly, it probably deserves to be owned by someone who knows more about what they are actually doing with a telescope than I do (i.e., someone like one of you folks.)notFritzArgelander wrote: ↑Fri May 01, 2020 4:50 pmLooks like a one off. US optical materials, Intes Micro figuring, German mechanics. A special order gone sideways?Lady Fraktor wrote: ↑Fri May 01, 2020 4:45 pm At first I thought this was Markus Intes Mak then realized it is a 10", I wonder where he had this hidden!
I would drool but will restrain myself.
* Celestron C6 SCT on a Twilight 1 Alt-Az mount
Prof. Barnhardt to Klaatu in The Day the Earth Stood Still: "There are several thousand questions I'd like to ask you.”
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Re: Request pleasant discussion of med/large CATs for visual use.
Excellent, and congrats. I am looking forward to learning what you think of it.notFritzArgelander wrote: ↑Sat May 02, 2020 4:26 am BTW I took delivery today of a VMC200L as part of my risk reduction looking at an eventual VMC260L or 11" Edge.
* Celestron C6 SCT on a Twilight 1 Alt-Az mount
Prof. Barnhardt to Klaatu in The Day the Earth Stood Still: "There are several thousand questions I'd like to ask you.”
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Re: Request pleasant discussion of med/large CATs for visual use.
That clarifies to a degree. What you describe sounds a lot like my experience with my eyes and also with the Celestron 9.25AntennaGuy wrote: ↑Sat May 02, 2020 3:50 pm Thank you. I expect an aplanat would be beneficial for me, although I have not looked through one. My eyes' lenses have become remarkably inflexible compared to when I was younger. I now need tri-focals (but I bought separate prescription full-lens eyeglasses instead, and switch between them for different purposes.) Even so, I have to adjust my eye-to-target distances (books vs. computer screens, etc.) or simply settle for things being a bit out of focus, while swapping eyeglasses when appropriate. My younger self took my ability to focus my eyes for granted. Anwyay, I noticed the effects of field curvature using my Celestron 6" (conventional type) SCT recently. Actually, I had noticed it before but without realizing what it was; I kept thinking that it was simply a telescope-focusing issue (i.e., that I wasn't turning the knob to the right position, or perhaps that the focus was drifting mechanically), since re-adjusting the focus at any given moment tended to correct the problem; yet ultimately I would then have to refocus again when looking at a different direction within the field of the eyepiece. Based on all I've read here and elsewhere, that is the tell-tale sign of field curvature. And then... I learned more about field curvature, and that my inexpensive SCT was likely among the worst for this sort of thing (e.g., see https://starizona.com/tutorial/field-curvature/), and it all made sense.
I'll be reporting in greater detail in another thread on the VMC200. I've unpacked it. My initial impression is that it is really superbly built compared to the Celestron 9.25 Edge which in turn was better built than the plain 9.25
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Re: Request pleasant discussion of med/large CATs for visual use.
My pockets are insufficiently capacious! My experience with closed tube Maks is that the cooling time is large and dewing time is short. There seems to be some provision in thisAntennaGuy wrote: ↑Sat May 02, 2020 4:03 pmnotFritzArgelander wrote: ↑Sat May 02, 2020 4:28 amHere it is: viewtopic.php?f=71&t=9552Lady Fraktor wrote: ↑Sat May 02, 2020 4:00 am The Celestron/ Meade Aplanatics are better than the standards, Vixen has probably the quickest equalization and for the price of a top of line Tak or Vixen you could buy a small vehicle to drive to darker skies
Unfortunate that the Vixen sale has just ended.
APM has a nice custom 275mm Mak-Cass from Intes Micro for sale right now at 17.000€
If I could I would but.... :shrug:I realize that that may be a great scope, but it's rare, I'm not ready to buy yet, it's expensive (17,000 EU = $18.7k), and frankly, it probably deserves to be owned by someone who knows more about what they are actually doing with a telescope than I do (i.e., someone like one of you folks.)notFritzArgelander wrote: ↑Fri May 01, 2020 4:50 pmLooks like a one off. US optical materials, Intes Micro figuring, German mechanics. A special order gone sideways?Lady Fraktor wrote: ↑Fri May 01, 2020 4:45 pm At first I thought this was Markus Intes Mak then realized it is a 10", I wonder where he had this hidden!
I would drool but will restrain myself.
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Re: Request pleasant discussion of med/large CATs for visual use.
https://agenaastro.com/gso-10in-f12-cla ... -tube.html
Agena Astro says the mirrors are quartz and they (Agena) also do optical tests/checks before shipping.
S&T Review at: https://agenaastro.com/mwdownloads/download/link/id/65/
* Celestron C6 SCT on a Twilight 1 Alt-Az mount
Prof. Barnhardt to Klaatu in The Day the Earth Stood Still: "There are several thousand questions I'd like to ask you.”
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Re: Request pleasant discussion of med/large CATs for visual use.
* Celestron C6 SCT on a Twilight 1 Alt-Az mount
Prof. Barnhardt to Klaatu in The Day the Earth Stood Still: "There are several thousand questions I'd like to ask you.”
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Re: Request pleasant discussion of med/large CATs for visual use.
See Far Sticks: Elita 103/1575, AOM FLT 105/1000, Bresser 127/1200 BV, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS 100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, SXP2, AXJ, AXD
Az/Alt: AYO Digi II, Stellarvue M2C, Argo Navis encoders on both
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Tak prism, TAL, Vixen
Eyepieces: Antares to Zeiss (1000101)
The only culture I have is from yogurt
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Re: Request pleasant discussion of med/large CATs for visual use.
Presently leaning toward a Losmandy mount (G11 something), with the particular choice to depend on it being a good fit to theLady Fraktor wrote: ↑Sun May 03, 2020 3:01 am An interesting telescope, what mount are you planning on using?
* Celestron C6 SCT on a Twilight 1 Alt-Az mount
Prof. Barnhardt to Klaatu in The Day the Earth Stood Still: "There are several thousand questions I'd like to ask you.”
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Re: Request pleasant discussion of med/large CATs for visual use.
That looks nice and has an attractive price point. The weight at 38lbs would require something like a Losmandy G11 with a 60lb carrying capacity. Oh you might get by for visual only with a 40 lb mount like the Atlas but if you are on a high and windy hill.... (a little movie music reference there).AntennaGuy wrote: ↑Sun May 03, 2020 2:03 am Just saw this one, at the relatively-low price end:
https://agenaastro.com/gso-10in-f12-cla ... -tube.html
Agena Astro says the mirrors are quartz and they (Agena) also do optical tests/checks before shipping.
S&T Review at: https://agenaastro.com/mwdownloads/download/link/id/65/
The Classical Cassegrain design has a few aberrations to worry, so let's worry them.
The primary mirror is hyperbolic, like a Newtonian, so just like in a Newtonian that adds
However there are two things I did find that are helpful. First a pair of reviews:
https://agenaastro.com/mwdownloads/download/link/id/65/
https://astronomytechnologytoday.com/20 ... pe-review/
The second review is of the 8" model but Classical Cassegrain scale linearly with
Secondly the advice in Rutten and Venrooij. It is likely that the design uses a fast f4 parabola and a magnification factor of 3. (We know
Looks good.
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Re: Request pleasant discussion of med/large CATs for visual use.
Comparing the spot diagrams of a 200mm Newtonian with f10 and f15 200 mm Classical Cassegrain designs in R&V I find that the f10 CC is worse and the f15 CC is better.AntennaGuy wrote: ↑Sun May 03, 2020 2:47 am Hmm. At f/12 in a classical Cassegrain, there will be more coma. Will need to learn more about that. (Evidently, avoiding coma is the main reason that other large classical Cassegrains have higher focal ratios.)
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Re: Request pleasant discussion of med/large CATs for visual use.
* Celestron C6 SCT on a Twilight 1 Alt-Az mount
Prof. Barnhardt to Klaatu in The Day the Earth Stood Still: "There are several thousand questions I'd like to ask you.”
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Re: Request pleasant discussion of med/large CATs for visual use.
I can run a model of an f12 M=4 CC design on the computer where I have my optical design
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Re: Request pleasant discussion of med/large CATs for visual use.
https://teleskop-austria.at/SWRMAK300
See Far Sticks: Elita 103/1575, AOM FLT 105/1000, Bresser 127/1200 BV, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS 100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, SXP2, AXJ, AXD
Az/Alt: AYO Digi II, Stellarvue M2C, Argo Navis encoders on both
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Tak prism, TAL, Vixen
Eyepieces: Antares to Zeiss (1000101)
The only culture I have is from yogurt
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Re: Request pleasant discussion of med/large CATs for visual use.
You're wicked placing temptation in my path like that! I even have an account there (Lacerta, right?)Lady Fraktor wrote: ↑Sun May 03, 2020 3:34 am What about this for a telescope?
https://teleskop-austria.at/SWRMAK300
That's what I think of it.
Mostly positive discussion of this highly anticipated release....
https://www.cloudynights.com/topic/7039 ... assegrain/
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Re: Request pleasant discussion of med/large CATs for visual use.
OK having gotten over my surprise and delight here are somewhat soberer thoughts.notFritzArgelander wrote: ↑Sun May 03, 2020 3:52 amYou're wicked placing temptation in my path like that! I even have an account there (Lacerta, right?)Lady Fraktor wrote: ↑Sun May 03, 2020 3:34 am What about this for a telescope?
https://teleskop-austria.at/SWRMAK300
That's what I think of it.
Mostly positive discussion of this highly anticipated release....
https://www.cloudynights.com/topic/7039 ... assegrain/
The design appears to be similar to the VMC design. So the competition will be on the price with the advantage there in favor of the
Optically Vixen has chosen the VMC260L to be f11.5 and the VMC330L to be f13. The
1) I think it the reasons for
2) Because of the double pass through the corrector errors in manufacturing are compounded so Vixen might still be a better or competitive choice. The slowness of the Vixen optics helps this issue.
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