Difference between SkyWatcher Explorer 130 RA and 130M?

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flord.lord
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Difference between SkyWatcher Explorer 130 RA and 130M?

#1

Post by flord.lord »

Hi,

The two scopes in the title are:

https://www.rothervalleyoptics.co.uk/sk ... drive.html

And

https://www.rothervalleyoptics.co.uk/sk ... scope.html

I was a bit confused by this:

- Is the only difference the multi-speed handset, and DC power/battery? How useful is the multi-speed handset?

-Do I need motorised tracking at all on this scope, let's say at 160x magnification (as without it is significantly cheaper)

Thanks!
---------------
5.1" SkyWatcher Explorer 130M EQ-2
4" SkyWatcher Heritage 100P Mini Dob

Greater London - Bortle 8
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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#2

Post by Refractordude »

At 166 magnification I would say a tracker is not needed. If I wanted a reflector around your price range I would get this https://www.firstlightoptics.com/beginn ... onian.html, and upgrade with a red dot finder if the stock finder is difficult to use. The 150mm aperture dob has a much better/very easier to use mount. Being a f/8 it will knock the planets and moon out the park.
Telescopes: Celestron 150mm f/8 Refractor, Meade LX70 120mm f/8 Refractor, Vixen 70mm f/12.9 Refractor, Tasco 49N 50mm Red Refractor
Binoculars: Zhumell 20x80 Giant, Oberwerk LW 11x70, Levenhuk Sherman 7x50
Mounts: Orion SkyView Pro Equatorial, Orion Versago II Altazimuth, Farpoint Universal Parrallogram Mount, Orion Tritech II Fluid Head Tripod
Finders: GSO 8x50 Raci, Svbony Red Dot
Diagonals: GSO Dielectric 2", GSO Dielectric 1.25"
Eyepieces: GSO Superview 30mm, Astromania-Olivon 22mm, GSO Plossls 32mm/25mm/20mm, GSO 20mm Superview, Svbony 20mm/15mm/9mm/6mm, Svbony Aspheric 23mm/10mm/4mm, Agena Super Wide Angle 15mm, Few No Name Brand Ebay Plossls
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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#3

Post by Refractordude »

Just recalled I have a review of a 6" f/8 dob. Right click the image.
Attachments
image 1.PNG
Telescopes: Celestron 150mm f/8 Refractor, Meade LX70 120mm f/8 Refractor, Vixen 70mm f/12.9 Refractor, Tasco 49N 50mm Red Refractor
Binoculars: Zhumell 20x80 Giant, Oberwerk LW 11x70, Levenhuk Sherman 7x50
Mounts: Orion SkyView Pro Equatorial, Orion Versago II Altazimuth, Farpoint Universal Parrallogram Mount, Orion Tritech II Fluid Head Tripod
Finders: GSO 8x50 Raci, Svbony Red Dot
Diagonals: GSO Dielectric 2", GSO Dielectric 1.25"
Eyepieces: GSO Superview 30mm, Astromania-Olivon 22mm, GSO Plossls 32mm/25mm/20mm, GSO 20mm Superview, Svbony 20mm/15mm/9mm/6mm, Svbony Aspheric 23mm/10mm/4mm, Agena Super Wide Angle 15mm, Few No Name Brand Ebay Plossls
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Lady Fraktor
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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#4

Post by Lady Fraktor »

flord.lord wrote:
Tue Jul 21, 2020 10:28 pm
Hi,

The two scopes in the title are:

https://www.rothervalleyoptics.co.uk/sk ... drive.html

And

https://www.rothervalleyoptics.co.uk/sk ... scope.html

I was a bit confused by this:

- Is the only difference the multi-speed handset, and DC power/battery? How useful is the multi-speed handset?

-Do I need motorised tracking at all on this scope, let's say at 160x magnification (as without it is significantly cheaper)

Thanks!
Tracking would be up to you, at higher magnifications for lunar and planetary it is a handy thing to have.
The motor with hand control should give multiple speeds and some more convenience over a simple RA motor.
Proper Telescopes: Antares 105 f/15, Bresser 102 f/13.2, Celestron 150 f/8, Stellarvue NHNGDX 80 f/6.9, TAL 100RS f/10, TS 102 f/11, UR 70 f/10, Vixen ED115s f/7.7
Mounts: Berlebach Planet w/ 410mm pier, Celestron AS-GT, Celestron CG-5 w/ Argo Navis & tracking motor, SLT w/ 250mm pier & tripod mods, Manfrotto 028b w/ SV M2C, Mantrotto 055Pro w/ 128RC, Skywatcher EQ-5 w/ dual drives, TAL MT1C w/ wood tripod, Vixen SXP w/ HAL-130 & 200mm half pier
Diagonal: 2" A-P Maxbright, 2" Baader Herschel Wedge (P), 2" Zeiss/ Baader Amici Prism (DX2), 2" Long Perng Amici Prism, 2" Stellarvue DX, 2" TeleVue EverBrite
Eyepieces: Antares to Zeiss
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flord.lord
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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#5

Post by flord.lord »

Refractordude wrote:
Wed Jul 22, 2020 12:06 am
At 166 magnification I would say a tracker is not needed. If I wanted a reflector around your price range I would get this https://www.firstlightoptics.com/beginn ... onian.html, and upgrade with a red dot finder if the stock finder is difficult to use. The 150mm aperture dob has a much better/very easier to use mount. Being a f/8 it will knock the planets and moon out the park.
A 6" dob (or any dob) I have considered, but price, portability, ease of use (bending over) and previously owning a small dob have driven me towards a newt on an EQ (yes I know it's not the sturdiest etc. etc.)

I ordered this : https://www.rothervalleyoptics.co.uk/sk ... scope.html but it's out of stock everywhere imaginable, so the ones in my original post are my other options, along with the non-motor driven: https://www.rothervalleyoptics.co.uk/sk ... scope.html.

I have considered the Explorer 130P, but it is more expensive and an f/5; the f/7 of the spherical makes it a good all-rounder for DSOs and planets.

So I just have to decide on motor drive or no.
---------------
5.1" SkyWatcher Explorer 130M EQ-2
4" SkyWatcher Heritage 100P Mini Dob

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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#6

Post by Lady Fraktor »

An interesting looking new version of a EQ-2, it will be interesting to hear how stable it is.
The tripod can be stiffened up quite easily for less shake as well.

If the f/7 telescope has a corrector and spherical mirror they are not great for mid high powers and up without a lot of rework.
Spherical do work well when f/10 or slower.
Proper Telescopes: Antares 105 f/15, Bresser 102 f/13.2, Celestron 150 f/8, Stellarvue NHNGDX 80 f/6.9, TAL 100RS f/10, TS 102 f/11, UR 70 f/10, Vixen ED115s f/7.7
Mounts: Berlebach Planet w/ 410mm pier, Celestron AS-GT, Celestron CG-5 w/ Argo Navis & tracking motor, SLT w/ 250mm pier & tripod mods, Manfrotto 028b w/ SV M2C, Mantrotto 055Pro w/ 128RC, Skywatcher EQ-5 w/ dual drives, TAL MT1C w/ wood tripod, Vixen SXP w/ HAL-130 & 200mm half pier
Diagonal: 2" A-P Maxbright, 2" Baader Herschel Wedge (P), 2" Zeiss/ Baader Amici Prism (DX2), 2" Long Perng Amici Prism, 2" Stellarvue DX, 2" TeleVue EverBrite
Eyepieces: Antares to Zeiss
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flord.lord
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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#7

Post by flord.lord »

Lady Fraktor wrote:
Wed Jul 22, 2020 5:57 pm
An interesting looking new version of a EQ-2, it will be interesting to hear how stable it is.
The tripod can be stiffened up quite easily for less shake as well.

If the f/7 telescope has a corrector and spherical mirror they are not great for mid high powers and up without a lot of rework.
Spherical do work well when f/10 or slower.
Do all spherical mirrors have correctors? Also, the spherical mirror focuses less light - does this mean I get less effective aperture?
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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#8

Post by Lady Fraktor »

No they do not install correctors on all models of spherical mirrored reflectors.

Normally a Newtonian with a spherical mirror will have a long focal length to deal with the larger light cone produced.
They also will have a larger secondary mirror because of this compared to a same sized telescope with a parabolic mirror.

The first two you listed are the correct tube length to be a natural f/6.92 and the Skywatcher website states they have a parabolic primary.
Proper Telescopes: Antares 105 f/15, Bresser 102 f/13.2, Celestron 150 f/8, Stellarvue NHNGDX 80 f/6.9, TAL 100RS f/10, TS 102 f/11, UR 70 f/10, Vixen ED115s f/7.7
Mounts: Berlebach Planet w/ 410mm pier, Celestron AS-GT, Celestron CG-5 w/ Argo Navis & tracking motor, SLT w/ 250mm pier & tripod mods, Manfrotto 028b w/ SV M2C, Mantrotto 055Pro w/ 128RC, Skywatcher EQ-5 w/ dual drives, TAL MT1C w/ wood tripod, Vixen SXP w/ HAL-130 & 200mm half pier
Diagonal: 2" A-P Maxbright, 2" Baader Herschel Wedge (P), 2" Zeiss/ Baader Amici Prism (DX2), 2" Long Perng Amici Prism, 2" Stellarvue DX, 2" TeleVue EverBrite
Eyepieces: Antares to Zeiss
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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#9

Post by flord.lord »

Lady Fraktor wrote:
Thu Jul 23, 2020 5:17 pm
No they do not install correctors on all models of spherical mirrored reflectors.

Normally a Newtonian with a spherical mirror will have a long focal length to deal with the larger light cone produced.
They also will have a larger secondary mirror because of this compared to a same sized telescope with a parabolic mirror.

The first two you listed are the correct tube length to be a natural f/6.92 and the Skywatcher website states they have a parabolic primary.
I'm confused...the first two I listed (Explorer 130M and Explorer 130RA) 100% both have spherical mirrors. Also they have the standard EQ-2. My question was what optical difference there is. Do I lose light?
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5.1" SkyWatcher Explorer 130M EQ-2
4" SkyWatcher Heritage 100P Mini Dob

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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#10

Post by Lady Fraktor »

I did some digging around and the f/6.92 are a spherical mirror.

These telescopes are good for low and mid power sweeping/ viewing but do not do higher powers well nor are they suited for AP if you are thinking of doing that.
If built correctly (long focal length) spherical mirrors will lose some contrast and resolution due to the oversized secondary that is required.
These I doubt will have a larger secondary so the light cone will be clipped off.

Personally the Newtonian with a parabolic mirror are better all round telescopes.
Proper Telescopes: Antares 105 f/15, Bresser 102 f/13.2, Celestron 150 f/8, Stellarvue NHNGDX 80 f/6.9, TAL 100RS f/10, TS 102 f/11, UR 70 f/10, Vixen ED115s f/7.7
Mounts: Berlebach Planet w/ 410mm pier, Celestron AS-GT, Celestron CG-5 w/ Argo Navis & tracking motor, SLT w/ 250mm pier & tripod mods, Manfrotto 028b w/ SV M2C, Mantrotto 055Pro w/ 128RC, Skywatcher EQ-5 w/ dual drives, TAL MT1C w/ wood tripod, Vixen SXP w/ HAL-130 & 200mm half pier
Diagonal: 2" A-P Maxbright, 2" Baader Herschel Wedge (P), 2" Zeiss/ Baader Amici Prism (DX2), 2" Long Perng Amici Prism, 2" Stellarvue DX, 2" TeleVue EverBrite
Eyepieces: Antares to Zeiss
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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#11

Post by terrynak »

I totally agree with Gabrielle - views with the 130/w spherical mirror will get soft at higher powers compared to the Explorer 130P, which has the parabolic mirror. A friend of mine had both types of 130mm Newts (spherical F/6.92 vs. parabolic F/5.0) and he was able to confirm this.

Phil Harrington (Star Ware) also recommended against this scope (reviewing the Orion SpaceProbe 130 version of it) because of the above and the weak EQ2 mount for this scope (130/900mm OTA).
Scopes: Reflectors, refractors, and 1 catadioptric. Ranging in aperture from 50mm to 150mm.
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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#12

Post by notFritzArgelander »

One can ask the question in a different way. As the focal length increases the spherical mirror is a better approximation to a parabola. So one could ask "when, for a 5" scope, is a sphere as good as a parabola"?

For a 5" scope the focal ratio would have to be greater than f/D = 7.8. At f/D = 6.92 these scopes will not be as good as parabola and should be avoided.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker III, Vixen Porta II, Celestron CG5, Orion Sirius EQG
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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#13

Post by helicon »

I had an f/10 reflector on an EQ mount with a spherical mirror which worked just fine.

However, as others have stated a parabolic is highly recommended in shorter focal lengths.
-Michael
Various scopes, 10" Zhumell Dob, ES AR152, AWB 5.1" Onesky newt, Oberwerk 25x100 binos, two eyeballs
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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#14

Post by terrynak »

helicon wrote:
Fri Jul 24, 2020 3:13 pm
I had an f/10 reflector on an EQ mount with a spherical mirror which worked just fine.
fas
However, as others have stated a parabolic is highly recommended in shorter focal lengths.

Michael, I'm thinking you're referring to the Edmund Palomar Jr. - the 4.25", F/10 scope. Nice long focal length, given the aperture.

The famous Criterion RV-6 Dynascope (6") had a reputation for excellent performance despite its spherically shaped mirror at F/8.
Scopes: Reflectors, refractors, and 1 catadioptric. Ranging in aperture from 50mm to 150mm.
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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#15

Post by notFritzArgelander »

terrynak wrote:
Fri Jul 24, 2020 10:19 pm
helicon wrote:
Fri Jul 24, 2020 3:13 pm
I had an f/10 reflector on an EQ mount with a spherical mirror which worked just fine.
fas
However, as others have stated a parabolic is highly recommended in shorter focal lengths.

Michael, I'm thinking you're referring to the Edmund Palomar Jr. - the 4.25", F/10 scope. Nice long focal length, given the aperture.

The famous Criterion RV-6 Dynascope (6") had a reputation for excellent performance despite its spherically shaped mirror at F/8.
The technical detail is whether a spherical mirror deviates from a parabolic mirror in a way that satisfies the Rayleigh criterion that a defect in the shape of a mirror should produce no more than a 1/4 wave error in the wave front.

In Jean Texereau's How to Make a Telescope the application of this is discussed in detail. On pp. 16-17 there are formulas and a table:

Measuring f and D in cm: f^3 = 34.9D^3.
Measuring in inches one gets: f^3 = 88.6D^3.

The table has f/D = 7.0 for a 4" and f/D = 8.2 for a 6".

Both the examples you cite are "close enough" to parabolic so that within the Rayleigh criterion I wouldn't care about the difference between parabola and sphere. If the difference is smaller than what is required to have perfect optics, there is no functional difference. I wouldn't care whether the Edmund Palomar Jr or RV-6 Dynascope was advertised as a parabola or a sphere. Rayleigh has them as being equivalent.

I built an 8" f9 with a mirror that was spherical with only slight parabolizing. The table gives f/D = 9.6 for a 10".... So a REALLY long tube.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker III, Vixen Porta II, Celestron CG5, Orion Sirius EQG
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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#16

Post by notFritzArgelander »

notFritzArgelander wrote:
Fri Jul 24, 2020 10:45 pm

The technical detail is whether a spherical mirror deviates from a parabolic mirror in a way that satisfies the Rayleigh criterion that a defect in the shape of a mirror should produce no more than a 1/4 wave error in the wave front.

In Jean Texereau's How to Make a Telescope the application of this is discussed in detail. On pp. 16-17 there are formulas and a table:

Measuring f and D in cm: f^3 = 34.9D^3.
Measuring in inches one gets: f^3 = 88.6D^3.


The table has f/D = 7.0 for a 4" and f/D = 8.2 for a 6".

Both the examples you cite are "close enough" to parabolic so that within the Rayleigh criterion I wouldn't care about the difference between parabola and sphere. If the difference is smaller than what is required to have perfect optics, there is no functional difference. I wouldn't care whether the Edmund Palomar Jr or RV-6 Dynascope was advertised as a parabola or a sphere. Rayleigh has them as being equivalent.

I built an 8" f9 with a mirror that was spherical with only slight parabolizing. The table gives f/D = 9.6 for a 10".... So a REALLY long tube.
In the bolded quote I made a stupid typo. I apologize.

It should be:

Measuring f and D in cm: f^3 = 34.9D^4.
Measuring in inches one gets: f^3 = 88.6D^4.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker III, Vixen Porta II, Celestron CG5, Orion Sirius EQG
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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#17

Post by terrynak »

notFritzArgelander wrote:
Fri Jul 24, 2020 10:45 pm

The technical detail is whether a spherical mirror deviates from a parabolic mirror in a way that satisfies the Rayleigh criterion that a defect in the shape of a mirror should produce no more than a 1/4 wave error in the wave front.

In Jean Texereau's How to Make a Telescope the application of this is discussed in detail. On pp. 16-17 there are formulas and a table:

Measuring f and D in cm: f^3 = 34.9D^3.
Measuring in inches one gets: f^3 = 88.6D^3.

The table has f/D = 7.0 for a 4" and f/D = 8.2 for a 6".

Both the examples you cite are "close enough" to parabolic so that within the Rayleigh criterion I wouldn't care about the difference between parabola and sphere. If the difference is smaller than what is required to have perfect optics, there is no functional difference. I wouldn't care whether the Edmund Palomar Jr or RV-6 Dynascope was advertised as a parabola or a sphere. Rayleigh has them as being equivalent.

I built an 8" f9 with a mirror that was spherical with only slight parabolizing. The table gives f/D = 9.6 for a 10".... So a REALLY long tube.
An 8" F9 Newt means a scope 1803mm long or almost 6 ft. in focal length!

I was lucky enough to find a 5" F/8 Newt (127/1020mm) - the Meade 127NT, which was available only in '97/'98 before it was discontinued. Fits the Rayleigh criterion for a spherical, but someone mentioned that it has a parabolic mirror as well. Came with a LXD 500A mount, with a payload capacity of 15 lbs (according to manual). Very sturdy mount for an OTA this size.

Bresser currently markets a 130/1000mm or F/7.7 Newt in Europe (Messier NT-130/1000 EXOS-1) - like the Meade above, it may even have a parabolic mirror as well (may not make a noticeable difference with a spherical at high magnifications, but still nice to have); the EXOS-1 mount also has a payload of 15 lbs.

Flord.lord, if you still want a long focal length 5" Newtonian, the Bresser scope is the one to get. Here's the link:

https://www.bresser.de/en/Astronomy/Tel ... scope.html
Scopes: Reflectors, refractors, and 1 catadioptric. Ranging in aperture from 50mm to 150mm.
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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#18

Post by notFritzArgelander »

terrynak wrote:
Sat Jul 25, 2020 1:19 am
notFritzArgelander wrote:
Fri Jul 24, 2020 10:45 pm

The technical detail is whether a spherical mirror deviates from a parabolic mirror in a way that satisfies the Rayleigh criterion that a defect in the shape of a mirror should produce no more than a 1/4 wave error in the wave front.

In Jean Texereau's How to Make a Telescope the application of this is discussed in detail. On pp. 16-17 there are formulas and a table:

Measuring f and D in cm: f^3 = 34.9D^3.
Measuring in inches one gets: f^3 = 88.6D^3.

The table has f/D = 7.0 for a 4" and f/D = 8.2 for a 6".

Both the examples you cite are "close enough" to parabolic so that within the Rayleigh criterion I wouldn't care about the difference between parabola and sphere. If the difference is smaller than what is required to have perfect optics, there is no functional difference. I wouldn't care whether the Edmund Palomar Jr or RV-6 Dynascope was advertised as a parabola or a sphere. Rayleigh has them as being equivalent.

I built an 8" f9 with a mirror that was spherical with only slight parabolizing. The table gives f/D = 9.6 for a 10".... So a REALLY long tube.
An 8" F9 Newt means a scope 1803mm long or almost 6 ft. in focal length!
Yes, and the mount I built for it was a beast. :sigh:
I was lucky enough to find a 5" F/8 Newt (127/1020mm) - the Meade 127NT, which was available only in '97/'98 before it was discontinued. Fits the Rayleigh criterion for a spherical, but someone mentioned that it has a parabolic mirror as well. Came with a LXD 500A mount, with a payload capacity of 15 lbs (according to manual). Very sturdy mount for an OTA this size.

Bresser currently markets a 130/1000mm or F/7.7 Newt in Europe (Messier NT-130/1000 EXOS-1) - like the Meade above, it may even have a parabolic mirror as well (may not make a noticeable difference with a spherical at high magnifications, but still nice to have); the EXOS-1 mount also has a payload of 15 lbs.

Flord.lord, if you still want a long focal length 5" Newtonian, the Bresser scope is the one to get. Here's the link:

https://www.bresser.de/en/Astronomy/Tel ... scope.html
Yes, that would be a good performer.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker III, Vixen Porta II, Celestron CG5, Orion Sirius EQG
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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#19

Post by terrynak »

notFritzArgelander wrote:
Sat Jul 25, 2020 1:55 am
I built an 8" f9 with a mirror that was spherical with only slight parabolizing. The table gives f/D = 9.6 for a 10".... So a REALLY long tube.
An 8" F9 Newt means a scope 1803mm long or almost 6 ft. in focal length!
Yes, and the mount I built for it was a beast. :sigh:
Yes, that would be a good performer.
I was going to ask about the mount (and whether it was an EQ or Dob) on my previous post but decided to hold back...

I was able to pick up a Bresser 150/1200mm OTA new from a seller who managed to get a hold of a few of these, as well as a few 130/1000 OTAs. Should have snapped up a Bresser 130/1000 OTA as well, even though I already had the older Meade 127NT. Seriously thought about it, but never managed to pull the trigger.
Scopes: Reflectors, refractors, and 1 catadioptric. Ranging in aperture from 50mm to 150mm.
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Re: Difference between SkyWatcher Explorer 130 RA and 130M?

#20

Post by notFritzArgelander »

terrynak wrote:
Sat Jul 25, 2020 2:26 am
notFritzArgelander wrote:
Sat Jul 25, 2020 1:55 am
I built an 8" f9 with a mirror that was spherical with only slight parabolizing. The table gives f/D = 9.6 for a 10".... So a REALLY long tube.
An 8" F9 Newt means a scope 1803mm long or almost 6 ft. in focal length!
Yes, and the mount I built for it was a beast. :sigh:
Yes, that would be a good performer.
I was going to ask about the mount (and whether it was an EQ or Dob) on my previous post but decided to hold back...

I was able to pick up a Bresser 150/1200mm OTA new from a seller who managed to get a hold of a few of these, as well as a few 130/1000 OTAs. Should have snapped up a Bresser 130/1000 OTA as well, even though I already had the older Meade 127NT. Seriously thought about it, but never managed to pull the trigger.
This was in the mid 1960s before the "Dobsonian revolution" rebranded altazimuth mounts. The original mount was a crude equatorial mount made from pipe fittings with no provision for latitude adjustment...... One had to be careful to not screw the OTA off of one axis or the other. :lol: The optics were quite nice though! Then I moved N about 15 degrees of latitude and got a proper commercial mount.

I'm sure you would have been pleased with those views. The designs are sound.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker III, Vixen Porta II, Celestron CG5, Orion Sirius EQG
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