some temptations are too cruel

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mcolbert
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some temptations are too cruel

#1

Post by mcolbert »


I am seriously trying to figure out how I could get my hands on this;

https://www.astrobuysell.com/uk/propvie ... iew=151282
Refractor - APQ 130 Reflector - Meade SCT Au coating. Mount - AYOMaster (on order)
Cameras - Blads, D70s, D3300, Lunar and Planetary Cameras (2)
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Re: some temptations are too cruel

#2

Post by notFritzArgelander »


Good luck!
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, 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 IV, Vixen Porta II, Celestron CG5
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Re: some temptations are too cruel

#3

Post by Thefatkitty »


Got any body parts you don't need...?? :lol: A 31.5" mirror, even uncoated, I know I'd be looking, wondering if I really need that appendix/appendage....

Still, to collimate that at f/4.7, you'd want collimation screws with a thread pitch measured in human hairs :D

Would be a fun project though if you have the room!

All the best and I seriously hope you get it!
Mark

"The Hankmeister" Celestron 8SE, orange tube Vixen made C80, CG4 & AZ-EQ5 mounts.
Too much Towa glass/mirrors.

H/A - PST stage 2 mod with a Baader 90mm ERF on a Celestron XLT 102 (thanks Mike!)
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Re: some temptations are too cruel

#4

Post by mcolbert »


thanks guys - on the one hand I have you encouraging me and on the other, my wife's silent 'look'. I can feel it even though she's teaching class at the moment!

I'm just thinking; how much would it cost for gold coatings for IR use??? :). I must have a serious injury wish. ;)

Back to plotting!
Refractor - APQ 130 Reflector - Meade SCT Au coating. Mount - AYOMaster (on order)
Cameras - Blads, D70s, D3300, Lunar and Planetary Cameras (2)
DIY Glass - German military and opthalmic sourced items, AGFA AVIPHOT DIA C
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Re: some temptations are too cruel

#5

Post by notFritzArgelander »


mcolbert wrote: Tue Aug 20, 2019 4:28 am thanks guys - on the one hand I have you encouraging me and on the other, my wife's silent 'look'. I can feel it even though she's teaching class at the moment!

I'm just thinking; how much would it cost for gold coatings for IR use??? :). I must have a serious injury wish. ;)

Back to plotting!
Think of it this way.... If you survive, you're certain that you're alive! ;)
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, 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 IV, Vixen Porta II, Celestron CG5
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Re: some temptations are too cruel

#6

Post by Lady Fraktor »


Shipping a 800mm x 43mm piece of glass from UK to Australia... It may be cheaper to make your own glass :lol:
See Far Sticks: Antares Elita 103/1575, AOM FLT 105/1000, Bresser BV 127/1200, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, AXJ, AXD
Az/Alt: AYO Digi II/ Argo Navis, Stellarvue M2C/ Argo Navis
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, Takahashi prism, TAL, Vixen flip mirror
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mcolbert
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Re: some temptations are too cruel

#7

Post by mcolbert »


notFritzArgelander wrote: Tue Aug 20, 2019 5:03 am
mcolbert wrote: Tue Aug 20, 2019 4:28 am thanks guys - on the one hand I have you encouraging me and on the other, my wife's silent 'look'. I can feel it even though she's teaching class at the moment!

I'm just thinking; how much would it cost for gold coatings for IR use??? :). I must have a serious injury wish. ;)

Back to plotting!
Think of it this way.... If you survive, you're certain that you're alive! ;)
ah but would I be able to enjoy the mirror???? Now there's the question.
Refractor - APQ 130 Reflector - Meade SCT Au coating. Mount - AYOMaster (on order)
Cameras - Blads, D70s, D3300, Lunar and Planetary Cameras (2)
DIY Glass - German military and opthalmic sourced items, AGFA AVIPHOT DIA C
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Kanadalainen
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Re: some temptations are too cruel

#8

Post by Kanadalainen »


Not to throw a wet blanket on this cool idea, but here are a couple of things to think about (not to be taken as criticism):

Even at 43 mm thick, this big boy might flex enough to require a massive supporting series of blocks behind it. A tree of triangles.

Coating something that huge will run into a lot of money.

The focal ratio is actually long for such a huge mirror. You will have coma at 4.7 anyway, so its better to hit the mid 3's or even low 3's so that you don't need a huge ladder to reach the eyepiece. Also a great coma corrector (for coma) and fantastic eyepieces would be needed to keep the FOV happy.

But I totally understand the lure of something like this, ha ha. Practicality be damned. :sprefac:

Maybe check around for someone who could supply a slumped blank for a meniscus mirror. With the basic spherical shape already there, then you could polish it to a parabola yourself (after building a Foucault and a bath interferometer)! :)
Last edited by Kanadalainen on Tue Aug 20, 2019 1:17 pm, edited 1 time in total.
Ian

Fracs: Stellarvue 70T f6; SW 120mm Esprit f7; "Mark Mk. II" - 60 mm Tasco f6; C80 frac f 11.4
SCT: C8 Edge f10 or f7 with reducer
Dob: 14.5" homebuilt strut dob (f4.5 ZOC mirror), Nexus II, Moonlite focuser
Mounts - Ioptron Skyguider pro, Astro Physics GTO900
Cameras and lenses - ZWO 2600 mc, 290 mm mini, Canon 60D modded with Rokinon 10mm 2.8; Rokinon 135mm f2

Skysafari 6 Pro, Astro Pixel Processor, Pixinsight - using Mac tablet and ASIair pro to run the AP rig.

"Mothers! It is there!" - Rafael Gonzales-Acuna, 2018.
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Re: some temptations are too cruel

#9

Post by KingNothing13 »


Kanadalainen wrote: Tue Aug 20, 2019 1:03 pm You will have coma at 4.7 anyway, so its better to hit the mid 3's or even low 3's so that you don't need a huge ladder to reach the eyepiece.
Wow - how far mirror making has come - that this would be a possibility!
-- Brett

Scope: Apertura AD10 with Nexus II with 8192/716000 Step Encoders
EPs: ES 82* 18mm, 11mm, 6.7mm; GSO 30mm
Celestron SkyMaster 15x70 Binoculars
List Counts: Messier: 75; Herschel 400: 30; Caldwell: 12; AL Carbon Star List: 16
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Re: some temptations are too cruel

#10

Post by Kanadalainen »


Brett, et al, have a look at this lovely scope, the f3 Zipdob by none other than Mel Bartels. I really like the way Mr. Bartels thinks! :D

He provides a beautiful description of the trend for main mirror F ratio changes over the past few decades, and suggests that EP technology facilitates it!

http://www.bbastrodesigns.com/ZipDob/ZipDob.html
Ian

Fracs: Stellarvue 70T f6; SW 120mm Esprit f7; "Mark Mk. II" - 60 mm Tasco f6; C80 frac f 11.4
SCT: C8 Edge f10 or f7 with reducer
Dob: 14.5" homebuilt strut dob (f4.5 ZOC mirror), Nexus II, Moonlite focuser
Mounts - Ioptron Skyguider pro, Astro Physics GTO900
Cameras and lenses - ZWO 2600 mc, 290 mm mini, Canon 60D modded with Rokinon 10mm 2.8; Rokinon 135mm f2

Skysafari 6 Pro, Astro Pixel Processor, Pixinsight - using Mac tablet and ASIair pro to run the AP rig.

"Mothers! It is there!" - Rafael Gonzales-Acuna, 2018.
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Re: some temptations are too cruel

#11

Post by mcolbert »


Kanadalainen wrote: Tue Aug 20, 2019 1:03 pm Not to throw a wet blanket on this cool idea, but here are a couple of things to think about (not to be taken as criticism):

Even at 43 mm thick, this big boy might flex enough to require a massive supporting series of blocks behind it. A tree of triangles.

Coating something that huge will run into a lot of money.

The focal ratio is actually long for such a huge mirror. You will have coma at 4.7 anyway, so its better to hit the mid 3's or even low 3's so that you don't need a huge ladder to reach the eyepiece. Also a great coma corrector (for coma) and fantastic eyepieces would be needed to keep the FOV happy.

But I totally understand the lure of something like this, ha ha. Practicality be damned. :sprefac:

Maybe check around for someone who could supply a slumped blank for a meniscus mirror. With the basic spherical shape already there, then you could polish it to a parabola yourself (after building a Foucault and a bath interferometer)! :)
no worries about thinking of your comments being criticism - in the negative sense that is. I read them as considered opinions highly constructive in nature and intent, so many thanks for that. ;)

I agree that there would be a lot of work to be done, with a magnificent instrument at the end of the day, something which would outlive my efforts - part of a legacy that ATMers leave behind. ;)

I don't know if a Dob would be the goal. It could be a work in progress. eg hollow out earth, place coated mirror in ground and then build platform for the secondary and imaging. A limited use scope but, as I say, a WIP. Then to consider other designs.

Coatings would be expensive, yes, the challenge would be more to find someone capable of doing them. I have one lead, the company which made the au coating for the Meade. I don't know their limitations as far as size. Something to follow up.

Now to spend the day looking at InGaAs cameras. Thanks! :)
Refractor - APQ 130 Reflector - Meade SCT Au coating. Mount - AYOMaster (on order)
Cameras - Blads, D70s, D3300, Lunar and Planetary Cameras (2)
DIY Glass - German military and opthalmic sourced items, AGFA AVIPHOT DIA C
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Re: some temptations are too cruel

#12

Post by mcolbert »


Lady Fraktor wrote: Tue Aug 20, 2019 5:04 am Shipping a 800mm x 43mm piece of glass from UK to Australia... It may be cheaper to make your own glass :lol:

I think the problem is one of where to find a company that can produce blanks of that size. I wouldn't be surprised if there were simply no companies doing that here in this country. As one example it took several weeks to find someone to do the au coatings for the 8" and that was searching companies Australia wide. But something else to put on the lst. Thanks. ;)
Refractor - APQ 130 Reflector - Meade SCT Au coating. Mount - AYOMaster (on order)
Cameras - Blads, D70s, D3300, Lunar and Planetary Cameras (2)
DIY Glass - German military and opthalmic sourced items, AGFA AVIPHOT DIA C
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Re: some temptations are too cruel

#13

Post by Kanadalainen »


mcolbert wrote: Tue Aug 20, 2019 8:43 pm I don't know if a Dob would be the goal. It could be a work in progress. eg hollow out earth, place coated mirror in ground and then build platform for the secondary and imaging. A limited use scope but, as I say, a WIP. Then to consider other designs.
8-) :shock: :lol: :lol:

Best line I've heard on this board!! ha ha.
Ian

Fracs: Stellarvue 70T f6; SW 120mm Esprit f7; "Mark Mk. II" - 60 mm Tasco f6; C80 frac f 11.4
SCT: C8 Edge f10 or f7 with reducer
Dob: 14.5" homebuilt strut dob (f4.5 ZOC mirror), Nexus II, Moonlite focuser
Mounts - Ioptron Skyguider pro, Astro Physics GTO900
Cameras and lenses - ZWO 2600 mc, 290 mm mini, Canon 60D modded with Rokinon 10mm 2.8; Rokinon 135mm f2

Skysafari 6 Pro, Astro Pixel Processor, Pixinsight - using Mac tablet and ASIair pro to run the AP rig.

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Re: some temptations are too cruel

#14

Post by ARock »


Maybe hire this guy as a consultant on your project :)

https://cosmoquest.org/x/blog/2017/04/n ... telescope/
AR
Scopes: Zhumell Z8, Meade Adventure 80mm, Bushnell 1300x100 Goto Mak.
Mount: ES EXOS Nano EQ Mount, DIY Arduino+Stepper drives.
AP: 50mm guidescope, AR0130 based guidecam, Canon T3i, UHC filter.
EPs: ES82 18,11,6.7mm, Zhumell 30,9mm FJ Ortho 9mm, assorted plossls, Meade 2x S-F Barlow, DGM NPB filter.
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Re: some temptations are too cruel

#15

Post by mcolbert »


I think that it would be far too small to sustain his interest. ;)
Refractor - APQ 130 Reflector - Meade SCT Au coating. Mount - AYOMaster (on order)
Cameras - Blads, D70s, D3300, Lunar and Planetary Cameras (2)
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Re: some temptations are too cruel

#16

Post by mcolbert »


Kanadalainen wrote: Tue Aug 20, 2019 11:47 pm
mcolbert wrote: Tue Aug 20, 2019 8:43 pm I don't know if a Dob would be the goal. It could be a work in progress. eg hollow out earth, place coated mirror in ground and then build platform for the secondary and imaging. A limited use scope but, as I say, a WIP. Then to consider other designs.
8-) :shock: :lol: :lol:

Best line I've heard on this board!! ha ha.
well we try to entertain. ;)
Refractor - APQ 130 Reflector - Meade SCT Au coating. Mount - AYOMaster (on order)
Cameras - Blads, D70s, D3300, Lunar and Planetary Cameras (2)
DIY Glass - German military and opthalmic sourced items, AGFA AVIPHOT DIA C
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Re: some temptations are too cruel

#17

Post by DeanD »


I don't want to be a wet blanket, but I suspect that piece of glass will need a lot more work before it is even remotely useable. If you wanted to refigure it to (say) f3 there wouldn't be much glass left in the centre, but at that thickness you might not have to refigure it: just work out a mirror cell that lets it sag! ;)
Seriously though, if it is plate glass that is 43mm thick at the edge and it wasn't pre-slumped before it was figured then it will only be around 32mm thick in the centre. Hmmm. Good luck trying to get that down to f3!
The cost for the final scope would be way more than the tiny (comparative) amount you would pay for the glass.
As a comparison, the Astro Society of South Aust. (ASSA) was working on building a telescope with a 36" f3-ish 6" thick mirror (ex- Woomera rocket range) for many years. The project is now on indefinite hold because the costs were getting over the $100,000 mark...
Although, if you are very serious about such a scope there is a big bit of largely figured glass sitting over here in Adelaide... ;)

Good luck!!!

- Dean
Telescopes: 12" f5 dob, Celestron CPC800, 150mmf5 Celestron achro, Tak TSA102, TV76, ETX125...
Binos: Steiner Wildlife XP 10x26, Swarovski 8x30 Habicht, Zeiss SFL 8x40, Vanguard Endeavour 10.5x45, Fuji FMTR-SX 10x50, Tak 22x60, Orion Resolux 15x70
Eyepieces: way too many (is that possible?), but I do like my TV 32mm plossl, 13mm Nagler T6, 27mm Panoptic and 3-6mm Nagler zoom, plus Fujiyama 18mm and 25mm orthos and Tak 7.5mm LE
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Re: some temptations are too cruel

#18

Post by yobbo89 »


i think it cost about $900 to $1000 to just coat a mirror that size
scopes :gso/bintel f4 12"truss tube, bresser messier ar127s /skywatcher 10'' dob,meade 12'' f10 lx200 sct
cameras : asi 1600mm-c/asi1600mm-c,asi120mc,prostar lp guidecam, nikkon d60, sony a7,asi 290 mm
mounts : eq6 pro/eq8/mesu 200 v2
filters : 2'' astronomik lp/badder lrgb h-a,sII,oIII,h-b,Baader Solar Continuum, chroma 3nm ha,sii,oiii,nii,rgb,lowglow,uv/ir,Thousand Oaks Solar Filter,1.25'' #47 violet,pro planet 742 ir,pro planet 807 ir,pro planet 642 bp ir.
extras : skywatcher f4 aplanatic cc, Baader MPCC MKIII Coma Corrector,Orion Field Flattener,zwo 1.25''adc.starlight maxi 2" 9x filter wheel,tele vue 2x barlow .

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