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whats the largest F4 to F6 focal ratio scope money can buy?
Posted: Sun Jun 28, 2020 1:10 pm
by realflow100
I dont like the really long focal length scopes because it makes it really hard to locate a target and center it. and the requirement of an obscenely long focal length eyepiece with humungus AFOV like a 2" 40mm 100*degree eyepiece with a focal reducer
I want to be able to take full advantage of largest exit pupil with 32mm to 20mm eyepiece as well as largest magnification that the telescope is capable of with 6mm eyepiece with or without a 2x barlow
What is a good wide view telescope around F4 to F6 focal ratio of size 8" to 12" that I could buy?
Re: whats the largest F4 to F6 focal ratio scope money can buy?
Posted: Sun Jun 28, 2020 4:46 pm
by Star Dad
I like my Orion 8" f4.9 fl1000mm Newtonian. Two fellows in my club have the Orion 8" f3.9 fl800mm astrograph. For me it was the compromise between planetary visual and DSOs. Hindsight being what it is - I probably should have gone with the astrograph as I have since inherited a number of refractor ~60mm fl1000mm and reflector 114mm fl1000mm scopes. Of course, I had no idea that I'd be this deep into AP.
I routinely use a 40mm and 30mm lens for visual in my Orion 8". Orion also makes a 10 inch version.
Re: whats the largest F4 to F6 focal ratio scope money can buy?
Posted: Sun Jun 28, 2020 5:07 pm
by realflow100
can I have a few links to various options?
Re: whats the largest F4 to F6 focal ratio scope money can buy?
Posted: Sun Jun 28, 2020 5:24 pm
by Star Dad
This is the site for Orion scopes:
https://www.telescope.com/ . word of caution - you might end up spending a lot of time and money on that site.
Re: whats the largest F4 to F6 focal ratio scope money can buy?
Posted: Sun Jun 28, 2020 5:38 pm
by realflow100
https://www.telescope.com/Telescopes/Re ... goryId=345 looks like the closest to what im looking for but DANG THATS EXPENSIVEEEEEE
if I saved up and got that I'd have one whopper of a deep sky viewing experience. and also pretty decent for planets too!
Re: whats the largest F4 to F6 focal ratio scope money can buy?
Posted: Sun Jun 28, 2020 6:02 pm
by Lady Fraktor
These are not the largest available nor the most expensive.
If you want quality you have to pay accordingly.
https://www.obsessiontelescopes.com/
Re: whats the largest F4 to F6 focal ratio scope money can buy?
Posted: Thu Jun 03, 2021 12:18 pm
by Ngc1514
Not sure it’s the largest, but it’s more than I’d care to handle! It’s a Tectron 36 incher called, appropriately, the Yard Scope. Used to be Tom Clark’s scope at Chiefland, but he sold it to Bob Summerfield of “Astronomy To Go.”
Re: whats the largest F4 to F6 focal ratio scope money can buy?
Posted: Thu Jun 03, 2021 9:30 pm
by turboscrew
Go closer to F/6. I have F/4, and everything tends to be expensive. Most eyepieces have difficulties to handle such a steep light cone - that means expensive eyepieces. Like Baader Hyperions are said to be good for F/6 or slower. Also, big aperture means a big minimum magnification. Andomeda galaxy may not fit into the view.
The minimum magnification of my 12" / 1200 mm is about 43X (assuming 7 mm pupil). For me (pupil about 5.5 mm) about 55X. With 50° AFOV that gives TFOV of 0.92°. Bigger tubes are more expensive and tend to need bigger (= more expensive) mount.
My tube costs about 2000 eur and the mount (CEM120 for possible AP) about 4000 eur.
That gives you some idea of cost between the tube and mount when the things get bigger.
(BTW, at the moment 1 eur = 1.21 USD.)
What kind of mount have you thought of? Dobsons make it cheaper, but if you want EQ-mount, the price jumps.
Re: whats the largest F4 to F6 focal ratio scope money can buy?
Posted: Thu Jun 03, 2021 9:40 pm
by turboscrew
One note: High price still doesn't guarantee good quality. Also expensive garbage is being sold.
Re: whats the largest F4 to F6 focal ratio scope money can buy?
Posted: Thu Jun 03, 2021 9:55 pm
by Lady Fraktor
turboscrew wrote: ↑Thu Jun 03, 2021 9:40 pm
One note: High price still doesn't guarantee good quality. Also expensive garbage is being sold.
Do you have some links to these?
Once you get into the Zambutto, Lockwood and Kennedy prices you have nothing to worry about from the optical side.
Re: whats the largest F4 to F6 focal ratio scope money can buy?
Posted: Thu Jun 03, 2021 11:10 pm
by turboscrew
Lady Fraktor wrote: ↑Thu Jun 03, 2021 9:55 pm
turboscrew wrote: ↑Thu Jun 03, 2021 9:40 pm
One note: High price still doesn't guarantee good quality. Also expensive garbage is being sold.
Do you have some links to these?
Once you get into the Zambutto, Lockwood and Kennedy prices you have nothing to worry about from the optical side.
Quality costs, but sometimes bad quality stuff is sold with high prices.
I haven't collected info about bad telescopes, but somehow I don't find telescopes, like this, convincing...
http://www.hioptic.com/telescopes/refle ... Q5_AT5.htm
Neither does this.
https://www.skyatnightmagazine.com/revi ... pe-review/
Oh, and anything from here:
http://www.sale-telescopes.com/
(even cheap price is high, if you don't get any products.)
Re: whats the largest F4 to F6 focal ratio scope money can buy?
Posted: Fri Jun 04, 2021 1:56 am
by realflow100
I think my issue more right now is mostly light pollution issues. rather than size of my scope.
I can very clearly and easily see the background sky is almost a mid-brightness yellowgray color (in terms of the darkest vs lightest things I can see in a scene. Shadows under trees look significantly darker than the sky itself)
its impossible to see orion nebula or andromeda naked eye. Even magnitude 4 stars are well out of my reach!
I can only see stars about magnitude 3 and brighter approximately. even with using averted vision to the best of my abilities. (I have below average eyesight. about 20/40 to 20/50 in either eye I think my left eye is the worse one.)
I can focus fine so its not focusing thats the problem for me.
its everything looks equally blurry/astigmatism at all distances. from 2 inches from my face. a couple feet away. and even the moon at night. all looks about the same amount of blurryness.
my current location where I live is definitely a bortle 9 for me naked eye. and even with optical aid. telescope or binoculars.
With binoculars andromeda galaxy is just a tiny faint fuzzy looking dot. almost looks like a very faint globular cluster (but no distinct stars of course) Barely the very center of the core visible.
and orion nebula is not visible at all
Pleiades is the only naked eye deep sky object I can see. And I can't see any distinct stars in it. looks too fuzzy for me. Siginificantly brightens with averted vision. Almost invisible looking directly at it.
Re: whats the largest F4 to F6 focal ratio scope money can buy?
Posted: Sat Jul 10, 2021 10:53 am
by 25585
realflow100 wrote: ↑Sun Jun 28, 2020 1:10 pm
I dont like the really long focal length scopes because it makes it really hard to locate a target and center it. and the requirement of an obscenely long focal length eyepiece with humungus AFOV like a 2" 40mm 100*degree eyepiece with a focal reducer
I want to be able to take full advantage of largest exit pupil with 32mm to 20mm eyepiece as well as largest magnification that the telescope is capable of with 6mm eyepiece with or without a 2x barlow
What is a good wide view telescope around F4 to F6 focal ratio of size 8" to 12" that I could buy?
Focal length will increase as
aperture does. What's the maximum
FL you want?
Re: whats the largest F4 to F6 focal ratio scope money can buy?
Posted: Sat Jul 10, 2021 11:05 am
by 25585
My 10" F6 is 60", same for my 12" F5. Both are solid tube. A 14" F5 would be the max for aperture. 12" F6, 10" F7, 8" F9 are all ones I would like.
Going below F5 makes collimation too fiddly for me, F6 & longer is more tolerant.
Re: whats the largest F4 to F6 focal ratio scope money can buy?
Posted: Sat Jul 10, 2021 7:28 pm
by Bigzmey
realflow100 wrote: ↑Fri Jun 04, 2021 1:56 am
I think my issue more right now is mostly light pollution issues. rather than size of my scope.
I can very clearly and easily see the background sky is almost a mid-brightness yellowgray color (in terms of the darkest vs lightest things I can see in a scene. Shadows under trees look significantly darker than the sky itself)
its impossible to see orion nebula or andromeda naked eye. Even magnitude 4 stars are well out of my reach!
I can only see stars about magnitude 3 and brighter approximately. even with using averted vision to the best of my abilities. (I have below average eyesight. about 20/40 to 20/50 in either eye I think my left eye is the worse one.)
I can focus fine so its not focusing thats the problem for me.
its everything looks equally blurry/astigmatism at all distances. from 2 inches from my face. a couple feet away. and even the moon at night. all looks about the same amount of blurryness.
my current location where I live is definitely a bortle 9 for me naked eye. and even with optical aid. telescope or binoculars.
With binoculars andromeda galaxy is just a tiny faint fuzzy looking dot. almost looks like a very faint globular cluster (but no distinct stars of course) Barely the very center of the core visible.
and orion nebula is not visible at all
Pleiades is the only naked eye deep sky object I can see. And I can't see any distinct stars in it. looks too fuzzy for me. Siginificantly brightens with averted vision. Almost invisible looking directly at it.
Have you considered how are you going to find the targets? I love to star-hop to my targets under dark skies, however under light polluted skies it becomes slow and painful. So, at home I deploy smaller scopes on
GoTo mount and this is the route I would suggest. It could be 5-6" reflector, 4-5" refractor or 6-8"
SCT. I would go with 8"
SCT and use focal reducer if you don't like slow focal ratio.
Re: whats the largest F4 to F6 focal ratio scope money can buy?
Posted: Fri Jul 28, 2023 12:26 am
by Mike Q
Two things, first find darker skies. Light pollution is the enemy no matter what scope you have. Secondly you dont have to spend thousands on the high end works of art when you can spend around a grand on something like an Orion Skyline. A 10 or 12 inch dob would be a lifetime scope and will give you unforgettable views of the night sky. The only real issues are possibly moving it around, and possibly transporting it. Even broken down they are large, but the individual pieces are awkward but not really heavy.