12" F5 scope

[TareqPhoto]

Hi again,

Does 12" F5 Newtonian be handled by a mount such as EQ6 only?
Does this kind of scopes suitable for planetary imaging using a Barlow and ADC without modification as moving the focuser ot secondary mirror?
Which is better to be used for planetary imaging, 12" F5 on AZ-EQ6 mount or a non GOTO 12" F5 Dobsonian?

[Don Quixote]

My friend Henry uses an AZ/EQ6 and an 8 inch quatro with his DSLR with reasonable results. I am not sure how a 12 inch newtonian would do.
Have you considered a 12 or 14 inch Schmidt Cassigrain?

[TareqPhoto]

My friend Henry uses an AZ/EQ6 and an 8 inch quatro with his DSLR with reasonable results. I am not sure how a 12 inch newtonian would do.
Have you considered a 12 or 14 inch Schmidt Cassigrain?

12 or 14 SCT are so much more expensive than 12" or 14" Newt, in fact i may able to buy 16" or 18" or even 20" Dob in the price of 14" SCT, and 12" SCT is nearly as much as 14"-16" Dob, and Newt up to 12" is also cheaper, so i don't want to spend over $2000 for larger scope than 10" as i am still saving to fund my 20" Dob, but i need a larger scope over my 8" and less than 20" to use last year, 20" won't be ready until maybe 2021.

[notFritzArgelander]

A 12" f5 Newtonian will be much too much for an EQ6 to handle. The mount is only rated for 20 kg which is equal to the weight of my Z12's OTA. The usual rule of thumb is twice the weight rating. So you want a mount rated at 40kg.

If you are interested ONLY in lunar planetary photography take a look at this article.

https://www.telescope.com/Capturing-Pla ... 116862.uts

I'd recommend using a motorized equatorial platform.

If you insist on an equatorial mount, the lowest cost mount to consider would be the Losmandy G11 which is rated for slightly less at 34 kg but you could probably get away with it. Then there is the EQ8 rated at 50kg.

[notFritzArgelander]

My friend Henry uses an AZ/EQ6 and an 8 inch quatro with his DSLR with reasonable results. I am not sure how a 12 inch newtonian would do.
Have you considered a 12 or 14 inch Schmidt Cassigrain?

12 or 14 SCT are so much more expensive than 12" or 14" Newt, in fact i may able to buy 16" or 18" or even 20" Dob in the price of 14" SCT, and 12" SCT is nearly as much as 14"-16" Dob, and Newt up to 12" is also cheaper, so i don't want to spend over $2000 for larger scope than 10" as i am still saving to fund my 20" Dob, but i need a larger scope over my 8" and less than 20" to use last year, 20" won't be ready until maybe 2021.

Yes but an 11-12" SCT is lighter and more compact than equatorially mounting a Newtonian. See what they can do at http://www.damianpeach.com

[TareqPhoto]

A 12" f5 Newtonian will be much too much for an EQ6 to handle. The mount is only rated for 20 kg which is equal to the weight of my Z12's OTA. The usual rule of thumb is twice the weight rating. So you want a mount rated at 40kg.

If you are interested ONLY in lunar planetary photography take a look at this article.

https://www.telescope.com/Capturing-Pla ... 116862.uts

I'd recommend using a motorized equatorial platform.

If you insist on an equatorial mount, the lowest cost mount to consider would be the Losmandy G11 which is rated for slightly less at 34 kg but you could probably get away with it. Then there is the EQ8 rated at 50kg.

Well, i mentioned it is either a Newt or a dob.

I saw someone used Skywatcher 300/1500 [12" F5] on EQ6-R mount for DSO not planetary, DSO is more complicated than planetary, so i don't know how he was able to do it if that is a risky for the mount actually? either he doesn't care or he just want to use that until it reached the end, but if it was possible for DSO then planetary is easier, i use video for between 1min p to 5min, even with slight drift i can manage to get results.

I also like the idea of a Dob and EQ platform, i just can't buy both, i can just buy a 12" Dob or even 14" Dob without anything until i afford a platform someday in future, so i can just try with AZ/Alt mode or use it for visual, or practice for planetary even without tracking, some add devices not EQ platform that allow them to track those planets or the moon for short time at least like 10 minutes, if it is possible then that is all what i need.

[TareqPhoto]

My friend Henry uses an AZ/EQ6 and an 8 inch quatro with his DSLR with reasonable results. I am not sure how a 12 inch newtonian would do.
Have you considered a 12 or 14 inch Schmidt Cassigrain?

12 or 14 SCT are so much more expensive than 12" or 14" Newt, in fact i may able to buy 16" or 18" or even 20" Dob in the price of 14" SCT, and 12" SCT is nearly as much as 14"-16" Dob, and Newt up to 12" is also cheaper, so i don't want to spend over $2000 for larger scope than 10" as i am still saving to fund my 20" Dob, but i need a larger scope over my 8" and less than 20" to use last year, 20" won't be ready until maybe 2021.

Yes but an 11-12" SCT is lighter and more compact than equatorially mounting a Newtonian. See what they can do at http://www.damianpeach.com

I don't care about lighter, i care about cheaper, and yes, i saw results, but a 12"-14" Newt/dob isn't any less than those SCT anyway, they all using good enough mirrors inside, so in this case the only factor for me is the budget, not weight, Damian himself in his "Paid" videos mentioned he recommends Newt more as SCT are more difficult for collimating and all can produce nice results anyway, he saw or tested Newt of others but he went with SCT for his reasons, i saw mind blowing results from Newt and Dob same as SCT, so i believe all can do the job so then i will think about the price, i will always choose 14" Newt/Dob over 11" SCT for example or 16" Dob/Newt over 14" SCT, i do from my house/yard so i don't need to travel with gear far for planetary, they are clear from our skies.

[notFritzArgelander]

A 12" f5 Newtonian will be much too much for an EQ6 to handle. The mount is only rated for 20 kg which is equal to the weight of my Z12's OTA. The usual rule of thumb is twice the weight rating. So you want a mount rated at 40kg.

If you are interested ONLY in lunar planetary photography take a look at this article.

https://www.telescope.com/Capturing-Pla ... 116862.uts

I'd recommend using a motorized equatorial platform.

If you insist on an equatorial mount, the lowest cost mount to consider would be the Losmandy G11 which is rated for slightly less at 34 kg but you could probably get away with it. Then there is the EQ8 rated at 50kg.

Well, i mentioned it is either a Newt or a dob.

I saw someone used Skywatcher 300/1500 [12" F5] on EQ6-R mount for DSO not planetary, DSO is more complicated than planetary, so i don't know how he was able to do it if that is a risky for the mount actually? either he doesn't care or he just want to use that until it reached the end, but if it was possible for DSO then planetary is easier, i use video for between 1min p to 5min, even with slight drift i can manage to get results.

I also like the idea of a Dob and EQ platform, i just can't buy both, i can just buy a 12" Dob or even 14" Dob without anything until i afford a platform someday in future, so i can just try with AZ/Alt mode or use it for visual, or practice for planetary even without tracking, some add devices not EQ platform that allow them to track those planets or the moon for short time at least like 10 minutes, if it is possible then that is all what i need.

Dobsonians are just alt-azimuth rocker box mounted Newtonians so the Dob versus Newt issue is not an exclusive or.

Any person who does DSO AP using a 12" f5 OTA on an EQ6 is either very lucky, very foolish, or doesn't care. I owned an EQ6 in the past and was happy with a 10" on it. If I were to convert my Z12 to an equatorial I wouldn't look at the EQ6. It would either be an EQ8 or the Losmandy.

With those short exposures you can probably get a start doing without the equatorial platform.

[TareqPhoto]

A 12" f5 Newtonian will be much too much for an EQ6 to handle. The mount is only rated for 20 kg which is equal to the weight of my Z12's OTA. The usual rule of thumb is twice the weight rating. So you want a mount rated at 40kg.

If you are interested ONLY in lunar planetary photography take a look at this article.

https://www.telescope.com/Capturing-Pla ... 116862.uts

I'd recommend using a motorized equatorial platform.

If you insist on an equatorial mount, the lowest cost mount to consider would be the Losmandy G11 which is rated for slightly less at 34 kg but you could probably get away with it. Then there is the EQ8 rated at 50kg.

Well, i mentioned it is either a Newt or a dob.

I saw someone used Skywatcher 300/1500 [12" F5] on EQ6-R mount for DSO not planetary, DSO is more complicated than planetary, so i don't know how he was able to do it if that is a risky for the mount actually? either he doesn't care or he just want to use that until it reached the end, but if it was possible for DSO then planetary is easier, i use video for between 1min p to 5min, even with slight drift i can manage to get results.

I also like the idea of a Dob and EQ platform, i just can't buy both, i can just buy a 12" Dob or even 14" Dob without anything until i afford a platform someday in future, so i can just try with AZ/Alt mode or use it for visual, or practice for planetary even without tracking, some add devices not EQ platform that allow them to track those planets or the moon for short time at least like 10 minutes, if it is possible then that is all what i need.

Dobsonians are just alt-azimuth rocker box mounted Newtonians so the Dob versus Newt issue is not an exclusive or.

Any person who does DSO AP using a 12" f5 OTA on an EQ6 is either very lucky, very foolish, or doesn't care. I owned an EQ6 in the past and was happy with a 10" on it. If I were to convert my Z12 to an equatorial I wouldn't look at the EQ6. It would either be an EQ8 or the Losmandy.

With those short exposures you can probably get a start doing without the equatorial platform.

I still have time until next year, so i am still not sure between 12" Newt on my EQ6 or a 12" Dob without EQ for a while, i may get 14" Dob if that is possible, many recommended me 12" as a sweet spot aperture between 8" and 20", i just someone with 22" and 8" reflectors having 16", i thought that 14" should be the ideal choice for him, so between 2 apertures i will get i am not sure if it is 14" or 12", if 14" then only a dob, if 12" then a Newt or a Dob are options, unless i can find 12" SCT somewhere that is less than $1200 brand new.

[yobbo89]

Hi again,

Does 12" F5 Newtonian be handled by a mount such as EQ6 only?
Does this kind of scopes suitable for planetary imaging using a Barlow and ADC without modification as moving the focuser ot secondary mirror?
Which is better to be used for planetary imaging, 12" F5 on AZ-EQ6 mount or a non GOTO 12" F5 Dobsonian?

nope, i use a 12'' sct which is a alot lighter and it struggles in tracking, i will have to manual correct it with fine pulse while imaging planets.even a 10'' is a little to heavy

might get away with overloading the eq6-r...

[TareqPhoto]

Hi again,

Does 12" F5 Newtonian be handled by a mount such as EQ6 only?
Does this kind of scopes suitable for planetary imaging using a Barlow and ADC without modification as moving the focuser ot secondary mirror?
Which is better to be used for planetary imaging, 12" F5 on AZ-EQ6 mount or a non GOTO 12" F5 Dobsonian?

nope, i use a 12'' sct which is a alot lighter and it struggles in tracking, i will have to manual correct it with fine pulse while imaging planets.even a 10'' is a little to heavy

might get away with overloading the eq6-r...

But that 12" SCT you have is $2900 the scope alone?

[notFritzArgelander]

Clearly you seem strongly inclined to put the 12" on an eq6. I would prefer a 10" f5 for planetary photography since that plan is less risky. I don't doubt your claim that you've seen ok results with that kind of set up. There are folks who "get lucky". Having registered my opinion that it's ill advised I'll be quiet now.

[TareqPhoto]

Clearly you seem strongly inclined to put the 12" on an eq6. I would prefer a 10" f5 for planetary photography since that plan is less risky. I don't doubt your claim that you've seen ok results with that kind of set up. There are folks who "get lucky". Having registered my opinion that it's ill advised I'll be quiet now.

I will have time to think, will see what i will decide about.

Thank you very much!

[dcrowson]

Planetary imaging is ruled by long focal lengths - SCTs... With the exception of the moon, the planets are fairly small and benefit from the long focal length (3000mm+ for a 12", think 6000mm+ with a 2x barlow). I think someone did mention that these are more compact than the newt and you might be able to get away with one on a EQ6. It would be overloaded but you're also taking sub second exposures so tracking isn't much of an issue.

Dan

[TareqPhoto]

Planetary imaging is ruled by long focal lengths - SCTs... With the exception of the moon, the planets are fairly small and benefit from the long focal length (3000mm+ for a 12", think 6000mm+ with a 2x barlow). I think someone did mention that these are more compact than the newt and you might be able to get away with one on a EQ6. It would be overloaded but you're also taking sub second exposures so tracking isn't much of an issue.

Dan

Hey Dan,

That is what i was thinking about, also i do have Powermate 2x and 5x, i will buy also PM 4x as Damian said that is almost the best Powermate to be used with Newtonian/Dob, so i can buy 4x, then i can easily use any of those PM to reach longer focal length, i did think about it so i had the plan, SCT are mostly at F8/F10/F11 so i can only or barely use 2x/2.5x, at the end if i will use 4x or 5x with something like 12" Newt it will be similar to SCT 12" with 2x, but look at 12" SCT prices against 12" Newt, even if i buy that 12" SCT it will be so heavy for EQ6, so in both cases if i buy 12"SCT or 12" Newt i need another mount, but the scope itself is expensive with SCT, with 12" Newt i may save again for better mount in future, but i wanted to take the risk with 12" Newt on EQ6.

Tareq

[notFritzArgelander]

Planetary imaging is ruled by long focal lengths - SCTs... With the exception of the moon, the planets are fairly small and benefit from the long focal length (3000mm+ for a 12", think 6000mm+ with a 2x barlow). I think someone did mention that these are more compact than the newt and you might be able to get away with one on a EQ6. It would be overloaded but you're also taking sub second exposures so tracking isn't much of an issue.

Dan

A celestron 9.25 or 11 would be carried comfortably for planetary on an EQ6.

[yobbo89]

I agree, a c 9. 25 or c 11 will be a better fit with the eq6 and obtaining a usable focal length with a 3x - 4x barlow. A C11 with a 4x barlow will give you 11200mm fl which in my opinion is a reasonable focal length for detailed planetary imaging. A 12" f5 newt/dob will give you 7500mm fl with a 5x barlow.. You'll have to stack Barlow's to get a higher magnification, doable but may not be the best practical solution, things like internal reflections /artifact can be a problem and focusing.

A 12" sct or 12 " astrograph is going to be expensive and to fully utilise those scopes you will need something like an eq8 - eq8r which are at $6k to $7k aus price range.

If you're really keen on a 12" newt or sct either bite the bullet and get a solid mount at the same time or get the sct and Overload the eq6 until you can obtain a better mount later.
I have a 12" sct on a eq6 it's just enough to image planets despite the consequences of wobbly tracking and chances of quicker bearing wear.

Another cheaper option might be to go with a 14"-16" go to dob but I don't know what tracking will be like and you'll still might want to stack Barlows to get to a reasonable focal length, an even cheaper option would be to make your own platform tracker for a regular dob. This type of setup really limits option to visual work and planetary imaging, I doubt you'll be able to do any deepsky imaging..

I almost forgot to mention that a motorised focuser is almost essention for fine detail planetary work..

[TareqPhoto]

Planetary imaging is ruled by long focal lengths - SCTs... With the exception of the moon, the planets are fairly small and benefit from the long focal length (3000mm+ for a 12", think 6000mm+ with a 2x barlow). I think someone did mention that these are more compact than the newt and you might be able to get away with one on a EQ6. It would be overloaded but you're also taking sub second exposures so tracking isn't much of an issue.

Dan

A celestron 9.25 or 11 would be carried comfortably for planetary on an EQ6.

Ok, let me put it this way then.

I visited 2 places or centers of Astronomy in my country, and they do visual even for public, one placing C9.25, and the other placing Meade 10" SCT, i looked through both of them, both are amazing, BUT, none impressed me enough, i mean they are almost the same view or even less than my Mak, my Mak is sharper and their SCT are brighter, that's all, so i couldn't feel the difference, so in imaging even with larger aperture advantage i don't think both of C9.25 or C11 will impress me, i already saw hundreds or thousands of results from C11 on the net, none of them changed my mind from C14 or 16" Dob results, in fact even 12" Newtonian is better result than C11 from what i saw, means i have to forget about 9" or 10" or 11" and start from 12", and because i will have 20" Dob later so i feel i will not go with 16" or 14", but 14" is still in list but less priority, 12" is shining more in my list and head, but i have to wait and see, i may buy anotehr mount, or i may risk with 12" on EQ6, or maybe i can increase the 20" scope so i can buy an EQ platform and use that, but nothing is yet confirmed, but the only confirmation i have is that 9.25"/11" are not in list and also 12"/14" SCT are not in list, if i must buy a new mount for 12" SCT or 14" SCT then it is very affordable for me to get 12" Newt and another mount then, i can save more by this.

Your point about is C9.25 and C11 is very correct, i should start with that actually last year so maybe i won't think about larger scopes yet, but my mistake [maybe not] is that i went with 7" Mak and 8" Newt, and results telling me that 10" and closer aren't gonna cut for me on planetary, 12" is also not much, but it is the largest cheaper options i can get right now later.

[TareqPhoto]

I agree, a c 9. 25 or c 11 will be a better fit with the eq6 and obtaining a usable focal length with a 3x - 4x barlow. A C11 with a 4x barlow will give you 11200mm fl which in my opinion is a reasonable focal length for detailed planetary imaging. A 12" f5 newt/dob will give you 7500mm fl with a 5x barlow.. You'll have to stack Barlow's to get a higher magnification, doable but may not be the best practical solution, things like internal reflections /artifact can be a problem and focusing.

A 12" sct or 12 " astrograph is going to be expensive and to fully utilise those scopes you will need something like an eq8 - eq8r which are at $6k to $7k aus price range.

If you're really keen on a 12" newt or sct either bite the bullet and get a solid mount at the same time or get the sct and Overload the eq6 until you can obtain a better mount later.
I have a 12" sct on a eq6 it's just enough to image planets despite the consequences of wobbly tracking and chances of quicker bearing wear.

Another cheaper option might be to go with a 14"-16" go to dob but I don't know what tracking will be like and you'll still might want to stack Barlows to get to a reasonable focal length, an even cheaper option would be to make your own platform tracker for a regular dob. This type of setup really limits option to visual work and planetary imaging, I doubt you'll be able to do any deepsky imaging..

I almost forgot to mention that a motorised focuser is almost essention for fine detail planetary work..

No comment, i wanted to post links of different scopes to show you about the prices but then i thought it won't help much here, even with 12" SCT i still think it is too much pricey for just 12" scope, and even i asked people about 12" SCT and they think it is not much idea on EQ6 as well, they think anything above 12KGs or 26LBs is already too much on EQ6, so i know Newtonian is more risky here, but it won't be huge different as well, i saw that Meade 12" SCT and its size is about 16KG at best, while Newt is nearly 20-22KG, not sure if that 4-6KG difference is really a huge difference, maybe for EQ6, but i think as long i think about any 12" scope then it will be a risk for EQ6 even a compact SCT, so then i just pass this point to the budget, 12" SCT is twice the cost of 12" Newt or 12" Dob non GOTO, in fact i saw 14" Dob GOTO cheaper than 12" SCT tube.

Again, larger scope i want is only for "PLANETARY" imaging and visual of anything, no DSO imaging in the plan.

[notFritzArgelander]

Ok, let me put it this way then.

I visited 2 places or centers of Astronomy in my country, and they do visual even for public, one placing C9.25, and the other placing Meade 10" SCT, i looked through both of them, both are amazing, BUT, none impressed me enough, i mean they are almost the same view or even less than my Mak, my Mak is sharper and their SCT are brighter, that's all, so i couldn't feel the difference, so in imaging even with larger aperture advantage i don't think both of C9.25 or C11 will impress me, i already saw hundreds or thousands of results from C11 on the net, none of them changed my mind from C14 or 16" Dob results, in fact even 12" Newtonian is better result than C11 from what i saw, means i have to forget about 9" or 10" or 11" and start from 12", and because i will have 20" Dob later so i feel i will not go with 16" or 14", but 14" is still in list but less priority, 12" is shining more in my list and head, but i have to wait and see, i may buy anotehr mount, or i may risk with 12" on EQ6, or maybe i can increase the 20" scope so i can buy an EQ platform and use that, but nothing is yet confirmed, but the only confirmation i have is that 9.25"/11" are not in list and also 12"/14" SCT are not in list, if i must buy a new mount for 12" SCT or 14" SCT then it is very affordable for me to get 12" Newt and another mount then, i can save more by this.

Your point about is C9.25 and C11 is very correct, i should start with that actually last year so maybe i won't think about larger scopes yet, but my mistake [maybe not] is that i went with 7" Mak and 8" Newt, and results telling me that 10" and closer aren't gonna cut for me on planetary, 12" is also not much, but it is the largest cheaper options i can get right now later.

Well since this was addressed specifically in response to me, I'll answer. You are going by "what you can see" which is fine if that is what gives you confidence. But there are other criteria such as objective measures of telescope performance For planetary observation light is almost never a problem but one is more concerned about 1) resolution and 2) contrast on small objects. Those are completely different considerations.

Now I don't like standard SCTs for visual use. They always appear "soft". However aplanatic SCTs like the Celestron Edge HD and Meade ACF are something else again. They are full up to giving crisp visual views like a refractor or Maksutov. They also cost more. But I have to say that while the plain vanilla SCTs don't hold a candle to a Rutten-Maksutov the aplanatic SCTs are worthy rivals (Edge, ACF).

Nevertheless Damien Peach's results show that at the right site a standard SCT does splendidly at planetary imaging. Visual appearances should not be taken as an adequate indicator of what to expect when imaging. I know this from experience studying and working at a university observatory in the US. For imaging, one must go by the numbers. So what do the numbers say about 1) resolution and 2) fine contrast?

1) Resolution

Without an atmosphere, resolution is determined by the aperture. The resolution is inversely proportional to the aperture. For most places on Earth resolution is limited by the atmosphere so that 10" aperture or 0.5 arc second of resolution is about all you will ever get. Board member Luc CATHALA gets exquisite lunar images with his large Newtonian optic because he is fortunate to have a site with better than average seeing. For most places on the planet for almost all days anything larger than 10" gives no resolution gain.

2) Fine contrast

Visually folks note that the large central obstruction of SCTs diminishes contrast on large objects. However the obstruction increases fine contrast.

The quantitative measure of fine and coarse contrast performance is given by the modulation transfer function or MTF.

https://www.telescope-optics.net/mtf.htm

The effects of a central obstruction are shown in figure 104 at the following link.

https://www.telescope-optics.net/obstruction.htm

The green line in the graph shows the MTF of a perfect unobstructed optic. The orange line shows the MTF of a perfect 32.5% obstructed optic. Notice that for low frequencies the orange line is below the green line showing the loss of contrast for large objects compared with the perfect unobstructed optic. However above 0.6 in frequency see that the orange line is above the green line showing that for planetary contrast discrimination an obstructed perfect optic is BETTER than an unobstructed perfect optic.