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Alternative scopes for planetatry than SCT

TareqPhoto
31 Aug, 2018 15:16
I asked a lot and always ask about scopes, and one of questions is about which scope for planetary, and likely 95% of answers directing me towards SCT, mainly Celestron ones from 8" up to 14", so i got it as one of best choices.

Now the question is, are there any another options that are better than SCT either Celestron or Meade maybe? or alternatives if not using SCT?

from 8" up to 11" it can be managed as if i decide on one then i can use with my mount, but i tell all people everywhere that i want larger than 11" anyway, and if i go larger then it means another mount which add big cost too, so that i asked, but if i have to spend too much anyway then i need to know what other options if not SCT then, i mean is C14 for example the only option or best option in the world for planetary imaging?!!!
2ghouls
31 Aug, 2018 17:33
Tareq Abdulla
i mean is C14 for example the only option or best option in the world for planetary imaging?!!!

Meade makes the LX200 16" which is a 16" RC with 4064mm f.l. Not sure it would be worth the cost, and as you said the bigger scope you buy, the more you would have to spend on a mount.

I don't have any experience with that scope, I was just impressed by this photo showing surface details on Ganymede taken with it: 
TareqPhoto
31 Aug, 2018 17:51
Nico Carver
Meade makes the LX200 16" which is a 16" RC with 4064mm f.l. Not sure it would be worth the cost, and as you said the bigger scope you buy, the more you would have to spend on a mount.I don't have any experience with that scope, I was just impressed by this photo showing surface details on Ganymede taken with it:
Something not right, this Meade 16" isn't an RC, it is SCT.

As i said, i can't afford SCT larger than 12" unless i afford the mount as well, so it is out of question, also not many mentioned this Meade 16" SCT, all are mentioning C14 only, if not then C11, so it is like that from others recommendations:

1. C14
2. C11
3. C9.25
4. Anything else
2ghouls
31 Aug, 2018 18:06
What is your budget? If you are only using it for planetary imaging, you could probably get by with one of the packages that includes an Alt-Az fork mount.

Tareq Abdulla
Something not right, this Meade 16" isn't an RC, it is SCT.

Why do you say that?  Here is a link to the scope for sale, and it says it is an RC in the description. Anyways, I only mentioned it because you seemed to be asking if SCT was the only design used for planetary imaging, and I remembered that Meade (and probably other companies) make large RCs that people use for planetary.
TareqPhoto
31 Aug, 2018 18:28
Nico Carver
Why do you say that? Here is a link to the scope for sale, and it says it is an RC in the description. Anyways, I only mentioned it because you seemed to be asking if SCT was the only design used for planetary imaging, and I remembered that Meade (and probably other companies) make large RCs that people use for planetary.

No, it is not RC, but they made it to be like an RC or rivals it, but it is NOT RC, search more and you will see that i am right, i also asked about if an RC is good for planetary, and many was like against this idea, or let's say not many recommended RC for planetary due to design.
Thirteen
31 Aug, 2018 19:41
If you want to keep the budget more manageable, I’d consider a Newtonian.

I was was pleasantly surprised.   Here is Mars through the 12” f/4 TPO Newtonian and a 5x powermate (thanks Nico  smile ).

TareqPhoto
31 Aug, 2018 20:16
Jason Guenzel
If you want to keep the budget more manageable, I’d consider a Newtonian.I was was pleasantly surprised. Here is Mars through the 12” f/4 TPO Newtonian and a 5x powermate (thanks Nico smile ).
In fact i was thinking about getting 12" Newtonian before i decide on any larger scopes for planetary, i did saw enough superb images from this 12" Newt anyway, but i am not sure if 12" Newtonian can be fine on EQ6 mount anyway.
Thirteen
31 Aug, 2018 21:44
I’ve run that scope on two different eq6-class mounts and it’s been just fine for planetary.
TareqPhoto
31 Aug, 2018 21:51
Jason Guenzel
I’ve run that scope on two different eq6-class mounts and it’s been just fine for planetary.

I am more thinking about 12" f5 Newtonian instead of f4, so will see if that is gonna be fine too or not.

Thank you very much!

Are there any 14" Newtonian but not Dobsonian?
Gerardoborn
01 Sep, 2018 00:46
You ask for better or alternative than a sct?
Dobsonians are not better but are a definite alternative. I own a humble goto 10" dob and get good planetary images. Just make sure it is collimated properly and has a decent dedicated planetary camera and you'll get rewarding results, with practice. It won't break the bank either. If you want to know what this combination is capable of check out my images. Larger dobs will give better results but are heavier and more expensive. Cheers.
Thirteen
01 Sep, 2018 01:12
Tareq Abdulla
Jason Guenzel
I’ve run that scope on two different eq6-class mounts and it’s been just fine for planetary.

I am more thinking about 12" f5 Newtonian instead of f4, so will see if that is gonna be fine too or not.

Thank you very much!

Are there any 14" Newtonian but not Dobsonian?

There are certainly 14" options, yes, but not that would ride well on an EQ6.
TareqPhoto
01 Sep, 2018 02:25
Gerard O'Born
You ask for better or alternative than a sct?Dobsonians are not better but are a definite alternative. I own a humble goto 10" dob and get good planetary images. Just make sure it is collimated properly and has a decent dedicated planetary camera and you'll get rewarding results, with practice. It won't break the bank either. If you want to know what this combination is capable of check out my images. Larger dobs will give better results but are heavier and more expensive. Cheers.
Not sure if better or alternative, as if i asked about better then some will say there is no such or NO, and if alternative then they will give many many options.

I saw your images, not that bad although i saw better results from larger Dobs, and i am definitely not looking for 10-12" Dobs, only 16" and larger dobs, if Newtonian on EQ i think up to 12".
TareqPhoto
01 Sep, 2018 02:29
Jason Guenzel
There are certainly 14" options, yes, but not that would ride well on an EQ6.

I see, then better stay with 12" Newtonian and never look back, until one day in future i can get larger.

I am still thinking about an EQ motorized Dobsonian larger than 14", i saw 16" and 18" Skywatcher dobsonian GoTo, and i was thinking about Skywatcher Stargate 20" dobsonian goto, but someone told me to stay away from it as it is not that good and he heard others are complaining about it, so i think i better stay away, i still don't know if i really can find an EQ mounted dpbsonian up to 18" then, 16" sounds is a sweet spot, but also i was thinking why not 20" as i can use this for visual sometimes, and many said that nothing can beat larger Dobsonians over 18" for visual, just not sure about planetary imaging, and i have EQ6 so i was thinking a Newtonian is a starter but larger than 10" and can handle EQ6.
Starminer68
01 Apr, 2019 09:58
I am also thinking to buy a new scope for planetary viewing and imaging as well as for small DSO. I sold out my Newtonian and small MAK). So far, I see two options: Celestron 8” SC with reducer/corrector 0.63 orMeade 8” ACF LX 85 with Altair reducer 0.6 (reducer only). Any opinions???
I like Meade scopes (I already have Meade 80 ED triplet and Coronado PST, good quality abd capable scopes). But any other suggestions are welcome😉
kajouman
01 Apr, 2019 11:05
Maby a kutter telescope would be something.. for planetary its great. but a 8 inch is king a huge scope. https://www.google.com/search?q=kuttertelescope&client=firefox-b-d&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi-36rt367hAhVOWBoKHXETCNsQ_AUIDigB&biw=1710&bih=916
glennb44
01 Apr, 2019 11:57
Tareq
Have you considered the refractors ? Some of my best viewing of Jupiter has been with my SW ED100 refractor.

GlennB
Duke2k
01 Apr, 2019 12:21
A 12" f5 Newtonian is big physically. It,s not something that can be moved or mounted easily by one person and the other issue with Newtonian scopes on EQ mounts is that the finder and eyepiece can end up in awkward positions. Rotating the tube after alignment almost always involves re aligning everything.
If you use an ADC with your planetary camera, it has to be aligned with the local horizon. Again a big issue with Newtonian scopes on EQ mounts.
An SCT doesn't have this issue. Either mounted AZ or EQ.
Edited 01 Apr, 2019 15:11
TareqPhoto
01 Apr, 2019 13:37
Well, i have to add something here.

8" Is good, but it is not enough for planetary imaging, i have 7" Mak and soon i will use my 8" F5 Newtonian and i already look for 14" minimum, so 8" as starting out is good idea, but it is not for long term the best highest quality at all, so make sure if you really don't want to go there, otherwise it will be a waste, 2-4 years and you will ask for more no doubt.

Glenn, refractors aren't the best for planetary, the only ones are those the largest ones if possible, and those are much much more expensive than SCT or reflectors for example, and i am planning to get an APO refractor of high end later only for DSO imaging, but my goal for planetary is reflectors, 14" up to 20", all those amazing ones i see all around are from those big ones and not refractors, i have better results with my 7" Mak than your SW ED100, way better, and i still think they aren't good enough, and i am sure my MEADE 8" F5 will slash this 7" Mak or your SW ED100 without mercy, so i know what i am talking about.

For me now, the best easiest option for planetary not SCT is 16" Dobsonian with motor, this is likely the best option out there, 14" Dob isn't bad too but i prefer 2" more anyway, 18" and 20" Dob are even better but all are talking about the weight and transport and portability, but i swear that 18" and 20" are even better than those of C14 or 16" Dob, even if it will magnify the sky issues, it will deliver more details as well anyway, and i saw enough results from big scopes that magnifying the issues with bigger is just subjective and it is isn't an issue always anyway, 14" Magnified results from my 7" Mak and it murdered the results from my 7" Mak, so what did that magnification affect really?!!!
TareqPhoto
01 Apr, 2019 13:42
Duke2k
A 12" f5 Newtonian is big physically. It,s not something that can be moved or mounted easily by one person and the other issue with Newtonian scopes on EQ mounts is that the finder and eyepiece can end up in awkward positions. Rotating the scope after alignment almost always involves re aligning everything.If you use an ADC with your planetary canera, it has to be aligned with the local horizon. Again a big issue with Newtonian scopes on EQ mounts.
An SCT doesn't have this issue. Either mounted AZ or EQ.

Dobsonian is better in this case, but let's say even with Newtonian if it is about imaging then issues aren't that big deal, but for visual i think there is no match to Dobsonian performance in that, in fact i see people using Dobs for imaging too although the EQ is a big headache with dobs, but i saw results that telling me that a Dob is as good as Newt because they are the same material or design only dob is manual mount, and to be honest, i think Newtonian mirror quality is better than SCT, don't just think because you saw mind blowing results from SCT they are the best, they are amazing yes but not the best, it is only they can be mounted and transported so that the issues are less so people can use it more for imaging and thus you see more results, but i swear i saw images from Dobs or Newtonian that are better than this SCT such as C14 the most popular one, and i trust of what i see and not what others say or trying to say.
glennb44
02 Apr, 2019 08:01
I had an 18inch newtonian/and a 16inch cass on a Titan mount.
https://www.flickr.com/photos/glennb-rockeye/2861690485/in/dateposted/
It was before the days of the ZWO cameras but the views were very nice when seeing was good - rare events.  Comparing at that time with the SW ED100 the view was better with the refractor. The DSLR camera results I got were pretty useless.  Maybe the seeing is more critical with the large scopes.
If you got a big dob motorised or on a platform and a high frame rate planetary camera and good barlow you'd be well set up for both planets and DSO where aperture comes into its own.

Can you guide though for the DSO?  Can you get 2-5 minute exposures as required for DSO?

Cheers
GlennB
TareqPhoto
02 Apr, 2019 08:06
glennb44
I had an 18inch newtonian/and a 16inch cass on a Titan mount.https://www.flickr.com/photos/glennb-rockeye/2861690485/in/dateposted/
It was before the days of the ZWO cameras but the views were very nice when seeing was good - rare events.  Comparing at that time with the SW ED100 the view was better with the refractor. The DSLR camera results I got were pretty useless.  Maybe the seeing is more critical with the large scopes.
If you got a big dob motorised or on a platform and a high frame rate planetary camera and good barlow you'd be well set up for both planets and DSO where aperture comes into its own.

Can you guide though for the DSO?  Can you get 2-5 minute exposures as required for DSO?

Cheers
GlennB

I have 3 planetary cameras from ZWO and planning for forth later.

I don't know how to guide yet, but for DSO with my DSLR lenses i can go up to 2-3 minutes unguided, with guiding i can go for 5 minutes easy but i don't know how yet, i still have 8" F5 that i am sure it needs guiding for longer exposures, for planetary guiding isn't critical or necessary, but if i buy large dobsonian and can get a motorized drive or EQ platform then i may add guiding if i need to, but for now i have to think about larger scopes for planetary as Aperture and focal length wins, i do have 2x and 5x Powermate and later i will add 4x and even 2.5x just in case.
macnenia
02 Apr, 2019 21:47
I don't think the type of OTA is that important per se. But aperture wins and it is cheaper to get large aperture scopes as SCTs or Newtonians.  This normally means refractors are less favoured. Aperture wins because, if conditions allow, lucky imaging can get us down to the optical resolution of the OTA which varies inversely with the diameter. Equally the amount of data/ photons that can be gathered in a video run, before planetary rotation becomes an issue, is a function of the square of the OTA's diameter. The light bucket needs to be sufficiently large such that at least 50fps can be achieved.
The Mount needs to be capable of tracking the planet. However, tracking is less important for planetary than for deep sky, since one is taking videos at 50fps or greater. So any reasonable Mount that can lift the OTA will do. Equally programs like Firecapture with the right ASCOM protocols can track the planet, so again tracking accuracy is less important. Also if you are prepared to manually adjust the Mount to ensure the planet is kept in the FOV, tracking the planet is unnecessary.
If your set up is mobile rather than fixed in an observatory the compact folded light path design of SCTs will be preferred.
The focal length increaser required to achieve an adequate image scale/ pixel resolution is ~ 5 x pixels size (microns)/ focal ratio. SCTs generally come with high focal ratios so the focal length increaser required is less.  However, if the camera pixel size, focal ratio and focal length increaser combination can deliver an adequate image scale, then that OTA is suitable.
Newtonians are better for imaging Venus in UV since there is less glass in the imaging train to absorb the UV.
I think if you are looking for the cheapest option for planetary then a large tracking Dobsonian is a good option. If you are also considering deep sky then an SCT or Newtonian on top of a high quality Mount, will allow you to do both.
TareqPhoto
02 Apr, 2019 23:27
Niall MacNeill
I don't think the type of OTA is that important per se. But aperture wins and it is cheaper to get large aperture scopes as SCTs or Newtonians.  This normally means refractors are less favoured. Aperture wins because, if conditions allow, lucky imaging can get us down to the optical resolution of the OTA which varies inversely with the diameter. Equally the amount of data/ photons that can be gathered in a video run, before planetary rotation becomes an issue, is a function of the square of the OTA's diameter. The light bucket needs to be sufficiently large such that at least 50fps can be achieved.The Mount needs to be capable of tracking the planet. However, tracking is less important for planetary than for deep sky, since one is taking videos at 50fps or greater. So any reasonable Mount that can lift the OTA will do. Equally programs like Firecapture with the right ASCOM protocols can track the planet, so again tracking accuracy is less important. Also if you are prepared to manually adjust the Mount to ensure the planet is kept in the FOV, tracking the planet is unnecessary.
If your set up is mobile rather than fixed in an observatory the compact folded light path design of SCTs will be preferred.
The focal length increaser required to achieve an adequate image scale/ pixel resolution is ~ 5 x pixels size (microns)/ focal ratio. SCTs generally come with high focal ratios so the focal length increaser required is less.  However, if the camera pixel size, focal ratio and focal length increaser combination can deliver an adequate image scale, then that OTA is suitable.
Newtonians are better for imaging Venus in UV since there is less glass in the imaging train to absorb the UV.
I think if you are looking for the cheapest option for planetary then a large tracking Dobsonian is a good option. If you are also considering deep sky then an SCT or Newtonian on top of a high quality Mount, will allow you to do both.

Thank you very much!
glennb44
03 Apr, 2019 02:26
FWIW I can get about 300fps for Mars and 150fps for Jupiter with the ZWO camera and 12in SCT.   Firecapture can hold the image steady in liveview on my Titan.

The next thing to consider is the question of what camera you get and the degree of sampling you want…

Great fun!

GlennB
macnenia
03 Apr, 2019 06:40
glennb44
FWIW I can get about 300fps for Mars and 150fps for Jupiter with the ZWO camera and 12in SCT.   Firecapture can hold the image steady in liveview on my Titan.
Some people advocate taking the Gain to the maximum to achieve the highest framerate. Another school of thought, which I now follow and believe to be beneficial, is that you should get to ~50 fps and then wind the Gain down accordingly to get the desired histogram percentage. 50fps is a high enough speed to "freeze" the seeing. The longer the exposure, the more photons are received by each pixel and the signal to noise ratio improves. The theory is that it is better to have fewer better quality frames to integrate. If the object is very bright like Mars or Venus you may end up reducing the Gain to its lowest possible setting and then need to decrease the exposure time. I have also seen it suggested that very low Gain settings can cause issues, but I haven't experienced these myself.
 
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