Astrophotography -- Best Telescopes?

[Kelson Adams]

What are the best telescopes for amateur astronomy? I realize that there are many differences between telescopes, but let's face it. If I'm going to invest in a great telescope, I want it to produce a high-resolution image and to survive for a significant amount of time.

-- and I absolutely do not want a telescope based off planned obsolescence purchasable in superstores like Walmart, despite their "everyday low prices."

Thank you for your help :)

 

[montoyas7940]

I would suggest starting here.
https://www.physicsforums.com/forums/stargazing-and-telescopes.234/

Also more than once I have read the best telescope is the one you will use. A cryptic statement to be sure -but true. I think it means if you enjoy it enough and it is not too troublesome to use it is the best scope for you (because you will actually use it).

The best telescope for me is a set of binos...

 

[Chronos]

Serious astrophotographers would generally recommend the Ritchey-Chretien for AP. It has unrivaled optical quality quality, short tube and wide field of view. This is the design preferred for most modern professional grade telescopes. The short tube gives it superior portability and permits use of less beefy mounts - which often cost more than the telescope itself. It's a moderate cost telescope. A popular low cost alternative is the Newtonian astrograph. These are short focal length Newtonians of decent optical quality. They are, however, awkward and require firmer mounts than RC or catadioptric designs. The refractor is also an option. The drawbacks are expense and high f-ratios. The high f-ration demands a very stiff mount which only adds to the already considerable expense of the optical train. They are preferred mainly by purists. For a beginner, you don't even need a telescope; just a high quality digital SLR camera like Canon or Nikon. Add a decent telephoto lens and you have the equivalent of a small, fast refracting telescope. The magnification is low, but, you can achieve stunning photos, especially with a relatively inexpensive mount.

 

[Sylvie]

Sorry to be late!I just want to ask you: if you were a beginner astronomer which kind of astronomy instruments would you buy first?

 

[davenn]

Sorry to be late!I just want to ask you: if you were a beginner astronomer which kind of astronomy instruments would you buy first?

hi and welcome to PF

look in this PF thread ---
https://www.physicsforums.com/threads/planning-to-buy-a-first-telescope.391086/also suggest to you reading the PF thread listed above and I repeat here

https://www.physicsforums.com/forums/stargazing-and-telescopes.234/

cheers
Dave

 

[Loren]

What are the best telescopes for amateur astronomy? I realize that there are many differences between telescopes, but let's face it. If I'm going to invest in a great telescope, I want it to produce a high-resolution image and to survive for a significant amount of time.

-- and I absolutely do not want a telescope based off planned obsolescence purchasable in superstores like Walmart, despite their "everyday low prices."

Thank you for your help :)

The best thing is find a local astronomy club.

You will get a lot of help and the chance to see and try a lot of equipment.

In the mean time, buy a pair of binoculars.

 

[Chronos]

What looks good to your eyes, is usually good for photography. Is that not what you are 'looking' for? Do not be discouraged [nor encouraged] by advertisements. If you like what you see in your camera, take a picture!

 

[davenn]

What looks good to your eyes, is usually good for photography.

in a really rough way
Poor mounting rigidity for a scope can still make a useful visual system
Astrophotography requires 2 major ingredients
1) a very solid as vibration free as possible mount ... else you are just wasting your time
2) The need for a motorised tracking mount, again, unless photographing the moon or planets, will be a total waste of time without itDave

 

[russ_watters]

in a really rough way
Poor mounting rigidity for a scope can still make a useful visual system
Astrophotography requires 2 major ingredients
1) a very solid as vibration free as possible mount ... else you are just wasting your time
2) The need for a motorised tracking mount, again, unless photographing the moon or planets, will be a total waste of time without it

Dave

Yeah, there is more to it than even that. For the telescope itself, thermal and mechanical stability are also significant issues. There'simply also flatness of field and internal baffling for reducing Internet reflection.

 

[davenn]

Yeah, there is more to it than even that. For the telescope itself, thermal and mechanical stability are also significant issues. There'simply also flatness of field and internal baffling for reducing Internet reflection.

Yup
Astrophotography is a whole new ball game over visual workD

 

[Drakkith]

internal baffling for reducing Internet reflection.

I knew my router was missing something...

 

[Chronos]

The best way to dabble in AP is to start without a scope. A plain DSLR will work fine. Start with some still [unmounted] photos to get a feel for how long you can expose without getting excessive star trails. You can then affix it to a mount and try again with tracking to see how long you can expose without the camera drifting off target [again, producing star trails]. Once you have mastered that part you can better decide what kind of scope to attach to the mount. An AP scope is typically a short tube because a less massive [and expensive] mount is nescessary to keep the camera on target. Again, you will need some trial pix to ascertain how long you can expose without producing unacceptable image drift. Most people go the stacking route, taking a number of shorter exposure images and 'stacking' them onto one another [using special software] to bring out fainter details. As should be apparent, you need the patience of Job [and a healthy dose of cash] to achieve proficiency in this art form. Expect the mount to become your deepest money pit and source of frustration.

 

[davenn]

Start with some still [unmounted] photos to get a feel for how long you can expose without getting excessive star trails.

you don't have to guess there is the 500 rule

500 / focal length gives time in seconds
eg, for a full frame sensor
500 / 24mm = 20.8 sec ( keep it to 20 sec) maximum exposure time before trails

for a crop sensor, you have to take into account the crop factor
most canon crop sensor dSLR's are x1.6, many Nikon crops sensors are x 1.7
check your particular make and model online there's plenty of info

so let's take that 24mm lens on a canon x1.6 crop sensor
firstly multiply the focal length by the crop factor --- 24mm x 1.6 = 38.4mm equiv.
now use the main formula
500 / 38.4 = 13 sec

you can see a substantial reduction in max exposure time compared to that lens on a FF camera

An AP scope is typically a short tube because a less massive [and expensive] mount is nescessary to keep the camera on target

No, good polar alignment keeps the target tracking accurate, regardless of the size of the scope

Expect the mount to become your deepest money pit and source of frustration.

This is true . a very solid mount is an absolute necessity for good AP, not for tracking but to eliminate vibrations

This is one of my mounts ...
http://www.bintel.com.au/Mounts---Tripods/EQ-Mounts/Sky-Watcher-HEQ5-Pro-GoTo-Mount/96/productview.aspx

it is really solid ! the next best thing would be a concrete pier in a home observatory. That isn't an option for me
1) I live in rental accommodation 2) its in a very light polluted city sky
I need something heavy but something I can transport to a dark site and this mount accommodates that

I also use a tracking scope to correct for errors in the polar alignment
http://www.bintel.com.au/Astrophotography/Autoguiders/Orion-Mini-Deluxe-AutoGuider-Package/1547/productview.aspx

this really is a gem and "worth it's weight in gold"cheers
Dave