Astrograph Newtonians - Pros and Cons

[TangoCharlie]

I read up on the importance of good eyepieces and mount already.  Can someone give me the positive and negatives on Astrograph Newtonians.
such as the Orion 10-inch Newtonian Astrograph F 3.9 as a first telescope to use for lunar, planetary, DSOs, and astrophotography. Anyone own an Astrograph or are knowledgeable of this type of telescope?

Thanks,

TC  

[Earl]

posative is price, negative is collimation

[ollypenrice]

An astrograph is a telescope used to take pictures. It may or may not have been specifically designed with that in mind, or maybe the marketing just calls it that because you can take pictures in anything, after all.

As Earl says, a fast Newtonian can be cheap but is very unlikely to be easy to collimate. The cheaper they are the more primitive the mechanical parts and the harder still the collimation.

My own view is that an F4 Newt is not a beginner's best bet. It is much easier to use a refractor or a somewhat slower Newtonian.

Olly

[Chris]

You mention Lunar, planetary and DSO imaging. Go with an F/5 Newtonian, this will be suitable for all three types of imaging and f/5 is way kinder on collimation than F/4, trust me, been there done that. Don't buy a cheap f/4 unless you like doing some mechanical engineering to try and improve the tube rigidilty, focuser, and primary mirror cell. An f/5 will need non of that

[Uranium235]

Yep, can confirm the above, but even an f5 8" needs some work doing to it. The 200pds im using right now had to have its focuser replaced, tube wall strengthened (if using a heavy camera and FW), and primary mirror fixed in place a bit better before it got anywhere near what I would call useable.

If youre just casually snapping with a DSLR you might not need to be so rigourous with the modifications, but if you want to get the very most out of a large chipped CCD camera - some fettling is required.

[Skyline]

I agree with the others, anything from f4 down, you need good mechanics for the scope to perform and experience in collimation using preferably with a sight tube and a Cheshire.

Also sky conditions play a factor as well. A decent made f6/f5 Newtonian would be better if you really want to go down the reflector route. Check out Niles Olaf Carlin.

http://web.telia.com/~u41105032/kolli/kolli.html

[TangoCharlie]

Dear StarGazers,

Thanks for your input on this Astrograph question.   I am presently looking at the following F4.7 10" scope since I am looking at retirement in the future- so one purchase of a scope.
I know it is pushing the heavy side but I wanted more aperture with a decent mount.  

TC

Orion Atlas 10 EQ-G GoTo Reflector Telescope

[ollypenrice]

6 hours ago, TangoCharlie said:

Dear StarGazers,

Thanks for your input on this Astrograph question.   I am presently looking at the following F4.7 10" scope since I am looking at retirement in the future- so one purchase of a scope.
I know it is pushing the heavy side but I wanted more aperture with a decent mount.  

TC

Orion Atlas 10 EQ-G GoTo Reflector Telescope

Why do you want more aperture?

In imaging you first think of focal length because that defines what targets will fit on your chip. It also defines, with a given camera, the pixel scale in arcseconds per pixel. If you go too low in arcsecs per pixel you starve the pixels of light and will not really reach the theoretical resolution of the system anyway because the seeing and guiding will stop you. So first decide on the kind of FL you want.

Once the FL is decided, the aperture defines the speed of the system because it is the only variable now governing focal ratio. Yes, fast is good but fast can also be difficult. If this extra aperture means overloading your mount then your guiding will suffer and, therefore, so will your image quality. And if you are struggling with collimation instead of taking pictures then fast is not fast! Fast also means shallow depth of field which means focus needs watching like a hawk and any tilt on the chip will throw part of the frame out of focus.

The cute thing about imaging is that you can collect light over time, so aperture becomes less critical and you can prioritize other things like optical and mechanical quality.

From 85mm aperture:

From 106mm aperture:

From 140mm aperture:

 

In visual observing aperture is far more important than in imaging.

Olly

 

 

[Davey-T]

One time purchase of a scope that's going to have you tearing your hair out trying to produce consistent images doesn't make for a relaxing retirement 

Dave

[nightster]

That scope weighs 27 lbs before you add anything that takes a picture. Add the weight of the guidescope and guidecam and it's mounting plates/rings.  Add an imaging camera, if a Mono CCD add a Filter wheel, also add the weight of a coma corrector and extension tubes.  Plus cords and cables you got quite a load for and EQ6/Atlas.  Plus that OTA looks surprisingly similar to the sails on my friends boat. Any bit of a breeze and I suspect you'll have to become an expert at EQ6 backlash tweaking.  I can also foreshadow a memorization of the steps on Astrobaby's site, tools and parts from Rowan Astro and anodized aluminum from focuser.com. All just to get that scope to work with that mount.  Do yourself a favor and get a nice lightweight, wide, well corrected refractor and mount that on that on the Atlas/EQ6. And if you have to have them, add the spikes in post.  I don't mean to be brash, but I've made decisions like this and ended up spending more in the long run then jyst getting the more expensive frac at the beginning.  

[jetstream]

20 hours ago, ollypenrice said:

Why do you want more aperture?

I must say Olly, you are a vast resource for astro-photographers. All your comments and info is much appreciated miigwech