Help please!! Orion 8" Newtonian Astrograph v Celestron C8

[Costas Soler]

Hi! 

I plan on getting a little more involved with astrophotography. I have decided on an Orion Atlas mount, but I am on the fence about which OTA to use. My primary interest is in photographing small DSO's. I am unsure as to whether the Orion 8" Newtonian Astrograph, or the Celestron C8 SCT would be better suited to the job. I really do adore both OTA's, I'm just a little hung up on the pros and cons of each. Let me know what you think, and if you have any personal experiences with either. 

Thanks a lot!!

[Dave In Vermont]

For the sake of clarity, I am guessing you mean Orion-USA, yes?

Hope this helps,

Dave

[Costas Soler]

Yes the USA brand

[Costas Soler]

Thanks!

[ChrisLX200]

Your 'small DSOs' would cover the range of the smallest PK planetaries up to include all galaxies (with the exception of a handfull of large ones). Because of the image scale involved you need a substantial aperture, high magnification (focal length), and good quality optics together with an expert focusing technique to reveal all those fine details. You will of necessity need a mount capable of both holding and accurately tracking the large OTA, and guiding will be mandatory. If not using a refractor then an OAG would be preferable because the tube/optics will flex slightly - only refractors tend to provide the extra stiffness needed to get away with using a guidescope. In short, you've chosen to dip into the 'difficult' end of astroimaging.

That's not to say it cannot be done - just that you will need to face and resolve a lot of tricky problems and hone your techniques to get the best results. With the right equipment you will doubtless get some sort of image right at the start, but refining those results to the best that can be obtained with any particular combination of hardware will need experience and tweaks to many settings, and that will take some time and perseverence. The usual advice for new astrophotographers is to cut your teeth by using a small-ish refractor simply because that provides good results and is more forgiving of many of the difficulties noted above. You will get good images at the outset which only serve to provide encouragment.

If I had to choose between the 8" Newt and 8" SCT for a beginner I would probably sacrifice focal length in favour of a faster optical system and recommend the Newt - or perhaps the SCT using a reducer to knock the focal length down to f/6.3. An f/10 SCT is a significant challenge to use even for experienced astroimagers. However, as said, you will always get some sort of image with anything - whether you would find the quality of the results generally satisfying and rewarding would be a personal experience for you.

ChrisH

[MattJenko]

Chris has covered most of the points I would make with respect to long focal length imaging. I too would favour the Newtonian over the SCT and the reason is because I have seen much better images from Newtonians than SCTs. There seems to be something soft about SCT images that I can't put my finger on, I just prefer the crispness of a good Newt image. If you don't like diffraction spikes in your images however, then you have to choose the SCT :). The Newt is a bigger beast than the equivalent aperture SCT though, which makes it a serious challenge in any kind of wind, so if you live in a windy place, keep the whole rig as small as possible.

 

[Costas Soler]

Luckily, I do not live in a windy place. I believe I will go with the newt. I know it's a steeper learning curve than a little refractor, but it'll be fun. I'm very excited. Thanks to all!

[Uranium235]

Dont forget your coma corrector! (if getting the newt) Its pretty much an essential piece of kit required for imaging.