MID LEVEL ASTROPHOTOGRAPHY

Choosing your mid level astrophotography set up isn't altogether straight forward because you need to be sure your set up will deliver crisp stars before purchasing. To do that you need to know how much your mount will wobble (whilst guiding) and compare that wobble with the focal length of your scope (magnification) and the size of the pixels on your camera. The aim is to make sure the mount wobble won't cause the light from the stars your imaging to stray into the neighbouring pixels and thereby blur the image. I recommend calculating the resolution of each pixel in your scope/camera set up here and then make sure this resolution is larger than the wobble in your mount. To help you decide I have included the expected mount wobble whilst guiding in arcseconds of the two mounts that I recommend.

 

Celestron AVX GOTO Mount: (Wobble 1.5 - 2 arcseconds)

This is the modern upgraded version of the celestron GT mount I used in my £600 vs£600 video. It also suffers from backlash but hopefully not as much and its lightweight and as far as i know offers the best guiding performance in its budget class.

Best price in USA

 https://bit.ly/EQ6RProUS

Best price in UK

https://bit.ly/EQ6RProUK

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Best price in USA

http://bit.ly/celestronAVXUS

Best price in UK

http://bit.ly/avxUK

Once you've chosen your mount there are many different possibilities for your camera/scope combo. You could marry a sensitive astro camera with a smallish sensor together with a smallish apo refractor. This is a classy, simple to use set up which has the advantage of being light. And if money was no object then this is probably what I'd buy. The following camera, scope, reducer set up results in each pixel capturing 2 arcseconds of sky.

WILLIAM OPTICS GRAN TURISMO 81

A  fine apochromatic triplet. 

Best price is USA http://bit.ly/WOgt81US

Best price is UK http://bit.ly/gt81UK

I did think of putting in the even better televue NP101is here but they cost nearly 4 times the price...

WILLIAM OPTICS FLAT6III FLATTENER/REDUCER

 A flattener is essential for astrophotography with these triplets

Best price is USA  http://bit.ly/WOreducerUS

Best price is UK http://bit.ly/WOreducerUK

Or you could do what I did in my £600 vs £6000 video and make use of the fact that relatively cheap newtonian telescopes when combined with relatively cheap coma correctors are able to produce pin point stars across large pixel full frame DSLR's. This set up is larger but will produce a similar image at a much cheaper price. 

A Skywatcher 150pds with a full frame camera such as a canon 6D  and the 0.9x coma corrector makes each pixel cover 2 arcseconds of the night's sky.

Skywatcher 150pds

Best price in UK

http://bit.ly/150PDSUK

Skywatcher 0.9 x coma corrector

Best price in UK

http://bit.ly/skywatchercomaUK

TPO 6 inch f4 combined with a canon 6d (whcih I recommend) will result in each pixel covering 2.25 arcseconds of thh night's sky

Best price in USA

http://bit.ly/TPOnewtUS

Baader MPCC mark III coma corrector can be used with either the TPO f4 or Skywatcher f5 newtonian

Best price in USA

http://bit.ly/baadercomaUS

Best price in UK

 http://bit.ly/baadercomaUK

Laser collimator

Best price in USA

http://bit.ly/newtcollimatorUS

Best price in UK

http://bit.ly/lnewtcollimatorUK

Collimating a badly collimated newtonian is a skill... happily most newtonians bought from the factory only need a little tweak with the laser collimator but a badly colimated newt can't be fixed with a laser collimator alone. If you watch this video all the way through you will be a colllimation expert.  FYI I've never touched the collimation on my big newt big Bertha. It is entirely possible that you won't have to with your newt either. Be wary of cheap laser collimators as the lasers are probably wonky and can't be straightened. Here is a a video about checking the collimation of your laser collimator

To achieve minimal wobble both set ups will need a guide scope and a guide camera. Modern guide cameras have small pixels and this inturn means the guidescope can be very small.The kind of set ups we are using here will work just fine with these dinky and light guide scopes. The most important thing is to make sure the guide camera and guide scope are mounted super securely to your scope. In fact this is such a big deal that sometimes I use larger guide scopes simply because they are easier to secure  Also note that most planetary cameras double up as guide scope cameras.

The ZWO ASI120mm is fantastically sensitive.

http://bit.ly/asi120mmUS

Best price in UK

http://bit.ly/asi120mmUK

Mini guide scope

Best price in USA

http://bit.ly/miniguidescopeUS

Best price in UK

 http://bit.ly/miniguidescopeUK