Best Lucky Imaging Gear
The most important bits of kit for lucky imaging is the telescope. If your scope isn’t sharp enough then there is not point in lucky imaging. That’s because of the way optics works. Basically whatever is causing most blurriness in your system dominates all other sources of blurriness. So your telescope’s optics are making stars blur by about 4 arc seconds and if you are shooting on a night when the atmosphere wobbling around is causing each star to blur by 2 arc seconds then your resulting stars are going to have a blurriness of not 6 but 4.4arc seconds [ sqr(42+22)]. And if you do lucky imaging with this telescope and halve the amount of blurriness caused by the atmosphere (which would be very impressive) your resulting blurriness will be 4.1 arc seconds. All the effort of Lucky imaging has made almost no difference to the sharpness of your image and whats worse it will have cost you a huge amount in terms of your images noiseyness. In The BAT we only encourage folks to try lucky imaging when their scopes create less than 3 arc seconds of blurriness.
Find out about the lucky imaging theory here:
The Sharpest Scopes
So when buying a telescope for lucky imaging the prime concern is that it is sharp. Although telescope Companies don’t tell you how sharp their scopes are WE CAN! In The BAT we ask our members to test their scope by sending our team pictures which we can use to measure the Full Width Half Maximum (aka blurriness!) of the stars. We now have a database of hundreds of scopes (which can be seen here). The blurriness of the stars depends on the seeing conditions as well as the optics of the telescope itself, so this is not a perfect test BUT if the seeing conditions are good you would expect a very sharp scope to produce stars that have 2 arc seconds of blurriness or less.
Planewave CDK 12.5: £9,180
Apo refractors are the best telescope design in terms of sharpness but they are very expensive when they get fat. And you need to be at least 5 inches fat to play at lucky imaging. Most high end telescopes like the CDK tend to be big fat Dall Kirkham designs, still expensive but far cheaper than a similarly fat apo refractor!
Orion Optics ODK12 £5,800
Sky-Watcher Esprit 150 £4,749
The C9.25 (a schmidt cassegrain design -aka SCT) is in my opinion the best all round scope because its so versatile and relatively cheap. The C11 and C14 are better still if you can afford them.
Wow
GSO Newtonian 8" f4 £519
The simple Newtonian design is actually sharper that on axis than both the SCTs and Dall Kirkams AND its LOADS cheaper. The quality of the mirror and the smallness of the secondary obstruction are important factors but the diameter of the mirror is single most important consideration. The fatter the mirror the higher your potential resolution. Our tests show a good 8inch is fat newtonian is sharp enough to lucky image with...
All the scopes to the right have been tested by The BAT and are able to resolve stars with a FWHM of less than 2 arcseconds
The stand out budget lucky imaging scope is the GSO Newtonian. GSO are a Tiawanese optics company who clearly make beautiful mirrors. I now recommend GSO mirrors and optics. The GSO Newtonians are rebranded by different companies in different countries. Same scope different stickers. Here they are…
The Apertura/TS Photon/TPO nerwtonains
GSO 8inch F4
GSO 10 inch F4
You don’t have to buy a GSO newtonian. My OLD Newtonians are also very good. My little 6 inch 50 years young ‘red devil’ by Edmund scientific has broken the 3arc second barrier and is one of the sharpest 6 inch newts in The BAT. TBH though I think 6 inches might really be the limit for Newtonians to lucky image with. 8 inches is better and 10 inches better still. Big Bertha my 40 years young 10inch f6 newt manages an impressive 1.8arcseconds of blurriness.
My 6 inch lucky imaging rig
-
Telescope: Edmund Scientific Newtonian (with a 35mm Orion Optics Uk secondary)
-
FL 900mm, Diameter 152mm, F6
-
Mount: 2006 Skywatcher HEQ5 with Rowan belt upgrade (and a Dark Frame Optics tune up 6 years ago).
-
Camera: ZWO ASI178MM with home attached cheap peltier cooler (temp controlled by an LED dimmer)
PROs
-
High quality mirror: probably about 1/10th wave accurate
-
Small secondary: Old school visual guys say if you can get the diameter of the secondary down to less than 20% of the diameter of the primary then its impact is barely noticeable.
CONS
-
No matter how good the mirror and how small the secondary physics limits its resolution of this little 6 incher to about 1 arc second. Fatter scopes have a much greater potential.
-
At f6 its quite slow. A faster telescope would catch photons more quickly and enable shorter exposures for the better lucky imaging results.
Please help the biscuit by using these affiliate links
Best Cameras for Lucky Imaging
Sensitivity (mono or colour?)
Cooled or uncooled?
Lucky imaging relies on taking very short exposures. To gather enough photons in that short amount of time your camera needs to be sensitive (or your telescope needs to be very fast). Colour cameras have a problem here because they collect 1/3rd as many photons per second as a mono camera when the mono camera is shooting luminance frames. That’s why I’m not recommending colour cameras or dslr cameras for lucky imaging. Note this isn’t a hard and fast rule. Please try it if you have one.
When shooting long exposures the noise created by the camera's dark current is important so most astrocameras are cooled to help reduce it. Lucky imaging calls on very short exposures, so you don't need a cooled camera. However you're not going to be lucky imaging all the time, so on the whole I recommend a cooled camera.
Find out about the best camera settings here:
Pixel scale…
Sensor size
As we’re hoping to use lucky imaging techniques to resolve details around 1arc second wide I’d say as a rule of thumb we want our pixel scale (that is the amount of sky each pixel ‘sees’) to be around 0.5arc seconds per pixel. So my recommended choice of camera relies on matching the size of the camera's pixels to the focal length of the camera.
Small sensors are actually quite useful for lucky imaging. Each sub doesn't take up much space on your hard drive - and when you've got 10,000 subs that becomes important. Also we're generally looking at the fine detail when lucky imaging and small sensors are naturally looking at a smaller area of the sky.
Camera recommendations for telescopes with a focal length of 800-1400mm
ZWO asi178mm
-
2.4um pixels
-
Low read noise 1.4e per pixel
-
14mm diagonal sensor
-
Very Good Value
This a great camera for planetary imaging too
ZWO asi183mm
-
2.4um pixels
-
Low read noise 1.6e per pixel
-
16mm diagonal sensor
-
High sensitivity
-
Cooled version
More expensive than the asi178 but you can buy a cooled version of the 183 which is better for long exposures.
ZWO asi294mm
-
2.3um pixels in Bin 1 mode
-
Low read noise 1.2e per pixel
-
33mm diagonal sensor
-
High sensitivity
Brilliant camera. If you don't plan on taking long exposures you could save money by buying the uncooled version
Camera recommendations for telescopes with a focal length of 800-1400mm 1200 – 2000
ZWO asi1600mm
-
3.8um pixels
-
Low read noise 1.2e per pixel
-
21 mm wide diagonal sensor
-
Good bang for buck
ZWO asi294mm
-
4.6um pixels in Bin 2 mode
-
Low read noise 1.2e per pixel
-
23mm diagonal sensor
-
High sensitivity
You might be able to pick one of these up cheap second hand.
Brilliant camera. Needs to be cooled when taking long exposures due to its quite high dark current
ZWO asi2600mm
-
3.76um pixels
-
VERY Low read noise 1e per pixel
-
28.3mm diagonal sensor sensor
-
High sensitivity
-
Low Dark Current
Thx to everyone who helped me buy this. The sensor is large which actually doesn't help for lucky imaging. I'm actually cropping in when shoot with it in order to save disc space!
Please help the biscuit by using these affiliate links
My mount recommendations for lucky imaging
Find out about the best mounts here:
Essentially the mounts I recommend are here. If you really want to take the hobby seriously then maybe you should invest in an even better mount. Or you could see if Dave Woods from Dark Frame Optics can tune the one you've got.
For years astrophotographers have said you must spend more money on your mount than anything else. The reason is that traditional long exposures are extremely susceptible to mount wobble. Lucky Imaging utilises much shorter exposures. Over a short period of time you may find that your mounts wobble is negligible. Or that your mount wobble is sporadic in which case you just throw away exposures during the unlucky moments of mount wobble. Its a bit like double lucky imaging where you only keep the frames where both the atmosphere and the mount aren't wobbling. The flip side of the coin is that hi resolution imaging is imaging at sub arc second scales and it is therefore critical to minimise all sources of blurriness as much as possible.
TBH I don't yet know how important having a good mount is for lucky imaging. I suspect if you are able to get down to 1 second exposures then guiding is unnecessary but even 1 second exposures could benefit from having a finely manufactured mount whose worm gear is microscopically smooth. Dave Woods from Dark Frame Optics has to use special machines to smooth the worm gears on the factory produced cheap amateur mounts from china that he tunes up. Also a good mount will reduce the number of frames you have to throw away. And of course a good mount will mean your longer exposure shots (to get the faint bits) will be sharper. I will find the answer to this conundrum when I start being able to analyse data from the good folks who are taking part in THE BIG AMATEUR TELESCOPE
Fancy Mount: I've got an old version of the Avalon Linear Fast Reverse. It uses belt drives rather than worm gears for extra smoothness
I am attempting to get a group of astrophotography nerds together to share lucky imaging data and thereby compete with giant multimillion dollar telescopes. I want us amateurs to be able to capture unimaginably good images and potentially shoot objects that the professional telescopes struggle to get (like variable nebula). We can only do this if we work together. If you are a lucky imager or if you are a whizz at processing then please come and join us
.