Top 10 Biggest Improvements in Astrophotography

With every image I take, I get incrementally better results. There is no substitute for having lots of practice in order to get better at something. Sometimes however, there is a noticeable improvement due to a technique or piece of hardware or software that you’ve bought or recently become aware of. These can be described as mini ‘eureka’ moments that take your images to the next level. So for those earlier in their astrophotography journey, I though I would try and summarise the 10 biggest improvements I have made with my imaging techniques, and to make you read all the way to the bottom, they are in Top of the Pops, chart rundown reverse order.

Number 10: Understanding what is possible

If you build up a network of likeminded people all doing the same hobby, you quickly learn what certain kit and combinations can achieve. Using your friends for inspiration is a great way to learn what should be possible and something to aim towards. This shouldn’t be confused with expecting to get similar results as really good images and composition often are backed up by years of practice. If you ask, people will often share their setup and settings so you can try the same. In a hobby where there are lots of hours wasted on trial and error, getting a few timesaving tips can be a real help. It is important you pick the right people; you will never get the same results as the guy living in a remote Bortle 1 site with a 14” scope, so be realistic.

Seek out a community, enjoy what they are doing and use it as inspiration

Number 9: Bahtinov Mask

These have become so ubiquitous that they are now even built into the lens caps on some scopes. These masks are placed over the end of the scope to achieve focus quickly and accurately. Before I had one, focus was a bit pot luck, and many a clear night was ruined by out of focus images. These masks make it virtually impossible to be out of focus if you use it as part of your setup process. I have one for each of my scopes to suit the aperture size. I really notice when I use my telephoto DSLR lens how hard focus is without one. Unless you have super whizzy software or an autofocuser, you should have one as part of your essential kit. They are cheap and very effective.

Don’t ruin a clear evening by being out of focus

Number 8: Horses for Courses

There is no telescope that can do everything, so don’t try a force a small refractor to do planetary imaging or convince a long focal length scope to tackle the whole of NGC7000. There are enough great objects to suit the optimal range for each scope type, so until you have two or three scopes for different purposes (and you will…), don’t waste time trying to make it operate outside its comfort zone - it’ll be hard work and the results will be mediocre. Over the years I have amassed a collection of telescopes (some from new, others second hand) to compliment each other. This means I have a scope optimised for wide nebulae, one for galaxies and one for lunar / planetary. A forth is now largely redundant but converts well for solar imaging and eclipses. For each project I know which to use and use Sky Safari app to test the framing combinations of scope and camera to get the best scale. This avoids any disappointment that the object is too small or unimpressive.

Know the limits of your scope and use the right scope for the right target

Number 7: Calibration Frames

If you make the move from taking ‘snaps’ through an eyepiece or getting one grainy frame of Andromeda, you will need to commit the time and patience to both stacking and calibration. Most start with stacking and see the benefits of increased brightness and resolution of deep sky objects along with the reduced noise that comes from stacking. However, these stacks will still contain blemishes, banding and camera noise unless you really commit the time to make calibration frames. They are a necessary evil to get your images up to the next level, taken ideally in the same session to ensure the optical path and temperature are the same. A great set of Light subs can be ruined by poor Flats or take 10x as long to polish up in post processing.

If you want to get decent images, don’t shortcut your calibration process

Number 6: Photoshop Layer Masks

Until you know how to use PS Layer Masks, they are hard to understand and describe to others. I’ll try….they are effectively ways to add selective adjustments to your images as you process them, and once you learn how, you will find you cannot do without them. When processing any image, you’ll have areas with huge contrasts in brightness, saturation and detail; applying effects or modifications across the whole image might help one area but blow out the other areas. Using layer masks allow you to duplicate the layer and just add brightness here, or sharpening there without changing the rest. For something like M42 The Great Orion Nebula, it is essential in order to reveal the clouds of nebulosity without overexposing the core around the trapezium. I use masking all the time now to make a galaxy pop against the background stars or sharpen up features within an overall composition. I simple terms I use the top layers for detail, sharpening and colour adjustments and often fade down and smooth off the background to make the target object appear more three dimensional and dominant. I regularly return to older images, slap on a mask a make a few subtle improvements now I have this technique in my arsenal.

Layer masks help you make local corrections and adjustments to make your targets really pop

Number 5: Starnet++

I used to see people post starless images of nebulae and found them a bit pointless. You either like the aesthetic or you don’t. What I didn’t realise is how useful they are for images processing and within the past month I have been converted. Any image will have highlights you’ll want to brighten, but this will also brighten the stars. By running an image through Starnet++ you can create a layer without any stars. If you subtract this layer from your image you can then create a layer of only stars. You then have the power to control the nebulosity and the star brightness/ stauration/ sharpness independantly. Combing this with layer masks is a great way to be highly selective about which areas are adjusted. Changing the blend layer of these star/ starless layers also changes the final composition; stars can be subtle or bold depending on your preference. So I’ll admit I was wrong here, starless images are very helpful and I now run everything through the free Starnet++ software at the start of processing.

Creating star only and starless layers give maximim control over your processing

Number 4: Narrowband Filters

Given I live on the edge of a city, I have pretty decent skies right on the edge of Bortle class 4 & 5. We still have streetlights though, and a nearby University with its bright floodlighting for all-weather sports pitches. Often, when I show people my images they are amazed that I can see these faint objects and nebulae from my home; I can’t I say, but my filters can. Filters do a remarkable job at expanding the range of objects you can photograph. They have visual benefits but I have always found these pretty marginal, unlike photographic filters which are transformational. A few years ago I invested in a 2” STC Dual Narrowband filter which captures Ha and OIII. This opened up a huge selection of objects that I never though possible to capture from my location. Even during a full moon, these filters are hugely effective and allowed me to venture into widefield targets that are invisible to the naked eye. Dual Narrowband is also a great pairing for a CMOS single shot colour camera and although not as sensitive as a mono camera with individual pass filters, produces results that I am still thrilled by.

Narrowband filters open up a vast range of targets from light polluted areas across all seasons

Number 3: Astro Pixel Processor

Having good data is only half the battle. Processing an image can take as long or longer as the hours spent photographing your object. When I started out, being a Mac user was a huge disadvantage for image processing options. I had to run a disc partition in Boot Camp to run Windows 10 for free software like Deep Sky Stacker and Registax. Deep Sky Stacker is the go-to for free and simple image processing, but I was never very good at using it, despite watching various tutorials and guides. My Twitter feed was full of images produced in APP, so I downloaded the free trial and tried running the same data sets again. I found that the difference was remarkable and although its far more complicated to use, gave far superior results. It also runs on a Mac, meaning I could ditch Boot Camp and install it properly. I have since bought a full license and use it exclusively for processing my FITS files. New features are always being added, like Comet processing, and I continue to be impressed by how great it is.

APP has made the biggest impact on how I process the data

Number 2: ZWO ASIAIR

Before I had the ASIAIR I had a standalone guiding device (i.e. no laptop). I think I spent longer each evening finding a star, calibrating it and keeping it guiding than doing any actual imaging. The interface was poor and you never really knew if you were guiding and what the camera could see. This is the total opposite to the ZWO ASIAIR which is a breeze to use, has a totally intuitive user interface and makes imaging and guiding incredibly easy. I think I only started guiding properly once I had my first ASIAIR and with the added benefit of Plate Solving, polar alignment and programmable image runs, it has made astrophotography incredibly easy and fun. It now supports video capture on th Pro version so I can also use it for planetary and lunar details. I could not do without it.

ASIAIR has made the biggest impact on how I capture my individual frames

Number 1: CMOS Cooled Astronomy Camera

Forget the scopes, the biggest change to my astrophotography was the move from a stock DSLR to a dedicated astronomy cooled camera. My cheap Canon 600D gave a lovely wide field of view but was always plagued by noise and banding that my image processing skills could never iron out. Distant objects could be captured but they were indistinct and grainy. When I took my first image with the ZWO 294MC Pro it was a true ‘wow’ moment. From that point my images took a huge leap, allowing me to capture better data and therefore process the results far better. Yes, it was an expensive investment but it was like gaining promotion to the Premier League. This has made the largest single contribution to my astrophotography and I class my images as pre-CMOS and post-CMOS.

A dedicated CMOS cooled camera will take your images from hobbyist to semi-pro

I hope you enjoyed this top 10 run down, and maybe learned a tip to take away.