EbolaBooze’s Fortnightly Astro Corner: A Guide on Astrophotography Purchases to Destroy Budgets and Ruin Relationships

Or: Burning absurd amounts of cash on space-looky-glass.

 

So, you’ve decided to start photographing space! (I assume you’ve decided to start photographing space, else you wouldn’t be reading this.) You want to take pictures of stars, and star clusters, and nebulae, and galaxies and SPAAAAAACE.

Now, you probably want to rush out and get your hands on a camera and a telescope, and bam, astrophotography, right?

Nope!

There are a few questions you need to ask yourself before you go out and lay down some cash money on expensive glass.

 

Okay, first question: On what image scale do you want to photograph?

This is a pretty damn important one, as it will form the basis for your entire purchase.

Do you want to image constellations? The Milky Way in its entirety? Any sort of landscape plus stars? You’ll want a decent DSLR or DSLR equivalent, plus a nice, fast f-ratio lens.

 

Do you want to image large nebulae, or take star field pictures? You’ll need a motorised tracking mount plus a telescope of focal length 600-1000mm, and a camera with a large sensor to make the most of the field of view.

 

Want to do really deep-space imaging, of distant galaxies, planetary nebula and some smaller nebulae? You’ll need a very good motorised tracking mount, and a telescope with a minimum focal length of 1200mm.

 

If you want to image the planets, get a tracking mount, a telescope with focal length 2000mm or more, a 2x-5x teleconverter or Barlow lens to bump your focal length to truly absurd levels, and a camera capable of taking video.

 

Made a decision yet? Let’s move onto the second question.

Do you plan on making this a long-term hobby?

Simply, you don’t want to be laying down thousands of dollars to find that you just don’t enjoy astrophotography. Telescopes and equipment do tend to retain their value very well over time though, as much as 80% of their value for certain brands.

 

Question the third:

How strong are you?

Surprisingly relevant! If you don’t plan on having a permanent setup like an observatory, you’ll need to move your equipment out of the elements once you’re finished imaging!

To put this into perspective, I have what I like to call a “portable” setup. The lightest component of this is my telescope and camera, which weighs in at a svelte 25 kilograms (55lb). Next heaviest is my tripod, battery pack and mount head at 45kg (99lb) a piece, and various counterweights and sundries. All up, 125kg (275lb) worth of equipment.

So, if you’re planning on getting a heavy-duty setup that you can’t mount permanently, start lifting!

 

Now for the most important question!

What is your budget?

Once you get past the stage of very wide-field imaging with a DSLR and lens, the cost of equipment starts to jump up dramatically. Here are some price points, and what you can buy for that amount that won’t have you hating astrophotography and all associated with it forever.

 

$500 and below

DSLR imaging

It’s pretty much your only option at this price point. Get a sturdy tripod, and a nice lens.

Recommended focal lengths for this sort of photography are 22mm and below, with as low an f-ratio as you can afford to buy, since the lower the f-ratio, the more light can reach the camera sensor. The shorter focal length you go, the wider the field of view.

The glass and the operator are the two most important things here; camera sensors are all very similar these days. Depending on the lens and what model of camera, an appropriate fast wide-angle lens will set you back between $200 and $700.

Deep-space imaging

Pthlblblblblt, jog on mate.

Oh, wait, you’re actually looking for equipment at this price point? Seriously, skip ahead a few hundred dollars.

 

$500 to $1000

DSLR imaging

A very nice tripod, and a very nice lens. What? Not like you can get a Hasselblad until further down the list!

Deep-space imaging

Here is where a lot of second-hand beginner equipment can be found, shop around! One caveat though is the assumption that you already have some form of DSLR, or imaging unit available to you.

A decent computerised, motorised mount is the Celestron Advanced VX Equatorial mount. Brand-new, around $700USD, can be found for a lot cheaper second-hand. It’s got an adequate payload capacity too, at 13.5kg (~30lb). A good telescope to match this mount would be a 152mm (6”) Newtonian telescope. They should weigh in at around 7kg plus camera. The telescope should set you back around $300USD, total package cost ~$1000 all told.

The focal length will be in the ~600mm range, so pretty good for wide field work when coupled to anything larger than a micro four thirds (22.5mm diagonal) sensor.

Remember, good polar alignment is key to good astrophotography!

 

$1000 to $2000

DSLR imaging

Go wild, splurge, etc. I think it’s pretty obvious by now that I don’t know DSLRs terribly well. A full frame or larger sensor here with good glass becomes an option at this price range and above.

Deep-space imaging

Here’s where the fun starts.

You can keep the mount from the previous price point, and add a 200mm (8”) aperture Newtonian to it (~$500), for a total cost of around $1200. This is a good telescope for deeper-field imaging.

However, even though the mount shouldn’t be overloaded, you don’t really want to go over ¾ of the mount’s weight capacity when doing astrophotography. Ideally you would only mount a telescope weighing ½ of the mount’s weight capacity.

Here’s where a larger variety of computerised mounts of similar quality become available to you. The Celestron CGEM is a popular choice here, as are the iOptron iEQ30, Losmandy GM8, Skywatcher NEQ-5 (Orion Sirius EQ-G) and Skywatcher NEQ-6 (Orion Atlas EQ-G). All these are between $1100 and $1500, with payload capacities up to 18kg (~40lb).

Other choices for telescopes to put on the mounts here are a Schmidt-Cassegrain telescope of around 152mm (6”) for deep-field and planetary work, or an apochromatic refractor telescope for wider views.

 

$2000 to $5000

We’re getting into second-hand car territory here, but still less than I’ve spent in total. Ahem.

For a mount, the lowest payload capacity you’d want to use is an 18kg (~40lb) capacity one. The SkyWatcher EQ6 or Celestron CGEM are the cheapest mounts I’d recommend here, but you wouldn’t want to put more than 15kg (33lb) worth of equipment onto them.

Higher payload capacity mounts would be the iOptron iEQ45E or CEM60, Losmandy GM-8 or G11, or Celestron CGEM DX. You’ll want to spend between $1500 and $3000 on a good quality mount at this price point.

Here, the choice of telescopes gets blown wide open; there are some very nice options available.

For deep-field imaging, you can’t go past a 200mm aperture Ritchey-Chretien telescope with a carbon-fibre tube from GSO, or one of the re-brands (~$1400). Want a bit more aperture? How about a 279mm (11”) aperture Schmidt-Cassegrain? That’ll set you back around $2000 from Celestron. Very good for planetary imaging.

Want a wider field? A 306mm (12”) imaging Newtonian will only cost ~$800, add a corrector lens for around $300, and you have a wonderful instrument for imaging very faint objects. Want wide-field starscapes? You can’t go wrong with a 100mm (4”) f/7 apochromatic refractor.

Also, you’ll want to buy and learn how to use autoguiding equipment as well if you have this sort of budget. What autoguiding does is compensate for mechanical error in your mount’s tracking machinery, and errors in polar alignment. Very handy, and it will allow sub-exposures up to 20 minutes is done right.

LittleScope

$5000 to $20000

Well, this is the price bracket where I’m sitting at the moment.

I have an Skywatcher EQ8 (Orion HDX110) mount (50kg (110lb) payload capacity, oooh yeah), a customised SkyWatcher 254mm (10”) aperture imaging telescope, and a very, very shiny KAF-8300 based CCD camera. All told, a little over $10000.

BigScope

This price point is interesting, as you can get some very nice equipment for not terribly much, compared to more expensive brand names. A Chinese-made 406mm (16”) aperture Ritchey-Chretien telescope with carbon fibre truss structure, quartz mirrors and all will set you back ~$6500, as compared to $42000 for a telescope of the same optical design and equivalent aperture from Officina Stellare.

If you’re aiming to get really incredible images, you’ll need a good CCD camera, and I’m of the school that you should buy equipment that you should be able to grow into, and only replace it when it’s holding you back. Decently-sized monochrome CCD cameras for astrophotography start around the $5000 mark, with the cost of a set of good luminance, red, green and blue filters included. You can buy colour CCDs, but if you do, you’re a heretic and deserve to have your entire family line purged from the face of the earth.

Honestly, learning how to use a good CCD and autoguider combo will open up deeper vistas for you all at once.

For a deep field telescope, a 406mm Ritchey-Chretien from TPO or Astro-Tech would be a dream scope, coupled to a SkyWatcher EQ8 mount, and a CCD camera with a KAF-16803 sensor.

Wide field, you can’t go past either a Takahashi FSQ-106 or a Officina Stellare Veloce RH200, same mount, same sensor.

 

$20000 and above

Hey big spender~

Spend a little (imaging) time with me.

Astro-Physics, Software Bisque, Astro Systeme Austria, Takahashi, Parallax, Mathis, Planewave, Officina Stellare; These big names start their big scopes and mounts at this price bracket.

Mounts with periodic error +/- 2 arc seconds, and payload capacities in the hundreds of kilos; telescopes with mirrors milled to nanometre tolerances by ion beams, adaptive optics, this is professional territory, and the prices still keep going up.

Space is the limit, and by limit I mean limiting magnitudes in the twenties.

Just send from of that money my way, eh?

 

Clear skies!

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