New Equipment vs Old
In the years since I began writing about astrophotography techniques and equipment (including review of the Polarie, pointing tips, and processing techniques) things have obviously changed for me. For one, I’m not working at astrophotography as hardcore as I expected. The reality of managing an informative website (this one!), creating publishing and supporting tools, conducting fairly frequent expeditions and workshops, writing and improving content for webinars *AND* having a day job means I have to temper my enthusiasm. Or to say it more plainly, have my enthusiasm tempered by reality.
However a student asked me this question and I felt it was a good topic. The question:
I read your review suggesting the Orion Astroview EQ mount with optional dual axis motors. I’ve been looking for a cheap way to do decent tracking and have considered making a homemade Barn-door mechanical tracker to something more reliable (motor driven).
On Orion’s website, I find their Astroview EQ mount (#09822) and the dual axis motors for the Astroview (07828).
Soooo, my question is this: Since you wrote that article, is that still the most bang for your buck, or have you found something better/bigger/cheaper?
— Bruce L.
As I noted in my article, there are definitely bigger and better and significantly more expensive things … though nothing cheaper that I’d recommend. The Polarie is in the same price league. After I made my recommendation my Astroview suffered a series of blows to the declination drive that rendered the drive useless. The first blow was that the locking nut fell off in the dark and was lost. Once I replaced the lost piece (at about $35) the next blow was quite literal and it bent the drive axis rendering the motor useless. The truth, however, is I really didn’t need the second axis at all and I’d have saved a few bucks by only buying the single drive motor to begin with. The Astroview is just beefy enough to carry the weight of my Orion 80ED refractor and a camera. And to be quite honest since it is lighter and not a “GoTo” mount it’s actually easier to set up and take down than it’s bigger cousin, the Sirius mount. But the Astroview is nowhere nearly as well made. So yes, I’d still recommend an Astroview as a minimum viable solution… provided you stick with a camera and telephoto / normal lens to do imaging. Most telescopes worth mounting on the Astroview will cross the boundary of what the Astroview is designed to carry and will be too heavy for good operation.
Automating Focus – Two Steps Forward, One Step Back
I had upgraded the focuser on my 80ED to one sold by ScopeStuff (#RNFR) – a $320 motorized focuser. That focuser proved easier to use and more versatile, but I later found it coming apart and it required some heavy tinkering and investigation to get it working again. I also realized that the system was not that well thought out – it was designed to have the motor base mounted to the focus TENSIONING screw rather than attached to a fixed screw on the focuser. That’s probably in part why when I got it, the tube would not travel all the way through the almost 4 inches of focus. I’ve restored it to operation but it still won’t travel in the final 3/4 of an inch… that’s fine, however as I have never needed that much in-focus – I’m usually working with the focus tube nearly fully extended.
In focus - moving the camera inward, toward the front element of the telescope, thus shortening the overall length.
Out focus (aka back focus) - moving the camera outward from the front element lengthening the apparatus.
Is A Barn Door Tracker A Good Solution?
Let me address the question about a Barn Door Tracker. There are no places that I have found to buy barn door trackers, it’s strictly a home-built type of thing. As I explain in the Astrophotography 101 webinar, a barn door tracker is a form of an equatorial mount that has been simplified to drive only one axis (the right ascension) and with a limited tracking time. Various designs like the double arm version improve tracking accuracy while complicating assembly. My personal bias is that even though I’m pretty handy with tools I’d rather spend $400 on a fully built system than $80 on parts and 10-20 hours of my own labor building and perfecting the system. I suppose if someone handed me a robust kit for $100 and told me I could assemble a motor driven barn-door tracker in an hour or less, I’d give it a try. But at much more cost in time or money the barn door tracker starts bumping into fully built solutions like the Orion Astroview and the Vixen Polarie or the iOptron SkyTracker.
One of the principle impediments with all things astrophography – and part of the reason I created the Astrophotography 101 course is that there is a LOT of language used that is foreign to most people. And, there are legion of difficult choices to make. For example, I recently bought a William Optics Telescope. It is a well built, heavier than expected, refracting telescope that features a power focuser. Perhaps as a surprise to the uninitiated the “power focuser” is not actually powered (motor driven), it is an improved version of the manual Dual speed Crayford focuser and the term “power” implies it’s ability to hold focus without slop or creep – even if the other end of the focus mechanism is a pretty substantial camera.
I had hoped my existing finder scope and guide scopes would easily attach to the new William Optics telescope, but they won’t. The fittings are all different. For the most part astronomy and astrophotography equipment is a wild west of non-compatible, non-interchangeable components. Much like you see if you try to use a Nikon lens on a Canon camera. Or an intervalometer built for a Sony on a Lumix camera. The difference, at least to my way of thinking, is that the compatibility of components is much better spelled out in the camera world than the astronomy world.
What about the Polarie?
The Polarie will work well with normal lenses. When I mounted my 70-200 with a 1.4x and the Canon 5D Mark II (or 40D) on the Polarie, tracking accuracy was pretty bad – but not directly because of the Polarie. The problem is that the systems is not balanced and there are three different points around which the apparatus gets sloppy: at the connection between the ring-collar of the lens and the head mounted on the Polarie. At the point where the head is attached to the Polarie screw, and where the “collet” with it’s two thumb screws attaches to the Polarie. Invariably one of those would become loose enough that it would slip. I found that putting a counter weight at the end of the lens reduced slipping and improved the tracking – but it’s a hassle and highly dependent on where you aim. A true equatorial mount is easier to balance. The Polarie system works better when there isn’t a lot of torque around those attachment points.
In summary, I like and use the Polarie because it’s compact, light, not bulky and easy to take with me literally anywhere I go. But I would not use it to take serious astro images. The Polarie best fits Landscape astrophotography. For example, below is a 63 second exposure using a Canon 40D at 1000 ISO, f/2.8 at 16mm. Using the 500 rule, star streaking would become apparent at about 12 seconds. In this small size there is nothing at all visible, but do notice how the foreground head frame at Bodie State Historical Park is blurred – that’s because the Polarie was tracking the sky at 1/2 sidereal (star) rate. The photo has been exposure enhanced (brightened) to see details, and noise reduced a bit.
Here is an exposure that is a bit more germane. Two exposures, actually. One focused for the hand-lit tree, the other focused on the stars and both were combined in Photoshop.
If you are using a tracking base, then how do you handle foreground images? Clearly, that foreground image would appear to move over time if the camera is properly tracking the stars?
Even if using only a single image for the foreground, it seems to me that the stars would then be occluded in the area around that foreground (eg, tree).
What am I missing?
I’m not sure what you mean. There are three primary solutions:
1. Track the whole image (at full or half sidereal rate) and capture everything in a single frame (like the Head Frame/Milky Way image).
2. Take a static foreground and track the sky for a more featured sky.
3. Take two separate images without tracking (like the Crater Lake Tree and Milky Way image).
The choices that require planning are the 2nd and 3rd. Which part of the image should you shoot first, the foreground or the sky? The answer depends on what you want to accomplish and whether the stars are rising or setting.
All night exposures with stars require a tradeoff. The question is how to minimize the tradeoffs in terms of desired effect, and what you are willing/able to do with single and multiple exposures. As with many decisions, you need to start by forming an idea what you want to accomplish as well as understanding the limitations of the equipment you are using. Those considerations may force you in one direction or the other.
For example: If there is a policeman with a siren behind me, my options are quite different if I am driving a fast car than they would be if I am riding as a passenger on a moped. Trying to outrun the police is generally a bad idea, but it would be silly to even consider it if the vehicle you’re in isn’t up to the task. My experience so far is that the police are chasing somebody else! The good news is trying the wrong approach in night photography with the wrong equipment probably won’t result in you being jailed 🙂
#3 is the only way I have done it, including in workshops with you.
I understand (I think) how to get a good image with tracking if only the sky is visible. One way is to shoot a single long exposure, where the camera is moving in sync with the stars. That camera movement would result in any foreground being blurry though, wouldn’t it?
The other way (as I understand it) is to shoot a series of shorter exposures, and then combine them using astrophotography software. I did that recently, combining 130 images of the supermoon and getting an amazingly detailed glorius image — but no foreground in the frame. I superimposed a foreground later, in Photoshop. All pretty clear to me.
Now, I look at your tree foreground, and I get fuzzy. Using the single long exposure would result in a fuzzy tree. Using a series of shorter images would allow me to use a single frame for the tree. However, the tree would be moving relative to the stars, so those stars that moved behind the tree during the camera tracking, would have incomplete data relative to those that never went “behind” the tree.
Does that clarify my confusion, or have I just added more mud to the water?
Clearer. I wrote a nice long response, but it looks like it disappeared into the ether. Harrumph.
This is a good topic for a separate article so let me get back to you later.
Thanks for the comprehensive and specific response to my earlier question.
From what you’re saying is that the most accurate and ‘best’ solution to taking great star and milky way tripod shots are to limit your exposure time to the “500” rule, or to use a Polarie for landscape included shots. BUT the landscape item if in the foreground may be slightly blurred?
I want to throw in my 2 cents to Astrophotography and how to start.
I began taking pictures of DSO’s (Deep space Objects) with an AstroTrac two years ago. Back then there was no Vixen Polarie or iOptron SkyView and the AstroTrac was the most portable and reliable tracking device but did cost around $750 with accessories. I later moved on to Celestron CG5 and then iOptron iEQ 45.
I still think starting with a camera tracking device (from Vixen or iOptron) to find out for yourself if you really want to do Astrophotography is the best option as you can use your already existing tripod (tripod needs to be very solid/stable, the heavier the better) and other gear. It is also easier to setup and you can also use it for Milky Way shots on the half speed to reduce star streaking or do longer exposures.
After that if you think you want to start taking pictures with a telescope and proper telescope mount I strongly recommend buying a mount that is at least a class higher than you think you need and has twice the load capacity you need. I personally don’t like the Orion/Celestron mounts below $2000 because there are better mounts from iOptron in the same class.
The reason is why I suggest to go with something better and more expensive is that you’ll have less issues and get more good data.
Astrophotography is not the hobby where you try to save money or get something cheaper as that usually doesn’t pay off.
Good suggestions. Since you prefer the iOptron ($1500) over the Orion Sirius ($1050) can you say why? Easier to set up? More accurate? Bigger payload? Here are the comparison points I see (iOptron iEQ45 vs Orion Sirius)
Cost: $1500 vs $1050
Capacity: 45 vs 30 pounds
Mount + Tripod: 35 vs 43 pounds
Total Weight: 51 vs 54 pounds
Heaviest item: 25 vs 33* pounds
Min/Max Lat: 4-70 vs 10-65 degrees
Heaviest item on the Sirius mount includes the counterweight bar since it is impractical to disassemble it.
Otherwise the specs are pretty similar. The new iOptron ZEQ25 looks more interesting to me. Here is a comparison with the Sirius:
Cost: $848 vs $1050
Capacity: 27 vs 30
Mount + Tripod: 28 vs 32 pounds
Total Weight: 38 vs 43 pounds
Heaviest item: 11 vs 31 pounds
Min/Max Lat: 0-60 vs 10-65
I Chose the iOptron iEQ45 over the Orion/Celestron because of the load capacity, weight, hand controller (bigger, more features and works below freezing point without issues), calibrated polarscope (also more acurate polar alignment) and integrated GPS.
All good points. Thanks! I know the iOptron GoTo has more in its database, too. I know my Sirius drives me nuts trying to align it. Just wrote a review about it for Orion. I’ll post a link when they publish it (if they do!)
You’re welcome. Of course there is always something better but also way more expensive.
Regarding your focuser issue. I strongly recommend NOT to use the standard Grayford manual focuser that comes with most telescopes for astropgotography as they are usually designed only for observing (looking through the telescope) and not for astrophotography. These standard manual focusers cannot keep heavy equipment such as your camera in place.
I’m using the motorized focuser (high res Stepper motor) from Moonlite for more than a year without any issue and they have an ASCOM driver which makes it usable with every astro software out there.
NOTE: At StarCircleAcademy we have the Vixen Polarie, the iOptron SkyTracker, the Orion Sirius Mount, the Orion SkyViewPro, and the iOptron ZEQ25. We will be publishing a review/comparison of these in August, 2014.