Until recently Amazon allowed sellers to give (for free or a deep discount) an item to a customer in exchange for a review. “Review clubs” where formed where this would work systematically, with sellers viewing the profiles of reviewers to select where to send their items. As you can imagine, this led to “reviewers” happily giving 4-5 star reviews to anything that didn’t right-out collapse in their hands, in order to score free stuff. I had noticed that the previously very useful Amazon ratings were getting sort of funky and unreliable the last couple of years, and the worst cases happened in the more sophisticated products, where the average review club serial reviewer would anyway be unqualified to pass judgment. At one point I noticed that Amazon was full of “30×60” binoculars, which, magically (for a set that claims 60mm objective lenses in the title), could fit in the palm of your hand! In some listings they even claimed night-vision! With these charactersitics and their stellar reviews they are the second most popular binoculars on Amazon.co.uk (fortunately they are a little less popular on Amazon.com). So I ordered a set. Then, I signed up in a review club myself, and got a discount on one of the most popular 10×50 sets and also I borrowed from a friend another cheaper, popular 10×50 set and reviewed them all. The spoiler is: don’t buy no-name binoculars based on dubious reviews, and especially avoid anything “ruby lens”, “red membrane” etc. I’ve left reviews on Amazon and some are prominent enough to spare some people from garbage purchases, although others get rather inexplicably voted down and disappear from the first page (I’ve been contacted by people who get stuff from seller for free to tell me the sellers ask them to down-vote me). My “Hobby Store” review actually pissed off the seller and there were some exchanges (they apologized in the end)… Anyway, here’s what I gathered to put to the test:
In a previous Solar filter test I explored how various filters help with getting some better white-light Solar surface feature photos, and I had noted that while I was using the Baader Astrosolar Safety ND=5.0 film, some narrowband filters would benefit from the photo grade Astrosolar ND=3.8 film, as with allowing as much as 1/6310 of the Sun’s light (vs the 1/100000 of the ND=5.0) gives you much smaller exposures that have less noise. It turns out that the photo film by itself gives you an improvement in results that no combination of filter can give you when using the ND=5.0 film, and allows you to use really long focal lengths. Because it speaks louder than words, just take a look at my first attempt at the Sun with the photo film and just my 80mm ED and Canon 600D in 3x zoom video (stacked with Autostakkert):
Great detail, right? It is at an effective 4000mm focal length using a 5x TeleVue Powermate and yet thanks to the high transmission of the filter I could do a 1/1250s exposure at ISO 400. Apart from stacking with Autostakkert I used Registax 6 for wavelet sharpening and made the color yellow in post-processing (normally the Baader filter gives you pink/purple with a modded DSLR). The filter is usually sold in 20x30mm and 50x100mm sheets (at £30-60 usually in the UK, similar in the rest of the world) but, strangely, there seems to be a shortage right now, so your best is to look at ebay – that’s where I got mine.
Price update Jan 9 2017: Some price updates. A few impressive price drops, the CEM25 in the UK (£699 from £899), the Orion HDX110 ($3505 from $4499!) and CGEM DX in the US ($1695 from $1999), otherwise mostly price increases in the UK, due to the $1=£0.82 exchange rate.
Note Oct 3 2016: After over a decade of listing the HEQ5 as 15kg payload and the EQ6 as 18kg img/25kg visual, Skywatcher has downgraded the capacities of these mounts as 13.7 and 18.2 respectively. To me it looks like a marketing idea to differentiate the more expensive AZ-EQ5 and AZ-EQ6, so I am keeping the listing as it was, at least for now.
Update Sept 19 2016: I added the three smallest/least expensive mounts (SmartEQ, EQ3, EQ5) just to be more complete, although they don’t really compete with the rest in astrophotographic capabilities. Prices are updated, mostly the weaker GB pound made some UK prices – especially Vixen – higher (with the notable exception of the CGEM DX which dropped dramatically). I added a separate price graph for UK, it has an extra mount compared to the US graph, as the EQ3 Synscan doesn’t seem to be sold in the USA (you can find it in Canada though).
There was a UK store that had a nice table with the basic specs of Sky-Watcher and iOptron which I had found quite useful especially to see at a glance which mount from a company was at the same category with what mount from the other. That page is no longer online, so I thought I’d compile my own table and try to include more and newer mounts. I’ll only include computerized EQ mounts from comparable/high volume manufacturers (under $5000), so no expensive Astro-Physics, Takahashi etc (but you can find all those and more mid-high end mounts on this comparison table here).
The specs were mainly lifted from the manufacturer page, except the peak to peak Periodic Error which is shown as a range (and before / after correction values) from various reports (this source was helpful also this and numerous CN threads). Note peak-to-peak error is twice the +/- values that are sometimes used and some extreme cases were not included. Also not included are values of 1-2 arcsec reported for some mounts (iEQ45, G11) with TDM. Payload normally means visual and sometimes I had to choose a source (e.g. Skywatcher and Orion give a bit different spec for the exact same mount). Prices are typical US & UK prices with basic tripod (or pier where applicable) included.
|Manufacturer / Model||Price||Mount Head (kg)||Payload (kg)||Resolution (arcsec)||Objects||Polar Scope||GPS||PE/PEC (arcsec)|
|Celestron CGEM DX||$1695/£1499||19.4||23||N/A||40000||-1||?/?|
|iOptron SmartEQ Pro||$499/£449||2.8||5||0.5||59000||Yes2||No||?|
|iOptron iEQ30 Pro||$1398/£1285||6.8||14||0.14||358000||Yes2||Yes||16/5|
|iOptron iEQ45 Pro||$1848/£1450||11.4||20||0.09||358000||Yes2||Yes||15/5|
|Losmandy GM8 G||$2495/£2240||9.5||14||N/A||40000||-3||13-20/8|
|Losmandy G11 G||$3150/£2850||16.3||27||0.14||40000||-3||9-20/?|
|Skywatcher EQ3 Pro Synscan||-/£399||4.2||5.5||?||42000||-4||?|
|Skywatcher EQ5 Pro Synscan (Orion SkyView)||$790/£549||6.2||9.1||0.288||42000||-4||?/?|
|Skywatcher AZ EQ5-GT (Orion Sirius Pro)||$1300/£999||7.7||15||0.25||42000||-4||16-40/?|
|Skywatcher HEQ5 Pro (Orion Sirius)||$1115/£779||10||15||0.144||42000||Yes2||20-50/6-7|
|Skywatcher AZ EQ6-GT (Orion Atlas Pro)||$1899/£1419||15.4||18-25*||0.144||42900||Yes2||25-30/8|
|Skywatcher EQ6/NEQ6 Pro (Orion Atlas)||$1395/£999||16||18-25*||0.144||42900||Yes2||20-50/6-7|
|Skywatcher EQ8 (Orion HDX110)||$3505**/£3289||25.4||50||0.12||42900||-4||6-8/?|
|Vixen SX2 (+SB10****)||$2199/£2449||7||12***||N/A||270000||-3||?/?|
*Orion rates these at 18kg, Sky-Watcher at 18kg imaging / 25kg visual (in the graphs below the average value is used).
**The price is with the Pier, as the mount is also sold head-only.
***Vixen rates their mounts for imaging, so they are probably more modest values compared to the rest.
****The SX2 comes with the Star Book One as standard. The Star Book Ten that provides goto is added to the price to match the list’s minimum spec.
Polar Scope Notes:
1. Optional non-illuminated available.
2. Illuminated Polar scope comes standard.
3. Optional illuminated available.
4. Optional non-illuminated available that attaches externally.
Let’s make some charts. We’ll start with the Payload vs Mount weight:
A y = x/2 line is drawn and there are actually some mounts that are below it, all from iOptron, meaning they can lift more than twice their weight. The CGEM seems like a disappointing outlier, being the only mount to lift less than its own weight, but it is possible Celestron is being modest about their payload spec.
I while ago I made a comparison table for mass-production mounts under $5k and some nice charts with its data. Since I was recently looking at the mid/high end mount category, which is even less straightforward, I thought it would be interesting if I made a similar table. So, this time nicer small mounts like Takahashi and Astro-physics are included, along with observatory-grade mounts up to $15k and 100kg capacity. There’s a Celestron and a Meade thrown in because they didn’t fit the other table, but otherwise this listing contains superior quality mounts and thus things like mount capacity are not comparable the other table, as high end manufacturers tend to be very conservative with their numbers, quoting “realistic” imaging loads. As before, the specs were mainly lifted from the manufacturer page, except the peak to peak Periodic Error which is shown as a range (and before / after correction values) from various reports (this source was helpful also this and numerous CN threads).
The table will not tell you which mount to buy obviously, but it should be useful to see at a quick glance what kind of competition there is in your desired category. The prices are current at the posting of this article, but don’t expect me to keep up with price changes, I will only update if the table becomes outdated overall.
|Manufacturer / Model||Price||Mount Head (kg)||Payload (kg)||Hand-controller||Polar Scope||PE (arcsec)||PEC|
|10 Micron GM1000 HPS||$9020/£6198||19.5||25||Yes||No||1||Yes|
|10 Micron GM2000 HPS II||$13703/£9514||30||50||Yes||No||1||Yes|
|Avalon M-Zero||$4150/£3399||7.5||8||Yes||Yes, illum||10-14/-||No|
|Avalon Linear||$5160/£3840||12.5||20||Yes||Yes, illum||10-14/-||No|
|Avalon M-Uno||$6289/£4660||14.9||20||Yes||Yes, illum||10-14/-||No|
|Celestron CGE Pro||$4999/£3889||34||41||Yes||No||14-18/5||Yes|
|Losmandy HGM Titan||$5995/£5799||34||45||Yes||Opt, external||7/14/2002||Yes|
|Mesu-Mount 200||?/£5199||25.7||65||Yes||Opt, external||2-4/-||No|
|Takahashi EM-11 Temma-2||$3350/£3043||7||9||Yes||Yes, illum||7-20/-||No|
|Takahashi EM-200 Temma-2M||$5210/£4198||15||18||Yes||Yes, illum||10/-||No|
|Takahashi EM-400 Temma-2M||$9150/£7596||27.7||35||Yes||Yes, illum||10/-||No|
|Takahashi EM-500 Temma-2M||$13020/£12324||45||45||Yes||Yes, illum||7/-||No|
|Vixen AXD (Atlux Deluxe)||$7500/£7999||25||30||Yes||Yes, illum||?||Yes|
As before, we start charting with the mount head weight vs payload capacity graph:
There are two popular kinds of inexpensive solar filters which you can buy in unmounted sheets, cut them and mount them yourself. The older kind is the black polymer type, with the most famous kind (especially in the US) being the one that Thousand Oaks makes (their glass filters are also popular), while the currently more popular (at least in Europe) type is Baader’s Astrosolar safety film. I have used the Baader film for a few years, but thought I’d give the Thousand Oaks a try in case it gives me something the Baader does not.
You can get the Thousand Oaks filter directly from the US manufacturer, or you can find a bit cheaper sheets on amazon.co.uk, amazon.com or ebay (starting at around $15/£14 for a 6″x6″ sheet). The Baader film can also be found on amazon.co.uk, amazon.com, FLO and ebay with prices starting at around £20/$37 for an A4 sheet. Be careful, we are talking here about the “visual” (ND=5.0) Baader film, as there is also the photo version (ND=3.8) which is only for high-power photo use (or visual with narrowband filters) – for a test with that filter check here.
Both materials are relatively easy to cut with scissors. Don’t worry if the baader film looks crumbled when you mount it, you are not supposed to tighten it, that’s how it should be. The black polymer seems like a tougher material, but as I’ve never had the Baader tear on me with some reasonable handling, I wouldn’t say it is too sensitive. It is always recommended to check your filters for holes before your session in any case – this particular Baader hasn’t developed any in the 3-4 years I’ve been using it.
The biggest difference when you see through these two filters is the color of the Sun:
We had an unusually sunny day at Heaton Park on May 9th, so we enjoyed the Mercury Transit along with many friends from the Heaton Park astro group and even more people who where just enjoying their day at the park.
The only downside was the strong wind, which tended to cover everything with sand and was adding a constant shake to my telescope. However, after stabilizing the video from the start of the Transit is quite pleasant:
One of the most inexpensive accessories you can get for your telescope is the Baader AstroSolar safety film which you can use to safely observe and photograph the sun. Baader also has the 540nm-pass “Solar Continuum” filter to improve the definition of some solar features, so I thought I’d run a little experiment to see exactly what this filter (which actually costs quite some more than the AstroSolar film) can do for me and also try out some other filters to see whether I can get better results than using the AstroSolar film by itself. Note that the AstroSolar film covering the front aperture of your scope in full is mandatory – a filter alone at the eyepiece side of the telescope is not enough to prevent instant blindness or the destruction of your imaging sensor.
I used my Skywatcher Evostar 80ED with a full-aperture Baader AstroSolar visual film and a 2x barlow with a full-spectrum Canon 600D. Narrow-band filters like the Solar Continuum would work better with the AstroSolar photo film (allowing shorter exposures), but that seems to be out of stock right now in the UK at least, so if I obtain it in the future I might update the article. In any case, for each filter tested below, I shot a few full frames of the solar disk, of which I stacked 3-4 to reduce noise, and also a short video in 3x Digital Zoom video mode stacking about 250 out of 1000 frames after converting it to grayscale and having the same wavelet sharpening applied to all cases.
UV/IR Filter (Optolong)
Since I was using a full-spectrum modified DSLR, the UV/IR filter is the “no additional filter” equivalent case. So this is what the AstroSolar film can do by itself at the visual part of the spectrum:
A couple of years ago I got one of the most popular Equatorial mounts for small to medium OTAs, the Skywatcher HEQ5 (known as the Orion Atlas outside Europe). I got along pretty well with it, it was paired mostly with an 8″ Skywatcher 200PDS newtonian which is near the maximum comfortable load. I stored it in a corner of the living room, although I had to loosen the accessory tray, rotate it so that the legs could be contracted to fit it through doors when taking it in or bringing it out of the house. At around 15kg for mount & tripod it was near the limit of what I would personally call portable. Then, last year, as I was considering upgrading my mount to the pro version, I started reading about the iOptron ZEQ25. Apparently, iOptron are relatively well known and popular in the US, but have only recently started becoming known in Europe. They have some “traditional” German equatorial mounts (the iEQ line), but also the “Z” or “center balanced” equatorial mounts ZEQ25 and CEM60. The latter are supposed to have the advantage of an increased load/weight ratio and a permanently unobstructed polar scope. In fact, the “small” ZEQ25 has a maximum load not far from my HEQ5, while being significantly much lighter. And this is the main reason I got it. I thought that a smaller, lighter mount would allow me to take it out more often and if I wanted to do astrophotography it would be well matched with a small apo refractor, making a very portable package.
While I started writing this review soon after I got the iOptron, for some reason it was left unfinished and unpublished. So I am finishing it up now, a year after getting the iOptron, having had more experience with it. In the meantime, iOptron has upgraded the electronics of the mount and renamed it to CEM25 (although, at least in Europe, it is not easy to get the updated mount yet) and also I got a new HEQ5 Pro for my vacation home (since I found an amazing deal on it), so I can do an even better comparison with it. (more →)
Although I got my C9.25 mainly for planets, the fact that my tiny iOptron ZEQ25 mount seems to handle it for longer exposures made me look into using it for DSOs as well. The problem of course is that it is quite slow at f/10, has a very demanding 2350mm focal length and has quite some coma on an APC-S sensor. Supposedly all these problems can be abated with the Celestron f/6.3 reducer/corrector (1480mm focal length, 2.5x less exposure, less coma), which is also relatively inexpensive as far as reducers go. One issue I found before trying the reducer is that there is not much info on using these photographically. Even the included Celestron manual doesn’t mention anything about proper distance from the sensor, how much correction it does (it vaguely says that it improves but does not eliminate) and what about things like vignetting? So I did some experimenting with my Canon DSLR and wrote down my observations for myself and whoever is planning to use one. (more →)
I’ve already tried this refractor Field Flattener on a SkyWatcher Evostar 80ED in a previous post. To sum it up, it did perform well on the Evostar and the best value was the Starguider 2″ Field Flattener sold by Sky’s the Limit on ebay.co.uk, which is identical to the TSFlat2 from TS (but the TSFlat2 is more expensive and does not include any adapters/extensions). So, without any delay here is my first test with the flattener at 119mm from the Canon 600D sensor:
I finally had time to process my photos from my “Supermoon” lunar eclipse photo session at Salford Observatory. It was a very cold and humid night, 4 people showed up, 3 stayed until at least after the eclipse maximum, but it was the best lunar eclipse I’ve observed (large moon and very nice red color – due to rayleigh scattering of course). It was my first ever session for both my Skywatcher Equinox 80 ED refractor (on the iOptron ZEQ25) and the Canon 600D which was un-modded at the time. The reason I did not make an eclipse post earlier is because I wanted to make a nice time-lapse video, something that takes a little time. It covers the eclipse from the start to the maximum (2h 50m) later and I hope the result is pleasing (try full screen HD):
For more pics and the how and why of the session and the timelapse, read on.
The not so young amateur astronomers like myself who were aware of how difficult and demanding planetary photography was in the “old days” (i.e. 20th century) are pretty amazed at what you can achieve nowadays with equipment as simple as a webcam. Granted, most of the “magic” lies in the software processing that stacks hundreds of mediocre frames in a video to produce a sharp, detailed image of a planet, however the hardware is still important. So, after experimenting with their webcam, people want to try something better. Specialized planetary/guiding cameras are the obvious choice, however people put in good use less expensive solutions, like putting the LiveView-capable DSLR they already have in planetary use, or re-purposing an Industrial/Machine Vision camera. I happen to have gone through all these categories and thought about putting all my imagers to the test to see what you can expect from each.
There is a new link on the left that says “AstroBuySell Alert” that should be useful to UK and Canada users looking for 2nd hand equipment. Just set up an alert for something you are looking for, and the alert service (currently in beta test) will send you an email when something appropriate comes up!
The number one enemy of planetary photography is the atmospheric condition, or “seeing”. Despite modern software being able to select and stack the best frames among thousands, the difference between results with good vs bad seeing can be great. Shooting at high FPS (60 or more) and using shorter exposures with sensitive cameras can help. An even better tool, especially for people who shoot with monochrome cameras, is to get a luminance frame through an IR-pass filter. Here is an example from last night using my C9.25 @ f/25 and a QHY5L-IIm camera, the left photo using for luminance a shot through the usual IR-cut filter, while the right one through an IR-pass (a “generous” one at 630nm), both processed with the same Registax 6 settings:
As you probably know, the best way to capture a good quality video of a planet is to shoot a video and combine the hundreds or thousands of frames using the magic of stacking software. That’s why a simple webcam will give you a better result than a single shot with your fancy Canon EOS DSLR. You also can’t use your DSLR’s regular video mode, as it only captures the large area that a DSLR sensor covers at a low resolution, giving you a low quality planetary image just a few pixels across. What you need is a way to capture in video all the pixels of one part of your large DSLR sensor. If you happen to have a 550D/T2i or a 60D, there is a “video crop mode” that does exactly that (at a nice 60fps). However, even if you have any other Canon EOS with live-view there is a way to get a 1:1 pixel video by capturing your 5x live-view with the help of a connected PC. This will allow you to get better planetary videos than with a simple webcam, so while there are dedicated planetary astro-cameras that are cheaper and much better at this than a DSLR, you can get some good results if you already have a Canon EOS and use the appropriate software: