Baader Astrosolar vs Thousand Oaks Black Polymer solar filter

September 11, 2016 // by ecuador

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.

The Material

SolarFilters

Baader on the left, Thousand Oaks on the right

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.

First impressions

The biggest difference when you see through these two filters is the color of the Sun:

Baader Astrosolar Safety Film

Baader Astrosolar Safety Film ISO100 1/160s

Thousand Oaks Black Polymer

Thousand Oaks Black Polymer ISO800 1/80s

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2016 Mercury Transit @ Heaton Park

May 13, 2016 // by ecuador

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.

HeatonParkMercury

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:

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Imaging the sun in white light and Baader Solar Continuum or other color filters

May 7, 2016 // by ecuador

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.

Setup

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

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:

Sun_80ED_20160504

UV/IR ISO 200 1/500s

Sun_80EDx2_20160504

UV/IR 30s video stack

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Review: iOptron ZEQ25 (CEM25)

April 12, 2016 // by ecuador

7100-2

Update: See how the ZEQ25 compares to the CEM25P update in my latest review.

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 →)

Celestron f/6.3 reducer/corrector with DSLR on C9.25

March 31, 2016 // by ecuador

reducerAlthough 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 →)

Starguider 2″ Field Flattener (TSFlat2) on SkyWatcher Equinox 80 ED

March 2, 2016 // by ecuador

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:

EquinoxTSFlat2B

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28/9/2015 Lunar eclipse photos & time-lapse

December 24, 2015 // by ecuador

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.
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Planetary imaging comparison: Webcams vs DSLRs vs Planetary Cams

August 27, 2015 // by ecuador

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.

From left to right: Canon 450D, Xbox Vision, QHY5L-IIm, Point Grey Firefly MV, Logitech Quickcam Pro 3000, Canon 550D

From left to right: Canon 450D, Xbox Vision, QHY5L-IIm, Point Grey Firefly MV, Logitech Quickcam Pro 3000, Canon 550D. A Canon 600D was obtained last minute, so it is missing from this photo.


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Planetary photography quick tips: IR filters & PIPP

July 5, 2015 // by ecuador

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:

L+RGB light sharpening

L+RGB light sharpening

IR+RGB light sharpening

IR+RGB light sharpening


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Planetary Photography with a Canon EOS and a Tablet

June 21, 2015 // by ecuador

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:

Jup127

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EOS Camera Movie Record Tablet Tweak

May 8, 2015 // by ecuador

  • Update July 6 2015: Canon SDK update with support for EOS 5DS/760D/750D.

There is a nice little free program called EOS Camera Movie Record that allows you to capture 5x live-view video from your camera, which is the best way to do planetary photography for most Canon DSLRs (with the exception of 550D and 60D which have the superior “video crop mode”). There are better programs like BackyardEOS to do this, but they are not free.

In any case, I sometimes want to use it but don’t want to carry a laptop, so I tried it with my wife’s Windows Tablet. It worked, however the buttons were too tiny to hit without a mouse. Fortunately, the software is open-source, so I build a custom binary with larger buttons. Here it is in case anybody needs it.

Download EOS Camera Movie Record 0.3.3 beta – Tablet Tweak b2
(Changes: Larger buttons, links to the latest Canon SDK with 7D mk II/5DS/760D/750D support)

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Review: Celestron Vibration Suppression Pads

April 30, 2015 // by ecuador

VSPMy first telescope returning to astronomy after many, many years was a Celestron NexStar 127SLT Maksutov-Cassegrain with an alt-azimuth goto mount. I have to admit that I was not  very happy with the mount. The biggest problem was that it would vibrate very easily and the vibration would take 5-6 seconds to subside. It made even focusing hard.

So I saw the Celestron Vibration Supression Pads (VSP) and thought I’d give them a try. They are not very cheap, especially in Europe they cost around £60, while they are a more manageable $40 in the US. There are other much cheaper versions, like “Seben” in Europe, or “Solomark” and various Chinese unbranded ones, which might or might not be similar. But I went ahead with the Celestron VSP, just to make sure that if they don’t work, I won’t have to wonder whether the more expensive ones would have worked.
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First Impressions: ADM Vixen Saddle for ZEQ25

April 18, 2015 // by ecuador

ADM
Although I am very happy with my iOptron ZEQ25 mount and would recommend it over the more popular (in Europe) skywatcher offerings, there are some areas where it could be improved. The first thing that comes to mind is the dovetail saddle. On paper and on first look it seems like a winner – it seems like a nice spring-loaded saddle that is not cheaply made and will easily secure your dovetail (without marking it). The biggest problem is that it has sort of an extra extrusion which, if you are not careful (e.g. in the dark) can “grab” the dovetail and you might think it is secure when it is not. The second problem is that the screws come dangerously close to the Dec house mounting, even rubbing against it (giving the motor a hard time) at least on my mount for a specific angle of the thumbscrew. Lastly, the two thumbscrews are not much spaced-apart, and that can make it harder to comfortably get a good grip in freezing temperatures.

Enter the replacement saddle from ADM that various ZEQ25 users have been praising. I decided to order one, even though it does not come very cheap at $99 before tax/shipping. Opening the box at least was not a disappointment, quality-wise the money seems well spent – it looks as well made and well finished as you can make a saddle. Replacement was a breeze. In 5 minutes you can remove the Allen screws from your iOptron saddle and use them to secure the ADM one. And then you get to use it…

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2015 Solar Eclipse @ Heaton Park, Manchester

March 20, 2015 // by ecuador

Well, that’s it for Europe until 2026. We had a nice gathering with a lot of people of all ages at Heaton Park, Manchester today, however the weather was not favorable. We did lose the sun completely near the maximum (and I don’t mean the moon covered it – it was due to thick clouds) and people were trying to figure out why the solar shades were not working (the clouds were already filtering the sun, hence they were not needed), but otherwise it was good, everybody seemed to have a good time.

A few shots with the Canon 550D through the Skywatcher 80ED (Baader astrosolar ND 5.0), with the sun behind the clouds:

IMG_3945b IMG_3947b
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