astrophotography

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Planetary alignment and Milky Way over Australia’s iconic Craig’s Hut in Victoria’s Alps – Olympus f/1.8 fisheye comes to the fore

Monday, February 8th, 2016

January 2016 was a month in which the planets aligned themselves nicely, and last night I took advantage of a few days off with lovely warm sunny days and clear night skies to head up to the rather remote Craig’s Hut at the rooftop of Victoria’s Alps and well away from major light pollution.

The original Craig’s Hut was built for the set of the Australian movie, The Man From Snowy River, but it fell into disrepair and was destroyed by a major bush fire in Dec 2006 (after reading the last blog post, you may be learning a theme – we cannot take things for granted in Australia, bushfires are a constant and increasing threat). It was re-built although not to the original specs, and despite this has continued to be an iconic image of Australia’s High Country which is dotted with huts although most have burnt down in fires and some re-built to provide shelter for hikers and skiers.

Road access to Craig’s Hut is 286km and just over 4hrs drive from Melbourne via Mansfield and Mt Stirling’s Circuit Road – a further 20km drive along a gravel road from the Telephone box Junction (TBJ), and if you have a 4WD with sufficient ground clearance, you can drive right up to the hut where there is a remote camp ground and drop toilet.

If, like me, your car is likely to bottom out on the access road to the hut, your main option is to leave the car in the parking area on the Circuit Road, and back pack up a grade 4 quite steep but well formed 1.7km walking trail which requires some 170m ascent but is readily doable even with a heavy pack and large tripod.

You can’t camp or stay in the hut grounds itself, and the water at the toilets is not potable. Hikers generally camp near these toilets amongst the snow gums, while 4WD campers use the dedicated camp ground some 100m lower down.

For some reason there do not appear to be the annoying aggressive alpine ants which gave me trouble at nearby Mt Stirling (see my blog post on this solo camp trip), and there were no mosquitoes of note, but lots of flies as soon as the sun rose.

Let’s get into some pics (all taken with the Olympus mZD 8mm f/1.8 fisheye lens):

sunset

Sunset on Craig’s Hut – note that you get 270deg views from the hut – all except the SW quadrant, this view is looking north towards Little Cobbler.

Magellanic Clouds

Evening shot of the Milky Way around Centaurus and Southern Cross with the two Magellanic Clouds rendered in sepia toning.

planets

This is the shot I was waiting for and why I only managed 3 hours sleep, although I did extend my iPhone alarm to give me just that bit more!
This is just before sunrise and shows the centre of our Milky Way galaxy rising above the hut with the constellation of Scorpio directly above the hut and a meteor and the 4 planets visible:
Mercury near the fence, Venus the bright one above the fence near the hut roof, Saturn below Scorpio, Mars high above the chimney (Jupiter is out of this frame).

Milky Way

The Milky Way arching over with astronomic twilight well gone just before sunrise.

jupiter

Jupiter high above the hut at dawn – hand held with camera resting on the fence for a 1 second exposure!

dawn

Just before the sun’s rays peaked over the alps but this image was shot with the Olympus mZD 12-40mm f/2.8 Pro lens.

I had a great time up there, even though this place has been photographed in almost every way possible, I am guessing this is the first time it has been imaged with a f/1.8 fisheye lens!

The Micro Four Thirds system’s weight makes uphill hiking such as this so much more enjoyable than a full dSLR kit, while the fisheye lens means I don’t have to waste my life doing panoramic stitches!

a lunar interlude – shortest lunar eclipse in 500yrs – and our last blood moon for 3 years

Sunday, April 5th, 2015

Last night (4th April 2015) we witnessed our last total lunar eclipse for the next 3 years and apparently the shortest in the past 500 years.

Shooting a total lunar eclipse at totality is challenging however there are are nice features on the Olympus OM-D cameras which do help such as:

  • continuous live view – no need to always be resorting to mirror lock up as on a dSLR
  • magnified live view to allow accurate focus which is actually quite difficult near totality
  • relatively cheap and high quality telephoto reach with the Olympus ZD 50-200mm f/2.8-3.5 SWD lens with Olympus EC-20 2x teleconverter
  • reasonable ISO performance at ISO 1600

So here are a couple of mine from last night taken with the Olympus OM-D E-M1 with Olympus ZD 50-200mm f/2.8-3.5 SWD lens with Olympus EC-20 2x teleconverter to give 800mm focal length (in 35mm full frame terms), on a tripod with IS turned off, but with 12 sec self timer ON to reduce camera shake. Both taken at f/7, 1/2 sec, ISO 1600 and have had some cropping done but minimal processing in Lightroom.

Some cloud over the 1st one:

eclipse

eclipse

Nikon’s new D810A astrophotography dSLR – why bother?

Wednesday, February 11th, 2015

Nikon has just announced a special version of the Nikon D810 full frame dSLR, the D810A designed purely for astrophotography.

So what is different about it?

  • infrared filter has been modified to allow the H-alpha 656nm wavelengths of light to better image certain nebulae
  • additional features to support long exposure photography:
    • Long Exposure M mode that provides selectable shutter speeds from 4 to 900 sec (15 minutes) – similar to the Olympus Timed BULB mode
    • a virtual exposure preview in bulb and time settings, similar to Olympus Live Time mode
    • a dark frame subtraction mode (called ‘astro noise reduction’ in Raw) – and I thought all cameras had this already!
    • red virtual horizon, so as not to interfere with night vision
    • ability to dim the viewfinder’s OLED

It will set you back $US3800 for the body only.

Is it worth it?

Maybe to some astrophotographers who are just into Milky Way landscape shots but really keen astrophotographers need more than this in an astro camera, such as:

  • cooling of the sensor
  • no SLR mirror to cause camera shake (the mirror is pretty much useless for astrophotography anyway)
  • electronic view finder with Live Boost (as with Olympus OM-D cameras)
  • WiFi full remote control to avoid touching the camera and causing shake

These keen astrophotographers would be looking more to modifications of cameras such as performed by CentralDS

For instance they will take apart your Canon EOS 5D Mark III and totally transform it by removing the mirror housing, changing the IR cut filter, adding in a cooling system for the sensor to keep thermal noise as low as possible, adding in a drop-in filter system, etc.

Perhaps a better suited camera is a mirrorless camera, and so this company will also modify your Sony A7s mirrorless full frame camera and turn it into a dedicated cooled astro camera with IR filter replaced for under $US1000 which should give far better results than an uncooled Nikon D810A:

modified Sony A7s

and this is what happens to thermal noise when you use a cooled camera vs un-modified camera:

thermal noise

Lunar eclipse over Melbourne

Friday, May 2nd, 2014

Last month’s eclipse of the moon at moonrise in Melbourne was quite challenging to photograph.

It would have been nice to find a location with the city’s buildings in the foreground, but given the position of the moon rise this was not easy and thus a spot along the shores at Williamstown was chosen which looked across the bay towards St Kilda’s Palais Theatre.

The very dim eclipsed moon was difficult to see rising over the Dandenong Ranges in the distance and it was not until it was some 5 degrees above the horizon that it could be seen through the autumnal haze. Manual focus was made much easier with the electronic viewfinder and image stabilisation during magnified view using the Olympus E-M5 camera.

My initial attempts were with the Olympus E-M5 with Olympus ZD 50-200mm f/2.8-3.5 lens with 2x converter (the EC-20) at full 200mm focal length giving an equivalent field of view of 800mm on a 35mm camera.

This is a favorite set up of mine for the moon but being so low and with the atmospheric disturbances it was not possible to get sharp imagery of the craters.

Timing of the shot of a lunar eclipse is quite critical as the most aesthetic image is when the sunlight just starts to hit the edge of the moon (as shown below).

I then resorted to doing wider angle shots to show the yachts anchored nearby, so here is my version of the lunar eclipse:

lunar eclipse

EXIF: 100mm focal length (50mm + 2x telecoverter = 100mm in Micro Four Thirds crop = 200mm in 35mm full frame equivalent), ISO 1600, f/7.1 (f/3.5 x 2), 1/4sec, tripod mounted.

See my wiki for how to photograph the moon.

At last! Comet ISON C/2012 S1 brightens after an outburst – should be an interesting couple of weeks

Saturday, November 16th, 2013

We all love comets, especially if they are bright, naked eye comets as these are quite uncommon.

For us in the southern hemisphere, comet ISON C/2012 S1 will only be visible BEFORE it passes around the sun on 28th Nov 2013,  and even then it will be difficult to see low on the east horizon just before sunrise.

But, for those with motor driven telescope mounts and cameras with wide aperture telephoto lenses, it may be an opportunity to capture some lovely images such as this one by Damian Peach which was taken yesterday after the comet had suddenly brightened to magnitude 5.3 after an outburst:

comet

This 2.5 deg wide image was created by stacking 5 x 2 minute monochrome “L” images with a 2 min color “RGB” image using a SBIG STL-11k CCD astro camera mounted on a 105mm aperture f5.0 telescope (ie. focal length = 525mm).

A very cool animation posted on SolarSystemScope.com:

For those in northern hemisphere, especially at latitudes north of 30deg N, if this comet survives perihelion, it may become a lovely naked eye comet like the one I took of comet McNaught below – only time will tell.

comet McNaught

My photo of comet McNaught taken 23rd Jan 2007, Olympus E330 dSLR, 60sec, ISO400, Zuiko 50mm f/1.4 lens at F/2 in a rural region see HERE for more of my photos and info on comet McNaught P1

Hopefully the skies will clear next week so I can try some imaging myself with my Olympus OM-D E-M5 Micro Four Thirds camera with my Canon EF 135mm f/2.0 L lens.

 Unfortunately for us in the southern hemisphere, the comet has become very difficult to see in the morning twilight as it has not become bright enough to offset the atmospheric extinction of being close to the horizon, as well as being close to the sun and with moonlight increasingly becoming a compounding issue  – not to mention the low pressure trough bring clouds to much of Australia from 20th November onwards.

Update 26th Nov: reports that the comet may be disintegrating however, this is far from conclusive – see Ian Musgrave’s blog post

Comet C/2011 L4 PANSTARRS with Olympus E-M5 and 75mm f/1.8 lens – time to get your camera out on the 12th March for crescent moon and comet image!

Monday, March 11th, 2013

2013 is shaping up as a great year for astrophotographers with a few comets around to have fun with although none as aesthetically beautiful as the awesome Comet McNaught of 2007.

I recently posted an shot of comet Lemmon as it passed the Tucanae globular cluster and the Small Magellanic Cloud galaxy here.

On the 2nd of March 2013, I drove down to one of Melbourne’s bayside beaches to get a shot of Comet C/2011 L4 PANSTARRS comet just after sunset using the Olympus E-M5 Micro Four Thirds camera with Olympus 75mm f/1.8 lens mounted on a tripod.

Unfortunately I miscalculated where the comet would set in relation to the beach and highway traffic headlights became problematic, nevertheless I think it is a lovely shot with the Dromana beach on a balmy warm night as a couple enjoyed the romantic ambience oblivious to the comet.

ISO 3200, f/1.8, 1 second exposure:

comet

Tomorrow night (12th March 2013) at sunset for those in Europe, America and Africa, they should get a lovely opportunity to photograph a thin crescent moon next to the comet just after sunset – unfortunately in Australia, the moon is too close to the sun at sunset and will set before the comet becomes visible in the twilight, although we may get a chance the following night on the 13th March if clouds do not obscure the view.

Occultation of Jupiter by the moon – using the Olympus E-M5 and iPhone TriggerTrap app

Tuesday, February 19th, 2013

Last night Jupiter was occulted by the moon as outlined in a previous blog post here and this makes for a nice photographic challenge for astrophotography enthusiasts.
It was only visible from southern areas of Australia, the best sites were in Western Australia where the event would take place at a higher altitude and thus allow better seeing conditions.
Unfortunately for much of South Australia and Victoria cloud due to an upper level trough and incoming cold front combined in some areas with bushfire smoke, made site selection critical to any chance of capturing this event.

The weather forecasts and SkippySky suggested that central Victoria should be reasonable and thus we decided to stay overnight in the historic gold mining town of Maldon and set up near the top of nearby Mt Tarrengower.

Unfortunately the clouds were closing in fast from the south west so we decided to head north-east to a site near Goornong, not far NE of Bendigo.

Even here the clouds and bushfire smoke adversely impacted our viewing and the seeing conditions, particularly for reappearance were poor making it difficult to capture the bands on Jupiter or to gain sharp images of the lunar craters at high magnification.

This is where a mirrorless camera such as a Micro Four Thirds Olympus OM-D E-M5 with its 9fps burst rate and ability to fire this remotely using the iPhone app called TriggerTrap for which you need to buy the dongle to attach the iPhone to the camera.

A mirrorless camera is critical as a dSLR becomes a nuisance managing the mirror lock up and live view.

The pixel density of the E-M5 combined with its good dynamic range and high ISO capabilities makes it an even better sensor than a Nikon D800 for imaging Jupiter as Jupiter will have ~50% more pixels in size on the final image when using the same telescope systems.

For the highly magnified images, I used a 10″ Newtonian reflector telescope with 25mm eyepice and the afocal method by attaching the E-M5 camera with the Olympus 75mm f/1.8 lens to the telescope eyepiece.

I set the E-M5 to:

  • highest quality jpeg only (to maximise burst shooting with minimal owntime as the buffer writes to card)
  • manual focus
  • High speed burst
  • Live Boost OFF (otherwise the display becomes over-exposed for such bright subjects as Jupiter)
  • manual exposure – ISO 800-1600, 1/80th sec (slower when the clouds came over and the moon was setting lower)

The critical aspect is accurate focus and the Live magnified manual focus function greatly assists this.

Then it was a matter of waiting for the breeze to settle momentarily and fire of bursts of shots hoping that one will be sharp given the microsecond atmospheric changes in seeing conditions – the trick is to take as many shots as you can – as in poor seeing conditions such as we were experiencing perhaps only 5% will be reasonably sharp and detailed.

Initial occultation phase being hidden by the dark limb of the moon taken at ISO 800, 1/80th sec:


1st phase partial occultation

 

Reappearance of Jupiter with significant deterioration in viewing conditions taken at ISO 3200, 1/15th sec :


reappearance

Finally, a romantic bushfire smoke colored moonset with Jupiter below the moon – taken with the E-M5 using a Canon EF 135mm f/2.0L lens at ISO 3200, 1/10th sec, f/2.0:


moonset

 

It was a beautiful night out with balmy 30degC warm breezes and an absolute pleasure using the E-M5 with the TriggerTrap app – make sure you leave the apps “Focus” to ON even though you have set camera to MF as otherwise it does not seem to trigger. I used the Bulb mode on the app – just hold button down for a series of bursts then release.

More on astrophotography here, and more on lunar occultations here.

Comet Lemmon (C2012/F6), 47 Tucanae globular cluster and Small Magellanic Cloud imaged with the Olympus E-M5 camera

Sunday, February 17th, 2013

It has been an exciting week in the astronomy world with the near miss asteroid this morning following on from the amazing fireball meteorite over Russia which created shockwaves sufficient to break window glass an injure hundres of people.

In my last blog post I explained in detail the forthcoming occultation of Jupiter in southern Australia (mainly Perth and NE Victoria due to the expected cloud conditions elsewhere).

And tonight, I had the pleasure of photographing one of the 2 reasonably bright comets that are in the sky at present – the one I imaged was comet Lemmon which is passing the beautiful globular cluster 47 Tucanae and our neighbouring galaxy, the Small Magellanic Cloud.

This image was taken on 16th Feb 2013 with the Olympus E-M5 Micro Four Thirds camera mounted on a equatorial mount unguided for 60secs using a Canon EF 135mm f/2.0L lens at f/2.0 and ISO 3200. The long dimension of the image represents ~7 degrees field of view.

No cropping, just minimal tonal adjustments and some purple defringing:

 

Lemmon

I initially imaged it with the awesome Olympus 75mm f/1.8 lens at f/1.8 which gave excellent images apart from a touch of aberrations on the far edge. However, the field of view was twice as large as I needed for this shot, so I had to resort to the Canon 135mm lens to get the field of view exactly right.

Photographing the Feb 2013 lunar occultation of Jupiter from southern Australia

Sunday, February 3rd, 2013

Those of us who live in the southern parts of Australia may be fortunate enough to photograph this lovely celestial event which will take place about midnight on Monday 18th February 2013 in Victoria, but just after sunset in Perth.

The highest quality images of Jupiter will not be possible in Eastern states due to the event taking place very close to the north-west horizon and thus high resolution imaging will not be anywhere near as detailed as if Jupiter were high in the sky where there is less atmospheric disturbances.

Nevertheless it should be a fun and rewarding event for those who have the equipment and are prepared to do some planning.

As a minimum one would need a super telephoto lens with effective focal length of at least 600mm in 35mm full frame terms – the more the better, plus a sturdy tripod.

Those wishing to taking highly magnified images will need to attach their camera or video cam to a good telescope on a sturdy motor driven equatorial telescope, although with some hard work, a Dobsonian mounted telescope will be possible given the short exposure.

Traditionally, the best images of Jupiter are taken using a video camera attached to a telescope shooting frames at 10-60fps for up to 1 – 2 minutes (longer than 2 minutes causes blurring due to the rotation of Jupiter interfering with images), and then these images are stacked using special sofware such as Registax, then sharpened using wavelet or deconvolution technologies, then contrast is adjusted to get the final image.

The occultation of Jupiter will limit this approach as there is also the confounding movement of our moon.

Interpreting the astronomic data:

  • the moon phase will be 56% which is a touch after 1st quarter being at an angle of 97deg to the sun in relation to earth
  • the northern limits of visibility of the occultation (where it will be a grazing occultation) is an almost linear line running from near Canarvon in Western Australia, through just north of Flinders Ranges in Sth Australia, then to just north of Albury in NSW. there is no southern limit in Australia however, Hobart will not be able to witness the reapparance phase as the moon will be setting.
  • it will not be visible in any other country.
  • for Melbourne (latitude 37deg 43.7 south)
    • Jupiter will disappear behind the dark part of the moon at 12h 32:56 UTC (add 11 hours for AEDT daylight saving to give 23:32:56 local time) and will be 11 deg above the horizon at azimuth 307deg (37 deg north of true west)
    • Jupiter will reappear behind the bright part of the moon at 13h 10:01 UTC (add 11 hours for AEDT daylight saving to give 00:10:01 local time) and will be 5 deg above the horizon at azimuth 301deg (31 deg north of true west)
  • for Perth (latitude 31deg 56.4 south):
    • Jupiter will disappear behind the dark part of the moon at 11h 39:43 UTC (add 8 hours for WST to give 19:39:43 local time, ie not long after sunset) and will be 36 deg above the horizon at azimuth 344deg (74 deg north of true west)
    • Jupiter will reappear behind the bright part of the moon at 12h 45:38 UTC (add 8 hours for WST to give 20:45:38 local time) and will be 30 deg above the horizon at azimuth 327deg (57 deg north of true west)

Choose a camera, preferably a mirrorless one:

If you wish to use a camera instead, the best camera to choose would be one of the latest Micro Four Thirds cameras such as the Olympus E-M5, E-PL5 or the Panasonic GH-3 for the following reasons:

  • the pixel density is higher than on any dSLR and thus Jupiter, which has a diameter of only 0.01 arc seconds, will cover many more pixels (and thus theoretically capture more detail) on one of these cameras than on a dSLR for a given lens or telescope set up – here is the math:
    • if using a 5000mm effective focal length telescope, this will cast an image of Jupiter of only 0.9mm on the sensor
    • if you use a 36mp Nikon D800 full frame camera, Jupiter will cover 150 pixels
    • if you use an Olympus E-M5 camera, Jupiter will cover 240 pixels – that is 60% more pixels available
  • you will generally only need ISO 1600 on a 10″ Newtonian telescope to give a shutter speed of 1/600th sec at f/20, although if using a 3″ refractor telescope, you will need to be using closer to f/66 to achieve 5000mm focal length, and thus you may need ISO 6400 and shutter 1/300th sec
  • there is no mirror so you do not constantly need to be putting the camera in mirror lock up mode (not doing this will destroy your image detail by causing vibrations from the mirror)
  • they are designed for continous live view and magnified live view to assist manual focus is easier to access
  • the E-M5 can shoot at 9fps if you did want to select out the sharpest images or stack them – but you will want a remote shutter cable to avoid shaking the camera, and consider just shooting jpegs to avoid having to wait for the buffer to empty after a burst (use a fast SD memory card to optimise this)
    • hint: use TriggerTrap iPhone app and dongle connected to the E-M5, set E-M5 to Hi Drive mode, set exposure to desired shutter speed (not Bulb as suggested by TriggerTrap), and either use:
      • TriggerTrap “Cable Release” mode and hold iPhone app shutter release down for duration of burst – perhaps the easiest mode to use!
      • TriggerTrap “Timelapse” mode to duration (eg. the minimum of 13secs), and number of photos to desired number, press and release the app button and the app will control shutter release, although, as the camera’s cache is saturated, capture rate declines while the app still keeps pretending photos are being taken at the set rate.
      • works with iPhone 5 as TriggerTrap uses the headphone socket
  • they are amongst the lightest cameras which is handy when mounting on telescopes

First, the super telephoto approach:

  • sturdy tripod
  • super telephoto lens attached to camera of choice, lock the focus and change to manual focus
  • aim to compose image aesthetically in relation to horizon subjects
  • if you are lucky enough to have a few small clouds around, time it so the cloud is covering the moon and not Jupiter to better balance the contrast in brightness
  • consider 2 types of exposures (but bracket these to get the best for your set up and allow for atmospheric extinction if low altitude as they will be this time):
    • one for Jupiter itself eg. ISO 400, f/8, 1/600th sec
    • one for the Jovian moons and earthshine on the dark part of the moon: eg. ISO 400, f/8, 1 sec
  • don’t forget mirror lockup and use the self-timer to reduce camera shake

The telescope approach:

  • ensure telescope temperature has equilibrated by leaving outside for several hours to reduce poor refractive effects inside the telescope
  • if the telescope is a reflector, ensure it is accurately collimated
  • use an equatorial mount where possible and try to get reasonably accurate polar alignment – given the short exposures, precise alignment is not needed unless you are stacking many images
  • don’t forget to have the battery fully charged to drive the mount
  • decide between:
    •  prime focus (no eyepieces but lower magnification, although can use teleconverters)
    • eyepiece projection (use eyepiece and special eyepiece projection adapter for higher magnification)
    • afocal technique (use eyepiece and camera lens – useful for point and shoot cameras where the lens cannot be removed)
  • ensure focus is precise
  • consider 2 types of exposures (but bracket these to get the best for your set up and allow for atmospheric extinction if low altitude as they will be this time):
    • one for Jupiter itself eg. ISO 1600, f/20, 1/600th sec
    • one for the Jovian moons and earthshine on the dark part of the moon: eg. ISO 1600, f/22, 1 sec
  • don’t forget mirror lockup and use the self-timer to reduce camera shake
  • consider burst shots or video mode to help address issues with poor seeing conditions

Choose a location:

  • this is particularly a problematic issue with this occultation given it occurs so close to the N-W horizon
  • in Melbourne, the disappearance phase occurs when it is 11 deg above the horizon and the reappearance phase occurs when it is only 5 deg above the horizon
  • Perths viewer are much more fortunate here, as it starts at 36 deg above horizon with reappearance at 30 deg above horizon, so they should get far better images that the eastern viewers
  • so those in Melbourne would do best to find an elevated position with a clear view to the NW (the disappearance occurs at azimuth 307 deg (37 deg north of west) while the reappearance occurs at 301 deg (31 deg north of west) )
  • the good news is that light pollution is not such an important factor – it could be done in a suburban backyard if you can see the event without trees, buildings or mountains intervening.
  • determine horizon – given it will be just 5 deg above the horizon for the last phase in Victoria, Victorians may well wish to calculate how far east of a mountain they need to be so it does not hide it:
    • a top of a mountain will hide the horizon, if the viewer is within a certain range dependent upon the relative height of the object (eg. mountain or trees) above the viewer:
      •  ignoring refraction of light issues, the approximate distance in km = 3.57 x square root (height difference in metres)
      • thus for a 100m hill, the viewer should be more than 40 kilometres away if they wish to see the horizon without the hill intervening
      • for a 400m mountain, the viewer should be  more than 70km away
      • the Lerderderg State Park rises to over 500m and is NW of Melbourne and one needs to be 80km away
      • Mt Macedon at 615m height requires the viewer to be more than 90km away unless they can stand on another mountain
  • search for a site on Google maps in topography mode (so you can see heights of hills)  and use a paper triangle cut out to ensure line of site is clear of hills or mountains:
    • using A4 sheet of paper, use its width of 21cm as your East-West base, create a triangle with a north-south side of 15.8cm (for 307deg) and mark on it a 2nd hypotenuse line at the 12.6cm mark for the reapparance at 301 deg (assuming you are in Victoria)
    • hold the triangle with the right angle corner in your left hand, holding the base parallel with your screen, and the right side apex on your location.
    • the hypotenuse will then be your line of site to the occultation
    • for other locations with different azimuth readings, use N-S paper measure = E-W paper measure x tan (azimuth-270deg)
    • your selected site should also be able to be easily accessible with a telescope and on public land, and have no trees to the north west
  • lastly, the location should preferably be out of the prevailing wind on the night – in Victoria, this is usually south-westerly but may be westerly or north-westerly and occasionally south-easterly or easterly
  • potential locations near Melbourne include Mt Dandenong, Mt Macedon, south-west of Geelong, north-east of Ballarat, areas north of the Great Dividing Range.

 Then you need the weather to be kind:

  • thick cloud will obliterate your chances, as will any significant cloud on the horizon which does take a long time to move out of your way
  • strong winds will play havoc with your ability to keep the set up still
  • as it is summer, a hot day could really affect your telescope’s seeing if it is left in the hot car so give it plenty of time to equilibrate with the night air
  • seeing is likely to be poor at such low altitudes – unless you are in Western Australia, good details on the planet Jupiter will be hard to capture, you may just have to accept the outline of it’s bands.

If you plan well, practice and are lucky with the weather, you may be able to capture an image similar to this grazing occultation I took using a Canon S30 point and shoot camera through a 10″ Newtonian in 2005:

 

Jupiter

see also my wiki page on photographing occultations which also has links to data and maps for this occultation

BONUS: 2 fairly bright comets to photograph!

You may as well tackle 2 fairly bright comets if the conditions are good, you are away from light pollution and can piggyback your camera on a motor-driven equatorial mount telescope:

  • comet C/2012 F6 Lemmon
  • comet C/2011 L4 (PANSTARRS)

Appendix – examples of Olympus E-M5 for Jupiter:

  • Olympus ZD 50-200mm f/2.8-3.5 lens with EC-20 2x teleconverter:
    • Jupiter measures only 25 pixel diameter at effective focal length in 35mm terms of 800mm f/7; tripod exposure for Jovian moons at 20deg altitude: ISO 800, f/7, 1/4sec
  • Canon FD 500mm f/8 mirror lens:
    • Jupiter measures 30 pixels; exposure for Jovian moons ISO 800, f/8, 1/4-1/8th sec; For Jupiter’s bands: 1/200th sec;
  • Maksutov 500mm f/5.6 telescope with Olympus EC-20 2x teleconverter tripod mounted:
    • Jupiter measures 75 pixels; exposure with Jupiter at 30deg altitude: ISO 800, f/11, 1/4sec for the Jovian moons (the longest without substantial star trailing effect at eq. 2000mm focal length and can use IS set at 1000mm focal length)
  • 10″ f/5.6 Newtonian prime focus plus Olympus EC-20 2x teleconverter:
    • Jupiter measures 145pixel diameter; exposure ISO 1600, 1/200th sec at effective focal length in 35mm terms of 3625mm f/14
  • 10″ f/5.6 Newtonian afocal method using Olympus mZD 45mm f/1.8 lens with 25mm eyepiece:
    • Jupiter measures ~125pixel diameter; exposure ISO 1600, 1/300th sec at effective focal length in 35mm terms of 3125mm f/12
  • 10″ f/5.6 Newtonian afocal method using Olympus mZD 75mm f/1.8 lens with a 25mm eyepiece:
    • Jupiter measures ~215pixel diameter; exposure ISO 1600, 1/100th sec at effective focal length in 35mm terms of 5375mm f/21
    • this is probably the best compromise however resolution is still very highly dependent on timing of the shot in relation to the rapidly changing seeing conditions
    • sequential shooting highly recommended to allow selection of the sharpest images
  • 10″ f/5.6 Newtonian afocal method using Olympus mZD 75mm f/1.8 lens with a 25mm eyepiece plus 2x Barlow lens:
    • Jupiter measures 430pixel diameter; exposure ISO 3200, 1/60th sec at effective focal length in 35mm terms of 10750mm f/42

Don’t forget, this event will be at about 5deg from horizon for Eastern states, so you need to adjust your exposure to allow for about 2 stops of atmospheric light extinction!

Olympus OM-D E-M5 Micro Four Thirds camera takes a portrait of the lady of the night – the Transit of Venus

Thursday, June 7th, 2012

The transit of venus across the sun is quite a rare astronomical event happening on paired events each century or so.

I captured the 1st of this paired event in June 2004 whilst I was in Cairns in northern Queensland, Australia using the only digital camera I had at that time – a hand held Olympus C8080WZ 8 megapixel prosumer camera with a teleconverter attached and an astronomical solar filter – here is a collage I made at the time:

 

2004 transit collage

Today I decided to get a quick shot in before I had to race off to work just minutes before this event finished and none of us will see such an event again.

This time, I had the luxury of using the awesome Olympus OM-D E-M5 Micro Four Thirds camera combined with my Zuiko Digital EC-20 2x teleconverter and ZD 50-200mm f/2.8-3.5 SWD lens, and the same solar filter hanging on the end of the lens (it is way too big for this lens!)

At a 35mm effective focal length of 800mm and resorting to manual focus, a sturdy tripod with self-timer was critical to success.

The exposure I chose hopefully optimised image quality by using ISO 200, f/11 and 1/160th sec through the clouds which dominated today in Melbourne.

The image shown below is a cropped, and resized version for quick web display, you can click on it to view the original, unprocessed (except for default Lightroom export sharpening) image which has been cropped to give a nicer aspect.

The big circle is the sun with clouds in front of it, while the black dot is Venus just about to finish her transit across the face of the sun. You can also see a number of sunspots – better viewed on the large version by clicking on this image.

2012 transit