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:
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.
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.
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.
highest quality jpeg only (to maximise burst shooting with minimal owntime as the buffer writes to card)
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:
Reappearance of Jupiter with significant deterioration in viewing conditions taken at ISO 3200, 1/15th sec :
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:
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.
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:
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.
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:
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
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:
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 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!
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:
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.
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.
Part of camping out in the beautiful night skies of the remote regions of Australia well away from light pollution of the cities is to just lie back and observe the myriad stars while waiting for meteors – fantastic in the desert regions in May where there are no mosquitoes to annoy you and the night is not yet too cold as to be uncomfortable.
What better time to see how this amazing camera can make astrophotography easier.
Unfortunately, I did not bring my telescope mount to provide guided long exposures and so had to limit myself to tripod mounted long exposures.
How does the E-M5 make life easier for astrophotography?
no mirror, so no need to remember to set mirror lockup to prevent camera shake
no mirror, so live view is easy to use
flip out LCD avoids having to strain looking at awkward angles, particularly when shooting straight upwards
AF is good enough to AF on bright stars as long as the sky is dark and offering good contrast and you have a wide aperture lens such as f/2.0
touch LCD can be set to AF only thus makes it easier to AF on a bright star instead of having to manually move the AF region onto the star
magnified manual focus is easy to use if AF does not work
can set Live Boost ON to make it easier to see the fainter stars on the LCD
can use Live BULB so that they can see the image forming during long exposures – very handy to check that you have the composition correct and abort the exposure if it isn’t instead of waiting a full 1-2 minutes to find out
NR ON automatically performs a dark frame subtraction for long exposures
ISO 1600 is VERY usable
timed shutter speeds extend to 60secs in manual mode (most cameras only go to 30secs which is inadequate for most astrophotography)
can set a timed limit to BULB and Live TIME of 1, 2, 4, 8, 15, 20, 25, or 30 minutes – very few cameras have this feature
camera is light so that mounting it on telescopes causes less issues with weight balancing compared to a full frame dSLR
can use a remote cable and set drive mode to continuous and AntiShock to the interval between exposures to work as an intervalometer
can attach a TriggerTrap cable and use your iPod or iPhone to control intervalometer aspects
can use almost any lens ever made (via adapters) as well as direct attachment to eyepiece of telescopes (via M43-T2 adapters)
One of the holy grails of astrophotographers is to find a wide angle lens that captures stars as points instead of with the usual spherocoma and astigmatism aberrations which are a characteristic of nearly all wide angle lenses.
My main aspiration of this test was to see how the AF and MF worked as well as to determine if the Olympus 12mm f/2.0 would perform in this very demanding domain.
During my trip I found the Olympus 12mm to be superb for most of my needs such as hand held infrared photography, hand held urban night street scenes, and general travel photography but like nearly every other wide angle lens ever made, it too was not optimised for astrophotography and the over-exposed brighter stars had the very annoying coma and astigmatism with purple CA in the coma aberration:
Milky Way with Southern Cross and Centaurus on top right and Scorpius bottom left: Olympus 12mm at f/2.0 ISO 1600 20 secs (click for larger view):
Note that I did play with contrast a bit on this image but I did not do any CA correction.
So as lovely as this lens is, and with the very nice switchable manual focus controls, it is a useful but not brilliant, astrophotography lens.
Full frame astrophotographers generally resort to expensive wide angle lenses such as the Zeiss 21mm f/2.8, although I have heard the Samyang/Rokinon 14mm f/2.8 does an admirable job and is very cheap in comparison, so this lens may be the answer for Micro Four Thirds users needing a wider angle than a Panasonic Leica-D 25mm f/1.4.
I also briefly tested the Olympus m.ZD 45mm f/1.8 lens and this performed better but still had CA around the bright stars and there was some coma and astigmatism in the corners. Unfortunately, the focal length of this lens means tripod mounted images are restricted to about 8-10secs to avoid obvious star trailing.
For those who are interested, THIS LINK will open a full jpeg straight from camera of a dark frame at room temperature (~16degC) from the E-M5 taken at ISO 1600 and 60secs exposure with no dark frame subtratction (NR = OFF) and Noise Filter = LOW.
Now I will be even better prepared for the next bright comet that comes our way, here is a manually guided image of Comet McNaught I took with an Olympus E330 and an Olympus OM 50mm lens in January 2007:
Surprisingly, Comet C/2011 W3 Lovejoy, a Kreutz sungrazer comet which was only discovered in November 2011 by Brisbane amateur astronomer, Terry Lovejoy, passed through the sun’s corona earlier this week and is now putting on a dazzling display at 3.30-4.30am daylight saving time in the southern hemisphere before sunrise twilight interferes.
It is currently showing a 22 deg tail which is up to 2 deg wide and is visible to the naked eye above the south east horizon, but it seems it is getting dimmer each day and so you would be best to get away from cities and their light pollution.
If you are planning on photographing it, a focal length equivalent to 50mm-80mm in 35mm full frame terms is all you need, preferably with wide aperture of f/1.4-2.8 range and if you need a shutter speed longer than 15-20secs, then an equatorial mount rather than tripod would be advisable.
It has been difficult to see in Melbourne due to cloud conditions.
Here is the path of the comet for the next 2 weeks heading almost straight for the South Celestial Pole!
It has been very amenable to photograph even without an equatorial mount given its brightness but this may change soon.
Here is an example photograph from Adam Marsh, an Australian in Tocumwal, NSW taken with a Canon 1000D with Olympus OM 50mm f/1.8 lens at ISO 1600 with a 13sec exposure:
The comet will pass near the Pointers in Centurus and become circumpolar which means for southern viewers it will be visible ALL night long but unfortunately dimmer each night as it travels away from the sun.
A beautifully composed shot by Alex Cherney at Cape Schanck using Nikon D700, 14-24mm lens at f/2.8, ISO 3200, 30sec:
Update 26th Dec 2011:
John Drummond from NZ took this fantastic image on 26th Dec, 28sec exposure at f/2.8, 12800 ISO using a 20mm f/2.8 lens on a Canon 500D showing the tail is actually getting longer – now 27deg long and 3 deg wide!:
Update 27th Dec 2011:
Tail now has lengthened to a visual length of ~35deg but currently is overlying the bright Milky Way making it harder to see well and giving it more of a ghostly appearance. It should move out of the Milky Way region over the next few days and hopefully will be more visible then.
Image by Adam Marsh 27th Dec morning using Canon 1000D,18mm f/3.5 lens, ISO 1600 as comet tail approaches the Pointers:
Update 31st Dec 2011:
The comet has now moved out of the brightest parts of the Milky Way which hindered viewing the last few days, but unfortunately has suddenly became a lot dimmer and is now a little less bright than the Magellanic Clouds and only just visible to naked eye away from pollution and with a visible tail at least 15deg long. Imaging is possible on a tripod with a standard lens at f/1.8, ISO 1600 for 30sec exposure. It is now circum polar and visible in the evening although low in the southern horizon in southern Australia and NZ. It is still best viewed after 3am, but really, the show is now over other than for astrophotographers, and even those will have issues once the moon is in the sky.
Stuart’s annotated photo on the morning of 31st Dec taken from Mt Macedon showing light pollution from Melbourne and Gisborne:
If you get to a dark sky, such as this time lapse video by James from Pambula, NSW on the morning of 31st Dec, it still makes a reasonable photographic subject:
My image of the now almost invisible comet taken 2nd Jan 2012 using a Canon 1D Mark III, 50mm lens at f2.2, 2 minute exposure and ISO 1600 can be seen on my Flickr account.
Now a timelapse sequence of the comet over 6 days taken from the Gippssland Lakes by Phil Hart:
This week my friend and I took the opportunity of clear skies and no wind to brave the Winter cold and set up his computerised telescope mount and Williams Optics 4″ f/7 refractor telescope.
Just before the clouds came in, I managed to swap his Nikon D700 with my Panasonic GH-1 Micro Four Thirds camera body, and without having time to check focus (and forgetting to switch to my usual RAW + JPEG), I managed to get one shot in.
Thankfully, it was practically parfocal with his Nikon D700 and even though the GH-1 had twice the magnification as the full frame D700, the focus was very acceptable.
I decided to shoot at ISO 3200 despite knowing that my version of the GH-1 (being one of the first), suffers from severe banding noise at high ISO.
Nevertheless, given the circumstances, I am very happy with this shot which was an unguided 60sec exposure at f/7 with automatic dark frame noise reduction done in-camera and the only PS was levels to darken the background and minimise the banding, and, cropping and resizing for the web (no sharpening or NR in PS):
I have always wanted to image this globular cluster as it has always amazed me at how many stars can be located in one cluster like this – just awesome!
The Nikon D700 having the same number of pixels but much larger photosites given the larger sensor, obviously had much less noise but was also at half the magnification – you can’t have everything!
Unlike my Olympus dSLR which has Live Boost option for Live Preview which really helps visualise stars, the Omega Centauri at f/7 was NOT visible in the GH-1 EVF or LCD, nor the D700 live view, and thus to focus accurately, I would have needed to find a brighter star or planet.
The banding is an issue primarily with the early models of the GH-1, but most digital cameras, even the Canon 5D Mark II can show banding in shadow areas. It can be reduced using Nik Dfine software – perhaps I shall buy it one day to try it out!
And here is my friend’s Nikon D700 version which I think was a 4 minute exposure at ISO 1600 and thus has a lot more stars visible and the centre highlights are blown given the exposure was 4x the exposure of the above GH-1 exposure, and he did not need to resort to adjusting levels to remove banding:
You can now order a modified Panasonic G1 or GH1 so that the IR blocking filter has been replaced by a clear filter which will allow better hand held infrared photography and much better nebula astrophotography.
The momentum for Micro Four Thirds is escalating, although it would be nice if Panasonic or Olympus added live video output feed and improved remote camera control in future models to make them even more useful for astrophotography.
Hutech will modify your camera for $US500 or you can purchase a modified camera from them.
To shoot IR, you can just purchase an IR filter for the lens.
To shoot daylight, you will need the daylight filter and do a custom white balance.
If you do not want to use IR filters on the lens, and you wish to shoot IR, then replace the IR blocking filter with a 715nm filter – but you may also need to remove the dust-shaker glass (thus disabling dust protection) as it seems this also blocks IR, at least on the Panasonic cameras.
ps.. another conversion service in the USA (Precision) is discussed here
Here is an example of a hand held photo by Carl Schofield from a Precision IR-converted G1 using a 715nm conversion filter with 14-45mm kit lens at f/8, 1/320th sec (click for larger size):
Last night whilst on a brief holiday to the countryside, I took advantage of the darkish skies (although contaminated by the nearby light of a 1st quarter moon).
So from the camping ground in a small town in country Victoria, using only my tripod (I did not bring my motor driven equatorial tracking telescope mount), my fun little Panasonic GH-1 Micro Four Thirds camera and the superb Panasonic Leica-D 25mm f/1.4 lens, here is what one could achieve – definitely not perfect but pretty good. Focus achieved my manual focus on Jupiter (not shown in this image).
Taken in 16:9 aspect ratio at 3200 ISO, f/1.4 for 15 secs RAW file with dark frame NR turned on, and processed in Panasonic’s SilkyPix RAW software with all noise reduction turned to zero, and gamma set to 0.80, and Black level set to 100 to give the background a black sky and remove the effects of the moonlight.
No other processing other than resize and compression for web via Photoshop.
Tail of Scorpius is towards the top of this image.
Now if one looks closely there is the usual “horizontal banding” sensor problem in the dark areas (it will be vertical here as the image has been rotated into vertical format) which increases as one goes from ISO 800 up to 3200. In addition there is some visible star trailing due to 15 sec exposure using a 50mm equivalent focal length lens (in 35mm terms) – so don’t look too closely – this is just a demo of what can be done, but which could be considerably improved upon with a tracking mount and on a night when there is no moonlight to interfere.