Imaging | WATCH THIS SPACE(MAN)

Last night was the so called “Supermoon” of 2014 as, in its eliptical orbit, the Moon passed at its closest point to Earth for this year. Its relative closeness to Earth, plus atmospheric lensing, caused by the Moon’s location in the southern part of the Zodiac, means that for observers in the higher latitudes of the Northern Hemisphere the Moon appears particularly large at Full Moon on 10th August. As a result it is possible to get good photographs without the use of a telescope so, in my case, I shot this using a 200mm telephoto setting:

Supermoon from Fairvale Observatory 10th August 2014
Canon 700D | 200mm telephoto | 1/160th f11 ISO200

Of course, since getting my telescope last year the Moon has been a frequent subject for viewing and imaging, with some very close-up results in some cases almost seeming to take you there. Viewing the Moon is best during the early stages of a new “waxing” Moon, particularly along the edge where the dark section meets the light section – the so called “terminator”. Views of this can be stunning, with the WO GT81 and a x2 Barlow an 10mm eyepiece it almost seems like you are about to land on the surface! Very soon after first looking at the Moon I got a Moon filter, which I have found essential as the Full Moon approaches and the light is almost otherwise blinding; the filter reduces the glare and makes observing more comfortable.

Whilst a good view of the entire Moon can be obtained, such is the optics of the 150PL (and I think the WO GT81) that to get focus the DSLR camera has to be used in conjunction with a Barlow lens. Unfortunately this results in such magnification that the Moon can only be imaged in parts, rather than as a whole but the image is nonetheless exciting:

The Moon 11th February 2014
Canon 700D | SW 150PL 2xBarlow | 1/100th ISO 400

Notwithstanding, using a suitable computer programme these individual images can be stitched together to produce a photo mosaic, such as this one made from x6 separate sections of the Moon. The result is impressive:

Photo mosaic 11th February 2014

Finally and probably most amazing is using a webcam / CCD to video the Moon. Once again this needs to be undertaken using a Barlow and the resulting magnification is even higher but with spectacular results as can be seen with this video taken with the ZWO 120 MC in May this year(the shimmering effect is the Earth’s atmosphere): https://www.youtube.com/watch?v=13Nb_lBBaxk&feature=youtu.be

Snapshot of Moon video (see above link)
ZWO 120 MC

FOCUS: The state or quality of having or producing clear visual definition – Oxford English Dictionaries.

Splashed the cash and got the equipment, done the reading and asked all the right questions on the astronomy forums, got a clear night, time to catch those images – what can go wrong? Having recently purchased and got a new AZ-EQ6 mount and WO scope working OK visually, it was time to embark on my new DSO photographic quest. Not for the first time I unfortunately underestimated just how difficult this astrophotography is; forgetting that I’d already battled before to image with the Newtonian 150PL using both the DSLR and ZWO webcam (more on that another time).

This time the challenge was using the new WO Field Flattener http://www.williamoptics.com/accessories/flattener6A_features.php. So – set up scope, align mount/scope, find object, centre and visually focus. Then attach the field flattener (FFL) to the DSLR and slide directly into the focus tube, focus and take images – easy? No! Even now I am not sure what went wrong but after three evenings and numerous questions on the Stargazers Lounge forum (SGL), I was completely unable to get a clear picture through the camera, let alone an image. Initially I just thought the set up was wrong (whilst all the WO various equipment is excellent, none of it comes with instructions. I am told this is par for astronomy but, when you are forking out this kind of money I find that quite unacceptable) or I needed yet another piece of equipment to achieve focus (surprisingly the ‘expert’ dealer from where I bought it wasn’t even sure on this!), spacers perhaps? By now I was very concerned.

Another clear warm night soon came and with perseverance low and behold a result. This time I was much more meticulous: visually focusing on the bright star Arcturus, then switching to the DSLR + FF. Using the Canon EOS Utility and Live View, with the ISO set very high I was at last able to see something on the screen, which with very fine adjustment came into focus as a small, very bright dot. Placing my other recently discovered brilliant invention, the Bahtinov mask http://en.wikipedia.org/wiki/Bahtinov_mask

over the objective lens I was able to refine the focus perfectly:

Now carefully transferring the scope and refining the position via Live View I was ready for a serious attempt on my first DSO, M13 The Great Globular Cluster in the constellation of Hercules:

WO GT 81 + FF 10x16sec at ISO800

Bingo + what a relief! Like my first crude afocal image of the Orion Nebula last year, getting the picture was exhilarating. OK it’s not brilliant and I have seen the image in numerous publications and online but, it was mine, having captured those photon’s which had been travelling for the past 25,000 light-years on my camera, just outside my back door. WOW!

http://apod.nasa.gov/apod/ap120614.html

I hope to improve on this one day, once I have mastered all the other software, guidescope etc but I doubt I’ll feel quite the same next time. In the end, focus was everything, it is very difficult to achieve and only goes to show just how difficult this astrophotography is but after the light spent so long getting here, the least I can do is focus it right on my camera sensor, which requires a fraction of a millimeter accuracy.

Later on the same night I also captured M57, the Ring Nebula (more another time). Apart from refining this process (which I can see will take what ever’s left of my lifetime) my next ambition is to capture a galaxy out my back door, I can’t wait!