I’d been trying to get this comet for some nights, desperately cutting down vegetation in my neighbour’s garden (with permission) to get low enough. I managed to capture it on the 28th, the same night as several other amateurs in the UK achieved the same, at an altitude of 14 degrees above the horizon, much affected by the London skyglow to the south of my observatory.
The single 30s exposure best shows the globular cluster M79. The stack of 17 images (stacked on the comet) shows the comet best; this image has been subjected to several stages of non-linear stretch and also had gradient and colour cast removal with GradientXterminator and noise removal with NeatImage. Also given is an inverted mono version stretched further to show the tail better. Click any image to enlarge.
Click twice to enlarge to full size.
This could be subtitled ‘goodbye to AR 2192’, as the great spot approaches the limb.
Seeing very poor today in the afternoon, but I took images of the spot in IR and H alpha, which I have put side by side here, though the quality of the H alpha image doesn’t really justify this image scale. A flare was active during the H alpha capture.
AR2192 in reasonable seeing in IR light.
Here’s my take on the giant sunspot AR 2192.
The features I find striking here are the linear streakiness seeming to emanate from a point W (celestial) of the group, manifested in its upper part, and the slightly lighter bridge running right across the main umbra. I used to think sunspots were only bi-tonal, but they are not. (Click twice to enlarge)
Here are some large images I produced in the process of writing an article on ‘Imaging the Sun in Narrowband’ for the December 2014 issue of Astronomy Now.
The first is a 3-part mosaic taken with a 100mm f/9 telescope, a vertical slice of Sun. Lack of IR blocking of this image has reduced the H-alpha contrast and put the sunspots back in. I was avoiding using the Lunt blocking filter, which has the defect known as ‘rust’. (Kudos to Lunt that they have offered to replace it free, though it is an old piece of equipment, but I haven’t got the replacement yet.)
The second is a three-part mosaic with the Lunt LS60T, which gets the whole disk in. I hit on a very successful IR blocking method here. This was to use a 2″ Baader 35nm H alpha filter, that I sometimes use for deep-sky imaging, in the imaging train as a blocker.
Click once or twice to get images full-size. The first won’t fit on most screens.
Here’s a white light whole disk image from the 8th and a more detailed IR image from the 22, that I produced in the process of doing an article for the November ‘Astronomy Now’.(Click to enlarge.)
I thought I should take Jacques with a longer focal length than I used on August 05 with the Hyperstar, so I imaged it here with my 100mm f/9 refractor at prime focus with a Canon EOS 400D (as it’s inconvenient to remove the QHY8 CCD camera from the Hyperstar).
A couple of things went wrong with this image. Firstly the exposure I chose was too long: there is noticeable drift of the comet in 2 minutes at this image scale, so it is not as round as it should be. Secondly, it clouded over after I had only got 6 subs.
I have tried stretching the image and inverting it, as I did before, but there is no evidence of a tail here at all (though this is a much better calibrated image than the Hyperstar one).
Processing was in Nebulosity 2, and Photoshop CS4 using GradientXterminator and Neat Image plug-ins.
(Click to enlarge)