Ganymede shadow transit from indoors
Taken by James Roger Samworth on August 9, 2022 @
Nailstone, Nuneaton, UK
Click photo for larger image
| |
Camera Used: Unavailable Unavailable
Exposure Time: Unavailable
Aperture: Unavailable
ISO: Unavailable
Date Taken: 2022:08:09 09:49:29
|
|
| More images
Details:
Most of my window-sill observing images are wide-field ones through the glass. These seem reasonably successful. However, high magnification planetary images less so. Of late I have been successfully imaging the Sun through an open window. I put this down to the fact that the images are not that high magnification, and since at the moment, indoors and outdoors temperatures are similar, air currents through an open window are not severe.
Anyway, a couple of nights ago the GRS on Jupiter was transiting at a reasonable time so some imaging was called for. I decamped to the patio with the 90mm Mak, only to find that for some reason it was totally out of collimation - so much so as to be virtually unusable.
That nailed that one on the head!
I recollimated it yesterday, and since last night a Ganymede shadow transit was in the offing, decided to have another go. I had had one of my insomnia episodes the previous night so I was reluctant to venture out in the early hours, and wondered if a window-sill session through an open window might work, given the inside-outside temperature differential was low. Wrong! it was pretty hopeless! Much image turbulence! Closing the window gave a much steadier image at the cost of loss of detail. After some experimentation, I eventually used the open window method but severely limited the number of frames in the stack. Still not very satisfactory, but not too bad.
So, the moral is that for detailed high-magnification planetary images you have to go outside - not really a surprise I suppose! Fortunately, the 90mm Mak is an excellent "grab 'n go" scope. It is just that I can be reluctant to go outside in the early hours after a sleepless previous night.
Photographer's website:
No URL provided.
|
|
|
