In spite of bad seeing and strong gusts of wind I did set up the big refractor to do some astrophotography. I spent quite some time to get things running – in the end the spring galaxies were already too far west in the glare of the train station, so I switched my targets to two globulars and a planetary nebula. Here is a list of what went wrong:
I wasn’t aware that the D750 uses a non-standard USB port on the camera, I had to search for half an hour to find the original cable
the laptop I usually use has been upgraded to Windows 10, installing the drivers for the guiding camera did not work
on the backup laptop guiding with PHD worked, but Backyard Nikon crashed and/or got no connection to the camera, I tried many combinations of USB extension cables, USB ports, removing the SD card, formatting the SD card, upgrading to BackyardNikon 1.0.5, in the end I focused using live view of the camera and used the built-in interval timer of the camera to shoot 30 second exposures…
the seeing was really terrible, making focusing difficult, and bloating the stars during the exposure
for reasons unkown (user error?) the quality setting on the camera was changed to FINE, so I only took JPEG images instead of NEF( Raw)
After a long spell of clouds of rain, on sunday evening I took advantage of a few clear hours to get some more data on M51. This image is a combination of raw images from April 20th and May 10th. The total exposure time is now at 64 minutes.
After I acquired the 127mm refractor I was on the search for an affordable mount suitable for astrophotography, serendipitously I learned that my astronomy club is in the possession of an old but working Meade LXD 650 mount. It turns out, the LXD carries the refractor quite nicely, here are the first images shot with that combination:
NGC is a long time favourite of mine, the galaxy is beautiful in the eyepiece as well as in pictures:
NGC 4565, Astro-Physics 127mm f/8 refractor, Nikon D7000, Meade LXD650 mount, 14×120 sec., darks, flat, processed in Deep Sky Stacker, Lightroom and Photoshop
At first I had to wait for about two hours until the floodlights on the adjacent soccer field were turned off, then I had trouble locating the galaxies as the 6×30 finder is not really adequate in a light polluted sky, then came problems with the connection from BackyardNikon to the camera, and when everything was set up correctly, the guiding was not working properly, resulting in trailed images… so quite a lot of effort went into this picture, but of course a lot has been learned.
At last the sky was reasonably clear to try out my new toy. In fact the Astro-Physics 127mm f/8 refractor is not exactly new, as it was manufactured in 1989, so I was even more curious as how it would perform.
The Super Polaris mount is definitely overwhelmed with the weight of the big, long refractor, but on a windstill evening it works tolerably well. As this was basically a test, and I didn’t want to make matters even more complicated, I didn’t use any autoguiding, and therefore limited the individual exposure times to 30s. I had to throw away about half of the epxosures due to tracking errors, but 14 exposures looked good enough to use. Transparency was pretty bad, a slight haze due to the freezing cold air and smoke from wood-powered heating combined with the light pollution of the rhine valley made the sky very bright. In the color version, the sky looks quite murky, I like the black and white rendition better:
M42, 14x30s Nikon D7000 ISO 1600, Astro-Physics 127mm f/8