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By Ken Mitchell
For a long time I wanted to shoot this frame, probably from the early days of my astrophotography adventure.
Finally after all these years I managed to get a decent result of the 'stuff' between these two beautiful nebulae. Fairly happy with the image but always looking for improvement.
I hope one day to redo this all with a mono camera and filters.
Apart from NGC1499 , M45 and the Baby Eagle Nebula no idea what else is in the picture. If you happen to have an idea feel free to educate me.
Some info on image and capturing:
Widefield Pleiades to California.
Taken over 2 nights with a total of 11hrs 25min integration.
With a stock Nikon d610 and Nikkor 85mm 1.8 objective.
Tracking was done with the Skywatcher Star Adventurer.
Lights and all calibrations frames were stacked in DSS.
Processing was done in Adobe Photoshop CC using Adobe Raw, GradientXterminator plugin, HLVG plugin, Nik software plugins and Photokemi action set.
To celebrate the 25th anniversary of Sir Patrick's DSO catalogue, I've added the available Caldwells to my basic Marathon search sequence.
Those interested may be pleasantly surprised by how many of the additional treasures are only a short hop from a given (or en route to the next) Messier.
The sequence for 40°N can be found at the SEDS Messier Marathon homepage or at my blog.
This system consists of two yellow giants having types G0III and G8III (some sources give K0III), similar masses and brightness. The orbital period of the components is 104 days.
The fact that one of the stars has a later spectral type is very convenient 😀. It has stronger spectral lines of metals, including sodium.
This allows you to immediately recognize which star is approaching and which is currently moving away.
I made 3 observations so far with using a DIY 3D printed LowSpec spectrograph in the version v2 designed by @Paul Gerlach and a 1800 l/mm holographic grating.
Based on these observations, the spectral spread for both observations for the sodium line is 0.79 Å (0.079 nm) or 4 pixels, which gives a difference of radial velocities of 40 km/s.
Assuming that component A belongs to G8III and component B to G0III:
2019-12-03 component A was moving at relative vr to the barycenter of the system of -20 km/s and component B was moving at a relative vr of +20 km/s.
2020-01-23 component A was moving at a relative vr of +20 km/s and component B was moving at a relative vr of -20 km/s.
I called radial speeds relative, because the radial velocity of the Capella barycenter to the Solar System wasn't included.
I took the radial velocity of the Capella barycenter into account and I received this phase plot:
The background is the plot of radial velocities from paper:
M. Weber, K. G. Strassmeier, 2011, The spectroscopic orbit of Capella revisited
By LR Watanabe
Is the Nikon Nikkor 55-200mm f/3.5-5.6 II a good lens for astrophotography? I plan on using the Nikon D5300 with it and I wanted to know if the 55-200 would be a good lens for photographing DSOs. Does anyone use this lens and if so, may I see some images taken with it? I can't seem to find images on Astrobin. Also, is it possible to photograph DSOs (M42, Rosette, Flaming star, M45 etc.) from a bortle 7 sky with the 55-200mm?
The weather has been so bad I have had the time to finish a video on using astro filters with the Nikon Z bodies and Nikon camera lenses. There is a manual alternative to the FTZ allowing 1.25 inch filters to be fitted between camera and F-mount lenses, and for some lenses and end of lens solution make sense. FAstroTZ is described here: