My Plan.  I've been experimenting with using several old Nikon lenses with new ZWO cooled cameras.  This is my first light of a narrowband imaging setup that pairs an ASI1600MM camera and 1.25" narrowband filter wheel with a vintage Nikkor 300mm ED f/4.0 lens.   I realize that given the pixel size of the ASI1600's CMOS sensor and the 300mm focal length of the Nikon lens that I am under sampling the image, but it's what I have to work with.  Earlier, I had tried the ASI294MC Pro one-shot color (OSC) camera with the Nikon 300mm ED lens, but noticed some chromatic aberration.    Switching over to the ASI1600MM monochrome camera with narrowband filters eliminated the chromatic aberration problems entirely.   I absolutely love this set up.  For an older telephoto lens (I bought it new in 1987), the Nikon 300mm f/4.0 seems to perform beautifully for astrophotography.  Off to one side of the lens, I mounted a ZWO EAF electronic auto focuser on a an aluminum bracket.  The EAF drives a toothed silicon belt that goes around the lens focusing collar and achieves perfect focus quickly using the autofocus feature of the ASI Air app.  

Setup.  Auto guiding done using ZWO 30mm mini guide scope, ASI120MM mini guide camera, and ASIAir's software application (a version of PhD lite).  The entire rig weighs 9.2 lbs which is easily handled by an SkyWatcher HEQ5 Pro mount.  The HEQ5 mount, ASI1600MM imaging camera, ASI120MM guide camera, EFW, and EAF are all connected to an ASIAir Plus and operated easily using my iPhone or iPad.  The ASIAIR does a good job communicating with the mount, locating DSOs and plate solving, and setting up imaging plans. 

Details.  This Ha monochrome image is a stack of only 17 light frames collected in a 2 hour window one night (October 15, 2022).    It's posted here to show what kind of image you can get using a monochrome camera and telephoto lens.  The light sub-frames had 300 sec exposures with the f/4.0 telephoto lens stopped down to 5.6 aperture.  The ASI1600MM camera's gain setting was 139 and temperature cooled down to -10°C.  Calibration frames include 60 flats, 60 darks, and 60 dark flats.  Stacked, calibrated, and integrated using PixInsight WBPP.

Comments[b]. [/b] I am completely new to this astrophotography thing and welcome your suggestions, thoughts, and advise.   The learning curve is steep, but the nights under the stars are just wonderful and peaceful.  Feel free to provide comments below.Clear Skies! 

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