Heart in the Sky

The Heart Nebula in Perseus is an interesting region of red hydrogen clouds mixed with dark nebulosity and bright star clusters. This was a test-run: first light with the Sequence generator Pro combined with the Nikon D750 (with autofocus by PegasusAstro, worked wonderfull). Second test (living dangerously!): first attempt to mosaic automatically with SGP.

The D750 would crash SGP when hitting the “link” button: as soon as I touched that button, SGP would collapse and simply vanish in thin air. Solution: install the 2013 C++ redistributables.

The Optolong Pro filter OR the reducer/flattener (or the combination) imho added a lot of vignetting and uneven illumination to the image, which I had a hard time eliminating. So next test would be with a regular Nikon T-ring. If that does not solve the issue then it must be the F5 reducer. I noticed earlier already that images at F7 with the Nikon were a lot cleaner.


IC1805 or the Heart Nebula in Perseus. Image dedicated to my mom who passed way in September age 79. 

Nikkor 300mm F2.8 further test

I discovered that the lens I purchased (used) had a UV drop-in filter inserted. So I removed that filter and tested again the last night, under a full Moon… On an EQ8 without any guiding, did 18 times 60 second 800ISO shots on F/4 using BackYardNikon.

There are still skewed stars left in the corners, especially to the left lower side. But that might fall within normal DSLR tolerances. I do not understand the assymetry though / left to right.

The only thing that still worries me is the darker circular donut in the middle of the image. It might be related to the large hood that this lens has, a sunshade. I need to test it without the hood (and with a dew band).

The bright star in the middle is Deneb, the red nebulosity at the top is the Pelican.

Heart in the sky

Note: I discovered weeks after this test that the filter drawer of this lens actually contained a Nikon UV filter. That might have influenced the result, so further testing required.

Further testing the golden oldie 300mm F 2.8 AF Nikkor ED. At F4 with 56×180 seconds on ISO800, Nikon D750, HEQ5 and the Lacerta MGEN II autoguider. A lot a gradients to remove, and really bad conditions with fog, cirrus, passing contrials, in general a sky not over SQM 19.50

Heart in Perseus

There is something wrong with the starshape in this image. The colors are ok and the nebulosity really stands out. However, zooming in reveals strange artefacts.

I checked the light frames and decided to delete 30 out of 56 lights, because the focus was not ok. In addition I removed some lights that were really off track, had very bad star shapes. Futhermore, were before AstroPixelProcessor refused to register the frames, it now did register and stack the frames. Obviously only half of what I had before. So I lost a lot of nebulosity and nuance in the image!