Galaxy NGC 4725

Notes

This is NGC 4725, an intermediate barred spiral galaxy. According to Wikipedia, it was first discovered in 1785 by William Hershel. The galaxy is located 40 MLY away near the north galactic pole.

I took the exposures for this image over five nights in June. This is the furthest galaxy I have imaged and it still shows quite good detail of the arms. 40 MLY is really really far away. I am still amazed that one can put together a picture like this with relatively modest equipment using modern digital techniques. It took 412 separate 60s exposures stacked together to produce this. As a point of reference, this is what a single one of those exposures shows:

Even this single image is far better than what one would see visually through the same telescope, as the human eye gives the equivalent of a 1/15th second exposure. The stacking of the 412 60s exposures creates the equivalent of an almost 7h exposure that dramatically increases the SNR.

Incidentally, you can see a tiny galaxy near the bottom of the frame. This is NGC 2712 which is 224 MLY away!!

That light is from the age of dinosaurs! But at this distance, it is little more than a blob for pictures taken anywhere but the high-altitude deserts or from space.

Galaxy NGC 4725

Jun 2024

Gallery

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