3 replies to this topic

[james7ca]

Just over one week ago I created a thread with images of the so-called Napoleon's Hat asterism in the constellation Boötes and this current post contains a repeat of some of the data that I shared in that earlier thread.

 

However, these are all new images using some additional subs and new processing to hopefully improve over my earlier results. In any case, immediately below is a link to WikiSky.org where you can view this same area as recorded in the Digitized Sky Survey (DSS2):

 

  http://www.wikisky.o...img_source=DSS2

 

My first image contains the entire field that was created from subs gathered over three separate nights using a Nikon Z50 II camera and a NIKKOR Z 180-600mm VR zoom lens at its maximum focal length (plate solve to 585mm, not the 600mm given by Nikon). This image was reduced down from the 3560 x 2868 pixel original to 1378 x 1110 pixels to conform to the CN posting guidelines. It covers the Napoleon's Hat asterism and the area between it and the bright star Arcturus. North is oriented upward in all of these images and there are additional capture details in the image captions.

 

Image processing was with PixInsight and Photoshop 2025. I should also mention that I'm taking these under Bortle 7 skies and thank heavens for PixInsight's MultiscaleGradientCorrection process.

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Edited by james7ca, 01 June 2025 - 04:53 AM.

[james7ca]

Here is a full-scale, 1:1 crop that covers just the asterism itself.

 

If you click on the preview/thumbnail you can view the full-sized image (1600 x 1200 pixels) as hosted here on CN. This full-scale reproduction shows stars down to about magnitude 18.

 

In addition to numerous background galaxies, if you look closely at the upper leftmost, bright star in the asterism you should note a close spacing between two stars. Interestingly, this ending star (TYC 1472-0320-1) is listed as a physical double at Stelledoppie.it (WDS), but the secondary is NOT the star shown in my image. There is actually a brighter and much closer star that is separated from the primary by only 3.6 arc seconds (again, not shown in this particular image). The companion star shown below has a magnitude of just 14.3 and a separation of 8.7 arc seconds (according to SkySafari). I've also included a 2X enlargement of this "false" (?) double as recorded with the Nikon Z50 and NIKKOR zoom lens.

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Edited by james7ca, 01 June 2025 - 03:29 AM.

[james7ca]

Next, I've also recorded this same asterism at the prime focus of a Takahashi FOA-60 when using a ZWO ASI678MC camera. In this case, I had enough image scale to resolve the true double and below is a crop and 2X enlargement from that image showing TYC 1472-0320-1 with its magnitude 12.8 companion. The primary star (TYC 1472-0320-1) has a magnitude of 10.2 (about the same as the six other stars that make up the outline of the asterism). It's also possible to see the fainter, third star that was shown in the image taken with the Nikon Z50.

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Edited by james7ca, 01 June 2025 - 02:49 AM.

[james7ca]

Lastly, here is an inverted and annotated image taken from the capture done with the Nikon Z50 that shows the dozen or more galaxies that surround the asterism. In this case there are a few galaxies that are as faint as magnitude 18 and at distances of up to several hundred million light years. It's also possible to make out the spiral shape on a few of these galaxies, even on one or two that were not labeled by PixInsight.

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Edited by james7ca, 01 June 2025 - 03:06 AM.