These are our observations of HII-region

• In the Region of the Summer Stars: The Coathanger Asterism

  At last, I've had a few clear nights and managed to get out and enjoy the sky again. I decided to forego the forensic probings of my Ritchey-Chretien scope and take in more of the context around some of our summer objects. So, for the first time, I installed the ASI 071MC camera on my APM 107 refractor and included the 0.75x Riccardi reducer. This combination gives a focal length of 530mm and an image scale of 1.8 arcsec per pixel, which is a bit on the big side and gives around two pixels per star. Thus, the expectation was to see some blocky star images, which I have.

  I have observed the Coathanger asterism previously but on this occasion, I deliberately shifted the "Coathanger" to the bottom of the frame so that I could explore the region to its north. The second night was plagued by high, thin clouds, which I did not see while imaging, but they became apparent during processing and produced a blue haze over the image. Rather than lose all the data, I used several tools and processing techniques to reduce the haze, and this image is the result of this work. There are over 19,000 stars in this image, says Pixinsight.

  

  Just for a bit of fun, I've been exploring the image and have identified the following objects of interest.

  NGC6802: a 10th magnitude open cluster forming an extension of the coathanger bar to the east.

  

  IC1299: a very 14th magnitude open cluster to the northwest.

  

  Sharpless 2-83, a 15th magnitude 2x2 arc-minutes HII region.

  

  And three planetary nebulae from the Strasbourg-ESO catalogue of planetary nebulae that were discovered by Henize during the 1960s. These are small, faint objects on this image and took a bit of finding, but I think I have them. You might, of course, disagree, but that is fine.

  

  • He 1-1: an 18.5 magnitude planetary nebula, 5 x 5 arcseconds
  • He 1-2: a 17.2 magnitude planetary nebula, 5 x 5 arcseconds
  • He 2-432: an 18.5 magnitude planetary nebula, 5 x 5 arc seconds

  The images of these planetary nebulae have been copied from the original image and magnified. The nebulae are the pinkish star-like objects in the centre of the frame.

  I'm astonished at the wealth of detail captured by my somewhat neglected refractor. The objects' brightness range is from 5th magnitude in the coathanger to 18th magnitude from the tiny planetary nebulae - that's around 140,000 times. It's time for a rethink on telescopes going forward, perhaps. I should go back to the objects using my RC telescope and see what it delivers.

  Image Details

  Data: 80 x 30s RGB sub-images collected on 27th and 28th July 2024.

  • Telescope: APM 107 refractor with 0.75x Riccardi reducer flattener
  • Camera: ZWO ASI 071 MC Pro
  • Mount: Skywatcher EQ8

  David Davies - (31 July 2024).

• NGC 281: the Pacman Nebula

  Image Courtesy of Paul A Brierley, East Cheshire, UK. Please click on the image for the high resolution version.

  I hope you are all enjoying this pre equinox sunshine.

  When the skies where I live, in East Cheshire, finally cleared least night. I was able to take 15 minute exposures of the "Pacman nebula" that is currently visible high in the Autumn sky near the star Schedar, Alpha Cassiopeiae.

  I used the usual equipment. And took 1¾ hours of image data, all 15 minutes through a Baader 7nm Ha filter.

  The images were stacked in DSS and post-processed in Startools and CS2. CCD and mount control via SGPro and PHD 1.