NGC 6888 ,the Crescent nebula, a matter of timing, and a late Venus

The Crescent nebula, NGC 6888Caldwell 27 or Sharpless 105 is an emission nebula in the constellation of Cygnus, that is some 5000 Ly away, formed by the stellar wind from WR136, a Wolf Rayet star – colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 250,000 to 400,000 years ago.

Here is a spectrum of WR136 that I previously captured, note the bright emission lines.

WR 136 Cygnus ngc6888
WR 136, Cygnus, NGC6888

I decided to image this object as I already had data in Ha, OIII and SII, as long as your using the same set up, telescope, field flattener and camera, you can keep adding to the data, that’s the beauty of digital imaging, I added an extra 4 hours of exposure to the data and came up with this image.

Cresent nebula hubble palette
Cresent nebula Hubble palette, WR136 is the central star

As I mentioned in yesterdays post, I was going to try and capture these Starlink satellites with my allsky camera, they would pass over this morning at 3.48am GMT, the following comes from the Express website.

Space enthusiasts will be treated to two opportunities to spot the synthetic satellites this week, according to the Find Starlink website.

Wednesday, May 27 at 3.48am GMT: Starlink-6,7 will be visible travelling from southwest to east for around five minutes.

This starts at 13° from the horizon and the constellation will reach a maximum elevation of 51°.

Thursday, May 28 at 2.50am GMT: You have a second chance of spotting Starlink-6,7 while traverses from south to east for approximately three minutes, starting at an elevation of 25° and reaching 29°.

Well the allsky camera caught nothing. the problem lies with the information re-produced by the express science collumist, Tom Fish, who starts his post with the headline.

SpaceX Starlink: These are the exact dates and times to see Starlink from the UK this week

He reported the times in GMT ( Greenwich Mean Time ), the website clearly states all times are in BST ( British Summer Time ) which is one hour ahead of GMT, so I was an hour late, now I challenge Tom Fish to see any satellite, unless it’s burning up in the atmosphere, at 17 minutes before sunrise.

I should of checked the findstarlink web site myself, lesson learned – tomorrow morning at 2.50am BST looks a better option. 

Here is an image of Venus from my backyard taken 3 weeks ago, I had my Canon EOS 600D on a timer hoping to capture some Eta Aquarid meteors so I took a quick shot of the planet before it started getting too low.

Venus, the evening star


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