Archive for September, 2016

A couple of planetaries in Aquila

Back in August using the 6″ refractor fitted with a flip mirror and Watec camera I picked up planetary nebula NGC 6772 this was a new object for me. The PN appeared as a round featureless smudge on the monitor via the small aperture, it was unfortunate that the 20″ wasn’t operational due to focusing issues! Kepple & Sanner list this object as being of mag 12.7 with a mag 18.2 central star, all I was able to see is shown in the sketch below made on the evening of Aug 6th 2016 N is up.

NGC 6772

NGC 6772

I have been struggling with the 20″ mirror cell since it was put into the existing open tube, it simply would not hold the mirror in collimation as we moved around the sky, Es Reid to whom I’m eternally grateful to for his great technical ability and endless patience has modded the cell a few times try to eliminate the problem each time improving it substantially, the last modification certainly stiffened the whole set up keeping the 20″ and piggy backed 6″ refractor pointing at the same piece of sky. The modification however pushed the mirror forward which mean’t the camera a prime focus was no longer focused on the starry firmament correctly, I tried using the Moon and bright stars on a number of occasions to get this rectified,, however it became plain that to do so was beyond my agricultural skills and one pair of hands! Fortunately Es came to rescue on Sept 7th determined to rectify the issue and get the scope operational once more.

Well he did it but it wasn’t easy taking him a good few hours and plenty of head scratching, the issue was that focus fell just between camera location positions and max in and out motor focuser settings! Es over came this by shifting the mirror in the cell to a position were focus on the camera chip could be made with the camera locked into one of the variable positions, allowing the focus motor to bring the image into focus, through focus and back into focus, hoorah! and thank you Esmo my friendly boffin 🙂

Es clowning around during adjustments to the 20"

Es clowning around during adjustments to the 20″

With the 20″ now operational again I was delighted that the next evening was clear giving me a chance to get back to business. I ‘zeroed’ the scope on Altair then looked for something interesting close by to look at and sketch. The object I chose happened to be a Planetary Neb NGC 6804, there was nice detail on the monitor, the central mag 14.4 star was very obvious, some regions of the disc showed darker mottling and there was a hint of extended nebulosity to the South, it was great to be back in business again and starting with a new object, after sketching in pencil on white sketch paper it was shut down and bed, these days work is physical and sleep is more precious than when I was a dosy office boy 😉

NGC 6804 a planetary nebula in Aquila

NGC 6804 a planetary nebula in Aquila

 

Dale

 

A nice pastel sketch from my friend Frank

Got this from my good pal in the US a couple of days back, very nice indeed.

The Moon & Venus over Mesa, Arizona

The Moon & Venus over Mesa, Arizona

Moon and Venus Just Past Sunset

 

I was in Arizona for the past 2 weeks observing with my daughter most clear nights.

I wanted to include the planet Jupiter in this sketch but I was not able to spot it.

It was somewhere nearby the lower right of the Moon in the haze.

 

 

Sketching:

Paper: medium blue sketching paper 9”x 12”

Mixed media used: pastel pencils, oil pastels, charcoal pencils,

Blending stumps,

No optical instrument used, naked eye sketch

Friday September 2, 2016, 07:12 local time

Moon at:

Colongitude: 283.4°

Phase: 163.2°

Lunation: 1.46 days

Illumination: 2.1%

Conditions

Slightly hazy, partly cloudy

102° F ( 39° C )

 

Location: Eastern side of Mesa, Arizona

Frank McCabe

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