December Monthly Challenge

[kt4hx]

Here are my observation notes for the December challenge objects.


NGC 7635 (Cassiopeia, diffuse nebula, mag~10.5, size=15.0'x8.0'):

An observation from our dark site using the 12 inch four years ago using 84x. This was during a moonlit night, so the sky was not as dark as typical. But since I was able to barely pick up the low surface brightness galaxy IC 10 in the moonlight, I decided to try the Bubble Nebula almost 6.5° WNW of Caph. Finding mag 6.9 HIP 115198 I dropped in the O-III filter and though dim, I could easily see some nebulous concentration northeast of this star. Obviously the moon was compromising the observation, but it was clearly present, and I could also see some haziness around the star at its center, mag 8.7 SAO 20575. However, I was not visually picking up the bubble feature around this star. Rather I was seeing the densest portion of this HII region to that star’s northeast. When I removed the filter I had a fleeting sense of a very tenuous haziness, but could never be certain. As a little bonus I also easily noted the presence of M52 nearby in the RACI and took a quick peek. At 84x it was a very pretty concentration of diamonds that was well detached and compressed.

NGC 1316 (Fornax, barred lenticular, mag=8.5, size=12.0'x8.5', SBr=13.4):

This is a recent observation of the radio source Fornax A from our dark site utilizing the 17.5 inch on a night of horrid seeing, though transparency was good. I only observed at 110x (ES 82° 18mm) and 152x (Ethos 13mm) because it was extremely difficult to hold focus on stars due to the turbulence, particularly closer to the horizon. The galaxy was only about 15° above the horizon. It presented a very bright and pretty large oval. It was very diffuse to the eye, with only a subtle broad brightness in its central region.

[helicon]

Thanks Alan, sounds like you were able to have good views of both objects.

[kt4hx]

Thanks Alan, sound like you were able to have good views of both objects.

Thank you Michael. Yeah, not too bad. A report for the session where I saw NGC 1316 is still a work in progress (happened night of the 9th). I focused on Sculptor, Fornax and Eridanus despite the awful seeing, particularly working toward the horizon as I was. I also visited NGC 7635 during that outing, but about all I could see, even with a filter, was some nebulosity around mag 8.7 SAO 20575 at the center of the complex and mag 6.9 HD 220057 at its southwestern edge.

[Graeme1858]

Excellent detailed report Alan. The O3 filter detail is interesting.

My signature weather forecast tells me I'm in with a chance tomorrow with a waning Moon too, fingers crossed!

Regards

Graeme

[kt4hx]

Excellent detailed report Alan. The O3 filter detail is interesting.

My signature weather forecast tells me I'm in with a chance tomorrow with a waning Moon too, fingers crossed!

Regards

Graeme

Thank you Graeme. It is interesting sometimes to compare the visual impact of using different filters on nebulae to see which is best or to compare how they each impact the particular object.

[BABOafrica]

Nice report. Trying for NGC1316 from VA ... Must be close to the horizon indeed.

Love your Santa beard!

BABO

[kt4hx]

Nice report. Trying for NGC1316 from VA ... Must be close to the horizon indeed.

Love your Santa beard!

BABO

Thanks Joe, It was about 12° to 13° in elevation. With the thick air mass that close to the horizon, plus generally poor seeing anyway, it was still quite bright and obvious.

For some reason I just thought I would try to edit my regular avatar in keeping with the holidays and thought it looked decent enough.