Saturday, August 28, 2010

first shadow; new career split (Blue Mountains)

10:49 PM, Fri 27 Aug. Visible ISS passes completed for the evening, I settled down to do some proper astronomical observing. I put the dew cap on the GBO C14, to hopefully get rid of some stray moonlight. Put the big cap on, with velcro strips, successfully, on the first try. But then decided to move it, thinking it a little crooked. Spent the next few minutes floundering. I hope no one saw me. Sheesh. Should have left it alone...

11:54. I emailed Phil. Told him I was trying to view the Great Red Spot on Jupiter but combined with the elevation and seeing conditions, the eyepiece views were not great. The gas giant was only 27° up. We agreed that it should improve as the evening wore on.

Tim took some looks from time to time.

I was very pleased to find that SkyTools3 could simulate the Jovian moon shadow transits.

12:25 AM, Sat 28 Aug. Upon reading Phil's urgent email, I viewed the GRS in the C14. I was still using the 27mm eyepiece. He said it was "fabulous." For us, the seeing was still spotty. You had to wait a few seconds, up to a minute, to get a good—brief—shot.

1:04. The GRS was just past centre. Easier to see. The Europa shadow just starting to show up.

1:08. No bugs this evening. Humidity was 69%. Light wind (although the anemometer was not spinning, again).

1:13. Margie and Bob looked through the eyepiece of the Celestron 14" SCT at Jupiter. I had been at very high power. It was a bit blurry and shakey in the marginal seeing. I dropped to 217x power with the 18mm eyepiece. We all thought it better.

Tim reviewed the Genesis manual. And found it a rough go.

1:16. The Sky Quality Meter read 16.09.

1:49. I was the last man standing. Margie and Bob had left and Tim had gone to bed.

I watched Europa move closer and closer to the king of the planets, touch the limb, black line between them slowly disappearing, and then merge, to become a bump on the surface.

2:18. Moved the ladder out of the way of the telescope. Almost had a collision.

I couldn't see Europa itself any more, as it moved over the disk of Jupiter. But the shadow was very pronounced now, with the planet up high. Easy to see.

That shadow viewing was kind of a first for me. It represented the first time that I planned for it and observed it from the beginning stages. Nice to get that under my belt.

Now I need to nail a dual shadow crossing...

Decided to view some double stars, for fun. Reviewed my summer list, based on Alan Adler's article at Sky and Telescope. But realised that most of the available, unseen targets were too low in the sky, or had already set. So I pulled the companion winter list. Ah, Andromeda and Aries were well up!

Looked at the double star 36 Andromedae. I still had the 18mm eyepiece in, yielding 217x power. Didn't mean to do that. I usually start with a lower power eyepiece... Still, with that high power ocular, it gave me a chance to view the star closely. Initially, it appeared to be one star but when I looked again, I could see it was two! It was a figure-8. Very tight pair.

Deep yellow or yellow-orange. Equal colours. Equal brightness.

2:23. The red film for the flat screen was rippling in the breeze. Very distracting noise (not unlike the old theatre production trick of using a metal sheet to simulate thunder). I taped it back up.

2:27. Turned Sony voice recorder VOR on but saw right away it didn't work. Turned if back off. Forgot that I had it in directional (mono) mode...

2:29. I had moved up the magnification power. I put in the 10mm eyepiece, kicking it up to 391x. This reinforced that the stars were the same colour and exactly the same brightness.

Sissy Haas, in double stars for small telescopes, says that these stars are 1.0 seconds of arc apart. This is also the same number quoted by the S&T list. Rather suddenly, this became my new career lower limit! Other stars below 1.0, I have not been successful with, and I intend to revisit, in better conditions. The previous lowest confirmed limit was with Σ1291 aka 57 Cnc at 1.5". Confirmed! I was happy.

Haas says they have magnitudes 6.1 and 6.5; the S&T list says 5.5 and 5.9.

Amazingly, this split was done very near the Moon.

2:38. Viewed the double star 56 And with the 27mm ocular.

Haas says they are super-wide. I agree with this. Haas: 200.5; S&T: 199.5.

She says they are equal in brightness. I agree with this. Haas: 5.8 and 6.1; S&T: 5.7 and 5.9.

I assessed the colours to be citrus-orange and pale or straw-yellow. She describes the colour as "whitish scarlet and whitish lemon." Huh?! Smyth says both stars are yellow. The winter list from Adler indicates a zero in the colour difference column which means the stars are the same colour. So, no one agrees.

Also interesting is that the winter list recommends viewing at 4x. That's very low power. In the range of binoculars.

I've noted before that at higher power, the colours of double stars changes. If they are more widely separated, the colours will not blend and merge.

2:44. Viewed 1 Arietis with the 27mm. Light yellow and pale, robin's egg blue. Very light blue. Very tight together.

Haas: sun yellow and ocean blue. I wonder if someone was enjoying a margarita as they wrote up this one... She says the separation is 2.9 arc-seconds.

Bumped up to the 18mm.

Viewed ε (epsilon) Ari. Tight. Both sources say 1.4" separation. Same colour, white. Didn't make good notes on this one... Should probably look again.

2:52. Wind was building. It's shaking the 'scope at times. Particularly with the dew shield still attached. Anemometer was still not spinning.

2:55. I was feeling tired. And a bit sore, uncomfortable. Sitting too long? Wandering around directionless. Decided to pack up.

3:08. Dropped the Sony recorder. First time. That's a sign I was getting dopey.

3:09. Outside, roof closed, I found Orion rising. The belt stars, over the horizon, were almost straight up. Betelgeuse was flickering orange; Rigel was flickering blue, shimmering wildly, at 2° above the tree line.

Pretty nice sky, overall. Not a lot of clouds. There was a glow all around the horizon.

Looked to the north to spot aurora. Wishful thinking. It's really the wrong time to look, in many respects.

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