Thursday, July 16, 2015

imaged HD 133389 (Blue Mountains)

[ed: Figured it out! I had forgotten about a little small side-project. My poor log notes at the time made for a bit of a mystery a couple of weeks later. But I was able to finally retrace my footsteps. Stumbling across the photos helped! Another factor complicating this matter was that the first sighting of the target was blogged but has not yet published so wasn't coming up when searching the front end! Anyway. Mystery solved.]

In my Evernote list of things to do on my vacation, I had a reminder about HD 133389. I wanted to look at it again. I had spotted it on 4 Jul 2015 (natch) and not seen things visually as presented by SkyTools. In particular, the Context Viewer showed two equally bright stars. But I had only seen one. I assumed it was an error in the app. Viewing it again would help me gather some evidence.

Through the week I had considered the target but just not gotten around to it. Wednesday, thought of it again. And moved on. But then tonight, I decided to do something about it. And then, not just visual. What better way to validate a presentation issue than to image it!

Attached the DSLR to the C14 and from 11:23 to 11:34 photographed the target area. Shot increasingly long exposures, starting at 20 seconds, and going to 120.

As the images started downloading to the computer, I quickly glanced at them and compared to ST3P, once again. And, like before, I thought something wrong. The bright pale yellow star HD 133389, aka H 6 53, was clearly visible at the bottom-centre along with the identically coloured bright HD 133483 up and left of centre (east). But no bright star immediately above 133389. I hovered over the star in question. The Context Viewer Status Bar read: J150230.3+474439 (star) in Boo, V8.6.

In the 40 second shot, curiously not shaky or blurry, the grey-white B companion emerged, a short distance away, at the 2 o'clock position (north). In the 1 minute picture, I noticed the pale sky blue star GSC 03484-1254 right of centre (further north of 133389). It made a nice triangle with the two bright stars. I also perceived it to be the same brightness as HD 133389 B, maybe a touch fainter. [ed: ST3P says they are both 12.9.] Which was rendered similarly in the computer chart.

One more pix for fun. The 2 minute image downloaded. Ironically, it looked best of all! No shake or vibration or bad seeing. Nice round stars. Finally... And that's when I saw it! A tiny orange point immediately next to the target star. That is what prompted my exclamation (in my other entry) at 11:43 PM.

So. That changed things around a bit. SkyTools did in fact have a star at the correct location. There was not a rogue star that had been there and gone out. What was throwing me was the chart appearance, both the Interactive Atlas and Context Viewer. They both showed a comparable star. Plus the Object Information box showed that the star was magnitude 8.6 (8.57 to be precise).

But the J label should have been a clue... That moniker is normally attributed to faint objects.

The net result then is that there is a error in SkyTools but it is simply the magnitude value.

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