Posted 07 November 2012 - 01:46 AM
Posted 07 November 2012 - 06:44 AM
Posted 07 November 2012 - 07:35 PM
Posted 13 November 2012 - 07:06 PM
Posted 13 November 2012 - 10:44 PM
Posted 13 November 2012 - 11:20 PM
Posted 14 November 2012 - 12:04 AM
Well, it would take some perfect seeing a maybe some "stupid" magnification. Sparrow is 0.71" in a 6", this one is at 0.45" arc. Theoretically there may be some elongation since they are not exactly on top of one another. But, the spurious disc probably covers up any elongation.
Posted 14 November 2012 - 10:37 AM
... The clean black void between the componets was estimated to be just as wide as the airy discs were in diameter!! ... Mike
Envy scope and especially the clear sky. Just another optical wonder - the Airy disk radius should be somewhat above 0.5 arc sec and to get here black space in this size would require the spurious disk radius being less than 33% of the Airy disk radius. Impossible with this bright components I would think - a clear 8 should be all you can get here with 10" aperture. Envy remains.
Posted 14 November 2012 - 11:06 AM
Posted 14 November 2012 - 11:18 AM
Anyway, you have quite the double star set up, Mike. Next time someone asks which scope is best for doubles (or anything else), mind if I mention yours?
Jupiter, to me, looks like just a few stacked images. Raw.
Congrats on Arietis 10, never heard of it. Probably out of my scope's league. So, what's your draw to doubles, color or separation, or both? I guess I like the challenge of close doubles, but there is no arguing the beauty of colored ones, either.
Posted 14 November 2012 - 07:13 PM
If I recall correctly he elongated doubles with an 80mm refractor (or there abouts) down to 0.5" . If I'm off its not by much. all that to say you can probably elongate 72. Aberrator leads me to believe something as low as 0.2 with the peculiarity being in the diffraction rings seen first. something about the elongated rings pop before its more easily seen in tge disc. That's sim. In practice I've seen a few Dawes and sub dawes but never attempted a value half that.
jus throwing it out there.
Posted 14 November 2012 - 09:23 PM
This implies the spurious discs are nearly on top of one another. If memory serves, Dawes limit was not tough to "split" with a definite peanut shape in great seeing. Reducing that by a few 10ths of an arc second (from 116/d to 107/d) should make little difference in the elongation observed. Much below that becomes another problem all together.
Intuitively there should be some elongation at any separation, it just get's progressively harder to observe. Maybe the fainter the better. But, with 6th mag pair at 0.5", one might imagine the brighter spurious discs will overwhelm each other being that close. In theory, but maybe not in practice.
Posted 14 November 2012 - 10:46 PM
Posted 15 November 2012 - 04:16 AM
Might give 72 Pegasi a look tonight. Pete's got me curious about the possibility of elongation. Dang him...he always does that to me.
Posted 15 November 2012 - 11:31 AM
At 313x and 384x, the diffraction pattern was slightly oval oriented basically east west. The spurious disc did appear elongated with a brighter component west and a dimmer component comprising the trailing edge (as the star drifted through the FOV.) I estimate elongation (PA) to be about 100 degrees +/- 10 degrees. No peanut shape, just an elongated spurious disc.
So, if I observed it correctly, the companion is somewhat dimmer with a PA ~ 100. Is that correct? (I have not checked it's stats, just putting up observation for scrutiny.)
Now, I did slew to 64 Peg to verify if the atmosphere was causing some distortion. However, 64 Peg, just west of 72 Peg, was a clearly white and round spurious disc with a faint circular diffraction ring. Its the same magnitude as 72 Peg.
Well, if that description is accurate (enough) I might have seen elongation. I really think I did, it wasn't too terribly difficult or nearly impossible, but it was not easy.
15 Nov 2012, 1500UT seeing 8/10, transparency mag 5.
Edit: Okay, just checked the PA at 070. Maybe I made a mistake, but it appeared to be just south of 90 degrees. Right? Or at least trailing almost directly behind, but just off a line drawn directly east and west at 90 degrees PA. So I added 10 degrees and guessed at it. Did I do the math right?
Edit, again: No, I read the data wrong:
2012 Theta = 102 and Rho = 0.566.
That was it! Wow, closest double I have observed (without splitting it.)
Edit: Sketch added. The image scale is enlarged to better show the very small details.
Posted 15 November 2012 - 05:47 PM
Posted 15 November 2012 - 08:18 PM
52 Ori has the same appeal to me, not as tight but more like a diamond ring. 31 Tau was a test double at the Dawes limit. Viewing it was a milestone. Yes, seeing here is usually upwards of 8 or better during the dry season. Very fortunate.
Anyone else out there attempting this nice yellow duo??
Posted 17 November 2012 - 08:19 PM
I tried powers up from 300X-750X in my 10" dob, and couldn't confirm a split of any kind. There were times when I thought maybe for a fleeting second or two, but it was probably an artifact of the seeing.
It was fun trying though.
Posted 17 November 2012 - 09:03 PM
Posted 18 November 2012 - 01:37 AM
I will try again if I get an uncommonly good night, though!
Posted 18 November 2012 - 02:24 AM
Posted 18 November 2012 - 08:35 AM