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Difference in colour Epsilon Lyrae


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Fairly recently bought an 80mm APO and have had a 120mm ED Refractor for a bit longer. The other night I had a good look at Epsilon Lyrae, the double double in Lyra.

This is always a favourite and I feel (along with Pi Aquilae, Delta Cygni and Epsilon Bootis, a good test of optics (cooling and collimation) and seeing conditions.

Although I have observed these pairs a large number of times I have never been so sure that I was seeing a notable difference in tone of one of the stars as recently through my two fracs. The star in question (the top star in EL1) was distinctly grey to my eyes from about 100x or higher. I manage 160x in the 80mm and 300x in the 120mm. 

Was I imagining things or has anyone else seen this difference?

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It's funny you should say that, I've been working on a 9mm EP comparison and used Eps Lyrae as part of it..  here's an abstract of my thoughts at the time..

"Epsilon Lyrae The northern pair, which has 1.5 mag difference and southern pair of similar magnitude (0.4 mag difference) both showed a clean split in to the 4 components at 124x.  The southern pair looked the most obvious split, although they are actually closer, but I feel this is due to the similar magnitude providing two more defined points of light"

I wonder if its the change in magnitude giving the appearance of  "Grayness" compared to it's brighter, clearer companion, maybe it's a trick of the eye picking up more detail in the brighter companion..

(hope I got those the right orientation BTW)

Hmmmmmm

Fozzie

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Referring back to my notes from 6th October 2013, I noted one star of each was yellow and the other blue/white.

I used the Baader Zoom set at 8 + 2.25 Barlow in my 120ed, this gives a mag of 253 and FOV of 0.269*.

Avtar

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I've been having a good look at Epsilon Lyrae this evening with my ED120, prompted by this thread. I was using a Pentax XW 5mm eyepiece for 257x.

With the E1 pair, the difference in magnitude between the components is very clear and to my eye tonight I thought the fainter star had just a tint of yellow / orange to it whereas it's close companion was white. This could have been the brightness difference rather than an actual tint variation of course.

With the E2 pair, the components look very similar in terms of both colour (again whiteish) and brightness and they are also very similar to the brighter of the E1 stars.

The E2 pairs separation appears to be a little wider than the E1 pair but again this could be an optical illusion due to the brighness difference between this pair of stars.

I hope I'm being consistent in my identification of the E1 and E2 pairs - I've come across a few other websites that seem to confuse them !

It's nice to spend some time on this object even though it is much observed. Taking notes and doing little diagrams seems like proper astronomy :smiley:

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  • 2 weeks later...

I've been having a good look at Epsilon Lyrae this evening with my ED120, prompted by this thread. I was using a Pentax XW 5mm eyepiece for 257x.

With the E1 pair, the difference in magnitude between the components is very clear and to my eye tonight I thought the fainter star had just a tint of yellow / orange to it whereas it's close companion was white. This could have been the brightness difference rather than an actual tint variation of course.

With the E2 pair, the components look very similar in terms of both colour (again whiteish) and brightness and they are also very similar to the brighter of the E1 stars.

The E2 pairs separation appears to be a little wider than the E1 pair but again this could be an optical illusion due to the brighness difference between this pair of stars.

I hope I'm being consistent in my identification of the E1 and E2 pairs - I've come across a few other websites that seem to confuse them !

It's nice to spend some time on this object even though it is much observed. Taking notes and doing little diagrams seems like proper astronomy :smiley:

I had another very long look this evening as the seeing was excellent, and the Moon was there as a standard "white" to judge colours against. I used a WO 5mm EP to give me x300 which was as high as I could go and keep the disks sharp. At this mag, I would agree John that the fainter of the E1 pair is distinctly yellow/orange compared with its companion, which to me seemed the same colour as the other pair. At lower mag, the E1 pair looks more or less the same colour.

Chris

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I have four records about the double double. Although I was more focusing on the separation, in one note I wrote that they (e1 and e2) appeared with the same colour (meaning 'white-ish'). This was at 103x and 206x using a Nagler 3.5mm w/o tele-extender 2x.

Great target. Always a pleasure to spend a visit to Lyra.  :rolleyes:

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