Moonlit doubles in Orion

[domstar]

Unfortunately, the January cold snap and its freezing transparent skies coincided with the full moon. Fortunately, Orion is filled with double star beauties, which kept me enthralled for three consecutive nights.

Everyone knows the biggest attraction- the Trapezium. I quickly reaquainted myself with the E star and had a long look for the elusive F. On the second night my head jolted a couple of times as I seemed to catch it for a moment and the next night I had it for sure. I found it interesting how your brain seems to have a memory for sights that makes it so much easier to see a faint target subsequent times. Once I've seen something, it's often waiting for me the next time, conditions allowing.

Rigel was wonderful. Sigma Ori gave up its fourth star easily as I'd done the hard work last year. Iota Ori, Meissa and Alnitak are wonderful too (Alnitak showing a difference in colour).

I was given some advice on new ones (for me) and I find the first time more thrilling and more of a challenge. Eta Ori was a surprise as I expected a tight double but the companion wasn't close at x112.5 but it was very faint. Psi Ori was another fine one which looked single at x90 but was split at x112 (I might have it confused with 32 Ori. And one or two failures such as 52 Ori.

On the second day I was so awestruck by the transparency that I spent about 20 minutes trying to split Sirius at x90. Later research revealed that I was wasting my energy although I enjoyed it so much I can't say I was wasting my time. Anyway, on a less than dark night, Sirius is a good place to hop from to find Beta Mon, which is another beauty.

All in all, a wonderful night leaving me with a sense of accomplishment and a peace, which has helped a lot in what has been a trying week. If I could take one piece of stargazing wisdom from these sessions it would be- a blanket for your knees can be more important than an extra eyepiece.

Thanks for reading.

Dominic

[cloudsweeper]

Nice work Dom, very rewarding.  I'm desperate to get out with my new ED80, but in the meantime reports like yours keep up the spirits!

Doug.

[Stu]

Good stuff Dom. I tried last night with similar targets but soon got clouded out. I managed Alnitak through quite thick cloud before packing in.

[John]

Great report Dom.

Eta Orionis is actually a rather close pair - about 2 arc seconds is the split I think, maybe a bit less. Maybe there is a 3rd more distant member of the group though ?

 

[Astro Imp]

Nice report Dominic.
I was out last night having a look round Orion. The trapezium seems to draw us all. I managed to catch a fleeting glimpse of the E star, I think, F has always eluded me.
I like your comment about a blanket over your knees, must try that next cold night. When I packed up last night everything was coated with frost.

[domstar]

Thanks @John I was hoping somebody would help me with this. Wrong star maybe- it was very orange. I'm not good at judging separation especially if the magnitudes are unequal but I would guess at least 3 or 4. I hoped that the separation had grown significantly since stellarium's 2015 figure of 1.8. 

Alnitak at 2.36 could be almost split at x 90. Any advice on minimum separation splits on beautifully clear nights? I like x90 but can also Barlow to x112.5. (My 6mm BCO at 150 usually gives pretty fuzzy views of stars)

[Littleguy80]

Really enjoyable report, Dom  

[domstar]

Hmm. Thanks again @John It seems I was looking at 31 Ori and not Eta. That's good- I found a lovely one and I still have something to look forward to. So nice to have such experienced eyes guiding me forward.

[John]

36 minutes ago, domstar said:

Thanks @John I was hoping somebody would help me with this. Wrong star maybe- it was very orange. I'm not good at judging separation especially if the magnitudes are unequal but I would guess at least 3 or 4. I hoped that the separation had grown significantly since stellarium's 2015 figure of 1.8. 

Alnitak at 2.36 could be almost split at x 90. Any advice on minimum separation splits on beautifully clear nights? I like x90 but can also Barlow to x112.5. (My 6mm BCO at 150 usually gives pretty fuzzy views of stars)

With a 100mm aperture the max theoretical split is either 1.16 or 1.4 arc seconds, depending on whether you go for the Dawes or Rayleigh limits.

 

[domstar]

2 minutes ago, John said:

With a 100mm aperture the max theoretical split is either 1.16 or 1.4 arc seconds, depending on whether you go for the Dawes or Rayleigh limits.

Well that explains my difficulty with 52 and 32 Ori ?.  With that in mind, I'm looking forward to the challenge of Eta (got to find it first).

[Eastman]

Really nice report Dom, I guess that SW 100/900 ED is graet on doubles.