Moon and Porrima

3 months 7 hours ago #108823 by flt158
Moon and Porrima was created by flt158
Hi everybody.
I have just noticed Porrima (Gamma Virginis) is almost directly south of the Moon tonight Monday 4th May by about 2 degrees.
Porrima's magnitudes are: A = 3.5. B = 3.5. Sep = 2.9". PA = 359 degrees.
Vallis Schroteri, Aristarchus and Herodotus will on view too as well as a host of other lunar features.

Clear skies,

Aubrey.
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3 months 6 hours ago #108825 by Keith g
Replied by Keith g on topic Moon and Porrima
It looks reasonably clear for most of us too...

Keith..

If a telescope can fit into your backyard it's too small. If you can't move it, it's too big." -- John Dobson
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3 months 5 hours ago #108826 by flt158
Replied by flt158 on topic Moon and Porrima
Go for it, my main man, Keith!

Both stars are yellow-white.
I wonder if it is possible to figure which component is the brighter.
There is only 0.05 difference in magnitude (Delta Mag)

Clear skies!

Aubrey.
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2 months 4 weeks ago #108829 by Keith g
Replied by Keith g on topic Moon and Porrima
Ah alas, I didn’t get to see it. My neighbour decided to light a fire ! My back garden was very smoky :-(

Keith..

If a telescope can fit into your backyard it's too small. If you can't move it, it's too big." -- John Dobson
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2 months 4 weeks ago #108830 by flt158
Replied by flt158 on topic Moon and Porrima
Gosh! What a disaster!
I'm sorry to hear that, Keith.

Thankfully I had no problems apart from the strong easterly wind.
Before Porrima appeared with my own eyes, my William Optics 158 mm apochromatic refractor was trying to split herself at 40X!
It was a glorious sight at 112X. The lower star was ever so slightly fainter than the upper one.
Through my small 70 mm apo at 11X the Moon and Porrima were in the same field of view of 6 degrees of course.

The Moon was very good indeed. Vallis Schroteri looked magnificent at 112X - as did Herodotus, Aristarchus, Prinz, Krieger Van Biesbroeck, Wolleston and Marius. Did anyone notice the Marius domes right on the terminator? There must have been over 20 of them. Further south had Schiller and Schickard.

All in all, I had a very satisfactory night of observing. Valerie was with me. I observed my very first S class star. It's at maximum magnitude right now: +9.5. The designation is AV Canum Venaticorum or AV Canum. I have submitted that magnitude on www.aavso.org

I also showed Valerie Upgren 1 that open cluster in Canes Venatici. There is no Upgren 2. Upgren 1 is about 7 degrees west of Cor Caroli.

The winds are due to die down tonight Tuesday.
So another night of observing for me.

Happy Days and nights from Aubrey
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2 months 3 weeks ago #108835 by Until_then-Goodnight!
Replied by Until_then-Goodnight! on topic Moon and Porrima
Hi Aubrey, 

Very many thanks for your 'heads- up on the event. I took a look at it my self, and Porrima was very nice indeed. 

In addition to observing Porrima, I also observed those lunar features you mentioned. Vallis Schroteri really stood out for me. I viewed it at 37.5X, 48X, and 133X. 

I attempted to sketch Cavendish at 272X, but the wind caused havoc, and there was a bit of a chill too. So after approximately 30 minutes, I put down the pencil, and packed-up. 

Clear skies,

Darren.
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2 months 3 weeks ago #108838 by flt158
Replied by flt158 on topic Moon and Porrima
Yes, Darren.
Porrima is very nice.
But did you succeed in splitting it?

Kind regards,

Aubrey.
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2 months 3 weeks ago #108840 by Until_then-Goodnight!
Replied by Until_then-Goodnight! on topic Moon and Porrima
I'm afraid not Aubrey.

While I love my XT6, I'm beginning to think that it is not a great scope for splitting stars. It manages to split the straight forward ones such as Mizar and Alcor; Epsilon Lyrae; and Delta Bootis; but it struggles on others. You might recall that I found it quite difficult to split Izar. Of course they say that a bad workman blames his tools, so maybe it has to do with my lack of experience splitting doubles. Regardless, I'll keep at it.

Clear skies,

Darren.
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2 months 3 weeks ago #108842 by lunartic
Replied by lunartic on topic Moon and Porrima
Your scope should be more than capable of splitting a huge number of doubles, Darren.  Perhaps you should consider making an off axis mask.  A smaller aperture should help, as it allows you to use higher magnification when the seeing allows.
I am not going to insult you by asking if your scope is collimated.

Paul

Programming today is a race between software engineers striving to build bigger and better programs, and the universe trying to produce bigger and better idiots. So far, the universe is winning.

Rich Cook
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2 months 3 weeks ago #108843 by flt158
Replied by flt158 on topic Moon and Porrima
Hi Darren.
I hope you are keeping well with all this crazy social distancing.

Okay, let us compare Izar with Porrima.
Izar's magnitudes are: A = 2.6. B = 4.8. Sep = 2.8". PA = 347 degrees.
Porrima's magnitudes are: A = 3.5. B = 3.5. Sep = 2.9" or almost 3" right now.PA = 358 degrees.

Therefore we can easily figure out that Porrima is the easier to separate.
Izar B companion is fainter than Porrima.
It is logical to presume that Porrima is more likely to be split through your fine telescope.

Last night (Friday) I did seek out Porrima with my own eyes. It was relatively easy to see before I looked into any telescope. And I did find it quite difficult to locate in my small apo. Whenever I had a "bright" star in the centre of the field of view, I proceeded to observe it in the main scope. No - that's not Porrima. This happened no less than 3 times! I then discovered that Porrima is low from my vantage point. When I did observe the correct star, my scope was almost parallel with the ground I was standing on. I found it easy to split at 112X. That is the same magnification I use to split Izar on a good night. I did split Izar earlier.

If you wish to try again to observe Porrima, Darren, please do make sure you have the right star. That is my advice.

By the way, I have now moved to Coma Berenices. Canes Venatici has become impossible for me because of my Berlebach mount and the proximity of the focuser. But I ought to return to C V later in the summer.

Kind regards to you and your family,

Aubrey.
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2 months 3 weeks ago - 2 months 3 weeks ago #108847 by Until_then-Goodnight!
Replied by Until_then-Goodnight! on topic Moon and Porrima
Hi Aubrey and Paul,

I tired three times to post my message last night, but I never got to finish it. I wanted to thank you both for providing such useful advice and suggestions. Based on the information you provided I reckon I was observing the wrong star. I doubt it was a collimation issue because I collimate the scope before each session. And please don't think you'd insult me by asking whether I had the mirrors collimated Paul...I don't think like...I only see such an approach as it is: helpful.

In terms of the axis mask, not sure what it is so I'll follow-up on that - thanks.

Again, very many thanks for your replies. I'll let you know how I get on over the next week,

Clear skies, and enjoy Coma Berenices Aubrey.

Darren.

And thankfully all is well with the family. The fine whether is certainly helping as we can enjoy the back garden. I hope things are good your end Aubrey and Paul too.
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