Ha, and the Horseshead nebular

[alan potts]

Well on the back of what Olly has said it is looking like a very tall order in my biggest scope. I am sure my skies are as good if not better than in Southern France due to total lack of anything here, that is apart from my walnut trees that sometimes get in the way. Can you believe I have to apply for permission to cut down my own trees, well walnut anyway. I could say it was a poltergeist with a chainsaw.

I think this could turn out to be an expensive filter for no gain, I am going to give it a try without in any case and have a look at john's findings.

Alan.

[ollypenrice]

Well on the back of what Olly has said it is looking like a very tall order in my biggest scope. I am sure my skies are as good if not better than in Southern France due to total lack of anything here, that is apart from my walnut trees that sometimes get in the way. Can you believe I have to apply for permission to cut down my own trees, well walnut anyway. I could say it was a poltergeist with a chainsaw.

I think this could turn out to be an expensive filter for no gain, I am going to give it a try without in any case and have a look at john's findings.

Alan.

I doubt your skies will be significantly different, Alan, because we clock up to 21.7 on the SQM here and are at 3000 feet. Mag7 zenith. They're probably very similar, I suspect, so I expect our experiences of viewing -or 'suspecting'- the darned nag will compare closely! I love that phrase, 'I suspected it...' Very Patrick Moore.

Cheers,

Olly

BTW, I think you'll find you need permission to cut down trees anywhere in Europe. I needed it to cut down Leylandii in Derbyshire. (Well, in truth I found they came easily enough without it but hey-ho...)

[Moonshane]

I like 'suspected it' too. someone also once said to me (about the Pacman Nebula) that he could not tell if he was seeing it or remembering it.

[alan potts]

Olly

I am sure you have fabulous skies, I to am at 1500 feet and that I am sure makes a difference. The best part of my sky is to the south there is nothing apart from the mountains which are about 40Kl away, I never even been able to see a light from a house.

What is SMQ?

I would ask a second question too, you say you have a 7th mag zenith, I thought this was what could be seen with the naked eye and I have always read the limit of the eye is 6th mag. Is this not the case.

alan.

[ollypenrice]

SQM is Sky Quality Meter. I don't have one but a lot of our guests bring them and the values have a kind of universal currency. The values recorded at the Tivoli astro place in Namibia are, I'm told, around 21.7 at the zenith but beat ours at lower elevations. Best ever are in the low 22s I think. It's a log scale.

I can't see Mag 7 with my eyes but Mag 6 is certainlly not the limit for those with great eyesight. It may be a good rule of thumb. We have a visual guy in his thirties who comes every year and we've played a game on occasion giving him little tests while using the bins and the star charts. He can see Mag 7, I'm quite satisfied. WIsh I could! I'm in the high fives at sixty. That's why I like imaging...

Olly

[alan potts]

Olly,

This must have a direct link to pupil size in the same way scopes that are big see more than scopes that are small. You of course know as we age our pupils cannot dielate like they once could. Therefore a 7mm pupil which I believe is about the maxium will allow more light in than a 5.5mm pupil. I still can see clusters here that I never saw in Englan even when I was younger, I think being away from industry like you and me are is the real key.

Namibia is a long way to go for slightly darker sky, would there be that much in it? My wifes Boss is off there next week to kill all the wildlife, one hobby I don't approve of.

Alan.