Azimuth & Iridium Flares

Richard · #1 17-05-2005, 05:54 PM

I was shown my first Iridium flare on Saturday and would like to see some more. I have accessed "Heavens Above" and found the time and location for some.

I can use my closed hand to work out the Altitude, I am not quite so sure about the Azimuth. Can I simply use my compass to determine this?

I am chasing one on the 22nd, 18:00, 66 (Alt) and 139 (Azimuth) as it will be at magnitude -8.

Also with limited experience can I use a star map to work out which stars it will be near?

Any help would be appreciated.

Richard

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gbeal · #2 17-05-2005, 06:21 PM

Hi Richard,
exciting huh?
I find the easiest way to work azimuth is find north (midday sun is north), and then work from there. 139 is 139 degrees from north clockwise, so if you face north it will be past your right shoulder. An outstretched hand at arms length is about 20 degrees, so get east and go 2 1/2 handspans. It is actually about SE.
I have an idea that most software programs will accept alt and azimuth co-ordinates as well.
Good luck,
Gary BEAL,
New Zealand

iceman (Mike) · #3 17-05-2005, 09:14 PM

Hi Richard.

to the forum!

Iridium Flares are great, very exciting when you catch a bright one.

The Heavens-above listing also shows you the compass direction (eg: South-East), I simply use that. And most times they seem to travel from south to north direction.

You will be able to use a starmap too. The hard part is catching them when they're faint.. sometimes you only see them when they get really bright as you were looking in the wrong direction

Richard · #4 17-05-2005, 09:46 PM

Thanks.

When we were originally looking for the listed one we were actually looking at another satellite and then saw the one we expected a minute or so later.

I am in the process of getting an 8" Dob which will be my first telescope and intend using it with my 7 year old daughter and the Tropical Starwatchers in Mackay. She an I have been watching the sky on and off for the last 18 months with eyes and binoculars.

Richard

iceman (Mike) · #5 18-05-2005, 06:24 AM

You're choosing a great scope, you'll love it.

Are you friends with Mick from the tropical stargazers? He's an avid iridium chaser and has taken some great shots of them.

Richard · #6 18-05-2005, 10:23 AM

Yes I have met Mick and he has been very helpful. He has suggested that the 8" would be a good starting point. Also another member bought one recently and is very happy with it.

Its good also as it should arrive in Sarina includuding freight for about $460 which is within the budget (Andrews Communications). It may not rival Hubble but it should be fun and a good start. The Dob should also make it easier for myself and my daughter than an EQ mount.

Also I downloaded the article about photography using a Dob, it was really interesting. But thats for later, maybe. My first task with my daughter is to learn the sky and look at some simple and pretty sites and the planets for now.

Richard

iceman (Mike) · #7 18-05-2005, 10:29 AM

Great plan, you're well on your way!

cahullian · #8 18-05-2005, 02:09 PM

hi Richard
You will love the 8'' I have been using binoculars for a while and when I saw the moon through my 8" dob also from Andrews I was blown away. When I showed it to my kids the were very impressed and looks like a family thing from here on. Look up and enjoy the ride : )

Richard · #9 19-05-2005, 07:47 PM

Cahullian

what eyepieces are you using? I get a choice of two which I think are a 9mm and a 20mm unless I specifically ask for a different one.

I guess the question is would a 12mm be better than the 9mm? What are your two most popular ones?

Richard

RAJAH235 · #10 20-05-2005, 04:35 AM

Hi Richard, Welcome.

If possible, get the 12 mm instead of the 9 mm. Reason for this, later, when you get a barlow, with the 20 mm you'll 1/2 it to a 10 mm. But if you 1/2 the 9 mm & to 4.5 mm, you may find this slightly overpowers the t'scope. 1/2ing the 12mm to a 6mm is a better, (IMHO), choice.
Mags you get if the t'scope is an f8, (please correct if not)(ie;1600mm long),20mm = 80x, 12mm = 134x, barlowed 20mm = 160x & 12mm = 267x.
To use the 9mm barlowed would give you around 356x mag. & this is very close to the max that can be expected with that aperture. (Remember the magic # is 50. ie; The aperture of your t'scope in inches x 50, ((8 x 50 = 400x)). This is the max mag. you can theoretically use). You'll need very good conditions to ever use that mag. unless of course you buy Naglers or similar E/Pcs. with a wider AFOV.
HTH.

L.
Thanks Mike. Wasn't sure of correct fl. or f ratio. (1000mm @ f5)???
Minor corrections needed with calcs!!!

L.

iceman (Mike) · #11 20-05-2005, 05:51 AM

The 8" is focal length 1000mm.

Richard · #12 20-05-2005, 06:58 AM

Thanks. That is very helpful. I didn't think about the implications of using a Barlow.

Richard

Mick (Michael) · #13 20-05-2005, 08:11 PM

Hello Richard and welcome, glad you made it to this informative forum I've just got back home. I can show you how to use Alt/Az to find Iridiums next time we meet, oh and you won't be disappointed with the Dob it's a great scope.

Richard · #14 23-05-2005, 01:35 PM

Might finish up with this thread. Just to say we did see the Iridium flare on Sunday that started this all off. (Well my wife spotted it, then I saw it). Just a pity we only saw it as it became bright and for a little while after. It was somewhere near where we were looking but not exactly.

Thanks to all that replied.

Richard

RAJAH235 · #15 24-05-2005, 12:47 AM

You're welcome.

L.