Astro session at Perth region dark sky site - 21 April 2012

[Airconvent]

Oh man...looks great Gavin. Wished I was there but trips like that tend to be more difficult for me.
Loved the LMC and SMC. I have yet to see those! And you were able to catch the Zodiacal lights! Did you try to look for the Gegenschein as well?

[Visionoz]

Hi Gavin

It was pleasure indeed for me to host you to our Tammin Dark Sky site on behalf of ASWA!

The gods were probably looking down kindly on you to have "organised" such a nice 3-nights run of the visual splendour of the Southern hemisphere's view of the Milky Way for your trip down to Perth!

I'm pretty pleased that you got the "shadow" shot and also the other pixs - they're mint to say the least

Well I hope that there are more avid amateur astronomers from your neck of the woods willing to come over to pay us a visit and as well as you are aware of the next biggie event for us would be in October 2012 for a trip down to Dryandra and hopefully you and your colleagues would be able to come - most welcome!

All the best!

Cheers
Bill
Tammin Site Administrator
ASWA Councillor

[starfinder]

Thanks Sam, Gary, Clifford, Airconvent for your comments!

Regarding the zodiacal light: based on a perusal of all of my photos, the zodiacal light was first seen before 4:30am, probably about 10 to 30 mins before that. At 4:30am on 21st April, the Sun was 27 degrees below the horizon. Therefore, the light was seen well within the period of full darkness (i.e. before astronomical twilight had begun; sunrise was at 6:35am). The photo is quite a good representation of how it looked like in real life. It was quite bright (definitely obvious) and extended for about 30 degrees from the horizon; it seemed broader at the base. I had at first thought it was some light pollution source, perhaps a passing car, but the light persisted for a long time. And since then I've checked a planetarium program which shows that it occurred squarely at the ecliptic where Mercury was (as noted earlier). All of that I think confirms that it was the zodiacal light, i.e. sunlight scattered by inter-planetary dust/debris orbiting on the ecliptic.

On Airconvent's query about the gegenschein (which I think is the zodiacal light that occurs at the point opposite the Sun), no I did not notice it, but was also not looking out for it. I think I shall look though all my photos to see if it was captured. Hmmm....

One previous occasion when I had seen the zodiacal light was at Kahang (in Johor) about 2 years ago, also before dawn in the east. RLow was also there and saw it. I recall it was a narrower (thinner) band on that occasion.

[jiahao1986]

Hi Gavin,

Wow man these are awesome shots. It was really wise for you to make it 3 nights so that you have time for both visual and photographic works, haha.

I'm sure the views through those big dobs brought by the locals are unforgettable under such skies. Can't wait for your detailed DSO reports

Best regards,
Jia Hao

[cataclysm]

Wow! You the man!!

[VeeJay]

Amazing pictures and write-up! There goes the rest of my day

Do you think you could put some arrows and labels on the pictures, to help us newbies? I feel this is much more helpful than the star-charts and software that I use.

[sTiCkY]

I should go to such a place at least once in my life.. haha!

[rlow]

Very nice experience, Gavin. Thanks for the report.

It was wonderful when i experienced the shadow cast by the Milky Way. I could almost read my star charts by starlight alone! The dark skies and clear transparency allowed one to observe at least 11-13 stars in Pleiades with naked eyes. I can imagine you had a good time there.

[starfinder]

Hi Bill, yes I'm glad I managed to image the shadow cast by the Milky Way. And thanks for your guidance on the polar alignment for the Astrotrac!

Jiahao, will describe the DSOs soon. Well, you were the first Singastro member to go to the Tammin region, last Dec!

Thanks too to Cataclysm (Kelvin), RLow and Sticky (Nicholas) for the posts.

Veejay, as requested, below are 2 of the images with annotations added, together with the original images again. A note: my outline of the Emu dark nebula is as I saw it; however, I believe that by definition, the Emu's body actually stretches all the way back to encompass the whole Milky Way's central region, i.e. more than twice longer than my outline.

Annotated image:


Original image:



Annotated image:


Original image:

[Gary]

Beautiful annotations!