Few questions

[Scooter]

Hi Folks,

Couple of quick beginner questions (using a 12" dob) :)

So far I have been setting the scope up on the deck and letting it cool etc. and then have been using it peridoically up to midnight.

At a guess I have been looking at stuff between <20 to ~ 40deg so I am assuming in astro terms this is pretty low. Am I ever likely to get good seeing at these levels (I know for planets etc. the higher in the sky the better so I assume this is a general rule for all things)? What sort of elevations do you folks do most of your viewing?

Like I said I am comming in and out (i.e check star maps on PC and then check scope etc. or watch some TV etc.) so I am not exactly properly adjusting my eyes etc. How much better would my viewing be if let myself fully dark adapt (got large openings to the deck that are lit although I am down one end in shadow etc.)? Probably not hardcore I know but certainly handy having it on the deck and being able to just have quick view when I feel like it through the night.

On the same vien as above if there are external light sources (like neighbours lights) should I be cutting them out (by viewing under ablanket etc.). How big a difference does it make?

How do you folks handle sessions given that best seeing is probably after 12-1pm etc? (is it? When do you think is best seeing or can it be anytime - i.e 9.00pm one night and 3.00am the next). I have thought about going to bed and then getting up but then you have cooling times etc. so just wondered what people do (staying up till 3.00am will put me out of comission the next day;)).

Anyone recommend some good dark sky sites near Brisbane?

Hmmmmmmm,

Thats about it for now :cheers:

[sheeny]

Hey Scooter,

Generally, the higher something is in the sky, the better the seeing will be because you are looking through less atmosphere.

While it isn't ideal to be in and out from inside because your eyes won't dark adapt properly, I say anything that gets your scope used is good! I am sure the Bris-Vegans will chip in with offers of ark sky sites and meet-ups etc.

Every once in while, I would suggest you either turn the lights out inside or take your scope somewhere dark and really enjoy it with dark adapted eyes. If you can set up somewhere that you can't directly see any lights, then that's a good start. Dark adaption will make a real difference to what you can see.

But as I said, if you are using your scope and enjoying it, even when not dark adapted, then that's OK... better than a scope that sits in the corner and doesn't get used!

Al.

[Karlsson]

Fully agree with Sheeny's comments. A few more:

Roughly speaking, at 40° altitude you are looking through 1½x as much atmospheric murk as compared to straight up (90°), at 20° about 3x... not just instability (seeing), but also light-scattering particles (dust, fine mist etc) You don't always have a choice (currently Mars comes to mind) but with faint fuzzies it pays to work out when they are closest to culmination, and observe them at the optimum time.

If you do not like planning but instead enjoy roaming the skies, try to point your scope a bit higher up, for example, have a look at the region around Sirius :thumbsup:

Likewise, if you want to see how much you are missing by not being fully dark adapted, put it to the test, at least once - sometimes I pull an inverted black Tshirt over my head and it does make a difference... make sure you keep the mozzies out though:scared:

If after the 'test' you decide you can't be bothered - fine, but at least you'll know the difference :)

[edwardsdj]

Hi Scooter,

Good seeing can happen at any time. Even on a night of poor seeing, moments of good seeing can creep in every now and then.

Altitude makes all the difference. Unless you have no choice, always try to observe an object when at a high altitude. 20 to 40 degrees is pretty low. Try looking at objects more than 45 degrees up.

Dark adaption makes a huge difference for viewing faint objects like nebula and galaxies. It makes little difference for bright planets or the Moon.

Keeping the telescope out of direct light is important though. Stray light getting into the telescope tends to bounce around inside and lowers the contrast of the view.

I'd love to know the dark sky sites others use too. I've been going to a picnic ground near the Winenhoe dam lately. It's far from ideal though. The day use area at Girraween National Park is one of my favourite spots but the three hour drive makes it hard to do without camping.

Girraween has altitude, is on the other side of the range, and the closest town is Stanthorpe (about 40km away) which while you can see its light dome isn't really a problem.

Seeing does often improve in the early hours of the morning as the air gets colder. Usually the time at which I observe has more to do with the position of the objects of interest than seeing considerations though. It is always better to observe the object when it is highest in the night sky without interference from the Moon.

If you really want to see what your scope can do, you really need to get it out to a dark site. A camping trip rocks for this as you can observe all night and then sleep in your tent.

Hope this helps.

Have fun,
Doug

[Scooter]

Thanks for the replies folks :)

The viewing angle to date has just been about convenience as it has been just too easy to have the scope set up on the deck and then come and go as I please. I have setup a relatively stable platform in the back yard so wil quit being so lazy and do some observing from there. At least then I will be able to compare the angles and views.

On dark adaption and light pollution in 2000 I spent several months in South America and for a week when crossing from Boliva into Chile had the most unbeleivable skys when up on the altiplano at 4000+ meters. Naked eye stuff and the milky way etc. was just unbeleivable so I can't even begin to imagine what views you would have gotten out of a decent scope :eyepop:(just a pitty I aint gonna have those skys from my backyard in Brissy but I do know what a difference location etc. can make).

I am keen to try out a dark site at some stage so will just have to wait and see what I can sort and it should provide some decent benchmarking. Only problem is what happens when you make the effort and the conditions aren't great (like cloud etc.)? That would have to hurt :doh:Last nights mission was to see a galaxy and on that score dark adaption could have cost me the prize :( (although it was low as well so I guess I ain't making it easy for myself). Target was the sombrero galaxy but all I could get was a faint (barely noticible) cloudy like blotch against the black of the sky. Oh well....allways next time :D

Have fun and thanks again

[chunkylad]

Hi Scooter

This might sound a little odd, but you could try the pirate's trick of using an eyepatch over your viewing eye when you're not at your telescope. This will keep that eye dark adapted while you go inside into the light.

I use a good set of star charts and a red LED torch when I'm observing, instead of the PC.

Good to see your DOb is being used!

Cheers

[erick]

A black plastic protective eyecover held in place with an elastic band around my head was $3.95 from a pharmacy. I use it to cover my no-observing eye while I'm at the eyepiece so I can keep both eyes open. Squinting - yuck! It should do what Dave suggests just fine!

[caleb]

are you saying as you look into the lens you have a black cloth over your face and head to keep any light out. As photographers do. Or use to.
Sounds like a good idea, il have to try it.

[dluth]

I've always wondered something - I read somewhere it takes 40 minutes for your eyes to fully dark adapt. Would then viewing the moon through the telescope then wreck this dark adaption? It's pretty bright!

[edwardsdj]

Hi dluth,

Yes, observing the Moon will ruin dark adaption.

Have fun,
Doug

[erick]

Yes, leave the Moon until just before you plan to finish and pack up! :D

[jjjnettie]

What part of Brissie are you from Scooter?

[ballaratdragons]

Yep, that's what Sombrero looks like. But if you dark adapt for atleast 15 - 20 minutes, you should be able to make out the dark band running thru Sombrero.

All DSO's need dark adaption. Even the bright ones like M42, Carina, 47 Tuc, NGC253 silver coin Galaxy (Sculptor Galaxy), etc

[dugnsuz]

How times have changed - for the better too !!!!!
Beginners with 12" scopes!!!!!

Point that sucker at M42 and enjoy the views!!!!!!!!!!!!!!
All the best
Doug:thumbsup::thumbsup::thumbsup:

[Scooter]

Ahhhhhhh... well it's folks like yourself that are to blame (apputure rules and all that) ;)

[Scooter]

Hi Jeanette, I'm on the soutside in Moorooka. What are the skies like out your way? You cop any of Brissie's and the Sunshine coats light pollution or are you far enough away to get decent dak skies?

[Bobj]

G'day mate, what I did when I started out squinting at the stars...oh, so long ago, last May:lol:, I bought 10" dob and a laptop, put stellaris and carte du ciel on the lappy, bought a 15ft extention lead and now I don't need to go inside to check.
I also try to set up a viewing plan to see certain objects and follow that schedule.
Of course being retired makes it better in that I don't need to get to bed early etc...