What can I expect to see?

[GPC]

Hi again, Thanks for the advice I recieved on my thread that i posted a few months ago. With that advice on board "santa" bought me a 20mm Super plossl eye piece and a 2x Barlow for my scope. It was quite a remarkable change in quality of what i was viewing. But this time my question is - My scope has a 70mm aperture and a 900mm focal length. What sort of deep space objects am I likely to bo able to observe - realistically? (It is refractor type scope.) I have been doing alot of reading and studying my astronomy book learning how to use the RA and Dec settings properly so any info would be great as i am keen to have a really good look at what is out there. Also the charts in The Astronomy Australia 2011 book I have tabulate the RA of objects and under it in brackets is some sort or time zone I think.(in the column heading) Can anyone offer an explination for me as to what this means if anyone has that book, I figure my not understanding it properly is due to my level of novice but as i said i am very keen to learn how to do this properly!

Thanks:)

[GPC]

Oops spelt probably wrong!!

Also any other suggestions for eye pieces would be great as most articles I read make note of saying that having a few eye pieces is better than just 1

[Rob_K]

Here's a good tool - put in your co-ords & play around with the other settings. Sort objects according to magnitude so you can work down the magnitude scale & see for yourself. I'd be looking for darker skies if you're based in Brisbane though. Good luck! :thumbsup:

http://dso-browser.com/

Cheers -

[mswhin63]

Limitation as express in magnitude. For a 70mm 900mm FL it is about -11 to -12 in dark skies. Most star charts of software can tell you the magnitude of stars and nebula. Visibility will be less in suburbs. This is assumed by the technical specs of a scope are usually based on good dark skies.

[GPC]

Thanks that tool is very handy, will have to try it out when the weather fines up!! With regards to the RA and DEC, I have my scope polar aligned (from instructions I found on this site) Do I simply move the respective axis to the numbers on the chart? or do I need to make any adjustments for time zone etc? cause thats where the tables in my book confuse me a little

[mental4astro]

Hi Glenn,

Santa was good with you, wasn't he!

I started out with a 50mm refractor some 25 years ago. Yet having four other scopes all larger than it, I am amazed at the ability of this little guy to show me stuff.

I too upgraded the eyepieces that came with it, and wow, what a difference as you found out.

With your scope, just about every type of object there is, is available to you. But the key is patience, and a dark sky will really help. As an example, I've been able to make out the Sombrero galaxy in a 30mm finder from a dark site, and it again in 50mm binos from my home in Sydney (though it was sitting in the darkest part of the sky for me at the time). Most galaxies that you can see will be faint.

Nebula wise, I've added a sketch I did of M42, the Great Orion nebula, done a couple of weeks ago with my 2" scope from my backyard in Sydney. The level of detail it revealed I never thought possible with such a small instrument. There are many other nebula & planetary nebulae that are attainable, but again, you will need patience and polish up your averted vision technique.

Globular clusters will mostly appear as fuzzy round blobs, as their constituent stars will be too faint for your scope to resolve to pin point stars. However, chase down 47Tuc & Omega Centauri, as your scope may just have enough guts to actually resolve these two giants.

Have a look in the Observation and Visual forum for the monthly Obs. Challenge. It is designed to give all levels of experience and scope sizes, even for naked eyes, targets to chase down. It isn't a competition, but a help on ideas on what to look out for.

70mm is a good scope to start out with. It may be small, but it is a great way to train your eyes to make the most of things.

If you can, even get to an astro club or some other star party. Take your scope along. Don't feel like your scope is no-good. On the contrary, folks there will feel impressed that you've made the effort to bring your gear and want to learn! They in turn will be only too happy to point out things, share tips, look through their gear, and may be even borrow an eyepiece or two.

[mswhin63]

WOW what a fantastic piece of website. :thumbsup:

[GPC]

Thanks heaps for the advice!! I have 1 more question but need to upload a couple of pics to show everyone to be able to help me out. Can anyone tell me how to upload a pic into my thread?

[mswhin63]

Hi Glenn, when writing new message under the text input section is a button called Manage attachments. There is a limit of 200K for images.

For quick replies there is no image insertion but would need to "Go Advanced"

[GPC]

Ok so thanks to everyone so far, you have all been very helpful with my quest to understand and really get into astronomy!! But......
Can anyone help me with the items in brackets in the RA and DEC column heading, i have also attached a pic of that particular books definition. Any help will be much appreciated!! :)

[mswhin63]

Hi Glenn,

http://en.wikipedia.org/wiki/Epoch_(astronomy)#Julian_years_and_ J2000 hopefully explain this.

[Rob_K]

This might help Glenn:

"Telescopes with an equatorial mount uses both azimuth circle axes. They are then a must for find deep sky objects. The procedure is as follows:
First, put the telescope in station, which means to align it so that its right ascension axis is perfectly parallel to the axis of rotation of the Earth. This step is necessary to reduce future coordinate errors.
Next, look for a reference star with precisely known coordinates. Generally this is a bright star which is located close to the object to locate. Center this star in the telescope and to write down the values of the right ascension and declination showned on the azimuthal circles.
Subtract the object right ascension from the reference star ones (both should be from similar catalogues). The difference gives the path lenght from the star to the object.
Move the telescope around its axes carefully and watch the declination circles so that the right ascension and declination increase equal those previously calculated. "

From:
http://www.deepskyobserving.com/How-to-locate-deep-sky-objects-with-an-amateur-telescope.htm

I find it easier to star hop using charts, and then plonking the red dot finder on the right area!

EDIT: The article's not so great on English LOL, but the point is you don't just turn scope to the given co-ords (as originally asked) - otherwise you'd always point to exactly the same place in the sky, while the object obviously continuously tracks across the sky.

Cheers -

[GPC]

Thank you very much for all the help! With this new knowledge on board I can not wait to put into prctice what i have been reading and reading and rading over!! Now I just have to wait for this miserable weather to clear up!!! Thanks agian!!!:) :thumbsup: :) :thumbsup: :D