hello, got a few new person questions

[vector101]

hi, im looking at getting back into astronomy with a 10inch gso dob, this will be my first real telescope, used to have a small refracter when i was younger but there was only so much you could see.

i got a few questions, ive read that with nebulas you cant see the colour only grey and green? im wondering if filters would do anything to put some colour into them? and can anyone show me some pics of stuff i can expect to see from a 10inch dob?
and will a 10inch reflector allow me to see as far away as say a schmit cassegrain one? im amazed by some of the images taken from them i know i wont get all the nice colours as there long exposures.

sorry for all the silly questions

[ballaratdragons (Ken)]

Howdy Vectorman,

With Nebulas almost all of them will appear greyish or whitish. The easiest Neb to see any colour in is the Orion Nebula which displays a Greenish tinge at first. But after training your eye you will see pink as well. Training the eye is not that hard but don't expect to be able to do it on the first attempt.

Photography brings the colour out, but it's hard for our eyes to see it (another story alltogether).

Unfortunately many people miss all the amazing detail by only having a quick look at each object.

To start training your eye, make sure your eyes are dark adapted (about 10 minutes will be enough), then don't just look at the object, really study it. See if you can find any detail, colour, count the stars buried inside it, etc. The longer you look at an object the more you will see. I can easily spend 15 - 20 minutes looking at the Orion Neb without removing my eye from the eyepiece. You will start to notice much detail even the first time. The second night at it your eye knows what to look for (coz you saw some of the detail last time) and try find even more detail. By this 2nd attempt (or 3rd maybe) you will notice the pink in the centre of the green neb.

Same with Globs, Galaxies, open clusters, dark matter etc. The longer you spend studying each object the more you will see.

As far as a dob v's SCT, well that's a whole different story. Dobs are designed mainly (but not only) for Deep Space. They hang around the 'F' range of 4 - 6. Whereas SCT's are mainly around 9 - 12 (someone correct me if I am wrong please). Dobs also have a slightly smaller 2ndry Obstruction than an SCT allowing more light in, which helps see the faint fuzzies easier. Although both scopes can work at both ranges (Planetary and Deep Space) they are designed for different viewing.

Hope all that makes sense!

Oh, I almost forgot!! Welcome

And they ain't silly questions.

[mickoking]

G,day vector, Welcome

With a 250mm (10") dob many nebulae will show considerable detail. If you add to the equation a filter like an OIII you are looking at photographic detail But in monochrome. With a 250mm at a dark site you may see some red in the Orion nebula (M42) and the small nebula surrounding Eta carinae is likewise orange-red. but most nebulae only register as shades of grey or green. Some planetery nebulae will present a vivid blue colour like NGC3918 in Centaurus. Ken makes a good point about training the eye's as well. even if you find a veeeery faint galaxy you can barely see, study it and ask your self questions like, can I see any detail? Is there brightness variation across the object? what shape, any colour? etc etc.

Cheers, Mick

[ving (David)]

welcome aboard!
plenty of colour in stars! try some doubles

anyhow ken and mo=ick have answered you question.. dont just look at stuff, study it and you will see more

[mickoking]

Good thinkin' Ving I forgot about doubles. Talking about doubles check out Pi Bootis they seem pale green to me (always on the lookout for green stars).

[ving (David)]

thanks mick, never seen pi bootis, have to check it out

[astro_nutt]

Welcome vector101..I'm a fellow 10"dob owner..with these scopes you do spend more time studying each object which does bring out more of the image details...eg Eta Carina at 240x... you'll see the amber coloured oval around a bright yellow centre..truely awesome!

[vector101]

thanks for the replies, i should i havent got the scope yet, i think what i was getting at with the SC telescopes was would the image quality be similar?

thanks for all your welcomes.

[jjjnettie (Jeanette)]

Ditto to all of the above.
The more you look the more you see.

[janoskiss (Steve H)]

Originally Posted by vector101

thanks for the replies, i should i havent got the scope yet, i think what i was getting at with the SC telescopes was would the image quality be similar?

Typically, yes. A well set up Newtonian will normally have bit more contrast because of the smaller central obstruction. But a good SCT like the C9.25 can be very good indeed. There are two main practical differences afaik.

One is the size. I think this is the main reason people buy SCTs. They are more compact so they are easier on the mounts and tripods. Also you can get them fork mounted for comfortable viewing and still have a reasonably portable setup. OTOH a 10 or 12" Newt on a fork mount is going to be a huge beast of a thing.

The other important diff is the limited true field of view of SCTs, because of the large focal ratio.

[Gargoyle_Steve (Steve)]

Should someone mention the price difference, just in case Vector (hi ya Vector!) hasn't explored that yet?

10" dob From Bintel or Andrews : prices around $600-700, scope and dob base, you'll even get 3-4 inexpensive (but not too bad) eyepieces included at that price (and if you read the little print in eveyones byline here you'll see how many people have these very same 10" or 12" dobs)

Something like the aforementioned Celestron C9.25 - $3.5 k or thereabouts on a mount? That pricemay not be dead accurate but I think it's in the ballpark - everyone feel free to correct me.

However there is one other important difference too ...... the C9.25 can easily be used to "track" along with objects as the sky rotates, and believe me the sky rotates a hell of a lot quicker than most people would believe, especially as you use higher and higher magnification.

The dob base at that price does not track, but you CAN get different kinds of under-base platforms that will allow a dob to track for up to an hour, plenty of time to view any object you may desire, even time enough to do some photography. Add about $1200 for something like that on top of your $600-700.

Hope that helps - and if you were already aware of these factors I'll just go sit quietly in the corner for a while.

Cheers!
Steve