What can i expect to see with a 75/700 newtonian reflector telescope
Hey all my name Adrian I'm from the Mornington peninsula Victoria. I just got my first telescope. It's a 75/700 newtonian reflector telescope I have an assortment of lenses it says it's up to 300x mag but I read I could really not get a clear picture at that. I've looked at the moon and get great pictures.
I was wondering what other great sites I can expect to see with this type telescope. Such as other plants I could view or clusters. I'm very new I'm hoping I can see a few other planets and things besides the moon. Thanks in advance guys
Hi Adrian, congrats on your first scope. It's not much perhaps, but it will show quite a lot of the nebulae and clusters in the Milky Way and exploring these will keep you busy while saving up for something larger. Suggest you find a copy of Nortons Sky Atkas, or a sky chart, maybe even Sky Atlas 2000, and explore the clusters and nebulae on these charts.
However with respect to galaxies, apart from a handful of bright ones the rest will be beyond your scope.
The maximum useful magnification from a reflecting telescope is about 1.2X per millimeter of aperture. With your scope that means about 100X, which means a 6-7 mm eyepiece (eyepiece fl = focal length / magnification).
You can push it higher than this if you like, the image will be bigger, but dimmer and you won't won't see any more detail. 300X is definitely not useable on yours - even with my 180mm maksutov I don't go beyond 200X.
You can get nice views of Jupiter and Saturn with your scope, and there will be occasional nights when the seeing is very good, when you may
be able to go a little further than 100x, say 120ish.
raymo
Thanks for the info guys I'm glad I can see more than just the moon haha. What detail can I expect to see Saturn in can I see rings and also moons around Jupiter? I've very happy with the telescope as it's brought back the amazement of space but now I want more haha. What is a good size telescope where I can see lots of great things other planets etc one I won't be bored of due to lack of power but something thays not going to cost me heaps.
I would expect you to be able to see the four Galilean moons of Jupiter to be able to see Saturn's rings well enough to whet your appetite.
Jupiter is rising at about 10:40 PM at the moment so if you can stick it out til about Midnight to let it rise decently above the horzon it is well worth a look. It is very bright and easy to find.
For a nebula to have a look at, try M42 (Orion Nebula) it is the middle "Fuzzy" star in Orion's sword and about the easiest deep sky target out there to find, it is visible pretty much as soon as it gets dark at this time of the year. your lowest power eyepiece is probably the best one for that.
As for a good size scope, there are heaps of threads on the forums about that, the general consensus seems to be an 8 to 10 inch Dobsonian which do come up secondhand, as a good blend of light gathering, ease of use and ease to transport (the Dobs are a Newtonian reflector and once you get to around 12" in aperture they can get start to get heavy and unwieldy to move around)
The smallest scope I've looked thru was a 5 inch newtonian, so not 100% sure what you should see with yours. Re Saturn, with my 8 inch cassegrain I can clearly make out the Cassini Division in Saturn's rings.. You should get a nice view of M42 (Great Nebula in Orion). If you have, or can get hold of, a wide view eyepiece it's a pretty awesome sight. M42 was my first ooh ahh deep sky object when I was a boy. Jupiter is a good view, especially when the Great Red spot comes into view. You might not see much detail in it though. Here's a picture I took of Jupiter with my C8, taken with my mobile phone through the eyepiece. It's an average photo. You should also get good views of most globular clusters.
Have you got a planetarium software? I use stellarium. It's a free download off the web. There are also free star charts available on the web. There's a link in the sticky threads in this section (Beginners Talk) of the forums.
I still spend some nights just exploring the sky. I also use Astroplanner, which you can also download.
Have a look at this website as well. http://www.12dstring.me.uk/fov.htm It's a scope simulator. Don't let the fact that things look small in the scope dampen your enthusiasm.
If you click on the BINTEL link on the right of this page you can see all the gear with prices. They are just one retailer. They are in Sydney & Melbourne. I've had nothing but great service from them. However, there are others.
Anywho, a 6" Dobsonion will set you back around $350 and an 8" $500. Also, keep an eye out in the Ice In Space Classifieds. There's a 12 inch dob in there with a heap of accessories for sale for $700. Looks like awesome value, and it's not far from you by the look of it. I wouldn't mind it myself.
Rather than spend money on something that's only slightly bigger, my advice would to be to save a bit longer and buy something bigger which will last you for many years. Aperture is everything, and you'll probably find that you will want to upgrade again before long.
Last edited by louie_the_fly; 06-01-2015 at 09:39 AM.
Reason: Wrong price indicated - Said $780. Is $700
Great thanks Louie. I really can't splash out on anything too expensive I think about $500 will be the limit for a year or so haha the mrs will kill me I spend too much on my 4x4 already haha. I'll keep an eye out for good 2nd hand one. Other than a 2nd hand ones I've read few reviews on the dobsonian 8" telescope lots of good things I looked up some pics and vids of what people have seen through them they look great for $400
You must have been using a low power eyepiece on Saturn Alan. A 10"
will give a very good image of Saturn, especially if it is favourably placed. You should easily make out the Cassini division if the seeing is good.
Jupiter's moons will look like stars in a low power eyepiece, but a high power one will show them as tiny discs. Saturn's moons also look like stars, but need very high power to render any of them as discs.
Jemmo, You should get a used 10" dob for $450-550, which is the largest
easily portable size in my opinion. If you end up with a Dob, just make
sure you get one that has enough back focus to allow you to attach a
DSLR camera. Many brands do not. Skywatcher is one brand that does.
You never know, after seeing some good things, you might want to try photographing some of them.
raymo
With a 75mm telescope, using low power you'll be able to see the 600 or so objects plotted in Tirion's Bright Star Atlas - provided you have a decent 6X30 or better finderscope on your telescope to actually locate them.
Unfortunately on inexpensive telescopes, manufacturers often cheat so that what looks like a 5x25 or 6X30 finderscope has an internal annulus to sharpen the stars, but turns the finder into hopeless 5X10 or 6X15 ones. Sometimes one can unscrew their front lens and remove the annulus, which then results in lousy star images but makes them more useful for locating faint objects.
If your telescope is well collimated, you can expect relatively good images of Jupiter and Saturn and should be able to make out bands across the surface of Jupiter. High power eyepieces usually provided with inexpensive telescopes are usually of the SR type which are hopeless. The Huygens eyepieces often provided for lower power aren't too bad image wise, but have an annoyingly narrow field of view.
I briefly owned a 70X700 and was quite impressed with it, so much so that I took it back and exchanged it for a 114X900. Unfortunately, the newer telescope wasn't as good as the first one because its collimation was out, and it took me years before I found good instructions to get it right (we didn't have the internet back then).
Also, as you live in Mt Martha, you can at some time join the Mornington Peninsula Astronomical Society who do their viewing at the Briars, where they have a great clubhouse. You can check out all sorts of telescopes there.
Regards,
Renato
Yeah thanks guys I live 3 mins from the Mt Martha clubs viewing place at the briars might head down next Friday. Since I posted this I have come across and old fella selling a 10" dobsonian for a cheap price as he's too old to lift it so looks like ill have a big toy soon too
Yeah thanks guys I live 3 mins from the Mt Martha clubs viewing place at the briars might head down next Friday. Since I posted this I have come across and old fella selling a 10" dobsonian for a cheap price as he's too old to lift it so looks like ill have a big toy soon too
The public nights are on the first Friday of the month.
If you want to attend at other times and are not a member, you should check the Contact Us info at their website at http://www.mpas.asn.au/
