Is my scope good enough for looking at the planets and the brightest stars?
Hello all,
I just have a couple of questions if you would be so kind.
I have a Saxon reflector scope 900 x114 with an eq mount.
With being brand new to this, and setting up the scope, my first attentions turned to the moon. I'm now a bit more used to the eyepieces, finderscope, barlow lens etc.
Also getting a bit better with the mount after a lot of messing about.
My main question is : Is my scope good enough for looking at the planets and the brightest stars?
I'm struggling to get a good view of anything except the moon. Obviously I don't really know the skies very well so really I just look for the brightest objects at the moment.
In the Instructions, it says I should collimate the scope which I haven't done yet, but I am going to have a go at it soon.
How much of a difference will it make once it is collimated?
Lastly, I was wondering if upgrading the eyepieces to some better quality ones would be a good idea, or are the ones supplied with my scope good enough?
I saw some on some of the websites for sale, which were called eye relief, and some wide view ones. Would it be worth getting any of these?
I have some books and reading material heading my way, so hoping to get a better understanding soon
It takes time and patience to find objects in the night sky .... it is only after quite a bit of practice, and after you can recognize constellations, that finding objects becomes easier.
Stellarium is a great free software program to help you, otherwise starcharts would be great too.
Bright stars and planets should be easy, as long as your scope is aligned properly, and collimated (hate collimation).
Your eyepieces should be 'OK' .... but down the track, when you can find objects, then upgrade
Good luck!!
Like Liz said, a 114 scope is a marvellous first scope.
Is you scope good enough for the planets? You betcha! The first time I saw Saturn was through a little 50mm refractor. You will have no problem. Just be patient. You will also see cloud bands on Jupiter and the polar caps of Mars
By the way, Saturn rises in the east at the moment with sunset. Have a go! Look for a yellowish bright star that does not blink! And Mars is dead north at the moment. You can't miss it with its fiercely red colour.
If when you look at a bright star and you see that it appears to have a comet like tail, especially when out of focus, then the optics need to be collimated. This will maximise the optical performance of the scope bringing in all the precious photons of light that it has collected to give the best possible image.
Eyepiece wise, yes better quality eyepieces will improve things, but there is much to learn about them, don't go just on price alone! However, I'd suggest learning with the eyepiece you have first. You will have become very proficient at moving and using your scope when you then decide to upgrade.
If you are having trouble with you mount, consider what I did to this 114 scope that belongs to my wife's school. You can still use the scope on its eq. mount- just remove it from its brace.
I guess the hard thing for me in these early stages is knowing what to expect from my viewing experiences. I have tried to focus on various stars and (what I thought was) mars, but I can't really get what I would call a good image. It always just seems blurry. There doesn't seem to be a comet-like tail as such, just a very unclear image.
I'm not sure whether i'm expecting too much or doing it wrong or both.
The only other thing that has me wondering is that my scope does move very easily but I suppose thats bound to happen under higher magnification.
I'm sure the things that I'm experiencing have been gone through by everyone that is new to the hobby, so hopefully i'm not alone!
Start doing your observing with low power, using your longest focal length eyepiece. This eyepiece will be your best friend. It gives the widest view, brightest image, and easiest to focus.
It is the most suitable for deep sky objects like open clusters, nebulae, and finding galaxies.
With the planets and moon, use this eyepiece first to locate the sucker you are after, than you can increase the power on it. You will still be able to make out even a tiny but definate disk on Mars, Jupiter, Saturn and Venus. Uranus and Neptune are more readily identified by their distinct colour.
There is also a major limiting factor to the quality of an image, other than the telescope, and that is the atmosphere. If there is a lot of turbulance in the upper atmosphere, the image quality drops markedly. So much so that the majority of the time, the highest usedable magnification is no more than 150X, regardless of the size of your scope.
The ability to use higher magnification is determined by atmospheric conditions, hence it is rare to go much above 250X, even rarer 500X. The only way to improve the odds is to wait for winter when the atmosphere is cooler and so less turbulant, or head for the hills, high hills, as this alone reduces the amount of atmosphere between you and the stars. That is why the major observatories are all located on the top of mountains covered in snow.
To give you an idea on how rare real high power useability is, I was able to crank up my 17.5" dob to 336X twice last year on Jupiter to give me just a good image, not excellent. 336X does not even come close to challenging the limits of this scope. I rarely go above 150X or 200X. Most of my observing is at 67X, my big scope's lowest power.
Just for your info, the way to determine the longest useable EYEPIECE for your REFLECTOR scope:
6 X focal ratio of your scope = LONGEST FOCAL LENGTH EYEPIECE IN mm.
Highest power:
50 X per inch of apeture
Magnification:
focal length of scope / focal length of eyepiece.
Mental.
Last edited by mental4astro; 04-03-2010 at 08:49 AM.
Thanks Mental for taking the time to explain a few things to me, I can only learn more as I go.
RE the comet like tail, I was just referring to Mentals earlier post where he said if I could see a comet-like tail on a star, my scope might need collimating.
Good advice from Alexander, stick to low powers except on bright stuff like Moon and planets. And as he said, 'seeing' will be very important. All planets look like mush at high powers if there's atmospheric turbulence (check for twinkling stars) and you won't be able to focus properly. You might only get a few nights of excellent seeing a year depending on your location, but boy are they worth it!!
Case in point tonight - I live in a very bad place for seeing, and I wandered out earlier and noticed the stars were unusually steady. I set the scope up, let it cool for 15 mins, then trained it on Mars, with 8mm eyepiece & 2x Barlow (225x). The planet was still bobbling a bit (and of course still tiny in the field of view), but in moments of clarity I could see the polar ice cap, and a large wedge of darker area. Believe it or not, that's the first time I've ever seen features on Mars from my place - it's always just been a pulsating, unfocusable blob! Features on Jupiter & Saturn are easier to see, but still require practise. Things like the Great Red Spot are pretty low contrast.
When the stars are twinkling, go for deep sky stuff, and there's plenty to see through your scope (I basically use the same - 114x900 Tasco brand). Dark skies really help at our aperture if you're chasing faint fuzzies. If you live in a light-polluted area, a little drive out to darker areas might be helpful if you're chasing faint fuzzies (planets & Moon are observable anywhere though). A decent set of eyepieces help, but there's no need to go overboard. I pretty much use just a 21mm for viewing, which gives me 47x. Then I have an 8mm (112x) which I rarely use, and ditto for the 2x Barlow. Our smaller scopes are a little more forgiving on collimation than the larger ones, but you should check and adjust it as soon as you can.
Anyway, good luck with it Grant, don't forget to submit an observation report (or two)!
OPPS! I made an error in the last post regarding 'lowest useable power', it should actuall have been -LONGEST FOCAL LENGTH EYEPIECE FOR A REFLECTOR.
The reason being that you will begin to see the shadow of the secondary mirror in the image, particularly in bright situations like the moon during daylight. This shadow gets worse the longer the focal lenght eyepiece you use.
Some people push this limit to 7X the focal ratio of the scope. It is possible, I've done it, but much more suseptble to shadowing in bright conditions as I've mentioned. I've had a 40mm TMB Paragon eyepiece (brilliant eyepiece) in my f/4.5 17.5" dob. The shadow was there in a dark sky, but careful focusing and head positioning managed to control it. Too hard though. I wouldn't go over the 7X rule, with 6X safer.
There is one more thing regarding eyepieces, those that come with the vast majority of 114 scopes are not the best of quality, especially the short focal length ones. You end up parking your cornea on the eye lens (the lens closest to your eye in the eyepiece, the 'field lens' is the one furthest away), and the field of view is usually narrow.
This makes observing difficult and uncomfortable, the objects drifts through the field quickly and is difficult to obtain.
The good thing about them is that you learn very quickly how to handle the scope really well, just how much 'tweeking' is needed to move it, and improves your 'centering' skills in the process. A challenge though. A skill I picked up after using my 50mm Tasco refractor for 10 years.
A tip when useing high powers if your scope is not motorised:
Center it and see which is the direction of the drift. Then, move the target to the opposite edge of view just out of the field of view, and allow it to drift through. This way you don't introduce as much vibration into the scope, allowing for a much more stable image.
...it says I should collimate the scope
...upgrading the eyepieces
Grant,
whether to collimate the scope is best judged by whether you NEED to. The easiest way to make this decision is to find a bright star in the eyepiece, get it reasonably well centred, then DEFOCUS a little bit.
You should see concentric rings if the scope is well collimated. If the rings appear badly non-concentric or skewed to one side, it needs collimating.
While you have it out of focus, and looking through the eyepiece, wave your fingers in front of the scope and point to where the centre of the rings has shifted. This will give a clue as to which of the screws on the mirror cell needs adjusting. Usually a quarter or half turn - AT MOST - will produce either a marked improvement (the right way) or deterioration (turned the wrong way).
As for eyepieces... I'd suggest you aim for just three - low, medium and high power.
For your scope, 25-30mm will be the lowest useful power.
The highest power useful is from an eyepiece in the range 5-6mm.
For a medium power, something around 12mm would be good.
Bintel have a decent range of Plossls at $39 apiece, including 6, 12 and 25mm which would be ideal for your scope https://www.bintelshop.com.au/welcome.htm
(look under eypieces, page 3)
The sky is the limit with eyepieces, as you will see from the Bintel pages.. What people are paying top-dollar for is extreme field of view (Televue Ethos) - though this may pose other issues.
There's nothing wrong with budget sets - one of the most sought-after sets on www.cloudynights.com are the Edmund RKE's; while their field of view is quite modest, they were exceptionally transparent and were comfortable to use (with good eye relief). And they are still in production after 25 years http://www.edmundoptics.com/onlineca...productid=2075
Is my scope good enough for looking at the planets and the brightest stars?
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