Don't Do It!!!

[Music] hello my name is jason welcome to my channel small optics now if you're a new telescope owner and you've had a chance to have a look at the planets uh one thing that's probably surprised you is just how small they look in the eyepiece now don't worry your telescope's not broken or anything like that this is the you know this is a normal thing um but this could lead on to the main subject of today's video and that is not to overpower your telescope now i blame a lot of this especially today on this the internet okay um we're inundated these days with such great pictures like i'm showing here and this leads on to expectation okay especially in beginners you think that this is what you're going to see through the eyepiece you're full of expectation you get your telescope you have a look and you're expected to see this and unfortunately you're going to see this now i say unfortunately um i shouldn't be saying unfortunately because that's amazing okay if you are seeing like the rings of saturn it's amazing all right and um and this is what you need to do you need to turn expectation into appreciation okay and uh and the problem is right it's very very difficult actually to overpower a telescope um and you just with the eyepieces that are provided with your telescope uh usually they're a 10 millimeter or a 25 millimeter or something like this sometimes we'll throw a slightly uh higher magnification in like an eight or a nine in there but with those eyepieces alone it's impossible to overpower your telescope okay now where the problem comes is barlow lenses okay now i've got a barlow lens at andy in a minute but i'm sure you know what i mean and i'm sure you've probably may have even got one provided with your telescope now the reason one of the reasons i'm i'm making this video is i didn't realize just how much of a problem this is because i have read often right it often crops up in forums on other people's uh comment sections on their channels uh a comment something like this can't wait for my five times barlow to arrive with my four millimeter eyepiece now this is where the problem arises okay now first off okay you need to know well it's like any let's let's let's rewind a bit okay you need to know just to not overpower your telescope the first thing you're going to need to know is what is the maximum power of your telescope all right whether it's a small um 70 millimeter refractor like this or a 130 millimeter reflector like this whatever it is if it's a 60 millimeter refractor if it's a 6-inch reflector whatever okay there's a very easy way to know what the maximum is okay uh in this case 70 millimeter refractor maximum magnification 140 times okay or there are thereabouts in this one here a 130 millimeter reflector in maximum magnification round about 260 times now if you're any good at maths you may have clicked on to what i've done there i've simply taken the aperture in millimeters and times it by two okay and that's how you're going to find out uh your maximum magnification no matter what size your telescope is it doesn't matter about the focal length how long it is okay it's this that's important just times the aperture okay in millimeters by two or double it okay so if you've got a 60 millimeter refractor 120 times is going to be there about the maximum magnification that that telescope will take okay now think of a telescope a little bit like a pressure valve or a car engine okay it's got a maximum to it okay and you start pushing beyond that maximum usually bad things happen you know engines blow up and uh pressure valves blow or whatever now i'm not saying your telescope's going to blow up but this is what'll happen okay if like you want to get the image up right and you want to see more detail so you get your five times bar low you should be four four millimeter eyepiece in there and you will probably get an image something like this now yeah nice size all right but you've just got this big fuzzy blob okay and you'll not even be able to probably get it in the field of view if you do get it in the field of view it'll if you've not a motorized telescope in any way it's going to be out in the field of view in in seconds okay now you're also going to need to know uh the power of what each eyepiece does with your telescope okay for instance a 10 millimeter uh eyepiece in this telescope is going to magnify completely different to this one okay a 10 millimeter if i take the same eyepiece out take it out there put it into this one it's going to magnetize more in this one now it's not because the telescope's bigger or anything like that uh as in aperture i mean it's in focal length now okay so the way we work this one out is we you need to know the focal length of your of your telescope but it's usually on a sticker right above the focus here just have a look it's usually says fl or something like that focal length now what you need to do is get again it'll be in millimeters so let's take for instance this one okay it's a 900 focal length okay and we want to know what a 10 millimeter eyepiece is going to magnify in this well that's it's easy this all you do is you multiply so it's it's uh sorry you take 900 and you divide it by the millimeter of the eyepiece so in our case it's 10 okay 900 divided by 10 90. so there you go 90 times i know straight away the maximum of this telescope is 260. okay remember i've just doubled the aperture and then a 10 millimeter piece in here is around about 90 times now all you need to do is do exactly the same with whatever photo length is with your telescope okay for instance if yours is a 650 okay we divide and we're using a 10 millimeter eyepiece divide that by 10 that's a 65 times magnification okay so you can see that focal length uh affects the magnification of the eyepiece it's not so much the aperture and this leads on to another misconception about telescopes okay if i was to say to you what does a telescope do okay or if you say this to the average person on the street they'll probably say it magnifies things it brings things closer well both those answers are wrong okay it's the eyepiece of the telescope that magnifies oh it's not even of the telescope is it really i mean an eyepiece is a separate thing without an eyepiece unless you're putting a camera in there a telescope's pretty useless okay if you think about it what a telescope actually does is it collects light okay this is why when you get into astronomy more you're just going to want bigger bigger bigger okay more light is you're always hungry for more light because what more light's going to do is going to bring the image a lot brighter enable you to put on a little bit more power but not too much remember there's a maximum to any telescope whether it's this big or this big or this big everything's got a maximum now my best advice for you on this one right is to go nowhere near the maximum of your telescope okay i think i've been to the maximum of this twice since i've owned it i think i did a video uh well i don't think i did do a video pushing it beyond its limits on the moon and with the moon you're probably going to get away with it but the planets you're not okay and just as a little bit of an experiment and a bit of a bit of a fun you see but as a rule um i can spend an entire evening round about 36 times magnification okay that's just with a 25 millimeter eyepiece in this telescope okay and this is what you're going to quickly find out lower magnifications will give you the best views all right high magnifications um need a lot of things to come into play okay you need to have good clarity good sky conditions okay if you're using a reflector it's got to be spot-on in collimation yeah there's so many things when you use high magnification if any wobble that's introduced into the telescope from the mount or whatever that's also going to be magnified don't forget if you're magnified 90 times let's say every magnet every little touch you put on the telescope is also magnified 90 times all right so just keep that power down moderate you know what i mean so if you remember what i said earlier in the video about these comments i'm seeing about five time barlows with four millimeter i am eyepieces well i mean i've even had to write this down the numbers are that bigger i'm no mathematician i'd never make a professional astronomer put it that way um so look let's let's take this we've got a 900 scope i'm gonna put a four millimeter eyepiece into it okay so uh 900 divided by four we've got 225 times now remember 230 is the maximum of this telescope so we're already getting close up to the maximum with just the eyepiece alone okay we now put a five times barlow in there we've now got an incredible 1120 times magnification it's just not gonna happen folks okay it won't work you're wasting your money all right um barlows do have their place but i can tell you now in all the years i've been doing astronomy i don't know anybody that uses a five times boholo for visual astronomy okay usually these powerful barlows are designed for astrophotography okay are usually designed for cameras with small small chip cameras basically to boost that image size up a little bit for visual they're just not practical now if you are going to buy a barlow lens here's a ball lens here okay go for something like a two times barlow maximum three times okay for visual work and even better if you can get a barlow with a removable cell piece okay and what i mean by that is the bottom uh was twist off now not all barlows come like this but some do and what you can do with this is if you screw this into the filter thread of your eyepiece this actually puts gives you two barlows if you like uh turning it into a 1.5 barlow all right so you see you're getting uh good value for your money with these but like i say just avoid for visual astronomy these high five times barlow like i say maximum three times you don't want any more than that for visual work so just to round this one up remember don't use too much power okay remember little power less is more basically all right so always always start whatever you're viewing okay with your lowest powered eyepiece whether that's the planets the uh a galaxy whatever lowered powered eyepiece always and gradually increase the power now this all those maths i told you about working out you know what eyepiece it'll become second nature to you okay you'll not worry about it too much when you get into the other more it's kind of you get obsessed with it when you first start okay like i say uh i've i don't know how much power it is i wonder how powerful the telescope is and it kind of separates for beginners from seasoned astronomers you see a beginner will say how powerful is your telescope a seasoned astronomer will say what aperture is your telescope okay and there's the difference well that about wraps it up for another video thank you so much for watching um if you haven't subscribed maybe hit that subscribe button because you never know that next video might be just the one you've been looking for in the meantime don't forget keep that power to a reasonable level and i will see you on the next one bye for now

Channel: Small Optics

Views: 325,782

Keywords: astronomy, astronomy for beginners, help, telescopes, skywatcher, stargazing, how to view the planets, saturn, jupitar, focus, solar system, stars, moon, galaxy

Id: TlmLuhK086Y

Length: 13min 44sec (824 seconds)

Published: Wed Jun 02 2021