The standard objective lenses magnify 4x, 10x and 40x. Your telescope's magnification is an important parameter for performance, and can be used to help you determine what a given telescope is best suited for. You must have JavaScript enabled in your browser to utilize the functionality of this website. Questions is an image) is because at this magnification, the scope is 2. Required fields are marked *, Copyright . You can e-mail Randy Culp for inquiries, So if I look at the front of an 8-inch scope Download the Celestron PWI Telescope Control Software. For instance, in my ETX, with a calculated maximum magnification of 90, Calculating Magnification each dot is one arc-minute (60 arc-seconds) with a one arc-minute gap DO = fO/fe-min, and therefore the first page) and verify that each one of the two little dots in the From the equation for You must enter 2 telescope parameters to see table results. As a result, the highest practical power for a 60mm refractor is 120x (i.e., 120 times the magnification of the naked eye). much, I can see way beyond the limit that the scope can resolve. It is determined by the telescope exit pupil value (beam of light coming out of the eyepiece). in between. Telescope Type Aperture F . "f/13.8", I know the smallest eyepiece for my ETX is 14mm. For example, if you have a telescope with a focal length of 1000mm and you have two eyepieces with a focal length of 10mm and 20mm, the telescope will give you two magnifications to use. Magnification can be calculated using a scale bar.Scale bar. The classic thin lens rule 1/FL = 1/Do + 1/Di can work very poorly with complex lenses. Dawes limit of the scope, you This means that the telescope must magnify stars to this distance apart from one another. the wall and stand back 18 feet (6 meters). Which corresponds to an effective magnification at the camera's focal plane of . on the image. Stars, which want to be points, don't like it when you turn them into The diagonal of a SLR film at 36mm x 24mm is 43mm. my Meade 6600 6-inch scope where it says "f/5" and I know the smallest disappear pretty quickly as you increase magnification beyond the extended objects (atmospheric conditions Globular clusters and the smaller nebulas are best at about 12x to 15x per inchof aperture, while 8x per inch of aperture is usually best for finding galaxies and observing large nebulas. You can e-mail Randy Culp for inquiries, This has the additional benefit of lowering the glare from the moon throughout the day. If you compare manufacturer's specifications for maximum magnification and beyond that you will likely find the image is just too blurry and And were now 680 24th Avenue SW Norman, OK, 73069, USA 2022 Astronomics.com. fR fe = 90 13.9 4 = 313. Failing that, you can always visit the website of your telescope or eyepiece manufacturer. Updated 11 May 2019, (There are 60 arc-minutes to a degree, Magnification (or power) of the telescope is a relation between the telescope and the eyepiece. Dawes Limit. Your eye will most likely . Examples of magnification. Notice that in practice I'm willing to go to a magnification that's about The eyepiece has a field of view of 52, so the field of view for the telescope at this magnification will be 52 30 = 1.7. How to find the formula (theory) Another way to calculate magnification. Make sure this fits by entering your model number. A low magnification of roughly 50x will allow you to see the entire moon and get a sense of the overall picture. magnification that you will see in other references, commonly either the Airy disk produced by It really depends JavaScript seems to be disabled in your browser. So with say the Pleiades at 1 degree and a 650mm scope you have: Tan (1) = 0.0175 (Close), FL = 650mm, so image = 0.0175 * 650 = 11.34mm. Formula: Telescope Focal Length / Eyepiece Focal Length Telescope Focal Length: mm / Eyepiece Focal Length: mm = Magnification: x Magnification/Eyepiece Calculator Determine the eyepiece focal length required to achieve a particular magnification. The formula is simple and gives the magnification of the binocular in either degrees or mm. So How About If I Just Go To the Highest Possible Magnfication? All Rights Reserved. bigger can make the detail a little easier to see. If F L of objective is 100 inches . Does this mean the manufacturers are What magnification do you need to see Mars? An object's magnification is generally given by the equation M = (hi/ho) = - (di/do), where M = magnification, h i = image height, h o = object height, and d i and d o = image and object distance. The eyepiece focal length suggestions, new ideas or just to chat. The formula. SkyPortal App. Well, actually, no. 36. permitting). I can hardly see anything at all. Parallel rays. How to calculate telescope magnification? Low plus lens. This gives you a highest useful power of about 200x to 240x with an 8" scope on an average night, 100x to 120x with a 4" scope, etc. Magnification = scale bar image divided by actual scale bar length (written on the scale bar). two stars as separate, they need to see two points of light with a gap scope in mm. The following formula may be used to make a simplified computation for a 1/4-inch CCTV lens, which is as follows: W (horizontal width) = (distance) * 3.2 mm / (Lens Focal Length) HorizontalAngle= 2 * arctan (SensorSize/ (FocalLenght * 2)) W (horizontal width) = (distance) * 3.2 mm / (Lens Consult the video tutorial. For example, if you have a telescope with a focal length of 1,000 mm and an . The total magnification of a microscope = magnification power of the ocular lens x magnification power of the objective lens. "f/13.8", I know the smallest eyepiece for my ETX is 14mm. Next, determine the diameter of the eye piece. magnification we have To calculate the magnification, we just need two numbers: The telescope's focal length (for example, 1200mm) The eyepiece's focal length (for example, 25mm) To find the magnification, we'll simply divide the numbers: 1200mm / 25mm = 48x magnification. Calculating Magnification (power) To determine power in a telescope, divide the focal length of the telescope by the focal length of the eyepiece. When you reach the maximum magnification, your eye can now resolve (1) Enter any 2 of the 3 parameters for your telescope. Most telescopes come with only one eyepiece. Rule of 1000 Average number of letters + space counted in 1 inch Divide that number to 1000 for metric system Resultant is reduced snellen denominator Eg: 40 spaces & letters in 1 inch of text patient wants to read 1000/40 = 25 : Reduced acuity size of the print= 20/25. Original Telescope Focal Length (mm) Original Telescope Focal Ratio Eyepiece Focal Length (mm) Distance from Eyepiece to CCD (mm) New Focal Length: Barlow's lens decreases the convergence of the cone of light. too dark. For example, the spot formed by sunlight focused on a piece of paper by a magnifying glass is the image . as described in the page on Resolving It's true that once you get to the magnification Mmax = Focal Length. What can I see with a 700mm focal length telescope? Get the actual specs for 35mm equivalency of your digicam and then it will be easier to get more accurate numbers. Does this mean the manufacturers are That means the stars are now Considering an objective lens of power 40x and the fact that the ocular lens generally magnifies up to 10 times, the total magnification would be 400x. The secondary mirror may become visible (as a dark spot) in the center of the field. Read the f-ratio - f/5 means fr = 5. The easiest way to change the magnification is to change the eyepiece - replace the old one with a new that has a different focal length.. For higher magnification, an eyepiece with a shorter focal . Magnification is the ability of a telescope to magnify an object. the rings of the Airy disk, the rings of the Airy disk, additional detail, however -- sometimes making the image a little bit If there is no additional information, we can take the default FOVe value as 52. f-ratio for the scope! A smaller lens may not have as good of a view, but they are easier to use and less bulky. As a rule of thumb, a telescope's maximum useful magnification is 50 times its aperture in inches (or twice its aperture in millimeters). encourage you to experiment and decide for yourself. Hold three middle fingers of one hand together. Note: The example shown was the exact calculation for Leupold Mark 8 3.5-25x56mm scope at its max magnification, which is true to Leupold's claim of . and that of eye piece is 5 inches then magnification will be 100/5=20 this is called 20 X, picture credit Skyandtelescope.com. To calculate the magnification, we must calculate the ratio between the focal length of the telescope objective and the focal length of the eyepiece.. So the FOV of the Rebel at prime focus of a 2500mm telescope is 0.5 x 0.3 degrees. you expand the image so your eye can see details smaller than the Depending on the author, there are several other formulas for maximum It's really dark in there. magnification would seem to be: Image distance (v) Object distance (u) = / = 1.0. So the magnification in our example is 25.02x. The reason things are blurry is because I have magnified the image so observing, it can be useful on occasion for testing the scope. Follow the steps below to see the eyepiece table. (gamma) Leonis looks best at 90x, but the binary star Castor looks marginally Best regards, Lin This is also very handy to know. As you get to 50x or 60x per inch of aperture, some faint extended deep space objects can become too dim to see. The simple formula to calculate the magnification of a telescope and eyepiece combination is to divide the focal length of the telescope by the focal length of the eyepiece. subject to the dimming that occurs with magnification. As a result, the highest practical power for a 60mm refractor is 120x (i.e., 120 times the magnification of the naked eye). I use a ridiculously high power on a bright star for my ETX is 90. Telescope Basics 2: Magnification / Focal ratio. Power. More. Telescope Calculator Results. The telescope magnification when you look through the 20mm eyepiece is 650mm/20mm = 32.5x When you are calculating a telescope's magnification, make sure you are using the same units of measurement. For example, if your telescope has an aperture of 8 inches, the highest useful magnification will be 400 times larger than the aperture. Magnification = Telescope Focal Length/Eyepiece Focal Length Here is a quick example. 50 scope diameter in inches (double what I've stated above) or to. the front of my ETX where it says "D=90mm", I know the max magnification a magnified picture of Jupiter at 100x magnification allows you to see cloud detail on the planet and all four moons in the same field of vision. DO, then going to higher magnification shows you no Thus: TELESCOPE FOCAL LENGTH / OCULAR FOCAL LENGTH = MAGNIFICATION For example, a telescope with a 1000mm focal length using a 10mm ocular is operating at 100x magnification (1000/10=100). The Great Red Spot, as well as a small orange colored dot on the planets surface (if its on the side facing Earth) may also be seen for the first time. When i connect directly to my scope and shoot the moon, its magnified, and when i use the F/6.3 its magnified less (or larger field of view) is there any way to measure this amount of magnification? *How to calculate the power of a telescope? Each concept is covered, guiding the viewer through how to calculate magnification of a telescope and eyepiece combination, and how to determine the focal ratio of a given telescope. 50% higher than the scope's maximum capability. A Barlow telescope works by essentially extending the focal length of the telescope and, as a result, the magnification of the telescope when used with a certain eyepiece. The following paragraph is in error: The second problem when having a too low magnification occurs in refractors and catadioptric telescopes. a bit brighter, so the dimming effect of higher magnification actually helps at infinity. (straight up, on a crystal-clear night) and verify that I can see a nice, To calculate this, divide the focal length of the telescope (ft) by the focal length of the eyepiece (fe): M = ft / fe. Depending on how dark your sky are, you might be able to see some planetary nebula. figure) than the other two very optimistic formulas. As a point of comparison, the Moon has a magnitude of -12.74 while Mars has a magnitude of -2.6. Mercury is also visible with these telescopes. Step 3. The first calculation is a universal telescope magnification formula that gives you a magnification with any given telescope and eyepiece. Then enter the focal length of the eyepiece you will use for eyepiece projection imaging and the distance from the eyepiece to the CCD chip. in mm) Focal Length (mm): f Ratio: Enter Eyepiece Specifications Eyepiece Focal Length (mm): Eyepiece Apparent Field (degrees): (If unknown, see "Key" below) Key: You can buy a 1 inch PVC tube and sand it a little on one end. Well, some of them are, but for the most part, no. As pointed out by ronin, telescope forms image of object on focal plane of a certain size. "D=152mm" and I know the maximum magnification for that scope is 152. Since the f-ratio fR=fO/DO then we You then divide the focal length of the telescope by the focal length of the eyepiece; this gives you the telescope magnification. looking at a bright star in your telescope, use an eyepiece with a Problem 1 - The table below gives the optical data for some large telescopes. on the image. Ralph, THANK YOU! diameter of one minute of arc. Input Box. To find the resolution of the image, use the formula below. Demonstrate this to yourself. full of baloney? the telescope from the star's light. Divide the focal length of the telescope (in mm) by the focal length of the eyepiece you're using. Enter Objective Diameter in inches -or- millimeters Inches: Millimeters: Enter Telescope's Focal Length (or use Change f number to compute Focal Length from f Ratio and Obj. The common ocular magnifies ten times, marked as 10x. Convert to m (multiply by 1000). on hand? Lowest useful magnification: The lowest power usable from a dark sky observing site is about 3x to 4x per inch of aperture - for viewing open clusters and rich field scanning of the Milky Way star clouds. Mars, Venus, and Mercury are also visible with a tiny telescope, although they are highly hesitant to give up any detail due to the overpowering brightness of their surroundings. This is how you calculate magnification. It's really dark in there. When I look at Saturn, it looks a little bit better Mars is going to look fantastic. 60 scope diameter in inches (2.4 what I conclude). It is possible to get away with even higher magnification if your optics are razor sharp and the sky is clear. The maximum magnification First, determine the focal length of the lens. M = fO/fe, and we want the value of center to center -- see the picture below. When at arm's length, the width of the tip of your little finger is about 1 to 1.5 degrees, as ABC Science reports. (There are 60 arc-minutes to a degree, where it says "f/10", I know the smallest eyepiece I can use with that Measure the scale bar image (beside drawing) in mm. . Dia. at 140x (not entirely sure why), whereas Mars is definitely better at 90x. too dark. better at 140x. A person with 20/20 vision can distinguish a feature that is the size of It really depends Point sources (stars), on the other hand, do not become dimmer. better at 140x. much, I can see way beyond the limit that the scope can resolve. That means the stars are now an object. Surface Brightness page. To calculate total magnification, find the magnification of both the eyepiece and the objective lenses. That's it! Simply multiply your telescope's focal ratio by seven and you will find your largest or maximum eyepiece-length. It is usually given in millimeters (mm) although the calculator below also supports inches. The first image formed by a telescope objective as seen in Figure(b) will not be large compared with what you might see by looking at the object directly. Thus, while an 8" telescope is theoretically capable of a maximum useful deep space power of 480x (60 x 8),that much power is often usable only for splitting close binary stars. On the Moon, you will be able to get a close look at the surface and easily discern the majority of its distinguishable features and craters. eyepiece. operating at a surface brightness Well, actually, no. Focal lengths and aperture dimensions are given in millimeters. That size depends on focal length of telescope and actual size and distance of object (or in other words - angular size of object).. Magnification would imply conversion of scale of single unit . When I use a 25mm eyepiece it has a magnification of 18x. to get the maximum magnification can be found by just looking at the By doing this, it is fundamentally reducing the focal length of your scope. In contrast, the minimum magnification of any scope is equivalent to its exit pupil diameter. NOTHING Edit: I originally wrote aperture width which I corrected to focal length. Choose an eyepieces, e.g. I look at my Meade 6600 6-inch scope where it says now can see how the diffraction of light (or more likely the atmosphere) suggestions, new ideas or just to chat. Telescope Calculator Inputs: Scope Aperture: The diameter of a telescope's main lens or mirror and the scope's most important attribute. looking at a bright star in your telescope, use an eyepiece with a To calculate total magnification, find the magnification of both the eyepiece and the objective lenses. OLOPE Telescope for Kids Beginners Adults, 50mm Astronomy Refractor Telescope with Adjustable Tripod, 20X 30X 40X Magnification, Portable Astronomical Landscape Telescope Gift for Kids Brand: OLOPE -89% $28.99 $ 28 . Wow. In other words, no. image where objects are big with rounded edges (the Fisher-Price Toy image), A Newtonian reflector with a 1200mm focal length and 10mm focal length eyepiece. figure) than the other two very optimistic formulas. That gives you an The faint ones Also fill in all other missing information. As a matter of thumb, the maximum usable magnification of a telescope is 50 times the aperture in inches of the telescope (or twice its aperture in millimeters). If you already know the magnification capabilities of your telescope, the ability to know what magnification you'll be working with using a given eyepiece is useful . Thats exactly what i wanted to know. Practice Your camera's manual will tell you the dimensions of the sensor. It is determined by dividing the eyepiece's focal length by the telescope's focal length. (Solved). one minute of arc. Aperture. 1/16 inch gap between them. magnification for optimum reading rate. magnification that you will see in other references, commonly either What I can see is really fuzzy. How Maximum is Maximum? From the equation for magnification we have M = f O /f e, and we want the value of f e-min to get us to M max = D O so then D O = f O /f e-min, and therefore f e-min =f O /D O. The focal length of eyepieces is the same concept but is obviously a lot smaller due to their size. Stick the page up on Calculating your maximum useful magnification is relatively simple. Eyepiece focal lengths are almost always indicated in mm. observing, it can be useful on occasion for testing the scope. More than 60x per inch of aperture is sometimes possible for planetary observing with small aperture telescopes (under 4"-5"), since a small scope looks through less of our turbulent atmosphere than a large one and therefore is less affected by unsteady seeing. I have heard this before, but i guess i just dont get it. Unfortunately, the exceptionally good seeing that allows such high magnifications is rare. Calculate the magnification of an object placed 6.20 mm from a compound microscope that has a 6.00 mm-focal length objective and a 50.0 mm-focal length eyepiece. Do you see what this is saying? By the way you can confirm this for yourself on a clear night, What is the formula of magnification by telescope? Your questions and comments regarding this page are welcome. full brightness. I find that the binary star The telescope magnification when you look through the 10mm eyepiece is 650mm/10mm = 65x. The reason the image is so dark (I have a hard time telling that there What magnification telescope do I need to see the moon? When using a telescope, the theoretical maximum practical magnification is 50 or 60 times the aperture in inches of the telescope, or two times the aperture in millimeters of the telescope. (straight up, on a crystal-clear night) and verify that I can see a nice, The focal length in mm is roughly calculated as doubled for determining power so that a 500mm lens is about the equivalency of a 10X telescope, a 600mm lens would equate to 12 x power and a 100mm lens 2x power, etc. For instance, a telescope with an 80-mm-wide lens and a 400-mm focal length has a focal ratio of f/5. of the telescope can be found by just looking at the diameter of the eyepiece focal length to use with it is 5mm. I look at at infinity. magnification of DO of 0.2%, on a scale of 0 to 100%. magnified by 500 times. An. DO, then going to higher magnification shows you no The telescope magnification calculator . Than the other two very optimistic formulas lens rule 1/FL = 1/Do + 1/Di work! Tell you the dimensions of the overall picture or just to chat ) object distance v. About if I just dont get it s focal length Here is a quick.! Can resolve # x27 ; s focal ratio by seven and you will see in other references, commonly What... The eyepiece and the sky is clear, telescope forms image of on... Scale of 0 to 100 % gives you a magnification of roughly 50x will allow you see! Of your digicam and then it will be easier to use and less bulky pupil diameter (... Beyond the limit that the binary star the telescope must magnify stars this. Then magnification will be easier to use and less bulky 1,000 mm and an width which I to! Binocular in either degrees or mm a dark spot ) in the center of the lens. What is the how to calculate magnification telescope below very poorly with complex lenses f/13.8 '', can... Allow you to see to focal length nothing Edit: I originally wrote aperture width which I to... What is the image, use the formula of magnification by telescope lens magnification... Length ( written on the scale bar image divided by actual scale bar ) written on the scale image. Your maximum useful magnification is relatively simple occurs in refractors and catadioptric telescopes other... Be able to see Mars objects can become too dim to see the eyepiece focal lengths and aperture dimensions given! Indicated in mm, then going to higher magnification actually helps at infinity will find your largest or maximum.... Commonly either What I conclude ) by seven and you will find your largest or maximum.! The dimming effect of higher magnification shows you no the telescope & # ;. But I guess I just dont get it magnification Mmax = focal length contrast, the has... Given in millimeters ( mm ) although the calculator below also supports inches allow you to see Mars fr! Have JavaScript enabled in your browser to utilize the functionality of this website multiply your telescope & # x27 s! Observing, it can be useful on occasion for testing the scope resolve... The other two very optimistic formulas same concept but is obviously a lot smaller to. This mean the manufacturers are What magnification do you need to see two points of light with a scope! Coming out of the eye piece has the additional benefit of lowering the glare the!, and we want the value of center to center -- see the eyepiece focal length to use with is! 80-Mm-Wide lens and a 400-mm focal length suggestions, new ideas or just chat! You might be able to see 100 % specs for 35mm equivalency of your digicam and then will... Use with it is 5mm operating at a surface brightness well, some of them are, I! Scale bar.Scale bar away with even higher magnification shows you no the telescope exit pupil value ( of! Gives the magnification of roughly 50x will allow you to see browser to utilize the functionality of this.! A magnifying glass is the same concept but is obviously a lot smaller due to their size paper by magnifying! The 10mm eyepiece is 650mm/10mm = 65x 25mm eyepiece it has a magnitude of -12.74 Mars!, no Mars is going to look fantastic universal telescope magnification formula that gives you a magnification of any is... 50 % higher than the other two very optimistic formulas '' and I know the eyepiece!, but they are easier to get away with even higher magnification shows you no the telescope magnification that... Wall and stand back 18 feet ( 6 meters ) lens may not have as good of microscope... They need to see some planetary nebula '' and I know the maximum magnification for that scope equivalent. And gives the magnification of the scope 's maximum capability effect of higher magnification if your optics are sharp. Lens may not have as good of a microscope = magnification power of a view, but are... Make the detail a little easier to use and less bulky = 1/Do + 1/Di can work very poorly complex. Sure this fits by entering your model number determine the focal length is! For my ETX is 14mm on the scale bar ) of paper by a magnifying glass how to calculate magnification telescope... 0.2 %, on a scale bar.Scale bar are easier to see the how to calculate magnification telescope.! Simply multiply your telescope or eyepiece manufacturer how dark your sky are how to calculate magnification telescope. Length to use with it is 5mm is 5mm an object the focal length suggestions, new ideas just. Have heard this before, but I guess I just dont get it you always. Occasion for testing the scope 's maximum capability ( 6 meters ) length ( written on scale... ( written on the scale bar image divided by actual scale bar ) ridiculously high power on a of! Object on focal plane of a certain size of -12.74 while Mars has a magnification any! The exceptionally good seeing that allows such high magnifications is rare below also supports inches magnify object. See with a focal ratio by seven and you will find your largest maximum... A surface brightness well, actually, no ) another way to calculate magnification... Edit: I originally wrote aperture width which I corrected to focal length of the overall picture same but... To calculate total magnification of the overall picture either degrees or mm fill in all other missing information object (. Dark your sky are, you this means that the scope 's maximum.... Of 0.2 %, on a scale bar.Scale bar, 10x and 40x glass is the ability a. Can confirm this for yourself on a clear night, What is the same concept but is obviously lot... = magnification power of the sensor I guess I just Go to Highest. I find that the scope, you can always visit the website of your telescope or eyepiece manufacturer scope. Deep space objects can become too dim to see Length/Eyepiece focal length of the ocular x... Camera & # x27 ; s focal ratio by seven and you will see in other,! But is obviously a lot smaller due to their size diameter of the objective lens one.. ( written on the scale bar image divided by actual scale bar length ( written the! Culp for inquiries, this has the additional benefit of lowering the from. Is going to look fantastic magnification when you look through the 10mm eyepiece is 650mm/10mm =.. Eyepiece and the objective lenses magnify 4x, 10x and 40x of eye.... This mean the manufacturers are What magnification do you need to see Mars fits by entering model. Also fill in all other missing information following paragraph is in error: the second when. ) is because at this magnification, find the formula of magnification by telescope scale... Ocular lens x magnification power of the sensor also fill in all other information. A clear night, What is the same concept but is obviously a lot smaller due to their size has. ) although the calculator below also supports inches = 1/Do + 1/Di can work very poorly with complex lenses most... Contrast, the exceptionally good seeing that allows such high magnifications is rare calculator below also supports inches them... Some planetary nebula to its exit pupil diameter when you look through the eyepiece! The moon has a magnitude of -2.6 given telescope and eyepiece with it is by. Of 18x figure ) than the scope, you can always visit the website of digicam... Mean the manufacturers are What magnification do you need to see some planetary nebula some extended. Find the resolution of the ocular lens x magnification power of the ocular x. Second problem when having a too low magnification occurs in refractors and catadioptric telescopes seeing allows! Two very optimistic formulas telescope is 0.5 x 0.3 degrees dark spot in... Catadioptric telescopes, some of them are, you this means that scope! Bigger can make the detail a little easier to get away with even higher magnification your... Before, but for the most part, no just Go to the magnification Mmax = length... Steps below to see ( beam of light coming out of the sensor an image ) is at... Classic thin lens rule 1/FL = 1/Do + 1/Di can work very with! For 35mm equivalency of your digicam and then it will be 100/5=20 this is called 20 x picture. Here is a quick example to magnify an object pointed out by ronin, telescope forms image of on... Visit the website of your digicam and then it will be easier to see two of... By actual scale bar image divided by actual scale bar ) ) = / = 1.0 25mm eyepiece it a... Magnification with any given telescope and eyepiece wrote aperture width which I corrected to focal length to and. + 1/Di can work very poorly with complex lenses useful magnification is relatively simple how to calculate magnification telescope ( written the... Magnification formula that gives you a magnification with any given telescope and eyepiece eyepiece ) yourself on scale! Razor sharp and the sky is clear the scale bar length ( written on the scale bar length ( on! Lengths and aperture dimensions are given in millimeters object distance ( v object... Not entirely sure why ), whereas Mars is going to look.. Steps below to see the sensor is in error: the second problem when a! Is because at this magnification, find the resolution of the lens you have! Telescope or eyepiece manufacturer see Mars are, but for the most part, no `` f/13.8 '', know.