I bought a Celestron AstroMaster 130EQ telescope, but I am not able to see the surface of Mars through using the 10 mm eyepiece. Instead I only see a glowing dot.
What should I do to view the mars surface?
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1$\begingroup$ some quick planet-viewing tips: change location: bricks and concrete accumulate heat during the day and release it at night, messing up the air in between you and the planet; gauge the seeing by looking at some stars: if they twinkle a lot then the views of the planet won't be great; Mars is small: check astronomy.tools to see how it should look in your telescope with your eyepiece under perfect seeing conditions; your scope's maximum magnification will be about 130x, but it might go up to 260x occasionally if conditions are perfect...don't expect much more than 130x though $\endgroup$ – Aaron F Oct 15 '20 at 20:44
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1$\begingroup$ @AaronF those are good tips. I'm thinking you should post that as an answer instead of as a comment. $\endgroup$ – Tim Campbell Oct 15 '20 at 21:54
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$\begingroup$ @TimCampbell thanks :) half the reason I left the comment was to remind me to come back at the weekend and write a proper answer, but I now see that there's no need: I'll upvote your answer instead :) $\endgroup$ – Aaron F Oct 16 '20 at 8:06
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Keep in mind that you have a 650mm telescope and Mars is small. While it is currently appearing larger because it is near opposition, it is still only 22 arc-seconds wide.
Here's a simulated view of what you should see using a 650mm f/5 telescope with a 10mm Plössl type eyepiece (51° Apparent Field of View - chosen because Celestron offers that so I suspect it may be the eyepiece included with your telescope):
It will be difficult to see much detail at that size even if seeing conditions were perfect. Add in typical seeing conditions and it becomes even more challenging.
You could use a 2x barlow or a 5mm eyepiece and that will make it a little larger ... but not much. Using a higher power barlow or a shorter focal length eyepiece (shorter than 5mm) will likely only result in a fuzzier image that doesn't resolve much detail. My experience is that average seeing conditions will let you increase magnification to the 1x of your telescope aperture in millimeters (e.g. 130x) and it turns out that an eyepiece with a focal length that matches the telescope's focal ratio will do that (in your case, a 5mm eyepiece ... or a 10mm eyepiece with a 2x barlow). Going beyond that (to the theoretical 2x aperture diameter limit or 260x in your case) is exceptionally rare and requires outstanding seeing conditions.
@AaronF offered suggestions to try to avoid factors that degrade seeing conditions (e.g. if you live in an area where it is currently warm during the daytime, viewing over rooftops or asphalt, etc. where a considerable amount of heat is still radiating from those surfaces will degrade the visual quality. But this can be improved by relocating your telescope.
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$\begingroup$ +1 Great answer. The simulated view is very useful, was it produced with a particular piece of software? $\endgroup$ – Dave Gremlin Oct 19 '20 at 15:29
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1$\begingroup$ @DaveGremlin I used Starry Night Pro Plus 8 using the Field of View feature. For a free alternative, you can do the same thing using Stellarium using the Occular feature. $\endgroup$ – Tim Campbell Oct 19 '20 at 15:56
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$\begingroup$ I'll give it a go in Stellarium, thanks $\endgroup$ – Dave Gremlin Oct 19 '20 at 16:12
