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Old 02-09-2018, 11:10 PM
duppeydude
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All I can see are tiny dots...

Hi all,

Just bought my first ever telescope. A Saxon 10 inch dobsonian. My childhood dream of seeing Nasa like images aside I at least thought Mars would be huge but it's literally just a yellow dot... What's going wrong? Well I at least think it was Mars as I was using the Night Sky app on my phone. Any thoughts would greatly be appreciated!
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Old 03-09-2018, 12:10 AM
Hemi
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Hi DD,

In your 10in dobs, Mars, with an appropriate eye piece should look like a small orange/red disc. A dot is usually a star.

Your post doesn’t narrow it down, but what I would do, google for the detail...

1.in daytime align your finder to the main telescope...this way you know what your pointing to. You can’t find anything looking though the main scope alone. Even the moon at the beginning!

2. If possible look at something very far away in the daytime (NOT THE SUN!!!) with the widest eyepiece you have (longest focal length) and focus, this will get you somewhere close to focus for nighttime. This step is just so that we know your near the correct focus as you’ve never used a scope before, and it’s all very daunting at night time.

3. At night, get mars in your finder and then it should be in your scope, roughly in focus....then focus on it. Change eye piece if you have one with a shorter focal length, which will magnify mars up a bit..... Mars is currently a very obvious, massive red orange ball to the naked eye. But your app will ID it for you.

I hope that helps.

Hemi
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Old 03-09-2018, 05:23 AM
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mental4astro (Alexander)
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Duppeydube,

Your expectations of seeing a NASA like image of ANYTHING through a telescope is a common trap for novices.

What most people are not aware of is the NASA images are not taken using Earth based telescopes, but with probes that are orbiting the planet! We wouldn't bother with probes if we are able to view the planets from Earth with the same quality otherwise.

AND, there are also several practical and optical limitations that dictate how much magnification a given scope can offer AND the prevailing atmospheric conditions of the night too! So even if you could max out your 10" dob at 500X on an exceptional night, Mars will still be a tiny blob!

Doesn't stop here either. Mars is currently experiencing a global dust storm that is obscuring the surface so the planet appears as a featureless orange ball! These global dust storms are not uncommon and unfortunately this dust event has coincided with the best Martian opposition in 14 years! It's peeved MANY people!!!! Crap happens on a global scale sometimes

Likewise the gorgeous colour seen in photographs of nebulae and galaxies, especially those advertising telescopes, are a complete misrepresentation of how things appear through a scope. Those photos are produced using cameras with an exposure time of upto several hours! Truth is our HUMAN eyes are poor at the low levels of light that deep sky objects are, and the colour receptors are just not triggered, so we essentially see things in shades of black and white.

Alex.

Last edited by mental4astro; 03-09-2018 at 01:13 PM.
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Old 03-09-2018, 10:42 AM
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Stonius (Markus)
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I would also add that it is possible to see surface details on Mars Jupiter and Saturn with that telescope, but it is dependent upon atmospheric conditions (seeing). It requires a steady atmosphere to see such tiny details.

In addition, you will notice the image shifts and wriggles about a bit. The details you will see through the eyepiece will come and go as the atmosphere shifts and the refractive index changes. Therefore, the finest details tend to be transient.

When you see a photo taken of mars with a 12", All the fleeting moments of details have been gathered and stacked together to create a final image. Those details *are there in the eyepiece, but it takes time pick them out as they flash by. Only occasionally are the details rock steady as in a photograph.

Your observing site has a bit to do with this too. Ideally you don't want to be on concrete or asphalt or bitumen - they radiate heat after the sun goes down. Grass is better, but prone to dewing up the optics. A nice dry patch of earth is best. And get away from the city. All the houses being heated creates a thermal plume that disturbs any steady seeing, like heat rising from a campfire.

Also, Mars is past opposition and shrinking now, so that will work against you. Jupiter is a better bet, or Saturn. See how you go with them.

Hope that helps.

Markus
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Old 03-09-2018, 11:34 AM
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Welcome to the world of visual astronomy, where everything is either a tiny dot or a faint blob. This is why I do astrophotography.
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Old 03-09-2018, 11:37 AM
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Just a tip on viewing the moon: The lid should have another 'little lid" on it of about 50mm. Use that aperture for the moon or otherwise you will having difficulty seeing afterwards due to the magnified brightness.
That little lid is also good with a solar filter for viewing the sun.
We were all disappointed as newbs that we couldn't magnify stars, but we get to magnify the light and size of amazing nebulosities, and the planets. A fair exchange I thought.
Trevor
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Old 03-09-2018, 01:14 PM
duppeydude
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I think I've collimated as good as I can without a laser collimator. Is it possible to accurately collimate without a laser? I tried aligning the finder with the main telescope in the dark using a lamp post in the distance so hoping that's not too far off either. How big should I expect Mars to be in a 10 inch aperture dobsonian? It's literally like dropping a pen on a piece of paper size. I live pretty rural as well... well if you count Gatton as rural but I'm still 10 minutes away from town.

I'll take another look to see if I have a "little lid" when I get home but I don't remember seeing anything like that in the package that I bought with the telescope. just came with a solar filter, planet filter and 2 eye pieces - 10 and 25 I believe
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Old 03-09-2018, 01:35 PM
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If it looks like a dot like you've described I suspect you aren't looking at Mars. You will definitely see a disc, with my 8" Dob, it might approximate a 5c piece in a milo tin, maybe a touch smaller? Not a pencil dot.....
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Old 03-09-2018, 01:54 PM
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What eyepiece are you using? First use a long one (more mm) to get a wide field and find the planet, Then swap out to a shorter one to get the magnification required to see Mars.
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Old 03-09-2018, 01:58 PM
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RE: "Little Lid"
I have copied this from another recent thread

Quote:
Originally Posted by Benjamin View Post
If you are observing through a 10” Dobsonian chances are it came with a dust cap that you can use to stop down the aperture when observing the moon. There should be a removeable small cap on the larger dust cap (see picture). This makes things much less bright, especially when the moon is quite full. I’m not much of a lunar observer but enjoy observing it when it’s less than half full (not too bright) and like viewing along the terminator (the division between the dark and light side of the moon). When it’s full the detail gets a bit harder to discern. Mars probably is a blurry blob at present (haven’t checked lately) but Jupiter should show some bands. Play with focus and a higher power eyepiece (10mm should be fine) and make sure you’ve let the scope cool down (around 30 minutes or so). See if you can find a nice adjustable chair to observe with (an observing chair is well worth the investment). It will make the process a bit more relaxing and should assist with relaxing the eyes :-) There’s lots of trial and error to start with (identifying stars, getting used to setting things up, trying different eyepieces etc.) so aim to keep it simple and roll with the punches.
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Old 03-09-2018, 02:07 PM
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Re: What Mars should look like in the scope.

I copied this from the same thread.
This is what Drew saw looking through his DOB.

It is small, but it is definitely a disc, not a dot.
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Old 03-09-2018, 03:38 PM
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You're not getting enough magnification with the 10mm.
1200mm / 10mm = 120x.

I would suggest a 6mm EP.
1200mm / 6mm = 200x.
A 6mm Plossl is $49 from Bintel.
If the seeing is good enough, you should see some surface detail.

Regards, Rob
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Old 03-09-2018, 06:21 PM
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Have you tried Saturn and Jupiter? They are definitely worth looking at and show a decent disc size.
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Old 04-09-2018, 08:50 AM
duppeydude
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I'm using a 25mm to get the object into view and then using a 10mm eye piece. Managed to see Jupiter's bands last night! Do you recommend getting a laser collimator?
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Old 04-09-2018, 09:09 AM
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Quote:
Originally Posted by duppeydude View Post
just came with a solar filter, planet filter and 2 eye pieces - 10 and 25 I believe

Please provide a photo of this particular item. We need to confirm the make / type, as there are some that are very unsafe.

OIC!
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Old 04-09-2018, 09:14 AM
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Quote:
Originally Posted by duppeydude View Post
I'm using a 25mm to get the object into view and then using a 10mm eye piece. Managed to see Jupiter's bands last night! Do you recommend getting a laser collimator?
No, waste of money. Most are not collimated themselves and when you get your eye in you can easily collimate by sight but you're still a novice, you'll grow to learn. Forget the gadget traps for now, most people never use them but if you want to throw money away on something you cant use be my guest.

Congrats on seeing jupiter! It never gets boring to look at, always spectacular. Likewise saturn. You may want to consider getting a Telrad to help with getting your scope pointed at targets in the sky like Mars. As others pointed out the planets should look bigger in the eyepiece (NOT NASA pic huge, and NOT pinprick points either. Stars Never increase in size in the eyepiece and the more magnification you use the harder it can become to catch a specific target in your eyepiece. For eye visible objects a telrad really helps, and you need it for a good starting star for star hopping to those fainter targets too.

I think you'd do well to save for a good 32mm eyepiece (baader) plus a baader zoom eyepiece. The eyepieces supplied with scopes are typically poor quality really, good ones will last a lifetime and you'll notice an instant improvement with your viewing. Eye relief will be better, the view will be much sharper with more contrast. Baader eyepieces are very good at a good price, though seemingly costly for beginners they are well worth the price. Down the line you can upgrade to Teleview eyepieces if you like. The baader zoom is possibly the best zoom eyepiece around and saves you having a heap of eyepieces and its easier to keep your target in the view when zooming in then when swapping eyepieces around. it covers 8mm-24mm range which does most of what anyone ever needs. to use higher magnification (yepieces under 8mm) you need a well collimated scope plus good atmospheric seeing conditions. So if you find yourself needing a bit more magnification for planets later on best to go for a high quality eyepiece for those rare occassions.

good luck on your sky journey
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Old 04-09-2018, 09:28 AM
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Sorry, but I think a good laser collimation tool is a must for a DOB.
Additionally, the use of a Cheshire collimation eyepiece is recommended.

Attempting to collimate by eye would not be a happy experience.
Admittedly, doing a star test (by eye) is a good way to see that your collimation is good, but its not so easy to use this method to adjust collimation until you are much more accomplished.
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Old 04-09-2018, 11:37 AM
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Quote:
Originally Posted by duppeydude View Post
I'm using a 25mm to get the object into view and then using a 10mm eye piece. Managed to see Jupiter's bands last night!
Well done! If you catch Jupiter at the right time you can see the great red spot also. You must see Saturn next.
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Old 04-09-2018, 11:54 AM
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OICURMT
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Quote:
Originally Posted by duppeydude View Post
Do you recommend getting a laser collimator?
Quote:
Originally Posted by sil View Post
No, waste of money.
I tend to agree with this statement. Bottomline is that if you buy a cheap, yet adequate 4-6mm eyepiece, it will do more for your collimation than a laser.


Using a high mag, thought not useful for visual purposes (i.e. too cheap), it does an exceptional job at determining how on-axis/off-axis your optical train is.


I've used this technique for decades and it never fails.
OIC!
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Old 06-09-2018, 10:32 AM
duppeydude
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If I'm working this out correctly a 4mm eye piece would be the maximum magnification I could achieve with a 10 inch dobsonian with a focal length of 1200mm? With all the different manufacturers of eye pieces which is recommended to get? Are there any other accessories people would recommend?
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