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Old 18-04-2014, 10:10 PM
Quickxb (Bruce)
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Planets look like white dots

Apologies if this has been covered before but I couldn't find anything that helped through search, recently bought a cheap ebay scope and it's not bad for looking at the moon BUT, looking at planets, or what I believe are planets they just look like white dots. Is this because A: I have a cheap scope.. B: It's because of the light fro the moon, currently lights up the night.. C: The artificial light from houses not letting my eyes adjust or.. D: All of the above? Appreciate any help..
Bruce
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Old 18-04-2014, 10:36 PM
Renato1 (Renato)
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What sort of telescope is it, and how is it described on the tube?

I ask because I own a $36 Dick Smith 50mm refractor, and it shows bands on Jupiter and rings around Saturn.

You nay have a dud refractor or just a reflector in need of collimation.

Regards,
Renato
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Old 18-04-2014, 10:51 PM
Quickxb (Bruce)
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It's a foco, 114x900 I think it's a refractor? Not sure what you mean by what's described on the tube as there is nothing but foco written on it. Thanks for the reply..Uhm how do you collimate?
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Old 18-04-2014, 11:09 PM
Quickxb (Bruce)
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Sorry maybe a reflector..
http://www.ebay.com.au/itm/350683270513
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  #5  
Old 18-04-2014, 11:22 PM
noeyedeer (Matt)
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could it be a focus issue? .. and possibly collimation. best thing to do is to focus on a star and get it to a pin point, and then look at the object in question, be it moon, planet or whatever.

that way at least you know your focus is good. if the star won't focus then there is collimation issues or worse...

matt

I could see bands on Jupiter with a similar Meade 114/900 with the supplied ma25mm eyepiece ..
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Old 18-04-2014, 11:29 PM
Quickxb (Bruce)
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Thanks Matt, focus seems ok, at least I think. The objects don't have distortion or haze or anything just lack colour really, looking at mars through the finderscope I can see the red glow but through the scope it's just white, same for, Jupitor or Venus, can't remember what the phone thingy said I was looking at. just reading about this collimation stuff now..seems a bit much really, you blokes must be very patient and calm.
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Old 18-04-2014, 11:33 PM
noeyedeer (Matt)
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after reading the eBay ad Bruce, you may have had the Barlow in and things. the supplied EP aren't the best, but the 20mm should've shown something. a blob sounds like too high of power, bad atmosphere etc
matt
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Old 18-04-2014, 11:34 PM
Quickxb (Bruce)
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Quick question, there is a small lens cap and a larger cap the diameter of the telescope, do I just remove the small lens cap when using it?
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Old 18-04-2014, 11:37 PM
noeyedeer (Matt)
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remove the whole cap
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Old 18-04-2014, 11:38 PM
Renato1 (Renato)
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Quote:
Originally Posted by Quickxb View Post
It's a foco, 114x900 I think it's a refractor? Not sure what you mean by what's described on the tube as there is nothing but foco written on it. Thanks for the reply..Uhm how do you collimate?

That's a reflector - long tube, little mirror in vanes just inside the top of the tube, eyepiece goes into the focuser at the side, near the top of the tube - right?

Assumimg no one has fiddled with the secondary mirror, collimation is pretty simple (a lot simpler in practice than what it sounds like when I describe it).

Aim at a star, get it sharp, then throw it out of focus a bit and you should get a bullseye pattern - just like this member has posted in another thread,
http://www.iceinspace.com.au/forum/s...d.php?t=119622

But if the dark centre of the bullseye is off to the side of the disc, so that it looks like a little comet, then you have to collimate the telescope and bring that dark bit back into the middle.

The back of the telescope has three or six screws. Where you have six screws, you unscrew slightly the three shallower ones which are locking the mirror down. Going back to the eyepiece, stick your finger in front of the tube so that you see it in the defocused disc - move it around till it's in line with where the distance between the dark central bit is Shortest to the edge of the ring. See where that finger corresponds to the screws at the back end of the telescope. If there is a single screw there screw it Out (i.e. anticlockwise) and screw In the other two which correspond to the dark bit being Longest away (i.e. clockwise). That's how I remember it, Out Short, In Long - OS, IL.

And when I say "screw" I mean no more than a quarter turn, less as you get close to your target.

But if your finger corresponds to a point in between two screws, do the same - screw them Out, and screw the opposite one In.

Eventually, you will get a nice bullseye pattern and the images will be the best you can get out of the telescope with those eyepieces. Just remember to do up the three locking screws (not too tightly).

If someone has fiddled with the secondary mirror, you have to wait till daylight, and get a film cannister or cannister lid from somewhere, put a little hole in the middle of it, put it over the focuser without an eyepiece in it, and look into it - you should see the secondary dead centre, with the reflection of the primary mirror totally filling it.

If you are well collimated and the images are still bad - it could be that,
a. the atmosphere is bad, twinkling stars are bad atmosphere or
b. it could be that neighbours have heaters going and you are looking through heat haze, or
c. initially, the telescope is cooling down and you have tube currents.

You can actually see these effects in the defocused star image if you look closely in the disc.
Good luck,
Renato
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Old 19-04-2014, 12:00 AM
raymo
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Hi Bruce, Your problem won't be any of your listed ones. Even a cheap
scope will show the rings of Saturn and the main cloud belts on Jupiter,
and the reddish brown tinge of Mars. Moon light has no discernible
effect on the planets. The planets are bright enough that your eyes
don't need any dark adaptation.
So you have several possibilities. a. You are not looking at planets, but
out of focus stars. b. You are using very low magnification, so the planets
appear very small, and you weren't looking at Mars, which has a distinct
reddish hue that's hard to miss. c. You looked at Venus when it was near
full, which would look like a white dot anyway, due to it's total cloud cover. If you don't already have one, I suggest that you download a free
planetarium program such as Stellarium, which will show you where the
planets are at any given time, so you are sure that you are looking at a planet, and remember that planets usually show little or no scintillation,
[twinkling] which helps distinguish them from stars, and also once
found with a low power eyepiece you will need to switch to a much
higher power one to make out some surface details.[assuming that
your scope is capable of resolving them].Hope this helped.
raymo
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  #12  
Old 19-04-2014, 12:03 AM
noeyedeer (Matt)
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going back to your original question, it could be A. maybe not the scope itself but the H type eyepieces. my nephew has some H eyepieces so I gave him the MA and a few plossls and now he loves his little aldi scope ..

if you can buy a few plossls from Andrews or similar and see if that improves the resolution.

matt
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Old 19-04-2014, 12:05 AM
Quickxb (Bruce)
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Quote:
Originally Posted by noeyedeer View Post
remove the whole cap
Thanks ol mate
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  #14  
Old 19-04-2014, 12:16 AM
noeyedeer (Matt)
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Thanks ol mate
no drama, let us all know what happens ..
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Old 19-04-2014, 07:25 PM
Quickxb (Bruce)
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For the fourth night tonight I braved the mosquitos and muggy weather to hopefully see something more than just the moon. Mars still disappoints me, well not such much the planet but my scope. I did the out of focus thing to check alignment and it looks pretty good. I did have some success with Jupiter though. With the barlow lens and a 12.5mm eyepiece I managed to focus enough to see two faint but distinctive rings..Really unhappy with the tripod and adjustments so I won't be attempting any more planet gazing with this. I was going to buy a plossl eyepiece though to see how much difference there is, at least if I then buy a "real" telescope I will have a descent eyepiece for it. Thanks for all the replies and help, Matt I think that taking that big cap of the end made the difference Goodonya!
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  #16  
Old 19-04-2014, 09:10 PM
-George-
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From what I have got from other professional Astronomers and reading is that for planetary and lunar viewing, you actually want the lights to be on. Because these objects are bright, you don't need your eyes to dilate to a larger aperture. By dark adapting eyes for planetary/lunar viewing, you are losing contrast, colour and resolution.

However as said, this only applies to planetary/lunar viewing. So for planets keep a light on, read your star chart with a white light etc to not allow dark adaption. If you do anything else, then you want dark adapted eyes.

Search Photopic, mesopic, scotopic in google and you will understand.

Plantary/lunar observation you want eyes in Photopic mode.
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Old 19-04-2014, 09:58 PM
Renato1 (Renato)
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Quote:
Originally Posted by -George- View Post
From what I have got from other professional Astronomers and reading is that for planetary and lunar viewing, you actually want the lights to be on. Because these objects are bright, you don't need your eyes to dilate to a larger aperture. By dark adapting eyes for planetary/lunar viewing, you are losing contrast, colour and resolution.

However as said, this only applies to planetary/lunar viewing. So for planets keep a light on, read your star chart with a white light etc to not allow dark adaption. If you do anything else, then you want dark adapted eyes.

Search Photopic, mesopic, scotopic in google and you will understand.

Plantary/lunar observation you want eyes in Photopic mode.
Well, that's a pretty easy hypothesis to test out.

Go outside and look at the planets then look at the moon.

Then get a bright flashlight, aim it full bore into your eyes for a minute, and repeat the excercise - liberally aiming the flashlight into your eyes while doing it.

I know one thing your advisors obviously don't know - it won't make any difference whatsoever on the moon.
Cheers,
Renato
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