Mars a tiny white dot

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jimmynitcher
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Post by jimmynitcher »

Aargh - tried again with a 6.5 and Barlow and its still just a bright white disc, maybe slightly larger - very disappointing.

Maybe someone with the same scope could tell me what I should see?

thanks in advance
Geoff Knight
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Post by Geoff Knight »

Good seeing is everything but Mars is not the easiest object to view in smaller telescopes. For one thing, it has a high surface brightness which washes out fine detail.

This time round, at closest, its size is 14 arcseconds and even at its very close approach a couple of years back it was only 25 arcseconds. Jupiter is typically between 30 and 45 arcseconds and the Full Moon is half a degree or 1800 arcseconds.

A combination of short focal length and smaller apertures is not always ideal for the planets. At the aforementioned close approach of Mars I remember looking at it through a six inch F5 refractor and being very disappointed. It wasn't as well placed as this time but even so I felt cheated. I went to look at it through a friends venerable thirty year old six inch reflector which had a focal length of F11 and the view was superior in every respect.

I reckon you will get better luck with both Jupiter and Saturn.

Geoff
jimmynitcher
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Post by jimmynitcher »

OK thanks a lot, I'll give that a go
Me7551
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Post by Me7551 »

Jimmy, if it's any consolation, I can totally relate to your problem. I was also gutted when all I could see in my telescope was a white dot. Still can't get it to appear any better than that, so I've resigned myself to holding on and viewing it another time, or perhaps going for something else until I'm used to my scope.

I had a notion in my head that I was going to see things like the Hubble sees (even though of course I knew not to expect that really when I researched it and eventually bought it!). I'm just going to try and be patient as possible and take my kit out any chance I can to get the most out of it. I live in a highly light-polluted area and don't have a car, so it'll be tricky, but worth it.
jimmynitcher
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Post by jimmynitcher »

thanks for the empathy!

All I want to see is something that I can't see with the unaided eye ! otherwise I'm not sure of the point of the telescope? The moon is obviously really impressive and I don't expect anything like that, but I now wonder if I stay up till 2 in the morning, will I see Saturn's rings? And what will Jupiter look like? I watched the sky at night the other day and they went straight from saying that you could easily see Mars now with an amateur telescope (they didn't mention the size) to showing pictures of the clouds and polar cap on it that amateurs had drawn after viewing - judging by the results they must have been much more powerful than mine!
stephinepoul7

Post by stephinepoul7 »

Geoff Knight wrote:Good seeing is everything but Mars is not the easiest object to view in smaller telescopes. For one thing, it has a high surface brightness which washes out fine detail.

This time round, at closest, its size is 14 arcseconds and even at its very close approach a couple of years back it was only 25 arcseconds. Jupiter is typically between 30 and 45 arcseconds and the Full Moon is half a degree or 1800 arcseconds.

A combination of short focal length and smaller apertures is not always ideal for the planets. At the aforementioned close approach of Mars I remember looking at it through a six inch F5 refractor and being very disappointed. It wasn't as well placed as this time but even so I felt cheated. I went to look at it through a friends venerable thirty year old six inch reflector which had a focal length of F11 and the view was superior in every respect.

I reckon you will get better luck with both Jupiter and Saturn.

Geoff
I must say that in practice planetary images through a telescope tend to seem smaller in some respects than might be expected. A combination of short focal length and smaller apertures is not always ideal for the planets. At the aforementioned close approach of Mars I remember looking at it through a six inch F5 refractor and being very disappointed. It wasn't as well placed as this time but even so I felt cheated. I went to look at it through a friends venerable thirty year old six inch reflector which had a focal length of F11 and the view was superior in every respect.
jimmynitcher
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Post by jimmynitcher »

OK thanks for the reminder - what I should have said is - what, (apart from the moon) IS worth looking at using the telescope I have? And would I be able to see the rings of Saturn yes or no?
Just trying to get a handle on this, bear with me...
thanks
j
Brian
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Post by Brian »

jimmynitcher wrote: And would I be able to see the rings of Saturn yes or no?

j
Even binoculars will show that there is something "odd" about Saturn. When the rings are well-open, it's clear to see that the planet isn't round, but is elongated where the rings protrude each side. Have a look at this image in the Albums section, taken with a webcam and 60mm f5 refractor (my finder) it shows the relative sizes of the Moon and Saturn, with the rings clearly delineated :
http://www.popastro.com/albums/displayi ... fullsize=1

One comment, Saturns rings are currently just opening after being edge-on last year, so are difficult in binoculars this year, but your 130mm telescope should be able to show them well. The equatorial belt systems should also be within your grasp.

Good observing!
Brian
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jimmynitcher
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Post by jimmynitcher »

ok great thanks Brian, I'll give that a go !
Barry B
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Mars a tiny white dot

Post by Barry B »

Hi Jimmy

I can relate to your problem. I have a 250mm f6.3 Newtonian with a very good quality mirror with wide angle lanthanum eyepieces and my views of Mars have not been very much more successful than yours.
My best views have been with a 22mm eyepiece with 2x Teleview Barlow giving a magnification of 143x. With this setup I am seeing a fair sized disc of creamy yellow colour I think that I can just about see faint surface markings, more like shadows, certainly not something that I could sketch nor does the polar ice cap seem very obvious.
I have tried higher magnifications, 197x and 394x but the image appears very 'washed out' whilst lower magnifications 72x are too bright and glarey to see anything.
I guess we just need more practise!

Regards
Barry B
jimmynitcher
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Post by jimmynitcher »

Thanks Barry, I'm beginning to see the skills (and kit) needed for this are a bit more than I expected!
Can anybody say what else is good to view with my size scope?
thanks again
j
Robin Scagell
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Post by Robin Scagell »

Don't give up on small scopes! The 130 mm is a good enough scope to show you detail on Mars at the moment if you persevere. Look at this month's Young Stargazers' Sky Guide to see a photo that I took at the beginning of January with an 80 mm refractor, which has slightly less power than the 130 mm Sky-Watcher in tests I have done previously. At the time, Mars was the same size as it is currently at the beginning of March, and is of the boring side of Mars which has the detail round the edges rather than in the middle.

The image shows the sort of detail that you should be able to glimpse during the best moments. Even if you can't see detail, you should be able to see the disc and be sure that you're seeing a planet rather than a star.

With the 130 mm Sky-Watcher you'll see the rings of Saturn easily, and it's well up in the sky at the moment in the late evening over to the east so you won't have to stay up late. It will be higher in the evening sky next month but you should still see the rings. If you still see just a white blob then we know there is something wrong somewhere.

As for other things to view, there are dozens of deep-sky objects around at the moment. Here's a list:

M42 (Orion Nebula); M44 (Beehive Cluster), M31 (Andromeda Galaxy), M35 (cluster in Gemini), M45 (Pleiades cluster), M36, M37, M38 (clusters in Auriga), M41 (cluster in Canis Major), Eskimo Nebula (planetary nebula in Gemini).

Trouble is, it would take too long here to tell you how to find each one, but they are all on star maps and in sky guides.

Robin
jimmynitcher
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Post by jimmynitcher »

Thats really useful thanks a lot - don't worry I will find them, I just wanted to know what was worth looking for.
I'll let you know how I get on - its very cloudy at the mo though.
cheers
j
Robin Scagell
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Post by Robin Scagell »

I just took a look at Mars through the Sky-Watcher 130. With the 20 mm eyepiece it was an orange dot, and with the 10 mm it was an obvious disc. Using the 2x Barlow and the 10 mm eyepiece (giving a magnification of 180) I could see details and the polar cap.

The scope was slightly out of collimation, which led to a slightly blurred limb on one side, and the Barlow really is not at all good so I also saw considerable false colour. However, the detail was obvious even if the image was imperfect.

Using a Celestron Ultima Barlow and the 10 mm eyepiece the image was much clearer and sharper. However, this Barlow alone costs £92 compared with £149 for the whole telescope so it would not be a sensible additional purchase!

So, Jimmynitcher, if all you can see remains a white dot, then maybe you are looking at the wrong object. Make sure that the finder is properly aligned (the Moon is a good target for this) -- it's possible that this could be the problem, and you are looking at Pollux instead.

[Edited later in the evening]

Here's an image I took with the Explorer 130 at 22.35 using a Toucam and the Ultima Barlow with extension, giving a focal ratio of f/24:

Image

{Further edit] I should add that I put the instrument on an HEQ5 mount to take the image, though I used it on the manual mount for the visual observations. I'm sure I could have taken the photo just as well if I had the motorised version.

Robin
jimmynitcher
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Post by jimmynitcher »

Well I would have been well happy if I had seen that, or even anything approaching it - can bad collimation affect colour? I'm going to colllimate it anyhow, I've had it a couple of years and only just found out about it and my little girl knocked it over once. The moon looks amazing through it though so I assumed everything was ok.

I still only have the barlow it came with and as I say I got a Plossi 6.5 eyepiece, so in theory I should have seen something like what you have there, no?

Re looking at the wrong thing - i wish it were that, that would sort everything wouldn't it? but I never even noticed Pollux, I just looked at a map looked up and there it was - slightly orange to the eye.
Anyhow, I checked the red dot finder in daylight and that should be spot on now, though it was a bit out before.

thanks again so much for all help this is a great forum.

jimmy
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