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Jupiter and how to improve.


xanthiax

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Hello Everyone!

I hope everyone had a great holiday n managed to get out at least once to look at the sky!

I've been quite lucky; my Mrs bought me a scope for Christmas n I've managed to get at least two good viewing sessions. I am a complete newbie at this however, I did get a great view of Jupiter last night. It was very still so I could see a lot of detail and all 4 moons.

Where I would like some help is simply with the quality of the image. I have a dob sl 200p 10mm & 25mm lenses that came with it.

I just want the image to be a bit closer and a little big bigger. I'm realistic in my expectations however I want just a little more. Any suggestions? Also, what do Barlow lenses do to the image?

Took this with my phone. Quality through eye piece is a little better than this.

6d6e664efe77c5d4b365ad12f01db081.jpg

6e0d4d936eb277e39bcf05d9e4c16e36.jpg

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If you mean the image through the camera then I suspect little chance.

The camera will expose for the whole "frame" as most of that is black then the Jupiter bit will be over exposed.

You would have to take over the camera settings and I suspect that that is not possible.

If you mean your visual view then an 8mm BST Starguider, from Alan at Sky's the Limit. £49.

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Hello Everyone!

Where I would like some help is simply with the quality of the image. I have a dob sl 200p 10mm & 25mm lenses that came with it.

I just want the image to be a bit closer and a little big bigger. I'm realistic in my expectations however I want just a little more. Any suggestions? Also, what do Barlow lenses do to the image?

Hi

Congrats on your new scope.

A barlow lens affect the focal length of your score. I imagine your dob has a focal lenght of 1200mm?

In that case a x2 barlow makes it 2400mm.

So with no barlow your 10mm eyepiece gives a magnification of 1200/10=120x

If you include a x2 barlow you get 2400/10=240x

Some claim that a good barlow will not degrade the image - others claim each additional piece of glass is a bad thing. I guess in the end its down to personal taste. A barlow is at least a cheap way to increase the options you have with your eyepieces. 

Jupiter wlll be bigger - but perhaps not better. Much depends on seeing. You don't write if its a manual or goto dob. Tracking manually with high magnification can be a frustrating experience as the object will leave your field of view quite rapidly.   

Hope you get some good nights out.

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xanthiax......Hi, The supplied eyepieces are about £15 each? they just do the job, but you can improve on their quality. The 25mm is fine for now, being the better of the two, but the 8mm suggested by ronin will not disappoint.

I  started another thread about the image scale at the focal plane, but no replies from that have been received yet? I too want a bigger image , but I don't necessarily need the magnification, as you will discover, not everything requires high magnifications.

I'm sure that to get the bigger image I need, either a step-up or a doubling of my  aperture is reuired? 

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Ah that's great thanks for the replies. I do mean the image through the eye piece n not the camera. I will get an 8mm lense next then.

Thanks for the Barlow information would you suggest I get one of these as well? I understand magnification isn't king. I just want maybe another 1/4 of an inch bigger, for a little more detail. I see a lot more than is in that pic I posted. I just wanted to show roughly what I see.

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If you have the Skyliner 200P Dob, then can I suggest a 1mm exit pupil for Planetary work, and a 2mm exit pupil size  for DSO (Deep Space Objects). This is all to do with the theory of how the telescope works,  and how your pupils work best at night time.

These exit pupils would  require a 6mm and a 12mm eyepiece. However a 12mm eyepiece with a 2x  Barlow saves having to buy the 6mm?

Work with or around these parameters to find what's best/comfortable for your eyes.

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A Barlow is a good piece of kit and is a must in your EP box, but after a while you will find (once you have you viewing eyes...comes with lots of viewing) that you will go back to the 10mm.  The reason is, you will see it bigger anyway with experience, but you will want quality over quantity.  At this point you will want to upgrade your 10mm or buy a good 8mm EP.

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This link http://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.Xbst+starguider+&_nkw=bst+starguider+&_sacat=0

shows you the Starguider eyepieces, in my humble opinion

they are all very good and very good value for money, the  

8mm will give you great views of Jupiter, but if you are anything

like me, you will want all of them, as for a Barlow lens, well I rarely

use mine, for the Moon it comes in handy sometimes, but I tend

to use the eyepieces on their own.

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Hello Xianthiax,

The 200P dob is a good scope but the supplied eyepieces are only just OK.

For Jupiter you need around x150 to x170 so a 8mm or 7mm would be good.

For Saturn you need around x170 to x200 so a 7mm or 6mm would be good.

For Mars you need around x200 to x240 so a 6mm or 5mm would be good.

Widefield eyepieces are best in a dob as you will have to nudge less.

Hope that helps

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........I almost have the full set of BST Starguiders! When you buy a telescope, you often get just two EPs. There is the assumption that you need three EPs for your 'set' HIGH, MED & LOW. 

With an f/6 telescope (Skyliner......not the EXPLORER @ f/5) the theory I now adopt is to use the focal ratio as a guide for selecting my eyepieces. Using the Diameter/Aperture of this telescope (200mm) I equate this to magnification ( practically achievable here under UK skies ) so to get the 200x magnification I use a 6mm EP ( BST doesn't provide (yet?) so I use the 6mm William Optics SPL instead ) this also provides me with the 1mm exit pupil. If You double this formula, the next EP would be the 12mm, giving 100x Mag with a 2mm exit pupil, and strangely enough, what's called the 'sweet-spot' for the telescope , i.e. Its comfortable (especially with the 60°afov 13mm eye relief  from the 12mm Starguider. I could triple the focal ratio to get my wide / LOW eyepiece, but I opted for the wider 2" Skywatcher  32mm Panaview.
Do you need a 12mm and 8mm ?  It depends on what's best for your eyes and your pocket (expenses) If you bought the 8mm and a Barlow, you could Barlow the 8mm to get a 4mm, and you could Barlow your existing 25mm to get 12.5mm (close!) Even the existing 10mm will Barlow down to 5mm, but its the quality of the 10mm were trying to improve on.
Buying on-line gives you better options for returning goods these days. The BSTs can be bought in pairs if you desired, and test them side by side. If you don't like what they represent to you, send them back and get  your money back (less postage to return) 
I bought the 8mm BST first, Its become my favourite simply to the fact it was first in the set. I like them all, and use them all. I'm still considering the latest 3.2mm Ed Starguider to complete the existing BST line-up provided by Alan at STL.
I also think the 6mm WO is going to prove very effective when the opportunity arrives to get my real test out of the way, that said their 3mm WO SPL could end up being my Highest magnification EP. The WO has a longer eye relief, the BST has a wider view.
For the sole reason of high magnification  Planetary detail, it looks like the WO may win.....then there's Orthoscopic and Plossl, but both have limiting eye relief for my needs.....still deciding?
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If a 200P dobsonian then it is f/6.

Stick to getting an 8mm eyepiece, at f/6 a reasonable plossl will (should) be OK.

That will likely be the most used "short" eyepiece you will get.

I do not bother with a barlow, I prefer to use single eyepieces.

To me it is easier, and that is likely the prime reason.

If it works as expected then it is your choice what to consider next, I would half suspect a 12mm or up to 15mm.

The focal lengths are sort of "guides" the actual values I have thrown in are the BST Starguider eyepiece focal lengths.

If you find you are spending time locating things then look at a 32mm or 32mm plossl. They have a wider field of view so better chance that when you point the scope somewhere that whatever you want may be in sight.

But an 8mm plossl should be a good workhorse item.

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Its a very difficult and subjective subject, buying eyepieces. It will always be down to personal choice in the end, to  what feels right, works best and costs the right amount  for your budget ? 

Working with theories and guidelines is ok, but  their only theories and guidelines! Practice makes for perfect, and unfortunately, unless you have the ability to try a few optics first, it will always be a case of buy and try and sell if necessary.

My recent foray with the best!  was an 8mm Tele Vue Plossl with its 6mm eye relief,  which  for me is far too short for my comfort, yet that is the standard 'er' for this focal length Plossl.  I can see the targets, just not comfortably?

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You may need to tweek the collimation of your telescope, even the slightest bit out will wash out the fine detail of

Planetary detail.

A set of color Filters will enhance detail as well, by suppressing some colors, while bringing others out, such as Cloud belts.

Blue will bring out the clouds, orange will bring out the GRS!

Finally, as you become more experienced, your eyes themselves will become trained. Soon you will begin to see Smaller and Smaller details.

It is funny when I show Jupiter to someone on the sidewalk, they will only see a couple lines and the globe of Jupiter!

Congrats on the new scope! A Planesphere and a set of Will Tirion Star Charts (Sky Atlas 2000) will help you. Also the National Audubon Field Guide to the Stars and Planets

is a MUST have! I call it my Astro Bible! I am on my second book having worn my first one out! GET IT!!

Good Luck my Friend.

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The first step is to get an 8mm BST to get you started at 150x magnification.

I use 165x most of the time, especially on Jupiter.

You will get better results if you:

- Put the scope out to cool down (with the end cap cover off, and pointing down to prevent dew)

Other wise it will struggle to go beyond 100x mag until the temperature stabilises.

- At some point you need to collimate the scope - a laser is best.

£15 here - http://www.ebay.co.uk/itm/Best-Selling-Seben-Laser-Collimator-LK1-Perfect-Telescope-Alignment-1-25-/161377222077

Astro baby's collimation guide is the best one to read.

http://www.astro-baby.com/collimation/astro%20babys%20collimation%20guide.htm

and this one is worth a read too.

http://www.skyandtelescope.com/astronomy-resources/how-to-align-your-newtonian-reflector-telescope/

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By all means get some better quality eyepieces but the best advice given here is to observe Jupiter as often as you can and to spend time studying the planet during each session.

orion61 is quite right in pointing out that your eye will become trained and the more subtle details will emerge as this happens.

The detail will come and go as you observe though and this is due to the varying atmospheric conditions which change by the minute. By spending time on a single subject you get more of the moments of good seeing when you will see what your scope can really do.

With regard to magnification, Jupiter does not respond as well to really high power in the same way that, say, Saturn does. The nature of the surface features and contrast mean that a sharp, contrasty image is preferrable to a more magnified but less well defined one. Even with my 12" scope I find that 180x - 230x are the optimum for the giant planet most of the time. Sometimes drapping back to slightly lower power gives a more detailed view. 

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I have called it a night tonight due to cloud.

One thing I have noticed from last year is the lack of sharp focus on my 200p dob.

I hope it is the moisture in the air in general, and the full moon tonight which is spoiling the viewing.

Although reading Johns comment above about spending time, and studying the view could be my problem.

Last year I would be out there for 2-4 hours on and off.

In that time, I would get several 2-second bursts of crystal clear image coming to me (instead of me having to chase it)

Watched kettle never boils and all that.

Good eyepiece around 180x  / collimated scope / temperature stabilised / at a good location away from rooftop heat / spend some time waiting, and bob's your uncle

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I have called it a night tonight due to cloud.

One thing I have noticed from last year is the lack of sharp focus on my 200p dob.

I hope it is the moisture in the air in general, and the full moon tonight which is spoiling the viewing....

I think the Jetstream is over the UK, at least in part, and is messing things up a bit for us !

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for planetary observations,aperture is not important as the object is bright/very bright and as many posters already said,it is the seeing conditions what affects how much detail you can get.Sometimes smaller aperture will actually perform better on planetary with the ability to "cut" through the atmospheric turbulence's better then that big light bucket.As for how much detail you can see,I will agree with John.You have to spend time on looking at the object.more time you spend,more chances of you seeing something more.

My personal opinion on eye pieces:i would rather save up longer but get excellent quality eye piece what i can keep for very long time and if i do decided to part with it,i am guaranteed to have my money back.Alternatively,orthoscopic eye pieces are cheap,but provide excellent planetary details and will be hard to beat for they value/performance.But this is my personal opinion.

As for the image size mentioned earlier.It does not matter how big is your scope,you will still get about the same image size as it is not the aperture but the magnification you can get out of Jupiter in this instance.Average magnification on Jupiter is 170-190 with rare occasion of good viewing in Uk we can push it to 200-240 as such,increase or decrease in size of Jupiter will be very minimal and will still be about the size of pea.With bigger aperture you will only make the image brighter but not bigger.

Bigger aperture will however,give you more detail on DSO due to light gathering ability but NOT on planetary.

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Thank you all very much. I will do some research on some eye pieces. If everyone is ok with me posting some questions here if I come across any?

I did buy this scope for dso's but since I'm very few to this the moon and Jupiter were two very easy targets.

Thanks again for all of the information it's muchly appreciated.

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Hello Xanthiax,

With my 200p Dob I use a variety of different eyepieces.

Revelation plossls are good at £22 each - but have a very limited 52 degree view - I use 9mm barlowed at 290x mag

Next up you have BST and Celestron Xcels at £50 and £59 -  these are still too narrow for me.

Maxvisions only go down to 16mm (£50 - £60), but have a wider 68degrees, I also have the 24mm.

My 11mm Explore Scientific 82 degree is my favorite (£100)

I also have a second hand Televue Delos 6mm. But given the choice again, I would go for two or three ES82o eyepieces over 1x Delos (£280 new)

If you can stretch to a 6.7mm ES 82o you will have your 180x magnification, and a super wide view which is sharp up to 10% from the edge.

http://www.365astronomy.com/Explore-Scientific-Eyepieces/

If you are on a budget, the BST will be good enough for £50, and can be resold very easily if you upgrade later on.

http://stores.ebay.co.uk/skysthelimitastroandoptical/BST-Starguider-ED-/_i.html?_fsub=2568750014

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I have the same questions as Xanthiax. My wife got me an Orion StarBlast 4.5 Equatorial 450mm telescope this Christmas and I've had a blast with it! It came with a 15mm and 6mm eyepiece and I just received a 3.2mm from amazon. Good thing to know about the Barlow's. Although, I think I will get one for the better moon viewing. Here's a few pictures of my first times through the scope. Any tips are appriciated!059a0d43f1ea131455fd6272a3db41d3.jpg

4e3019bcbcb5930d36874aa1fa371e4b.jpg

550b45a5b9bba8fd55dbc69215b6552e.jpg

-Garret-

Sent from my iPad

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