First scope

[Lynx10]

I am totally new to hobby and need some advice on my first telescope. I wish to view the planets rather than deep sky objects. My budget is around the £100 Mark. I am looking at the Orion 10012 SkyScanner 100mm TableTop Reflector Telescope 

[Cornelius Varley]

Hello and welcome to SGL. For a little more you can get the popular  Skywatcher Heritage 130p

[laudropb]

Hello and a warm welcome to the SGL. I agree with Peter. The Heriage 130 will give you much better options.

[Redscouse]

Hi, welcome to SGL. 

As the guys have said, and it just so happens FLO have one in their offers section.
Grab it whilst you can is my advice!  

Sold now I'm afraid.

 

[mark81]

hi welcome to SGL, +1 for the 130 tabletop scope. I know its a little out of the price you wanted to spend but you will get much more use out of the extra aperture.

[dannybgoode]

Also consider second hand. I got a lovely Sky-Watcher 150P and a manual Altaz mount for £130. 

The 150 has a 6” mirror which is a very useful step up from the 130 and will see you a very long way into the hobby. 

 

[Geoff Lister]

On ‎17‎/‎05‎/‎2018 at 16:22, mark81 said:

+1 for the 130 tabletop scope. I know its a little out of the price you wanted to spend but you will get much more use out of the extra aperture.

I agree. I am very pleased with mine.

Geoff

[Gabby76]

Hello and welcome Lynx10, the reflector you linked to is a good starter telescope which I am sure you will enjoy.

If the budget is limited to start out do not forget that a good set of 10x50 binoculars are also a handy way to learn the skies and will always have a use after you purchase a telescope.

Enjoy which ever you decide to get

[Alan64]

On 5/17/2018 at 07:45, Lynx10 said:

I am totally new to hobby and need some advice on my first telescope. I wish to view the planets rather than deep sky objects. My budget is around the £100 Mark. I am looking at the Orion 10012 SkyScanner 100mm TableTop Reflector Telescope 

I have a Zhumell Z100, which is the same as the Orion.  They're all made overseas, then branded with this name and that once they arrive at market.

It's a 100mm f/4 Newtonian, and with a 400mm focal-length.  I got mine as a specialty wide-field telescope, for low-power observations mostly.  It would be rather difficult to achieve the higher magnifications in order to observe an object up close, like the Moon and planets.  You'd need roughly a 2mm eyepiece to view an object at 175x, for example.  The consensus' 130mm f/5, the Sky-Watcher "Heritage", has a focal-length of 650mm, a bit longer, and where a more realistic 4mm eyepiece, or a barlowed(2x) 8mm, would result in same: 175x.  With the 130mm, it would be more well-rounded, and for observing most everything in the sky, at low-power and high-power, both.  That's why everyone is recommending it over the Orion, and I can see their point.  Also, the Orion 100m f/4 cannot be collimated, aligned, in a conventional manner; whereas the 130mm f/5 can be, which makes it much easier to get the best images possible.  

I had gotten my 100mm f/4 mainly for observing one and only one object: the galaxy in Andromeda, and with a 30mm eyepiece at 13x.  But even at that low power, the galaxy still cannot be viewed in its entirety, as a whole.  I will tell you this, though: the Moon at 13x, with the 30mm in the focusser, is breathtaking.    

[Lynx10]

Thank you for all you help and advice. I have taken it all on board and i am looking into all the suggestions made.... anyway I was round my father in laws today and was talking to him on the subject. He dissapered for a short while and came down with a Tasco telescope (Tasco 49te. I remember them as a child) anyway while I'm deciding on what to buy I'm playing around with it. Its got F=12.5mm eye piece in it. I looked at Jupiter tonight and to get it in focus it made Jupiter quite small. Is it the wrong eye piece and would I benifits buying a barlow lens? 

[Ricochet]

Check the barrel diameter of the eyepieces. If they are 1.25" you will be ok but if they are 0.965" you may have trouble sourcing decent eyepieces at a reasonable price. 

[Lynx10]

Ok. Unfortunately I think I'm out of luck with the size. 

[Ricochet]

That does look like the smaller size. As it's a refractor you've got, what you could do would be to buy a 0.965"-1.25" diagonal which would allow you use 1.25" eyepieces. Astroboot have a few different options but there may also be other vendors who stock them. 

I can see your telescope has a 60mm objective but haven't found the focal length which you will need to know to calculate magnifications. This diameter is quite small and undoubtedly you will want a larger telescope in future but it should be enough for you to decide whether stargazing is for you. 

[Lynx10]

Ok thanks. The focal length is 800mm

[Lynx10]

I have been looking and have found some eye pieces at the right size, they are 4mm, 6mm, 12.5, and 20mm. 

[Ricochet]

1 hour ago, Lynx10 said:

Ok thanks. The focal length is 800mm

From this we can calculate the focal ratio of your scope as 800/60= 13.33. This is useful when choosing eyepieces on the basis of exit pupil (the diameter of the circle of light that is projected above the eyepiece).

Exit pupil = Focal Length (Eyepiece) / Focal Ratio

We can then use the following exit pupil approximations:

• Maximum magnification for technically splitting double stars = 0.5mm
• Optimum planetary magnification = 0.85-1.0mm
• Maximum aesthetically pleasing magnification for objects visible as point sources (if they fit in the field of view) = 1mm
• Optimum magnification for unfiltered extended objects (if they fit into the field of view) = 2-3mm
• Lowest magnification without loss of light (subject to your eye and light pollution levels) = 5-7mm

Your 12.5mm eyepiece will produce an exit pupil of 12.5/13.3 = 0.94mm so we can see that in this scope it falls into the planetary eyepiece category and is probably at the top end for viewing star clusters as well. With such a "slow" focal length refractor you may be able to use a smaller exit pupil on planets (definitely on the moon) than I have suggested so you may wish to find a slightly shorter eyepiece but I wouldn't push it too far as you are already near the limits that a small scope can handle. You might find it more useful to look only for one longer focal length eyepiece for wider views and then put the rest of your cash into a fund for your next scope.

18 minutes ago, Lynx10 said:

I have been looking and have found some eye pieces at the right size, they are 4mm, 6mm, 12.5, and 20mm. 

I assume those are the set that can be found on ebay for wildly varying prices. They're all the same so if you do choose to buy them go for the cheapest. I bought that set for my first scope and discovered they just have cheap plastic lenses. The 4mm and 6mm are in fact identical eyepieces aside from the number stamped on the top and not worth buying. The 12.5mm won't be as good as the one you've already got so that's not worth buying either. The 20mm is ok and might be worth spending a few of pounds on if you can get it separately for less than the set costs. I see that ENS Optical have an old Japanese 25mm that would be better than the one provided in the set. 

http://ensoptical.co.uk/circle-t-25mm-huygen-eyepiece-.965?search=0.965

[Lynx10]

Ok thank you so much for your help and your advice regarding the eye pieces makes sense. I' still learning about the hobby, so need to do some research regarding exit pupil.  When I was looking at Jupiter last night it was very small in the eye piece when it was in focus, making it larger just made it out of focus. So would a 25mm eye piece help in that situation? 

[Ricochet]

Each eyepiece will only show objects at one size. The focuser is just that, rather than a zoom function. The point of best focus is when an object is at its smallest. 

For magnification we can use 

Magnification = focal length (scope) / focal length (eyepiece)

This means that an eyepiece with a smaller focal length will give a higher magnification. Let's say that you want to try going down to an exit pupil of 0.75mm. It is lower than the numbers I have above but your telescope is a refractor with a high focal ratio and small aperture so it might give nice views still. 13.3 x 0.75 = 9.975 so you buy a 10mm eyepiece. 800mm/10mm = 80x magnification. 

You should also be aware that the planets are very low in the sky over the next few years for us in the UK. This means we have to look through a lot of atmosphere which can really wash out details that are usually visible. 

[Alan64]

To see any object in the sky at its largest, the shorter the focal-length of an eyepiece required.  The magnifying limit of a 60mm aperture is about 120x, but under a cooperative atmosphere you might be able to push it up to 150x, perhaps.

The telescope's focal-length: 800mm...

800mm ÷ 150x = a 5.3mm eyepiece, or a 6mm for 133x.  The steadier the mount, the easier it will be to keep the telescope aimed at the object at high powers.  What's the mount like?  Take a snapshot of it and post it for us to see.  We may be able to help you with it.

[Lynx10]

With the last post that Ricochet posted, I worked it out at about 6mm eye piece. To be honest the mount isn' t great and part of the prob was that the scope was moving very slightly as I was looking into it. 

[Lynx10]

Wow! Just got a good view of Jupiter. I can see 3 dots on one side and one on the other. I take it that they are Jupiter's moons? I think this hobby is for me. ?

[JOC]

The thing with Jupiter is that it isn't a solid lump of rock with a defined perimeter, so even the best telescope will always give slightly woolly edges.  

[JOC]

Also don't forget to click, scroll down an then view rhe pictures in this thread 

 

 

[cletrac1922]

Lynx

Welcome from land down under

Glad u having so much fun

John 

[Alan64]

2 hours ago, Lynx10 said:

 To be honest the mount isn' t great and part of the prob was that the scope was moving very slightly as I was looking into it. 

I found an image of the kit during the interim...

I'm most familiar with that type of mount, a yoke-type; not bad, not bad at all.  It is possible to replace the focusser, and one that would accept 1.25" oculars.  If it says "Japan" on the focusser's specs-label, then the main lens should throw up rather sharp images.