First scope please help

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First scope please help

Postby Bertiebones » Sat Dec 10, 2016 11:33 pm

Hi everyone,

I'm completely new to this, however it isn't actually me that the telescope will belong to (Christmas present). I will however get to use it since it is a present for my partner. Anyhow, I've ordered the scope and am excitedly awaiting its arrival in the next few days. My question is though, what would you recommend in terms of a "starter kit" for lenses, filters, etc? (Both of us will only now be starting out in this hobby) I'd like it essentially to not be just the scope but also a few useful extra bits to increase its potential.

The scope is Celestron Evolution 8, and the extra bits I was thinking of getting are along the lines of the Celestron eyepiece and filter kit, but that is really just going by what I am guessing would be useful. Perhaps there is something better to get instead of a ready made filter/eyepiece kit?

Many thanks for your time and advice :)
Jake.
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Re: First scope please help

Postby Gfamily2 » Sun Dec 11, 2016 1:19 am

Hi, and welcome to the Forum.
Personally, I would advise against getting the EP and filter kit; most of them won't actually be ones you'd use in the long term, so I'd say wait until you get an idea of what you want to try next.

A really good piece of advice I read once was to get to the very best with what you have before you buy anything new.

So, what would I suggest you spend your money on...
+ A planisphere is well worth getting - it'll give you an idea of the constellations and bright stars that will be visible at any date and time, and (in particular) how the constellations relate to each other.
+ A red light head torch will preserve your dark adapted vision while you're working around your scope - using a 'white' torch will affect how well you can see things at night; a red light has much less effect.
+ If your scope comes with 40mm and 13mm eyepieces, you might consider a 2x Barlow, as that will effectively give you a 20mm eyepiece value as well - which 'fills the gap' between the two.

If you have a dSLR camera, the Celestron 2x Barlow lens with T adapter* comes with a threaded end that will accept a T-Ring, which means you can buy an adapter so you can fit your camera to the telescope and start to take astro images with your scope. It's a well priced 2x Barlow lens even if you don't have a dSLR camera though.

If you're only starters in this hobby though, I would most seriously advise you to find if you have a local Astronomy Society that you could link up with - and go along to as many meetings as you can to start with.
Find out where and when they have their observing sessions, and take your scope along with you, so that you can benefit from their experience (and try out / borrow their equipment).

* other vendors... etc
Scopes: Meade 8" SCT, Skywatcher 127mm Mak, Raffle winner of SW ST80
For imaging: Pentax K5, Asda webcam, Star Adventurer (new toy)
For companionship: Mid Cheshire Astronomical Group.
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Re: First scope please help

Postby Bertiebones » Sun Dec 11, 2016 10:34 am

Hi there :) Thank you for the welcome and the reply!

Thanks for the suggestion of tagging along to Astro society meetings, hopefully we will be doing just that. I have looked into the societies around here (we live in Shropshire) and there is some based around Birmingham as well as Shrewsbury, which is great because it isn't far either way :)

As fas as the eyepieces go, is there some sort of explanatory guide to them? I have seen so many when browsing the online shops, but frankly, while I understand the concept of the Barlow lens, and will certainly get one like you suggested, I have no idea whatsoever what different eyepieces do and what to look for when deciding on one. Is there perhaps (for example) one that is particulary useful (like a Barlow lens is from what I gather and from your advice) to have? Like you said, the scope comes with the 13mm and the 40mm ones.

I've invested in a red LED torch, however on the subject of the planisphere - if I/we would be using the SkyPortal or similar app, am I correct in thinking it does the same as a planisphere?

One last question, if I may, would a moon filter or some sort of planetary filter be useful, or indeed, like I was told by one shop I enquired with, a dew shield as well?

I'm sorry for all these questions, I just don't want to be "talked into" buying something I don't need, which sadly was the experience with some shops when researching the scope and any extras, but I would like to make sure that despite current limited (if any) knowledge on the subject, I got the perfect starting package and am able to offer my partner some sort of starting info on say eyepieces and begginer stuff.

Many thanks again :)

Jake.
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Re: First scope please help

Postby Aratus » Sun Dec 11, 2016 1:55 pm

Hello Jake. You are jumping in the deep end with an 8" telescope! There are a lot of objects within easy range of that telescope. You can spend years adding useful accessories to it, but Gfamily2 has given you some suggestions to start with.

Understanding eyepieces and barlows is just simply easy mathematics. You need to know the focal length of your telescope which is 2032mm. To get the magnification just divide that number by the focal length of the eyepiece. So your 40mm eyepiece will give a magnification of 2032/40 = 51x You can do that for each of your eyepieces. Barlows are used with the eyepiece. So a 3x barlow with the eyepiece mentioned above will give you a magnification of 3x51 = 153x
Commonly you can get x2, x3 x4 barlows

Magnifications of 50x are useful for wide objects like star clusters. Magnifications of 150x or more are useful for the planets and the moon. It isn't worth getting magnifications of much above 300x at this stage as most of the time it would be useless.

Filters just make the image dimmer! Their main use is making some colours darker than others. That can increase the contrast of some features. As you become more familiar with different objects, you can work out if it is worth buying a particular filter. My main concern with buying sets of filters is that you end up buying filters either you can't use, or ones you will never need to use.

A dew shield will be very useful. It won't stop dew forming on the corrector plate altogether, but it will extend your viewing time before it does. Something like this works nicely. https://www.firstlightoptics.com/dew-prevention/astrozap-flexible-dew-shield.html or if you are looking to save money you could make your own. They wrap around and are held in place by velcro.

I do have a moon filter. It came free with something else I bought! The moon through a telescope can be very bright, but I find the eye adjusts quite easily. The main problem is seeing anything afterwards through the green splodge that the brightness leaves behind! :)
I use an 11" Celestron SCT (CPC 1100) on an equatorial wedge, housed in a 2.2m Pulsar observatory. I use a ZWO ASI1600MC and Canon 500D for imaging.
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Re: First scope please help

Postby Gfamily2 » Sun Dec 11, 2016 7:37 pm

I started this hours ago, so this may repeat quite a lot of what Aratus has said, but having written it... :)

As far as eyepieces go, there are two main attributes to consider, power and field of view; and it's worth knowing about eye relief as well.

Power is determined by the focal length of the EP - and the magnification you get is found by dividing the focal length of the scope by the focal length of the EP. So, this means that out of the box you'll get the following
51x magnification with the 40mm EP
156x magnification with the 13mm EP
That's quite a jump, so the 2x Barlow will give you an intermediary value of 102x.
In principle, you could use the Barlow with the 13mm EP; but that would only give you good viewing on rare occasions when the skies are exceptional (a rule of thumb is that you can usually get good viewing with an EP whose focal length in mm is no less than the focal ratio of the scope (f/10) in your case).

Field of View has two meanings - in using an eyepiece you're looking down a tube - the Apparent Field of view measures how wide the view at your eye is; whereas the True Field of view is a measure of how much of the sky is visible through that tube - which determines whether you'll see all of a star cluster, or all of the moon for example.

The Apparent FoV depends on the design of the eyepiece used. EPs that are packaged with scopes usually have an Apparent FoV of about 50 degrees. Other designs are available (at higher cost naturally) that give a wider AFoV, these are often labelled WA (wide angle) or SWA (super wide angle).
The True field of view depends partly on the AFoV and partly on the scope you're using - because your scope is f/10 it'll never give really a large True FoV.*

I'd say the other main factor to take into account with EPs is Eye Relief - particularly if you wear spectacles. I'm not sure what the precise definition of Eye Relief is, but it's basically how close to the eyepiece you need to put your eye to be able to get the light into your pupil - it tends to get smaller with higher power EPs, which makes them harder to use comfortably. Again, some designs have better Eye Relief - at some cost of course.

Having written all that, there's quite a good summary page here
http://www.swindonstargazers.com/beginn ... pieces.htm

You ask about the value of a Planisphere since you'll have Sky Portal or something similar. I would still say a Planisphere is worth getting - it shows the whole sky at a glance, it doesn't produce any glare, and it's easy to pick up, use and put down in gloves with no need for a stylus. You'll also find it trivial to move the disc around to see what'll be up in a few hours time - no menus to navigate! Don't get me wrong, I have Stellarium and Star Walk on my phone and tablet and they're great, but the Planisphere is just simpler to use when you're out in the field. Get one that has the brighter stars named.

A moon filter is definitely useful - it can be an eyewatering experience looking at a nearly full Moon with an 8" scope - I have read a suggestion that you can just wear dark glasses instead, but that just sounds mad.
I've heard mixed things about using coloured filters for planets - some people like them, others think they're mostly a waste of money. I don't have any, but if you can link up with an Astro Soc you may be able to try someone else's out.

* You can buy Focal Reducers to fit to your scope - they act like a reverse Barlow to give you a wider field of view by changing your scope from f/10 to f/6.3 (usually).
Scopes: Meade 8" SCT, Skywatcher 127mm Mak, Raffle winner of SW ST80
For imaging: Pentax K5, Asda webcam, Star Adventurer (new toy)
For companionship: Mid Cheshire Astronomical Group.
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Re: First scope please help

Postby Gfamily2 » Sun Dec 11, 2016 8:23 pm

Oh, and get this book ...
Illustrated Guide to Astronomical Wonders
It'll give you lots of ideas about what to look for, as well as practical information about equipment etc.
Scopes: Meade 8" SCT, Skywatcher 127mm Mak, Raffle winner of SW ST80
For imaging: Pentax K5, Asda webcam, Star Adventurer (new toy)
For companionship: Mid Cheshire Astronomical Group.
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Re: First scope please help

Postby Bertiebones » Sun Dec 11, 2016 8:51 pm

Thank you, Aratus, that has been very enlightening! :) I notice from your signature, you have the scope that I ordered? And a pulsar observatory too! Envious...! :) Although a pulsar observatory wouldn't work in my small garden, even if light pollution is little uere and I will most likely use the scope occasionally in the garden. Shropshire Hills are 15 mins drive though :) Have you noticed anything particular to this scope from using it, that I should be aware of? Reviews very often are not quite as detailed as experience from long term use.

Gfamily2, thank you too for your invaluable info. Planisphere is duly noted down on the to-buy-list, as is a dew shield as mentioned before. I think i will also go for the moon filter on top of a 2x barlow. The former purely to be sure the moon isn't too bright to look at.

I still have one question that is more clear now having read both your replies. If I was to get one eyepiece, and I do fully accept the advice that an EP/filter kit may not be ideal (incidentally I noticed it provides a 40mm EP among other which comes with the scope anyway), which eyepiece would you suggest to buy? I am thinking predominantly not in terms of price (though ideally in the range of up to £200 (ish) max) but its versatility/usefulness. Obviously if one is great and costs £30, I'd be very happy.

Thank you again and I feel much indebted :)

Jake.

Thank you again for your advice and time,
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Re: First scope please help

Postby Bertiebones » Sun Dec 11, 2016 10:11 pm

Oh and get this book...
It'll give you lots of ideas about what to look for, as well as practical information about equipment etc.[/quote]

Thanks again! I definitely will. I was thinking along the lines of Astronomy for Dummies, but perhaps I can "upgrade" ;)
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Re: First scope please help

Postby Gfamily2 » Sun Dec 11, 2016 10:45 pm

I've only bought two EPs in recent years, so I'm not qualified to give a recommendation, but I would say that (with your 2x Barlow) something like a 30-32mm EP would fill the gaps between your two 'stock' EPs, and you should be able to find a quality EP well within your budget.

However, I would hold fire on buying that 'one' eyepiece until you've had a few months of experience with your new scope. Use the EPs that come with it and wait until you're familiar enough with it that you're beginning to say "I wish I could..." - you may find that you want more magnification, or a wider field of view, or a better 'middle power' view. As per the advice I heard above, "make the most of what you have before you buy the 'next' thing" - apart from a Barlow and a Planisphere of course :)
Scopes: Meade 8" SCT, Skywatcher 127mm Mak, Raffle winner of SW ST80
For imaging: Pentax K5, Asda webcam, Star Adventurer (new toy)
For companionship: Mid Cheshire Astronomical Group.
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Re: First scope please help

Postby Aratus » Sun Dec 11, 2016 11:55 pm

Gfamily2 wrote:I started this hours ago, so this may repeat quite a lot of what Aratus has said, but having written it... :)

I'm sorry about that. Great minds thinking alike ;)
Actually I think our respective replies compliment each other quite nicely, and there isn't much duplication. Besides it was expressed in different ways, which can be helpful.

Bertiebones wrote:Thank you, Aratus, that has been very enlightening! :) I notice from your signature, you have the scope that I ordered? And a pulsar observatory too! Envious...! :) Although a pulsar observatory wouldn't work in my small garden, even if light pollution is little uere and I will most likely use the scope occasionally in the garden. Shropshire Hills are 15 mins drive though :) Have you noticed anything particular to this scope from using it, that I should be aware of? Reviews very often are not quite as detailed as experience from long term use.

An 8" SCT is a pretty good all-round telescope. I’ve had mine 12 years now, and I’m still discovering new things, and using it in new ways. The Pulsar 2.2m observatory can be fitted into quite a small space, but of course the telescope is permanently in that place. I have taken the 8" out to remote places in the past without difficulty. A 12v ‘leisure battery’ like they use in caravans will more than power it and any accessories all night if required.
Problems with my shoulders meant I could no longer carry the telescope, so that is when I put it in an observatory. It’s allowed me to continue to observe so it was well worth it. It's pretty cool too. 8-)

Bertiebones wrote:I still have one question that is more clear now having read both your replies. If I was to get one eyepiece, and I do fully accept the advice that an EP/filter kit may not be ideal (incidentally I noticed it provides a 40mm EP among other which comes with the scope anyway), which eyepiece would you suggest to buy? I am thinking predominantly not in terms of price (though ideally in the range of up to £200 (ish) max) but its versatility/usefulness. Obviously if one is great and costs £30, I'd be very happy.

Well, as Gfamily2 has already said, the 2 eyepieces will give you magnifications of 51x and 156x, and a 2x barlow will give you 102x which fills that gap.
All I might add is that for good planetary conditions a 10mm eyepiece would yield a magnification of 203x which you might find useful for more detailed planetary work. An 8mm/254x eyepiece is an alternative. As Gfamily2 suggests, it isn't a priority at this stage.
I use an 11" Celestron SCT (CPC 1100) on an equatorial wedge, housed in a 2.2m Pulsar observatory. I use a ZWO ASI1600MC and Canon 500D for imaging.
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