Newbie question concerning eye pieces

[Lucasj34]

I just got my first telescope. Celestron astromaster 130eq. It came with a 20mm eye piece. Looking at Jupiter tonight and it is very clear however it is small in the eye piece. If i get a better eyepiece like a 6mm will it be larger in the eyepiece? My eyes aren't the best so need all the help I can get.

Thanks Lucas

[Grogfish]

Sounds like you had a enjoyable first astronomy session - that's great to hear!

Yes, a shorter focal length eyepiece will provide more magnification, so Jupiter will appear larger. However, they are generally speaking more difficult to use because they have shorter eye relief (you have to get your eye closer to the glass - an issue particularly if you wear glasses while viewing), a smaller exit pupil (the piece of glass you're looking through is smaller), and the increased magnification will show any imperfections in your telescope's optics.

I've not used the Astromaster, but I'd be tempted to get a 10mm or 9mm to start with before going any shorter, and work from there. Expect to pay around £25-30 for a standard Plossl from a brand like Celestron - which is probably a reasonable place to start.

Good luck with your new hobby!

[ronl]

Try this link http://www.swindonstargazers.com/beginners/eyepieces.htm it's a very good guide 

to eyepieces, it will give you an idea about the price and how they perform,

8 or 9 mm will probably be the lowest mag you will get down to, after that

you will loose any detail, and the longer you observe the better the view

gets, it all depends on the seeing anyway, so good luck and keep enjoying

your scope. 

[ronin]

In the 6mm options the William Optics 6mm planetary gets good reports.

If 7mm was adaquate then perhaps the Celestron X-Cel.

Not sure how well the 5mm X-Cel would perform it might deliver a bit too much magnification.

Sugges that you avoid the plossl options, the eye relief on those at the short focal lengths is not good and saying:

"My eyes aren't the best so need all the help I can get."

Makes me suspect you could wear glasses and if so you need 15mm or more of eye relief. Plossl's will not have that and the WO and X-Cel's will have.

Jupiter will never be big, as in filling the eyepiece, sorry but it is a planet and is a long way off from the earth. Also looking at a Jupiter that is "big" but is a fuzzy disc with a couple of fuzzy bands is not as good as a smaller disk that is sharp and has 4 viusible and sharp bands.

[Lucasj34]

Thanks for the help everyone. I wear contacts so I can get right on the eyepiece. I agree the longer I viewed the planet the better it got! Just wanting to increase the viewing size without getting a new scope already lol. That will be in a few years!

[SpaceWalker]

Most important thing for successful planetary observations is the seeing, when the atmosphere is most stable. For DSOs the transparency is more important. Go to Clear Sky Charts choose observatory closest to you and  keep tracking the observing conditions. When the seeing forecast is good (e.g. 3+ out of 5) your chances to get nice, sharp  views of planets are usually the best. Of course, keep in mind that it's a prediction, so I always recommend using   the Pickering Seeing Scale to estimate the actual  seeing conditions. For example, if the atmosphere is unstable (6 points or less) I don't waste my time  for Jupiter since the views will be blurry with minimum details available. What can be useful in getting more contrast is a filter like the Baader Moon & Sky Glow, works good on Jupiter and Mars.

For high power observations your scope collimation is also very important. Always check your collimation before observing. Allow enough cooling time, I guess your scope will need at least 30 min outside before you start your session.

IMO, you'll need for planetary observations eyepiece(s) like ~5-7mm FL. If you specifically want the 6mm, I'd recommend this Zhumell Planetary, it's the cheapest LER available now, a rebrand of WO SPL , Orion Edge-On and other LERs all made by Long Perng for a variety of vendors. Excellent eyepieces, sharp to the edge, ~55*AFOV. If you decide on it than harry up, they have already sold out the 5mm and the 9mm focal lengths and the cheapest available rebrand is the Orion Edge-On at $100+.

I also would recommend you looking into better eyepieces than just plain plossls, for example Zhumell Planetary (55*AFOV), Agena Starguider ED/AT Paradigm, Celestron X-Cel LX or Meade HD-60 (all 60*AFOV). If you get  a decent 1.5x/2x Barlow like this GSO 1.25"  2x  it'll convert each your eyepiece into three so you'll have a chance to save a lot of money on eyepieces. For example, just 2 eyepieces, like the 25mm and 9mm  Celestron X-Cel LX with that GSO Barlow will give you the 25mm, 16.7mm, 12.5mm, 9mm, 6mm and 4.5mm. This eyepiece collection will cover most of your needs. You can buy just one eyepiece at a time. For example, you are interested in planets, so get the Barlow and the 9mm Celestron X-Cel LX and you have at least 2 planetary eyepieces and your 20mm stock eyepiece with the 1.5x barlow element screwed into it gives the ~13mm eyepiece etc.

If you will want reading more about the eyepiece selection I can recommend you next articles

HOW TO SELECT AN EYEPIECE

Eyepieces - the very least you need

Choosing the Right Eyepieces

choosing eyepieces

Good luck.

[Lucasj34]

Thanks for the info! I just ordered a x-cel 5mm waiting to get it later this week. I do need to do the collumation but I'm nervous about that because I don't want to really jack things up. Jupiter was super clear when I looked at it a few days ago just small in the eye piece.

[Lucasj34]

Thanks for the info! I just ordered a x-cel 5mm waiting to get it later this week. I do need to do the collumation but I'm nervous about that because I don't want to really jack things up. Jupiter was super clear when I looked at it a few days ago just small in the eye piece.

[SpaceWalker]

Congrats on your new eyepiece! I'm sure you'll like the views of Jupiter when the atmosphere supports that magnification (25x/inch).
 
IMO, Jupiter was clear when you observed it through your 20mm eyepiece fist of all due to low (37x) magnification. When you start using your new 5mm X-Cel LX you'll get to know what means poor seeing or when collimation is off. When the collimation is off it doesn't affect too much low power DSO views unlike high magnifications. In fact, you need a set of magnifications (eyepieces) to have some room to back off when the seeing doesn't support the 130x provided by the 5mm X-Cel LX, that's why longer focal length eyepieces and a Barlow can be useful.
 
Actually, you shouldn't worry about the collimation, but you should check it every time before your session. If the collimation is good you shouldn't do anything, e.g. my Dob holds it pretty good and even long trips on the roof of my car in cargo bin from Maryland to Florida and back usually don't disturb it at all. There are a lot of videos on YouTube how to collimate Newtonian, check them out, it's not a rocket science .  You may also check out few basic references on collimation I've attached below 
 
Collimation Tools: What You Need & What You Don’t
How To Align Your Newtonian Reflector Telescope
A Simple Guide to Collimating a Newtonian Reflector
Collimating a Newtonian Reflector
Barlowed Laser Collimation Made Easy
Collimation of Newtonian (Skywatcher 200p)

[Charic]

I still have a Celestron 127EQ Powerseeker, and even with better eyepieces, the image/view  is  poor in detail AND size,  which I give full blame to the telescope itself.

With the same EP's on my 8" Skyliner, I  see a   brighter and more detailed image when viewing  Jupiter. I still want a  bigger image, which can be obtained from ( as you suggest ) using a higher magnification, but there comes a limit to how much magnification you can use, without further loosing details  when magnification is  exceeded?

To be honest, I think what I need next to achieve the desired result is to sell the 8" and invest in a 12" telescope. More aperture for me equals more light giving more detail, and a  better  image scale (size)  at the eyepiece, notwithstanding the usual restrictions that apply to astronomy?

[badhex]

Hi Lucas

Welcome to the world of astronomy, glad you had a good first observing session.

In terms of choosing a good set of eyepieces without breaking the bank, I can heartily recommend the second article Spacewalker linked (Eyepieces - the very least you'll need) along with Robin Wilkeys tutorial - the Swindon Stargazers link that ronl posted.

They are both excellent articles and will give you lots of good tips and background knowledge of different styles and focal lengths of eyepieces.

Of course, there will always be lots of people on SGL who can give you excellent feedback if you have further questions!

Enjoy your new hobby!