Newbie, the next step

[ccfcbob]

I have had for a few months a pair of old 10x50 binoculers which I have been using and thought I would take advantage of a recent birthday, so after researching online and reading various reviews received Celestron  Astromaster 70AZ. I am aware that this is not up to the standard of the hubble but looked a good introduction without having to spend the earth on one.

I have downloaded 'the night sky' app for my tablet which has been a great help and 'turn left at orion' has been ordered.

I am comfy using this telescope now and I am interested in any help moving forward now.

Santa at this time is asking questions so do I take advantage of him? There is a Celestron 94303 Eye piece and filter kit on amazon at £120, is this worth it? I have looked at cheaper eyepiece kits but some have received a bit of a hammering in reviews.

I am very lucky in my area as the local council now switch off the lights at midnight so viewing is much better than it would be otherwise.

 

[bingevader]

As far as eyepiece kits go, it seems to be a reasonably good one.

However, other than the moon filter, the other filters aren't likely to get much use.

The eyepieces are Super Plossls, and so pretty good in themselves. But you do need to bear in mind that for the smaller focal length eyepieces the eye relief will be quite short.

The 32mm seems to be well respected.

You won't get 5 plossls for the same money elsewhere (but then Amazon probably haven't paid any tax on them!  )

The only other consideration is your upgrade path! If you are happy with the 'scope and unlikely to change it soon, then go ahead. If you have other plans, then it might be worth looking at individual eyepieces that would be an upgrade now and transferable to a different 'scope.

Cheers

[Charic]

........... Celestron  Astromaster 70AZ. I am aware that this is not up to the standard of the hubble but looked a good introduction without having to spend the earth on one.........

.

I am comfy using this telescope now and I am interested in any help moving forward now.

Santa at this time is asking questions so do I take advantage of him? There is a Celestron 94303 Eye piece and filter kit on amazon at £120, is this worth it? I have looked at cheaper eyepiece kits but some have received a bit of a hammering in reviews.

I am very lucky in my area as the local council now switch off the lights at midnight so viewing is much better than it would be otherwise.

 

ccfcbob...........The Celestron 94303 Eye piece / filter kit seems good value for the bargain minded, introducing you to a wider range of focal lengths. 

H o w e v e r ! I agree with bingevader,  the 6mm and 8mm, will be difficult to view through because of their minimal eye relief and tiny field lenses. The other focal lengths include 13mm, 17mm and 32mm. The telescope supplied lens of 10mm would benefit from a better quality lens. This may improve your image slightly, but at the limitation of the telescope. Celestron say that your scope is capable of 165x power ( not easy to achieve ) I would consider just purchasing One, maybe Two lenses. Try and see.  Can you visit an astronomy club, just to try a lens in your telescope. (Dont try their telescopes, iT`ll cost you even more to upgrade?) Sky`s_unlimited will sell you a lens or two. you have to pay up front, but can send them back if their not suitable for you (within two weeks I believe) So if you bought two lens to compare the original lenses, ie a 12mm and 25mm @ £98 and you dont like one, it goes back and you get your £49 back. I think most here who get serious with the subject would suggest leave the kits, learn about the lens types, pick your price range and proceed from there. My choice of two lense would be the BST 12mm and 25MM. That would allow you to see the difference in lens quality, and you could always send one back, maybe try another.  But a 12mm would be fine. keep using the binoculars too, don't discard them. Might seem strange paying £98 just for two lenses when you can buy a complete kit for £120. Thats your choice. The price difference is all about the quality?  Check here http://stargazerslounge.com/topic/43171-eyepieces-the-very-least-you-need/  and here http://www.swindonstargazers.com/beginners/eyepieces.htm

[Qualia]

Your 70mm almost f/13 will make a lovely little grab and go on lunar and planetary work. Skies permitting, you'll also be able to pick out a good number of Messier objects and if you got some Baader Solar Film and made yourself a really secure solar filter, you'd also have a cracking white light telescope from which to view the Sun.

Regarding the eyepiece kit, personally speaking I'd recommend specific targeting of your eyepiece selection. You can then add additional eyepieces as and when you can afford them, or feel it is necessary.

There are two general rules of thumb regarding magnification which pretty much end up saying the same thing. The first is that the maximum reasonable magnification is twice the aperture size in millimetres, giving your scope a maximum power of around 140x. The second rule states that it is advisable not to exceed the rule of 50x per inch, and that most times you may well only achieve 25x to 30x per inch. Your scope is about 2.8 inches, which in this case indicates a maximum magnification of around 140x but to expect more often about 70x to 84x.

With this is mind, I'd be looking at four eyepieces maximum.

20mm - 45x - low power.

15mm - 60x - low mid range.

9mm - 100x - high mid range.

7mm - 130x - high power.

I imagine the 70mm has already been supplied with a 20mm and a 10mm eyepiece, so you're pretty much done for now. You may want to consider buying just one eyepiece for now to play around with. Either the maximum higher end, maybe something like a 7mm which will give you around 130x, or a lower power mid range around 15mm giving you 60x.

Such a set up will provide you with nice clear crisp views of the Moon, Star Clusters, single and many double Stars, quite basic views of Jupiter and Saturn, and great for browsing the night sky and larger, brighter deep space objects, many of which will appear like small, fluffy, grey ghost clouds, for example.

But with all this said, there really is no hurry to go out buying new eyepieces. Keep on posting and making enquries at SGL and you'll soon reach 50 posts, from there you'll be able to view the secondhand market taking place here at SGL. In the mean time, appraise and praise your gear. See what kind of things you like looking at, what gives you a buzz and work out what you feel might be missing from your kit. In the end, you'll have a much better idea of where you want to go and how you're going to get there. For example, you may decide that after a month or so, rather than buy new eyepieces for the f/13, you may in fact want to use that money towards a larger aperture telescope. Or you may feel you need a better finder, and so on.

Other than this advice, download Stellarium, get yourself a decent star atlas like that by Sky and Telescope, and check out sketches to see the kind of thing you'll likely to see with a telescope of your size.

Hope this helped a little and please don't stop asking questions

[breezy]

Fantastic advice given mate, I would just say that getting to know your scope and taking time with what you have is a good idea. Its really easy to get sucked into spangly new bits and go on a spendathon..... Cough cough

[Gomtuu]

Its really easy to get sucked into spangly new bits and go on a spendathon..... Cough cough

*whistles innocently*

[ccfcbob]

Thanks for the advice. This now has given me something to think about. I already have a moon filter (which I should have mentioned) so the fact that i'm getting another + with the other filters in this kit I would not use any of them due to the power of my scope. It would then make part of the kit a waste.

When using 10mm lens which I currently have I am finding that things disappear fast out of sight at the minute so it could be then the 6 & 8mm lenses it would be now you see me now you don't. So maybe a bit pointless at the minute then. The 20mm gives plenty of time to view. So i need to consider then is it worth paying £120 for 3 lenses, a barlow lense & a good solid case.

Regarding upgrades, this is something I haven't realistically thought about yet. I want to be able to find my way around 1st so it may be 12 months before I think about it. I may otherwise end up spending £250-300 on something that isnt suitable. The bonus is if I do purchase extra lenses they can be used in different scopes.

There are a couple of clubs in my area but 1 seems to be sitting in a church hall talking about it & the other meets on a Saturday which isnt good for me 30 or so miles away.

It is frustrating at the minute when you get good views of Jupitar and want to see better. I can't imagine getting bored of watching that, not sure what the technical term is but 1st time I got a good sighting it was definalty a 'wow thats mental moment!'. Far to easy to spend money on better lenses only to get disappointed if I don't get vews i'm after or see others getting.

[Charic]

ccfcbob...........thats the problem with higher magnifications (lower focal length number on eyepiece) As the magnification increases, then  the image gets slightly darker, and you lose the space around what your looking at, so you have to track and follow much quicker with the telescope. To correct that issue, you need to go to a low power lens (higher focal number) which gives a brighter wider view, but now at the loss of some magnification, so Jupiter may lose its detailed features.  So smaller number, higher magnification, less width of view, bigger number, wider brighter views (and less speed across the viewfinder). If / when you upgrade your telescope take note of the aperture. Take two boats with holes in their hulls, the one with a bigger hole sinks faster. Like wise two telescopes with different apertures, the one with the bigger aperture gathers more light. More light capture,see`s fainter objects, giving larger brighter detailed images, so larger extended features like Andromeda require low power lenses  to capture the whole vista, especially from a nice dark site. The lenses you get now, if chosen wisely, will survive not only this telescope, but telescopes to come? When the time does come, and for visual only observing, I would highly recommend an 8" reflector telescope on a Dobsonian mount for ease and simplicity of operation.

[ccfcbob]

I'm sure its not this simple but as I see it, if I purchase a barlow lense it would increase the magnification of selected lense but still maintain the field of vision?

Also may sound a daft question but when you have been out in a evening and bring the scope in it will obviously have a lot of condensation when its cold. Is it better to leave everything to adjust to room temperature before putting things away or ok just to put lenses away and caps on the scope

[Charic]

..........almost.  A Barlow effectivlely increases the focal length of the telescope only, as seen by the lens. If your using an 8mm lens, then insert a Barlow, your still using an 8mm lens. However the focal length of the telescope has changed by the amplification of the Barlow. In my case I have a telescope focal length of 1200mm using an 8mm EP gives me 150x magnification. Now same setup but including the 2XBarlow, my focal length is now 2400mm divided by the 8mm now gives 300xMagnification.  As the magnification increases the image gets slightly smaller and slightly darker. The AFOV (affective field of view) of my lenses are 60` degrees. That sound a lot, but once in the telescope, its changed again by the result of the TFOV (true field of view) this is determined by dividing the AFOV by the MAGNIFICATION in use. so for my 2xBarlow, my TFOV equates to  0.2 degrees against 0.4` degrees without Barlow. I hope this is confusing enough? lol

[Charic]

..............forgot the cooling..........I leave my telescope end cap exposed with just a plastic sheet laid over the 45`degree scope to prevent anything in the air settling on the scope. If it looks dry, then I put it away. (away is the same heavy duty plastic sheeting that I have created into a sack that goes over the telescope. i`m not sure the kitchen is the best place to keep a telescope, once you`ve seen the mess on tops off cupboards from the processes  of cooking?)

[Charic]

( the image gets slightly smaller and slightly darker)...... I said ? let me try again!  The image is magnified because your using a lower focal length, higher power  eyepiece, so the image, maybe the Moon, will  fill your viewfinder image, with maybe little or no border of space around it, so yes your field of vision will be slightly different, whereas at 18mm you see the Moon and surrounds, but at 5mm You only see the crater. So to some extent the fields of vision will change. Eye relief, thi distance from the lens to your eye is maintained, if not increased in some situations. (trying to  explain in simple terms here)

[ccfcbob]

..........almost.  A Barlow effectivlely increases the focal length of the telescope only, as seen by the lens. If your using an 8mm lens, then insert a Barlow, your still using an 8mm lens. However the focal length of the telescope has changed by the amplification of the Barlow. In my case I have a telescope focal length of 1200mm using an 8mm EP gives me 150x magnification. Now same setup but including the 2XBarlow, my focal length is now 2400mm divided by the 8mm now gives 300xMagnification.  As the magnification increases the image gets slightly smaller and slightly darker. The AFOV (affective field of view) of my lenses are 60` degrees. That sound a lot, but once in the telescope, its changed again by the result of the TFOV (true field of view) this is determined by dividing the AFOV by the MAGNIFICATION in use. so for my 2xBarlow, my TFOV equates to  0.2 degrees against 0.4` degrees without Barlow. I hope this is confusing enough? lol

needed to read a couple of times but think I follow....