First telescope, and it's cheap..

[Ericreichelt81]

So I got my girls a cheap scope for Xmas and I'm unsure how to make the best use of it. It's an f4.6. I'm starting to understand some about it needing higher quality eye pieces at this focal ratio. That being said, an adjustable zoom with be the simplest with two little ones wager to see. Is a zoom lens even an option on a scope this cheap? If not what's the solution to keep it simple and fun. I'm afraid I bought something so cheap it'll turn them off of the night sky. Thank you.

[vlaiv]

Hi and welcome to SGL.

Maybe best way to start would be to give us more info about the scope - maker and any markings on it?

I don't think that you should worry about F/ratio and eyepieces at cheap end of equipment prices. Eyepieces that people talk about that are well corrected in such fast scopes tend to be more expensive than cheap scopes themselves, so I'm guessing that is really not an option for you.

[Ericreichelt81]

Of course. It's a toyerbee 70mm aperture and 300mm focal length. I already have the next one in kind, an 8inch Dob. So ideally, if like to not buy eye pieces that won't carry over. In my mind, a decent zoom with an upgraded 2x barlow plus a quality 32mm wide angle might be enough. But I just don't know much about this really.

[vlaiv]

That sounds sensible. You won't find 32mm wide angle eyepiece in 1.25" format. Most you can get is around 50-52° AFOV with plossl (maybe you meant eyepiece for wide field observing and not necessarily wide apparent field of view eyepiece?).

Do be careful when selecting long focal length eyepiece for fast scope - at F/4.3 (70mm with FL of 300mm is ~F/4.3) you'll quickly get very large exit pupil and light will be wasted if your pupils don't dilate that much (some people say - well, a bit of light wasted, so what - and that is ok - but on reflectors there is issue with central obstruction - not so on refractors).

32mm plossl will give you exit pupil of 7.44mm and young people have pupils that dilate up to 7mm (sometimes even a bit more). Older can hit 6-6.5mm. Maybe go for EP up to 30mm?

Most people find this to be a decent zoom eyepiece:

https://www.firstlightoptics.com/ovl-eyepieces/hyperflex-72mm-215mm-eyepiece.html

this to be decent barlow

https://www.firstlightoptics.com/barlows/baader-classic-q-225x-barlow.html

here is decent 30mm 50° Plossl design:

https://www.firstlightoptics.com/vixen-eyepieces/vixen-npl-eyepieces.html

(select 30mm option)

 

[Ericreichelt81]

Thank you so much..do even though it's a shitty scope you think a zoom will give me a good image?

[Tiny Clanger]

Hi and welcome,

I've had a search for your 'scope, is it like this one ?

https://www.slinee.com/products/toyerbee-telescope

Before you do anything else, check that  the eyepieces are 1.25" diameter, which is the standard size of most reasonably priced ones .

I don't think that 'scope I linked to above has a mount which would make it easy to use for your children at higher magnifications.

[Louis D]

I bought another branding of that scope for $24 shipped last March off of ebay.  I've converted it into a 70mm superfinder with a 2" visual back for widest field views (9 degrees with a 40mm Pentax XW at 7.5x).

It uses 0.965" eyepieces, not 1.25" eyepieces.  Check the insertion barrel diameter of the supplied eyepieces on yours.

I has a ~35mm aperture stop just behind the 70mm objective, probably to improve image quality on such a fast objective.  I removed both the focuser and objective cell (three screws hold each in place) and used a small block of wood to push the stop out of the front of the tube.  It's just held in place by friction.  I then reblackened the interior because it got all scratched up by the plate being pushed out.

The focuser tube itself has another 50% by diameter aperture baffle that can't be easily removed, so buying wider field eyepieces may be of little use because they'll just vignette.

All that said, it makes a decent, low power spotting scope as delivered.  As I've redesigned it, it makes for an astoundingly good wide field finder.  It came with a pretty decently corrected 70mm f/4.3 achromatic doublet and metal tube that was worth the $24 alone.

[vlaiv]

If it indeed uses 0.965" and as I now pay more attention to details - it indeed does look like it - it won't be able to use regular eyepieces.

Alternative would be:

https://www.teleskop-express.de/shop/product_info.php/info/p6042_TS-Optics-45--Hybrid-Erecting-Prism---upright-and-correct-image---0-96-and-1-25-inch.html

but that still would not allow for 30-32mm plossl and highest FL eyepiece would probably be around 20mm (if 50° afov).

It makes more sense to get one of these instead:

https://www.firstlightoptics.com/startravel/skywatcher-mercury-705.html

or perhaps this one:

https://www.firstlightoptics.com/startravel/skywatcher-startravel-80-ota.html

and see how to mount it on photo tripod or similar.