Telescope advice

Willid1

Willid1

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David Williams
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Not sure which setion to spost this in so I'll try here first.

Granddad wants to buy our youngest a telescope for Christmas as son 1 is very into space and planets, stars etc.

I have found this telescope - an Infinity 76P

1.jpg


Which has the following spec

Magnification: x30
Diameter of Primary Mirror: 76mm
Telescope Focal Length: 300mm (f/4)
Eyepieces Supplied: 30x Erecting* (Provides upright image for terrestrial use)
Parabolic Primary Mirror
Helical Focusing
Tabletop Cradle
Gift Box

But as I know nothing about telecsopes I'm looking for a bit of advice.

Mainly I'd like to know what that spec translates to in terms of what you can see. Can you see the major plansts structres (saturns rings etc) can you see deep space things like nebulae?? I have no idea.

The Sky at Night review after giving it 92% finished with "It’s sad to end on a bad note, but the helical focusing mechanism prevents the use of standard 1.25-inch eyepieces" - what does that mean??

Thanks in advance for any help.

David
 
Willid1 said:
Mainly I'd like to know what that spec translates to in terms of what you can see. Can you see the major plansts structres (saturns rings etc) can you see deep space things like nebulae?? I have no idea.
Click to expand...
A bit more info. It isn't necessarily magnification which is important, but aperture - just like photography. A 76mm is a 3 inch aperture and you'll probably be limited in what you can see. Yes, you will see Saturns rings and you may make out some details in Jupiter, but that will be about it. I wouldn't expect to see much detail in Mars for example. You will be able to make out a lot more detail in the moon though. As to nebulae, planetary nebulae will be a (very) small fuzzy object almost indistinguishable from a star without any colour whilst larger nebulae will be invisible. Galaxies (if you can see them) will be small fuzzy blobs. A lot will depend on your surrounding light pollution. The darker your skies, the more you will see, but don't expect it to look like the photos :)

Willid1 said:
The Sky at Night review after giving it 92% finished with "It’s sad to end on a bad note, but the helical focusing mechanism prevents the use of standard 1.25-inch eyepieces" - what does that mean??
Click to expand...
Normally, you change the magnification by changing the eyepiece. It sounds like you are limited to a single eyepiece with that 'scope as the focusing mechanism is a screw thread rather than a rack and pinion style focuser. Why does changing the eyepiece matter? Well, magnification is given by the formula telescope focal length/eyepiece focal length. Changing the eyepiece allows you to change the magnification. Standard 1.25" eyepieces can be had for very little, but they tend to be plastic and very limiting. Decent ones start at £20 which is half the cost of the 'scope, but go upwards from there on (you can get to L series lens prices for some eyepieces).

As to how much magnification, it's normally reckoned 20-30x per inch of aperture, so with the scope I pointed you at (assuming the one you mention can't change eyepieces), reckon on 60-90x as max magnification.

+1 on Stellarium. You might need to configure it to suit the processing power of the PC it runs on as it can be a CPU/GFX hog.

Hope that helps as a starter - ask any further Q's you might have :)
 
Thanks very much for all the info and advice.

I think the Skywatcher Heritage 76 Mini Dobsonian is a better bet, but will need very close supervision in use as my son can be a little bit "gung ho" where new things are concerned.

I like the idea that above scope has some capacity for improvement, but will have to be careful I don't end up on the "upgrade ladder" just like my photography equipment.

Sorry did I say "I" I meant to say "my son" :D

Thanks again

David
 
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