how low can i go go

[usher4566]

Hi ime looking at geting a new eyepiece what i wanted to no is on the meade etx 80 how low can i go ?

[knobby]

Hi

I had the etx 70 for a while and found about 100 x was all it would take, the 70 is only 350 mm and yours is 400 mm so I'd guess somewhere around 120 x which would mean a 4 mm EP or maybe an 8 mm and a Barlow ( does the 80 ave one built in ? ) might be more useful.

Google ' weasner ' he's mad about ETX's

Good luck

Edit : heres a good link

http://www.cloudynights.com/item.php?item_id=1597

[malc-c]

As stated on your other thread. Magnification is a result of eyepiece focal length divided into the telescope focal length. Once you go below 4mm the cost of specialist eyepieces such as Nagler and you will be paying upwards of £200 or more. Your ETX80 has a focal length of 400mm, so a 2mm eyepiece would give a theoretical magnification of 200x, but this would not be practical on such a scope as the 3" aperture would not let enough light in to give a bright resolved image full of any detail

[Moonshane]

are you talking low power (magnification) or low eyepiece focal length?

[usher4566]

Ime all confussed sorry ime new to this .ive got a etx 80 and am looking at geting best out of it .what eyepiece should i go for .? Sorry about my lack of knolage i undersrand a bit .

[usher4566]

Has built in barlow .

[malc-c]

To be honest, the ETX80 is a small travel type scope that has a practical observing power of 150x if you read the blurb on the advertising. IMO it would be more suited for low power wide field views of bright nebula like the Orion nebula, the Moon, and large bright galaxies line M31 (Andromeda). Trying to use barlows, and high power eyepieces is not going to get the best out of such a scope. You have to realize that each scope will have it's practical limits in terms of performance. Taking things beyond this limit will not always give better results.

[usher4566]

To be honest, the ETX80 is a small travel type scope that has a practical observing power of 150x if you read the blurb on the advertising. IMO it would be more suited for low power wide field views of bright nebula like the Orion nebula, the Moon, and large bright galaxies line M31 (Andromeda). Trying to use barlows, and high poweyepieces is not going to get the best out of such a scope. You have to realize that each scope will have it's practical limits in terms of performance. Taking things beyond this limit will not always give better results.

ok many thanks i understand just wanted to see juipter a bit bigger than a dot could my other scope 2090 refracter do this .? Also can you recomend a good all round scope .not keen on having a big tube

[ronin]

If you decide on a 4mm eyepiece then avoid the plossl's, you will have to get that close that they end up like a contact lens, most find one uncomfortable. An 8mm with the barlow may be usable but I would doubt the qualty of the barlow. So what you get as an image may be poor.

At the 4mm range and in the budget area there is the TMB clones from Skies the Limit, not sure how good they would be on your scope, but they should be fair and wil have decent eye relief.

Jupiter should be reasonable at 80x with a 5mm eyepiece, would suggest the BST 5mm for this.

[bingevader]

I've the etx 90.

I have a 9.7mm super plossl which is great.

However, even on the darkest, clearest, steadiest nights I'm lucky to resolve anything other than the moon in sharp focus with the barlow x2 added.

But then I happen to like fuzzy blobs!

Cheers

[ronin]

The ETX-90 is a Mak at f/13.8, the ETX-80 is a refractor at f/5.

There is so little similarity between the 2 scopes that comparison across them is difficult if not impossible.