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21-12-2020, 11:33   #1
bogwalrus
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Recommend eyepieces

Hi there. I recently picked up a celestron Omni XLT 127 Telescope. It comes with a 25mm lens and was thinking of getting a few extra bits with the goal of hopefully seeing Saturn's rings and clouds on Jupiter, possibly some galaxies etc.

My thoughts were to get a x 2 Barlow lens but not sure what mm sized eyepiece to get. I know there is some calculation you can do with focal length etc but said I would just ask here in case I miss some detail.

Also I wear glasses myself so is there some brands of eyepieces that are best for people who wear glasses?

Any suggestions would be much appreciated,

Boggy
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23-12-2020, 11:44   #2
Jaden
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It's an opened question. Peek about on Donedeal or Adverts for cheap 2nd hand eyepeices.

The XLT is a 1.25 diameter, and these are generally cheaper. The high end pieces are worth the money for a better view, but can end up costing more than the telescope. I have a sybony plossel 6mm which is about 45 euros on Amazon, and is nearly as good as my 130 euro Meade 5.5mm - there is a difference to be sure, but it is x3 difference? That's a subjective point.

Myself, I have a Celestron 130 and a Skywatcher 250, so I try to get lenses that suit both, with a bias to the bugger bucket.

8mm-15mm range is where my sweet spot is, although I have 4mm to 36mm in my box.

If you don't have a collimation piece, get that first. Barlows are a good idea, but get a good one
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23-12-2020, 19:54   #3
bogwalrus
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Thanks.

Yeah I was trying to understand what the differences are with the cheap and expensive eyepieces. I suppose build quality but there are some pricy ones out there.

I have a 2x barlow, a 6mm and 12.5mm in my amazon basket. The eye pieces have a high enough eyelid so should be OK to use with my glasses on. I could not tell if the barlow has two lenses as most barlows on amazon did not specify.

Since the telescope i have is an sct I was not sure if a collimator would work well. I watchd a few videos on how to collimate without a Cheshire so hopefully that will work out fine.

It will be some trial and error I suppose.
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26-12-2020, 21:03   #4
Popoutman
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The more expensive eyepieces generally have:
  • Higher quality manufacturing with closer tolerances and better fit.
  • Sometimes, waterproofing.
  • Better polish and finish on the glass lenses
  • More exotic glass types for better colour control
  • More likely to be parfocal with other eyepieces in the same range.
  • Glass lenses instead of the plastic in the cheapest eyepieces.
  • Wider fields of view when looking through.
  • More eye relief - no need to smush the eyelids against the cold metal or rubbing eyelash oil onto the glass.
  • Better colour correction for things not dead-centre - no coloured seagull smears of stars near the edge.
  • Better handling of the steep light cones coming in from low focal ratio telescopes; this is often the biggest advantage.
  • Higher cost and better warranty terms.
  • (up for debate) Better visual design

The calculation the OP was looking for, was the focal length of the telescope divided by the focal length of the eyepiece, gives the magnification. You can see this when plugging in numbers and examples into https://astronomy.tools/calculators/field_of_view/
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