Celestron 7-21 zoom eyepiece

[Krishnam kalra]

How will celestron 7-21 zoom ep work with my gso 6" f6 reflector ?

[RT65CB-SWL]

It should be ok. But bear in mind the field of view will get smaller as you increase the magnification. My 'unbranded'/AstroBoot 7-21mm zoom does - (photo below). I purchased it for 'grab & go' sessions. As I do shift work at LHR, I have not had the chance to use it on anything celestial yet since I received it. There are quality zoom eyepieces but they do come at a price. 

Primary eyepieces, i.e. those of a particular type (Plossl, WA, SWA, UWA etc... or fixed focal length), will be better for longer viewing sessions when you want to get as much detail when conditions allow.

[John]

It will work but the 8-24 zooms are generally of better quality.

[Krishnam kalra]

5 minutes ago, John said:

It will work but the 8-24 zooms are generally of better quality.

Should i go for fixed focal length ep like plossl or something or this celestron ep. The celestron one will be more economical as it is 4 element ep with multicoating . Im getting it for 5700 rs but a plossl ep is for 2700 rs . What is you review ?

[John]

Decent plossls like the Celestron Omni range will work better than a low cost zoom like the 7-21 one. The 8-24 zooms (eg: Skywatcher, Seben, Celestron etc) are better and provide decent performance. You would still need a high power eyepiece around 6mm focal length and a low power, wide angle one such as a 32mm plossl because the zoom will not cover those ends of observing.

 

[Louis D]

On 23/06/2018 at 13:17, Krishnam kalra said:

Should i go for fixed focal length ep like plossl or something or this celestron ep. The celestron one will be more economical as it is 4 element ep with multicoating . Im getting it for 5700 rs but a plossl ep is for 2700 rs . What is you review ?

5700 rs works out to 84 USD which is a lot to pay for this particular eyepiece.  It only costs $45 to $53 (3000 rs to 3600 rs) delivered here in the US.  I recommend checking around for an 8-24mm zoom for that kind of money.