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Old 12-05-2021, 07:21 PM
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AG Hybrid (Adrian)
A Friendly Nyctophiliac

AG Hybrid is offline
 
Join Date: Nov 2009
Location: Toongabbie, NSW
Posts: 1,526
Quote:
Originally Posted by gregbradley View Post
4. Pentax - expensive, field of view is less at 62 degrees like a Panoptic or TV Delite but optically pretty perfect. 5, 7 and 10mm are the ones. The 30 and 40mm are also regarded highly. The 14 and 20 not so much.

8. Zooms often make top 10 favourites. Top of those is the Nagler.
The latest Baader 7-24 is another popular choice.
Pentax XW - which I assume your talking about, is 70 degrees sensibly identical to the delos. The Nagler zoom is 3-6mm and really far from a top choice with its 50 degree field of view and its enormous 10mm of eye relief all for the low low price of $650. Its going to get its max use with a short focal length refractor like a TV85 or TV60. But a 150mm F8. Its zoom range will be mostly unusable.



To the original poster.


You live just up the road from me in Blacktown so I know the light pollution is a problem. So unless you plan on going to a dark sky regularly. Don't get a 42mm as mentioned earlier your sky background will be completely washed out. What you really want is something that will help with contrast - making the sky background darker while increasing the image scale of your targets. Its surprising how many globular clusters you'll be able to see this time of year if your clever, as an example deep sky object from western Sydney. This can be helped with eyepiece exit pupil management. The best way to do that is with eyepiece focal length. The other option of course is using a different telescope with a longer focal length, but its still reliant on eyepiece choice.

Now what kind of exit pupil is useful? Its been noted,reported or documented by the most experience observers that 2mm is about the sweet spot between image surface brightness, resolution and contrast - in particular for deep sky observing. But, in the case of light pollution - less is more. I try to get around to 1mm when observing most things from home. More magnification, darker sky background. Its actually quite complex and clarity in the matter only really comes with experience and what you want to observe. But I am keeping it simple.

If I was to start my visual observation journey back to like 12 years ago. I wish I could have started out with a Baader Hyperion Zoom. My first scope was also 150mm Newtonian. In the case of yours however. The zoom will give you a magnification range 50x(24mm) to 150x(8mm). That gives you an exit pupil range from 3.1mm to 1mm. Ideal really. It's even a 1.25" barrel so no problems with a focuser upgrade.

The downside is of course its they are a bit over double your budget. I mean you do get 17 different focal lengths though.

If the Baader is too rich consider Orion E-Series 7-21mm Zoom Eyepiece. Its within your budget and I read not bad.




Word of advice though. Eyepieces are addictive.

Last edited by AG Hybrid; 12-05-2021 at 07:35 PM.
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