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Ceph and Cass

Visual observation issues -beginner


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7 hours ago, Ratlet said:

The zooms are okay, but be aware that they often have a fairly narrow fov and some aren't true parafocal and will require focus adjustment as you change the zoom.  I got an svbony 8-24mm.  Not sure it works well in my F5 newt,

I'm assuming, your 8" Dob has a focal length of 1000 mm (focal ratio F = 5) or, more probably, 1200 mm (focal ratio F=6). My Seben Zoom 8-24 mmf (seems to be absolutely identical with the Astromania zoom pictured above - even the slightly out-of-time plastic package!) works quite well with both of my F=5 Dobs (5.1" and 12"). It's lightweight and gets into focus with both scopes; good for grab-and go- situations. Add a Baader Turret Barlow 2.25x, and keep your 30 mmf, that's all you need.

Stephan

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2 hours ago, Nyctimene said:

I'm assuming, your 8" Dob has a focal length of 1000 mm (focal ratio F = 5) or, more probably, 1200 mm (focal ratio F=6). My Seben Zoom 8-24 mmf (seems to be absolutely identical with the Astromania zoom pictured above - even the slightly out-of-time plastic package!) works quite well with both of my F=5 Dobs (5.1" and 12"). It's lightweight and gets into focus with both scopes; good for grab-and go- situations. Add a Baader Turret Barlow 2.25x, and keep your 30 mmf, that's all you need.

Stephan

Nah mate, 130pds so 650mm focal length.  Svbony 8-24mm was giving fairly ratty looking stars, swapped to the 32mm Plossl and it was pinpoint. Only tried it the once though so it's possible there was some condensation on the lens or maybe not seated properly.  Still got to do some more testing once I get some clear skies again.  Will test it on the mak127 too.

Think the svbony 8-24mm is a different design possibly to the astromania one.  Certainly looks that way and wouldn't describe it as light lol.  

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On 06/08/2022 at 15:16, thestargaze said:

Can you recommend a video or some instruction with pictures for collimating with the cap? I don’t have an laser

Here you are my friend.

 

 

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On 07/08/2022 at 18:13, Ratlet said:

Nah mate, 130pds so 650mm focal length.  Svbony 8-24mm was giving fairly ratty looking stars, swapped to the 32mm Plossl and it was pinpoint. Only tried it the once though so it's possible there was some condensation on the lens or maybe not seated properly.  Still got to do some more testing once I get some clear skies again.  Will test it on the mak127 too.

Think the svbony 8-24mm is a different design possibly to the astromania one.  Certainly looks that way and wouldn't describe it as light lol.  

I'm just going to post a follow up to my earlier criticism.  The 8-24mm works fine.  It's really nice to use, although a little stiff.   I'm pretty certain the rubbish SW extension had inducsed an amount of tilt into things and caused the problems.

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