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Alan

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There's a very interesting article on "Computerized Telescopes" in the latest Popular Mechanics
 
Crusader

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Kalvaer said:
Think we might of solved it. Claire posted about it on her blog and got a reply from somebody about it being a rare double shadow event, Still need to check the timing to confirm but here is a link about it: http://www.oneminuteastronomer.com/2009/08/25/double-shadow-jupiter/
Click to expand...

I stand by Callisto as the likely culprit. The double shadow event will only be visible tomorrow morning at around 5am. Callisto fits the time perfectly.

Did it look something like this? That's Callisto and Callisto's shadow at 20:55 pm.

Europa and Ganymede weren't in a position to cast a shadow on Jupiter last night. The other moon was Amalthea, but that's a tiny moon so it shouldn't have been visible.
 
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Kalvaer

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It does, just the were slightly further apart, Seeing really wasn't good though as mentioned, I couldn't see the GRS at all, though according to stellarium, it would of been on the edge anyway.... what are you using to see the shadows?
 
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Kalvaer

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Time to throw another spanner in the works.

I've marked the location of the black spots on this image below. Then I've also used Stellarium to show the exact same time and angle.. Callisto and its shadow, are on the wrong side ??

8252723.jpg


stellarium-000.png
 
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Kalvaer

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AllBrain said:
Now I am looking at another eyepiece. Either a high end 3mm wide-angle or a mid-range 8-24mm zoomer. What do you think?
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Hmm cant seem to see on the page for it, but whats the biggest lense size you can use? 1.25" or 2"
 
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Kalvaer

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Hmm was going to suggest something like a nice 32mm wife angle 2" :)

But personally I would go for the 3mm then, and only because I am not so sure about the zoom EP. The idea of the more parts there are to move the greater the chance of something going wrong.

The 3mm will be getting very close to your maximum limit. So you'll never be able to use it with the barlow. Something like a 5mm though would allow you to get 5mm and the 2.5mm max for your scope, but you already have a 10mm/5mm (with barlow) so yeah, tough choice.

Has anyone else tried the zoom eyepieces?
 
Crusader

Crusader

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Kalvaer said:
Time to throw another spanner in the works.

I've marked the location of the black spots on this image below. Then I've also used Stellarium to show the exact same time and angle.. Callisto and its shadow, are on the wrong side ??

8252723.jpg


stellarium-000.png
Click to expand...

Did you take the flipped image into account for a reflector telescope (you do have a Newt right). My image was as you would see with the eye so does not account for a flipped image.

Newts give a flipped horizontal and vertical image doing the same to the Stellarium image it seems to match up with your pic.

BTW: My images are from Starry Night which shows the shadows as well.
 
Crusader

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I've got the Skywatcher zoom and it's a good eyepiece. It performs quite well in the 8-18mm range, but the FoV gets too narrow above that, so a fixed focal length will provide better views. The main plus point for the zoom is the ease of use since you don't have to switch out EP's constantly. It's not parfocal and needs small adjustments when zooming in and out. It's quite a nice experience though going from one magnification to the next by only twisting the EP.

Obviously this is not a premium eyepiece but it does well enough for the price. Normally it's the only EP I use when I go for a quick session with my refractor and it does pretty well in the 10" as well.
 
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Kalvaer

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Crusader said:
Wife angle 2"? That must be a new version since I've never heard about it! :D
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Its an upgrade to Girlfriend V4 :D

With regards to the flipped image.. yeah. I flipped it in stellarium so that was in the same position as I was viewing it. Confirmed with other photos I took which show Europa and Io
 
Crusader

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Kalvaer said:
Its an upgrade to Girlfriend V4 :D

With regards to the flipped image.. yeah. I flipped it in stellarium so that was in the same position as I was viewing it. Confirmed with other photos I took which show Europa and Io
Click to expand...

Ok, so my image should have been flipped. Does it match then?
 
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Kalvaer

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Nope.. thats why I'm now confused. Your image is correct and shows the moon and the shadow in the same band as the GRS. The dots we saw are on the opposite band.

Starting to think it was dust :D
 
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Crusader

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Kalvaer said:
Nope.. thats why I'm now confused. Your image is correct and shows the moon and the shadow in the same band as the GRS. The does we saw are on the opposite band.

Starting to think it was dust :D
Click to expand...

From the image it looks like they are in the same band, but that could just be me...
 
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Kalvaer

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Check the image from Stellarium I posted. It shows Calisto in the same band as the GRS. Now yours is the same, But with the shadow of the moon, which is also in the same band.

What we saw last night though where black marks in the opposite band to the GRS.

I really need to get a T mount so its easier to image next time
 
mercurial

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Both eyepieces are good. I love the William Optics eyepieces though. Not only are they superb, but the eye-relief is orgasmic lol.
 
Crusader

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Kalvaer said:
Check the image from Stellarium I posted. It shows Calisto in the same band as the GRS. Now yours is the same, But with the shadow of the moon, which is also in the same band.

What we saw last night though where black marks in the opposite band to the GRS.

I really need to get a T mount so its easier to image next time
Click to expand...

Ah, now I understand. That beats me then. Absolutely no idea except dust on the EP... :rolleyes:
 
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