Jupiter tonight

[steve-pinney]

People what ever magic you have use it! We need clear skies tonight. Scope is out on the patio.

What are you going to use to see Jupiter tonight?

[steve-fung]

Oh, I don't have the large scopes like some fine HAS folks, but I will be bringing out my largest scope C6 SCT (kinda sad), 8-24 mm eyepiece, and 2x Barlow. Maybe some eyepiece projection AP if seeing is agreeable. Houston Clear Sky Chart is showing a short window of relatively clear skies around midnight, but seeing doesn't seem too hot.


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[steve-fung]

It was clear skies, and seeing was fairly good as we got to midnight, so I took some quick videos just to document the opposition event. Jupiter was much brighter compared to even a few weeks ago during the triple shadow transit, and it was beautiful to see all four Galilean moons - Io, Europa, Ganymede, and Callisto - all lined up in a row to one side of Jupiter. Thanks to BillF's great lecture on Observing Jupiter just a few hours before made me appreciate all the details of the Jovian atmosphere. Now my daughter and I know the names of the cloud bands, their wind directions, and how to tell cyclones from anticyclones depending on their color. This is about as good of an image I could get pushing my little C6 SCT with 8 mm eyepiece projection.

2015.02.06 Jupiter DSC_9883c stacked wavelet ps.png

[stephen-jones]

It's amazing that you can get such great images with only a 6" these days. Great shot, Steve!

[richard-hind]

Awesome photo


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[steve-fung]

Thanks Steve, Richard. Actually, thank goodness for RegiStax. The hard part is in deciding how much wavelet transform to apply and not make the image look artificial with artifacts.


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[steve-pinney]

Really nice shot, eyepiece projection? Using a camera to take a picture through the eyepiece, yes? what were you using to photograph it with?

[steve-fung]

Yeah, I know - most people would recommend negative projection with a variable Barlow lens to get decent magnification for planetary AP. However, I've been experimenting with positive (eyepiece) projection, which also gives fairly high magnification if I use short focal length eyepieces. The three eyepieces I use most often are Baader Hyperions (8-24 mm zoom, 21 mm, and 36 mm), which have a M43 thread at the end of the eyepiece. This allows one to directly couple a camera body with a M43/T2 adapter system, i.e.

http://www.baader-planetarium.de/com/pdf/hyperion_brief_description_e.pdf

In my setup, I use a M43/T2 adapter ring attached to a Baader T2 Quick Changer system that is attached to a Nikon T-Ring to couple my Nikon D800 body to the eyepiece. To calculate projection magnification, I use the formula

Projection magnification = (A-F)/F
Effective focal length = telescope focal length x projection magnification
Effective f-ratio = telescope f-ratio x projection magnification

where A = distance between eyepiece and camera sensor (72 mm in my setup) and F = eyepiece focal length. So with an 8-mm eyepiece, I get a respectable 8x projection magnification, and my C6 f/10, 1500mm-FL SCT becomes a f/80, 12000mm-FL system. With an additional 2x Barlow in front of the eyepiece, I can in theory get something ridiculous like 17x projection magnification, and my C6 becomes f/170, 25500mm-FL system, but I never get anything worthwhile seeing.

BTW, I got all my Baader equipment from Alpine Astronomical, and Bob Luffel has always been very helpful and prompt with answering questions.

[steve-pinney]

Yeah, I know - . . . .

Lol! I know you know, its a great shot, I was just making sure I knew what it was.

I have 2 Hyperions 8mm and 21mm (awesome eyepieces and great price) never tried what you did. great info I think I have all the pieces to hook my Canon up.

How do you like the zoom? I am always a little nervous about zoom lenses.

[steve-fung]

Sorry, I did not mean to write so much, but I do that sometimes when passionate about a subject. Yes, I give high recommendations for the Baader Mark III zoom eyepiece. Before making my purchase, I was fortunate to examine the eyepiece in detail when visiting a friend living in Davis CA. Like all Hyperions, it is very solidly built with smooth but clearly defined click action at 8, 12, 16, 20, and 24 mm intervals. Images appear sharp with good contrast across the entire field of view, which appears flat and without significant distortion or aberration - at least to my amateur eyes on f/6.3-10 scopes tested. At short focal length (8 mm), it has fairly high AFOV (68-deg), which reduces to about 50-deg at long focal length (24 mm). It has 12-15 mm eye relief, which is good because I wear corrective lenses. It comes with 1-1/4" and 2" nosepieces with standard threads for 1-1/4" and 2" filters. My friend, also an avid photographer, showed me how he set up the eyepiece for eyepiece projection with a T2 adapter, and I was sold after that.

I did some research on Baader Hyperion eyepieces after getting back home, and found all of them were modular, i.e. have a removable 1-1/4" front barrel with negative lens group. I saw that by removing the front barrel of a 21 mm Hyperion eyepiece, it becomes a 32 mm eyepiece. By placing the front barrel on the Mark III, it becomes a 4-12 mm zoom eyepiece. I also wanted a super wide-field eyepiece for "spacewalk" experience, and the Baader 36 mm Hyperion Aspheric eyepiece with 72-deg AFOV fit the bill. So with just these three eyepieces, this combination allows one to have a set of equivalent eyepieces ranging 4 mm to 36 mm. I therefore made the plunge and purchased all three eyepieces and have been happy since.

That said, I should say among the Baader eyepieces, images in the zoom is slightly softer and has slightly less contrast, but I have difficulty telling when magnified at short focal lengths.

I can definitely let you (or anyone else in HAS) borrow the eyepiece for viewing on your own scope next time we're at a star party.