Three Saturns: A comparison

[merlin8r]

Hi guys,
I took three different shots of Saturn last night. One through a Vixen 2X Barlow, another through the Meade #140 Barlow, and the last through the Meade 3X Telextender. Note that the Vixen 2X and the Meade 2X are not the same size!

Clear skies,
Shane

[Ric]

That's very interesting Shane.
Were they taken with the Meade LPI?

Cheers

[merlin8r]

Hi Ric,
Yes they were taken with an LPI. I probably should have made more adjustments than just exposure time, as they noticably dim.

Clear skies,
Shane

[jjjnettie]

I wonder why there is a difference between the Vixen and the Meade?

[Ric]

Hi Shane, I have one on order so I am interested in the images they take.
With the barlow, I assume that the LPI just drops straight in.

Cheers

[merlin8r]

Hi Ric,
Yes, the barlow just drops in to your eyepiece holder, then eyepiece or LPI. Takes a few turns of your focuser to get it back in focus. I strongly recommend though that you find your planet visually first, centre it as best you can. Then insert your LPI, focus and centre. Then put the barlow in, and refocus. Otherwise you can go insane trying to find it!
I think the Vixen barlow is closer to 2X, and the Meade #140 is a bit more. I tried this with the Meade 2X Telextender some time ago, and the result was pretty similar i.e the #140 image was larger than the Telextender.
If my math is correct, the final shot with the 3X Telextender is a ridiculous 1250X magnification!

Clear skies,
Shane

[lineout]

How does the LPI compare in quality terms to the Meade DSI's?

[Ric]

Hi shane I was just doing some maths as well, I have the Meade #140 barlow as well so theoretically I should get around 1016X and if I had a 3X tele that would be around 1524X :eyepop:.

I assume that these would be based on perfect seeing conditions as well.

Cheers

[merlin8r]

In simple terms, the LPI is good for planets and the moon, and not deep sky (not sensitive enough). The DSI is good for DSO's, not so good for planets, although some good results have been taken.

[lineout]

How do both compare to a DLSR?

[merlin8r]

Both the LPI and DSI are about the equivalent to a 6mm eyepiece, so have quite high magnification. A focal reducer is needed for the big faint fuzzies. The DSI will be more sensitive than a DSLR, but I have just made the switch. Will be using a Canon 400D to image, and a DSI Pro to autoguide. The Canon cameras go against all convention, as they are a CMOS chip, yet still perform very well on DSO's.

Clear skies,
Shane