9 replies to this topic

[Hesiod]

Overall judge the FL55ss a good product. As a wide field astrograph is very proficient and easy to use, so would suggest it wholeheartedly, even to beginners (usually at this stages apreture does not matter, while the clever Vixen mini-refractor is very user-friendly and, at 300mm, gives a more forgiving sampling than the popular 60-80mm rebranded models).

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[Organic Astrochemist]

Great review. I do think these small refractors can be a lot of fun.
 
Another application for these small telescopes is spectroscopy!

I am sure your Vixen FL55ss would work as well as my Borg 55FL. This is not a great image of open cluster NGC 6231, but the Wolf-Rayet star (HD 152270 = WR 79) sticks out (the lines to the right are the spectra)

Here is the annotated spectrum, clearly showing features of a WC Wolf-Rayet star.

By contrast, here is a WN Wolf-Rayet star, WR 136, HD 192163

Here's a spectrum of planetary nebula NGC 6886, that is a mere speck even in much larger apertures, but reveals some details in its spectrum.

 

Thank you for promoting these wonderful small telescopes.

[RichA]

Good review!  I wonder though if anyone has compared these small, fast refractors against normal camera lenses?

[MortonH]

Where are the pictures of the scope???

[Hesiod]

@Organic Astrochemist
Very interesting! Which kind if equipment do you use?

@RichA
I use also a Canon ef200 f/2.8: the FL55ss is noticeably better even at f/4 (less CA, tighter stars, less coma).
The lens however is smaller, lighter (but the refractor+reducer is smaller than a 200 and a 300mm lens) and much faster.
I focus manually, sometimes with the help of a mask, and feel easier to do so with the refractor.
The lens is obviously more handy for daytime photography

[calypsob]

the star tests I have seen on a full frame via astrobin yield un impressive stars at the edges, I have no way of knowing if this was because of spacing. Have you tested with ff?

[Hesiod]

No, I have only an aps-c sized camera.

On Vixen's website there are the spot diagrams for flattener and reducer+flattener, with flats and a picture taken with a Canon camera (https://www.vixen.co...roduct/37253_9/ ).

With a FF there could be the need of some work on star shapes at the edges

I also contacted them through the site asking about spacing because am still pondering my next camera (FF DSLR or cooled ccd), and a couple of days later they answered me sending a diagram from which I understood that the sensor has to be 63,5mm behind the reducer, and that the adapter I have offsets that distance for Canon's cameras.

[Rat8bug]

How does it compare to Williams Optic Redcap 51 APO?

[Hesiod]

I can not say since do not own the RedCat

[JamesMStephens]

Great review. I do think these small refractors can be a lot of fun.
 
Another application for these small telescopes is spectroscopy!

I am sure your Vixen FL55ss would work as well as my Borg 55FL. This is not a great image of open cluster NGC 6231, but the Wolf-Rayet star (HD 152270 = WR 79) sticks out (the lines to the right are the spectra)

 

Here is the annotated spectrum, clearly showing features of a WC Wolf-Rayet star.

 

By contrast, here is a WN Wolf-Rayet star, WR 136, HD 192163

 

Here's a spectrum of planetary nebula NGC 6886, that is a mere speck even in much larger apertures, but reveals some details in its spectrum.

 

 

Thank you for promoting these wonderful small telescopes.

Organic Astrochemist,

 

Pardon me for commenting on such an old post (and straying from the thread's intent, perhaps), but this is very interesting.  Do you have a pic of your 55-mm scope paired with your spectrograph?