C90 bargain (1 Viewer)

[jaymoynihan]

I recently picked up a Celestron C90 for $159.95 on Amazon. If one is not philosophically opposed to Maks, and you want/need high magnification for nature observation, i recommend. I am using it with one of my other eyepieces, a 25mm Plossl for 50x & 1 degree FOV. So far, excellent performance.
Yesterday evening, (7-8 pm) humid and overcast (air still). Song bird IDs out to about a mile, (similar to 105 feet distance, naked eye), bright. At 1/2 mile, enjoyed sand hill cranes with young grazing.

 

[etudiant]

Sounds like a bargain.
How easy is it to work with this astronomy scope?
Is the image right side up or reversed?

 

[jaymoynihan]

Sounds like a bargain.
How easy is it to work with this astronomy scope?
Is the image right side up or reversed?

With a standard diagonal (90 deg. astronomical ) it is R-L reversed. It comes with a 45 deg prism diagonal to correct that (and a 32mm plossl and a little backpack) is ok. I intend to get a higher quality version of that diagonal.

It is important, i think, to understand, this is not a scope you carry already mounted on the tripod, like an armoured, wp spotter. While i can get "on target" pretty fast (I am used to using maks for astro stuff), it is not really something for that.
Best uses:
You are going to be at one spot for awhile
Nest observation and the like
a long distance "microscope". If i remember correctly the close focus is 15' or so.

It also seems subject to stray light, and does benefit from a lense hood, which is avail thrid party by astro suppliers.

 

[rmel66]

One addition: To get quick target acquisition a red dot finder (rdf) works wonders with narrow field of view catadioptrics like the C90. My cats (Celestron C70 and LOMO Astele 60) are so equipped. A good source for rdf's is your local neighbourhood USA Walmart (Daisy, about $10).

rmel66.

 

[jaymoynihan]

An update on my C90 usage.
I had been using the "Red Dot" on it, but sometimes problematic on bright days. Rummaged around my boxes of astro stuff and now have the C90 tricked out like this:

a 6x30 erect image finder
an Astro-Tech premium 45° image erecting diagonal (1.25")
a dewshield, used sometimes to reduce ambient glare
a Televue 26mm Plossl eyepiece (circa 1980's) for 48x. Probably my best 1.25" eyepiece (except for my orthoscopics )