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Something for nothing: Celestron C90

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#2301 Sarkikos

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Posted 12 February 2019 - 06:21 AM

You need a gas filter.

 

J

Just don't go too far north to reach dark skies ... assuming you're in the northern hemisphere.

 

Mike


Edited by Sarkikos, 12 February 2019 - 06:23 AM.


#2302 Jaimo!

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Posted 12 February 2019 - 08:49 PM

Just don't go too far north to reach dark skies ... assuming you're in the northern hemisphere.

 

Mike

...assuming you are interested in the MMM.  poke.gif

 

Unfortunately if I am making a special trip to a dark site for observing, the C90 will probably stay in the office...  Even though it was purchased as a "travel" scope.

 

Jaimo!


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#2303 Adun

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Posted 13 February 2019 - 05:49 AM

I have zero interest in Messier Marathons.

 

I don't really use my C90 for travel. If I travel by car I take my C6. If by air, my short achro.

 

My C90 is for guerilla observing, to sneak views before the clouds notice.

 

Side note: I've been getting into birding, and I finally found a use for the 8x21 optical finder that comes with the C90: pocket Monocular!


Edited by Adun, 13 February 2019 - 05:52 AM.

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#2304 Sarkikos

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Posted 13 February 2019 - 06:46 AM

...assuming you are interested in the MMM.  poke.gif

 

Unfortunately if I am making a special trip to a dark site for observing, the C90 will probably stay in the office...  Even though it was purchased as a "travel" scope.

 

Jaimo!

It doesn't matter if you do the MM or the MMM.  If you go too far north or too far south,  you won't be able to observe all the M objects in one night.  It has nothing to do with how good your memory is.  lol.gif

 

But would Messier have known by heart the locations of all his objects?  Yes, I think so.

 

Yep, I wouldn't bother taking the C90 to a dark site.  I take my larger scopes there.  If I'm on vacation camping with my family, I might take one of my smaller refractors or the C6. 

 

The C90 is for grab-n-go here at home.  It's also one of the few scopes I have that will fit in a small side bag for walking a mile or so to other observing sites here in the neighborhood.

 

Mike


Edited by Sarkikos, 13 February 2019 - 07:05 AM.


#2305 andycknight

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Posted 13 February 2019 - 08:02 AM

[snip...] Unfortunately if I am making a special trip to a dark site for observing, the C90 will probably stay in the office...  Even though it was purchased as a "travel" scope.

 

Not me... The little C90 takes up so little extra space - I would want to know what its really capable of.

 

But sure - my C8 would be there too.

 

Regards

Andy.


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#2306 azure1961p

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Posted 02 March 2019 - 02:33 PM

Not me... The little C90 takes up so little extra space - I would want to know what its really capable of.

 

But sure - my C8 would be there too.

 

Regards

Andy.

 

...assuming you are interested in the MMM.  poke.gif

 

Unfortunately if I am making a special trip to a dark site for observing, the C90 will probably stay in the office...  Even though it was purchased as a "travel" scope.

 

Jaimo!

 

 

I don't understand why this would be the case.  It's a nice addition for any kind of sky.  Barring a comparable performance ED refractor, it's too easy not to bring. Also while the bigger aperture is still cooling down, the C90 gets their quicker and allows for observing to begin quicker.  Even under a desert sky, it'd be fun to see just what that lets this tiny package put out.    Also if I'm standing to observe with the bigger scope, it's a nice respite to sit down and pots around with the little guy.  That's the interesting thing I've enjoyed with the 70mm Ranger and now the little C90, it's always a compliment to the bigger scopes wether it's 15x with the 70 or 31xwith the 90.

 

Pete


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#2307 Dave Ponder

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Posted 02 March 2019 - 03:08 PM

My Mighty Mak Grab and Go....

Attached Thumbnails

  • AE63C68C-139B-4C44-ACAE-E5528EB8BF5E.jpeg
  • CD75CB0B-1684-4575-8734-A58C704AFF3E.jpeg

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#2308 Fjelltronen

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Posted 03 March 2019 - 03:29 AM

I have the exact same setup grin.gif

 

I have a question. Yesterday I was looking at M44. No eyepiece of mine showed the cluster in its entirety. The longest focal length used were a 25mm plossl and a 17mm wide angle.

I know the cluster is big and the c90’s fov is small but it was almost there. Very few stars were left out of the view.

Is there an eyepiece that can show it all with the c90? Maybe a 20mm wide angle?



#2309 Uranotopia

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Posted 03 March 2019 - 06:15 AM

My Mighty Mak Grab and Go....

Great setup,

congrats!



#2310 Bejohnson

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Posted 03 March 2019 - 10:53 PM

Hello, long time lurker and just recently joined, I have read this whole topic from the beginning to the last and I guess I have mentioned the C90 enough times that my wife bought me one for my birthday. I opened it up the other night, and I guess as it usually goes, it is cloudy since 😭. Even though my passions have always been above, this is my first actual scope. So I’m super excited and have already gone back to read t all again to start getting some upgrades. I currently have a Celestron heavy duty alt-azimuth tripod, a iOptron Sky Guider Pro and a Canon Rebel XS so I’ll be looking to attach the canon to the c90 as well. 

 

Is there anything that is a must upgrade that maybe is hidden away in this thread? Thanks in advance!


Edited by Bejohnson, 03 March 2019 - 10:54 PM.

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#2311 Jim1804

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Posted 03 March 2019 - 11:35 PM

Bejohnson - welcome to the club! I think you’ll love your C90!

A couple of things - you may want another eyepiece or two (cheap Plossls work fine in this scope - or a lot of us use a zoom eyepiece with it. The 32mm, a 24-8mm zoom, and a Barlow, and you’re all set for guerrilla astronomy, C90 style!

You’ll also want a 90deg astronomy diagonal - much more comfortable, and will really improve your views. You don’t need to spend much - I have the GSO mirror diagonal, and it works fine.

Make yourself a cheap dewshield - I used a couple of sheets of craft foam. Needed to block stray light even if dew isn’t a problem.

A lot of people on the thread have also flocked the baffle tube - easy to do with the really thin flock paper. Improves contrast - although a dew shield will get you most of the way there.

Finally, check the collimation on Polaris. Mine was out of collimation when I received it. I’m still not sure it’s perfect - but it’s close, and the difference on planets was noticeable.

Most of all - enjoy your C90!

Edited by Jim1804, 03 March 2019 - 11:37 PM.

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#2312 Jim1804

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Posted 03 March 2019 - 11:42 PM

My Mighty Mak Grab and Go....


I have the same setup too. Rock solid, and works great with my ST80 too. I had to rotate the arm back so the slo-mo cable wasn’t whacking me in the face the whole time. The downside of the short C90!

#2313 Jaimo!

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Posted 03 March 2019 - 11:48 PM

You'll probably also want the Celestron T-Mount to mount the Canon XS to the scope.  The threads on the inside of the T-Mount match up with the visual back.  The T-Mount also will attach to the Celestron 8-24 Zoom...

 

Celestron Zoom 2.jpg

 

Celestron Zoom 1.jpg

 

Celestron Zoom 3.jpg

 

Have fun and welcome to the club,

Jaimo!


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#2314 Peter Besenbruch

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Posted 04 March 2019 - 01:55 AM

I hauled my 90mm Mak to Kauai to do a bit of birding. This time I brought along the 27mm Flat Field eyepiece, which yielded roughly 30x when coupled with a .63 reducer. The highlight was a pair of displaying Laysan Albatross at Kilauea Lighthouse.

 

On the way back TSA flagged it. After looking it over, the agent took it to his supervisor. It seems they had never before seen such a huge, serious scope before.


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#2315 Jim1804

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Posted 04 March 2019 - 06:40 AM

I hauled my 90mm Mak to Kauai to do a bit of birding. This time I brought along the 27mm Flat Field eyepiece, which yielded roughly 30x when coupled with a .63 reducer. The highlight was a pair of displaying Laysan Albatross at Kilauea Lighthouse.

On the way back TSA flagged it. After looking it over, the agent took it to his supervisor. It seems they had never before seen such a huge, serious scope before.


He had probably heard about its connections to guerrilla astronomy!
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#2316 Adun

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Posted 04 March 2019 - 07:55 AM

Hello, long time lurker and just recently joined, I have read this whole topic from the beginning to the last and I guess I have mentioned the C90 enough times that my wife bought me one for my birthday. I opened it up the other night, and I guess as it usually goes, it is cloudy since . Even though my passions have always been above, this is my first actual scope. So I’m super excited and have already gone back to read t all again to start getting some upgrades. I currently have a Celestron heavy duty alt-azimuth tripod, a iOptron Sky Guider Pro and a Canon Rebel XS so I’ll be looking to attach the canon to the c90 as well. 

 

Is there anything that is a must upgrade that maybe is hidden away in this thread? Thanks in advance!

 

The one "mandatory" upgrade is the 90° diagonal, for better ergonomics when aimed at the sky. The Celestron 94115-A is a great fit, and not expensive.


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#2317 Sarkikos

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Posted 04 March 2019 - 11:06 AM

In my experience, a 45 degree diagonal is torture for astronomy.  You really need a 90 degree.

 

Mike


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#2318 Dave Ponder

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Posted 04 March 2019 - 12:02 PM

I have the same setup too. Rock solid, and works great with my ST80 too. I had to rotate the arm back so the slo-mo cable wasn’t whacking me in the face the whole time. The downside of the short C90!

I ordered 2 short control cables off ebay, locktighted the screws, works great.


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#2319 Jim1804

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Posted 04 March 2019 - 02:09 PM

I ordered 2 short control cables off ebay, locktighted the screws, works great.


Dave - I see them now in your pic. Good solution!

#2320 Cajundaddy

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Posted 04 March 2019 - 03:55 PM

Agreed on the 90* diagonal, zoom EP, and I'll add a 1x Red Dot finder instead of the marginal finder supplied.  These and a solid tripod make C90 time fun.


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#2321 Adun

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Posted 04 March 2019 - 09:22 PM

I've recently taken up birding.

 

My inexpensive 10x50 binoculars suddenly seem inadequate. I also got a bridge / superzoom camera that's working well.

 

And now I wonder: if I was to use my (2016) C90 as a spotting scope for birding... ¿How should I set it up?

 

Maybe a focal reducer + zoom?

It's original finder, or maybe a red dot,  6x30 or 8x50?

Probably the original amici 45° erecting diagonal, right?

 

How would you (or have you) set up your C90 for use as a birding spotter?



#2322 PowellAstro

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Posted 04 March 2019 - 10:10 PM

The C90 is a super scope with just a little modification. You can see small things that make a huge difference here:

https://www.cloudyni...ffle-mod/page-5
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#2323 Cajundaddy

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Posted 05 March 2019 - 12:44 PM

I've recently taken up birding.

 

My inexpensive 10x50 binoculars suddenly seem inadequate. I also got a bridge / superzoom camera that's working well.

 

And now I wonder: if I was to use my (2016) C90 as a spotting scope for birding... ¿How should I set it up?

 

Maybe a focal reducer + zoom?

It's original finder, or maybe a red dot,  6x30 or 8x50?

Probably the original amici 45° erecting diagonal, right?

 

How would you (or have you) set up your C90 for use as a birding spotter?

I do sometimes use the C90 for birding and wildlife when I need a long reach or across water.  It compliments my binos pretty well and with a 32mm EP delivers around 39x which is plenty for daytime viewing.  I see little advantage zooming in further due to atmospheric seeing.  A 1x RDF is much more comfortable to use than the supplied finder. 

 

We have some vernal pools nearby and the migrating waterfowl seem very skittish there.  A C90 gives me a nice standoff distance for observing without influencing their behavior.


Edited by Cajundaddy, 05 March 2019 - 01:06 PM.

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#2324 Sarkikos

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Posted 05 March 2019 - 01:39 PM

Even better than a red dot finder for the C90, would be a laser finder.  Z-Bolt has the best. 

 

Of course, this is for astronomy, not birding.  The only birds I look at through my C90 are the Swan, Eagle ... you get the idea.  :grin:

 

Mike


Edited by Sarkikos, 05 March 2019 - 01:41 PM.


#2325 Jaimo!

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Posted 05 March 2019 - 04:03 PM

Laser finders have always been a little counter-intuitive to me, we constantly avoid light pollution but have no problem shining lasers up in the air.  I know they do not add significantly to light pollution.  I also live in an area with 3 international airports, even if I am not pointing at air planes, the guy down the block does not know this when he is calling the cops...

 

Jaimo!


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