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Something for nothing: Celestron C90

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#2476 Jaimo!

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Posted 29 January 2020 - 10:15 PM

Currently in the driveway taking 100x unguided 1 minute subs of M81...  We'll see how it turns out.

 

ASIair/ASI294MC Pro/CG-5 ASGT/C90

 

IMG_20200129_215053 - small.jpg


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#2477 Old Man

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Posted 30 January 2020 - 12:00 AM

  Well the big brown truck pulled up this afternoon and dropped off my new C90, just 3 days after my order was placed with Optics Planet. A big Hooray goes out to them for quick shipping, and also to UPS, the box never had one smashed corner or dents.

  I was very impressed when looking over this scope, seems very well built, very stout feeling. I let it acclimate inside for a couple of hours and then inspected its front meniscus, all looked good. I looked inside and everything looks real good, no bare spots in the baffle tubes at all which made me even more happy. Then I checked from the back to see if there was any of the flaring issues while pointing it at a bright light just out of the view and no flaring or halos. I did notice it might benefit from doing the flocking inside the baffle tube as there was a little shine to it, not real shiny just a little noticeable.

  I took it outside and focused on some tree branches and some power lines, this thing is very sharp, showing even the details in the tree bark and the wire winding on the power lines, but it was too cold for me, 36 degrees with some wind.

 Cloudy, overcast and plain dull outside with visibility maybe clear for about a half mile, then a hazy look at ground level, as Johnny Cash would sing  " I ain't seen the sunshine since I don't know when ", been like this for weeks, no sun, no stars. But I am very impressed with this and can hardly wait for a clear night/day to check it out better. I was even a little impressed with the tripod, much better than some of the throwaways I have had and I did get 2 eyepieces, a 32 and a 12.5mm.

  But I do have a few questions if someone can answer them.

 #1-- is the dew/light shields the same for the C90 as the ETX90 ?

#2-- When I order the thin flocking from Edmonds, is it better to order the 2 bigger sheets or the 5 sheets of 8x10 inches, they charge $3.00 more for the smaller sheets and I think there is more flocking paper with the bigger size.

#3-- What adapter fits these to allow SCT components to be used, I have found a bunch, but no mention of the thread size on the back of the newer model C90's.

#4-- I am going to replace the diagonal with another, I think everyone was agreeing on a mirror as the preferred one, would a GSO 99% be a decent replacement?

 

         Thanks and you can add me to the happy owners list,   Mike


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#2478 johnhudson922

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Posted 30 January 2020 - 08:04 AM

can anyone recommend some tube rings that will fit the C90? 



#2479 Old Man

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Posted 30 January 2020 - 09:18 PM

Looking forward to seeing your results Jaimo.

 

           Mike



#2480 Jaimo!

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Posted 30 January 2020 - 11:11 PM

Ugh...  I am going to have to work out my guide scope issues, as 1 minute unguided subs at ~f/14 will not cut it (and I could not pull off 2minute subs).  I have imaged this at ~f/4.7 and at f/7, but the C90's long focal length will require much longer subs.  Below is my shameful and quick processing of M81, I am not going to waste too much time on the colors and processing, but will share my failure.  I don't want to turn this into an imaging thread and to stay on the C90 topic...  But the bottom line is the C90 will require a significantly longer exposure than a short focal length refractor.  I know this is not the most optimal imaging scope, but this has become a challenge...  For reference, here's NASA's Hubble image.

 

Autosave - M81 C90.jpg


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#2481 Old Man

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Posted 31 January 2020 - 01:08 AM

Weren't you just starting to use this camera on the C90? If so, don't beat yourself up, it is still better than I will ever attempt. My pockets are not deep enough. lol.gif  AP is one rabbit hole I don't dare to venture down, at least you will get better. Just download the Hubble image and tell everyone yours just needed cleaning up a little more, I won't tell.wink.gif


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#2482 Old Man

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Posted 03 February 2020 - 07:35 PM

Well we had temps come up and one day of pretty clear skies on Sunday. First time I have seen stars in close to a month.

  I got out the new C90 for some star gazing and focused in on Sirius, low on the horizon. I am extremely happy with this little Mak. But a neighbors outside light did cause the proverbial flare, so a dew/light shield and flocking of the baffle is definitely called for to increase the contrast. I wish Celestron would fix the baffle problem. But as a spotting scope, I did not have any problems in daytime.

  I was using a Manfrotto tripod with an Oberwork 5000 head and it is a great scope for GnG. The stock finder leaves a lot to be desired. Moving up higher in the sky, the contrast got much better with pinpoint stars, so I am happy, if the flocking and a light shield will fix this.

  Today the clouds rolled in again, with the rain moving back in and rain, sleet and mixed winter weather for the next few days.

So, that is a first light report, pretty much the same as everyone else's.

 

            Mike 


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#2483 Old Man

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Posted 07 February 2020 - 06:48 PM

Well my Edmunds flocking paper arrived, I could not be happier in the difference in contrast, almost unbelievable. I am still awaiting my dew/light shield, but I am sure with this it will be most satisfactory. I got the flocking installed perfectly on the second try, just had to trim a little off so the edges fit right together and smooth it a little.

  I have read all 100 pages of this thread and I am hoping it will not die out. This little Mak is truly " a poor mans Questar ".

Now, my dilemma, I ordered the 2 big sheets of flocking paper and cut just one small piece to flock this baffle, I am going to also flock my C8 baffle which will still leave me with way too much left over and maybe my dew shield on my refractor.

What does everyone do with the left over??  lol.gif lol.gif 

  I can hardly wait for planet season and more comfortable temps to arrive.

C'mon lets keep this thread going to extol the virtues of this little wonder.

 

 Obligatory pics will follow when I receive the light shield.  waytogo.gif  


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#2484 Joe1950

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Posted 07 February 2020 - 09:18 PM

 

What does everyone do with the left over??

I still have quite a lot form 3 years ago. I would have sent you some for several tries had I known. It will come in handy, though. Good to have on hand.



#2485 Zapp Brannigan

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Posted 09 February 2020 - 07:46 AM

I'm still chipping away at the stuff too.  It should last a lifetime unless I use it in my XT-10.  The dew shield helped a lot too.  It's a great little scope for quick planetary viewing sessions. 



#2486 MCJ2087

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Posted 09 February 2020 - 07:51 AM

I use my 80’s era C90 (purchased used in 2019) for wildlife viewing around the house, nighttime visual astronomy using mainly 0.965” Plossls, some sky sweeping using an old rich field adapter, and now I’m starting to experiment with a ZWO ASI224MC - also a night vision monocular that was purchased in 2000.  So, my C90 is not optimum for any of the astronomy choices – but it’s my only telescope and I’m thankful just to have it to use.  Attached is my first halfway coherent live stack save using night vision prime focus at F11.  I’ve purchased a Bahtinov focusing mask, it’s on my to-do list.  Thanks for reading my post.

 

M42: 2/05/2020, SharpCap3.2Pro 260seconds/88frames/Mono8 - saved as viewed with stretch

 

MCJ2087_2_05_2020BStack_88frames_260s_WithDisplayStretch.png


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#2487 houndsbourgh

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Posted 22 February 2020 - 12:14 PM

Just picked up a used current model C90. I am impressed with the build and views. Much easier to use than my US black tube. I plan on keeping it in my Westy for camping. Decked out with a zoom, red dot, Zap dew shield and  diagonal I am almost set. Looks like the baffle had a failed flocking attempt. Tube had a large amount of adhesive stuck to the walls. After removing the primary lense I worked for a good hour with different solvents trying to remove it. In the end it was brake cleaner and long Qtips. Super spooky making sure I didn't contaminate the body of the scope. Got it done but the baffle is super shiny now. I installed some wet-dry painted with chalkboard paint. Works well but proper flocking would be best. If any of you have some leftover Edmond non adhesive #40 or #55 and would like to sell some please PM me. 

Attached Thumbnails

  • 122202094518.jpg
  • 122202094612.jpg

Edited by houndsbourgh, 22 February 2020 - 12:25 PM.

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#2488 Binojunky

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Posted 22 February 2020 - 12:53 PM

Regarding dew shields, the Astrozap I have fits both the C90 and ETX90, but its an older one so things may have changed?D.



#2489 houndsbourgh

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Posted 22 February 2020 - 01:00 PM

Not sure. I ordered mine off the Zap website. Description listed only the Celestron C90.



#2490 Old Man

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Posted 22 February 2020 - 07:22 PM

I also ordered my dew/lightshield from Astozap. But I emailed them and found out the ones listed on the website are for the older C90's and will fit, but I explained about the newer ones and Joe at Astrozap told me the dimensions are between the C90 and the C4/4se. So, at no extra charge they made me one that is a perfect fit and I also asked for a 10 inch length from the meniscus to the end, [ per the recommended length from somewhere in the 100 pages ] . It works very well and even though the first one was lost by the carrier, Joe replaced it and all is great, a big shout out for Astrozap.

  I had a clear day and the views were astounding, just wish the night time temps would come up some as all my pieces/parts are here and mounted. But the only stars I might see are if the wife finds out how much I spent on this little jewel and accessories, [ a frying pan upside the head is sure to produce some stars lol.gif , no scope required ].

  I will try to get some pics of the little one up as she is all dressed up for a night of partying under the stars.


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#2491 Old Man

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Posted 22 February 2020 - 08:51 PM

Well here are a couple of pics as promised, she is ready to dance under the stars even if I cannot yet.

Orion 6x30 Raci with shorter mount, Pinty GLP with red safety cover, GSO 99% mirror diagonal and Astrozap light shield.

C90 2.jpg [attachment

C90 3.jpg

 


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#2492 Old Man

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Posted 23 February 2020 - 08:26 PM

We had a beautiful day today, so I wanted to align my finder scope and play around with some different FL eyepieces.

 At roughly little better than a half mile, I was able to get some terrific views and pushed this little jewel to 250x with no problems. I noticed our local redtail hawk was flying around looking for a meal, when he landed on a power line about 125 yards away. I still had the Ex-cel LX 5mm eyepiece in and quickly turned in the direction and focused on it.

  Here is a pic through the eyepiece. I am not real good at hand holding my phone over the eyepiece, but did not have time to go back in the house for my phone holder, which I have never used. 

So please forgive the shot, but I thought for only my second or third attempt it came out pretty good for my old shaky hands. I did add a little contrast, but that is the only change in the image other than resize to fit here. It did find something to eat, there is some blood on it's beak.

I think it is a little soft due to pushing the scope to 250x, but I was afraid it would fly off before I could change eyepieces. 

  I sure am glad I got all wrapped up in this thread and bought this, it truly is "a working man's Q".

Redtail Hawk 3.jpg

 


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#2493 SandyHouTex

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Posted 24 February 2020 - 01:15 PM

We had a beautiful day today, so I wanted to align my finder scope and play around with some different FL eyepieces.

 At roughly little better than a half mile, I was able to get some terrific views and pushed this little jewel to 250x with no problems. I noticed our local redtail hawk was flying around looking for a meal, when he landed on a power line about 125 yards away. I still had the Ex-cel LX 5mm eyepiece in and quickly turned in the direction and focused on it.

  Here is a pic through the eyepiece. I am not real good at hand holding my phone over the eyepiece, but did not have time to go back in the house for my phone holder, which I have never used. 

So please forgive the shot, but I thought for only my second or third attempt it came out pretty good for my old shaky hands. I did add a little contrast, but that is the only change in the image other than resize to fit here. It did find something to eat, there is some blood on it's beak.

I think it is a little soft due to pushing the scope to 250x, but I was afraid it would fly off before I could change eyepieces. 

  I sure am glad I got all wrapped up in this thread and bought this, it truly is "a working man's Q".

attachicon.gifRedtail Hawk 3.jpg

That's a pretty amazing shot.


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#2494 Old Man

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Posted 24 February 2020 - 09:45 PM

Thank you very much, but I was pushing the little C90 pretty hard at 250x when this opportunity came up. Here are a couple more shots from the same time. The only changes made were a little more contrast and resizing to post here.

 

Redtail Hawk 7.jpg

Redtail Hawk 5.jpg

 


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#2495 Jaimo!

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Posted 02 March 2020 - 11:18 PM

Got a new accessory for Christmas, just getting around to implementing it's use.  A small, inexpensive flip mirror system by Omegon available on Amazon for $55.  It does have a plastic housing, but it fits the small footprint on the back of the C90.  I have always struggled with getting the subject in the center of the image and in focus with such a narrow field, usually resulting in a barrage of unintentional swear words flying.  I have set an old 12mm Kellner cross hair eyepiece equifocus (is that a word... the same focal distance as the camera sensor) I can eye up everything the eyepiece and just turn the knob for the camera.

 

I am getting ready for the planets to return this summer...

 

C90 flip mirror - small.jpg

 

Moon_211817_g4_ap16 - cropped small.jpg

C90 f/13.8, ASI224MC, Autostakketr2, GIMP


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#2496 Jaimo!

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Posted 03 March 2020 - 08:57 AM

By the way, the number of replies in this thread, ~25,000 has eclipsed the entire Questar forum, ~21,300.

 

Not saying it means anything, just useless trivia.


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#2497 Old Man

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Posted 05 March 2020 - 04:08 AM

By the way, the number of replies in this thread, ~25,000 has eclipsed the entire Questar forum, ~21,300.

 

Not saying it means anything, just useless trivia.

  Might be useless trivia, but I have to say I love it. Between my desktop crashing, [ still not fixed ] and a surgery I had last Monday, I have not been able to do much of anything. Supposed to be nicer today, maybe get the little one out on the front porch for a while.

 Hope to get my desktop up and running soon as this laptop just does not cut it for me. I only use it for mount control and a couple of other things.


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#2498 PXR-5

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Posted 07 March 2020 - 09:36 PM

Anyone using the Explore Scientific Exos EQ with the C90?

I have been on a quest for a lightweight tracking mount for my C90.

#2499 Cali

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Posted 15 March 2020 - 05:33 AM

By the way, the number of replies in this thread, ~25,000 has eclipsed the entire Questar forum, ~21,300.

 

Not saying it means anything, just useless trivia.

I think you meant ~2,500

 

- Cal



#2500 Jaimo!

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Posted 15 March 2020 - 04:21 PM

I think you meant ~2,500

 

- Cal

Oops, only off by an order of magnitude...  I think we need to try a little harder.

 

I deny any responsibility as to what I may or may not have posted in the past. grin.gif

 

Jaimo! 


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