Using a Celestron C90 Mak

[bsshog40]

I bought this C90 a few weeks ago. I have been able to see the moon good of course and was able to see this last conjunction pretty goo. Does any here have a C90 and how has your experience been with seeing anything deeper in space? I bought this for just a quick view of the sky once in a while. My Sky-Watcher AT-GTe mount will be in this friday. Hoping it will be pretty stable on the mount as I have been taking pictures also. I also have a Celestron CPC 800 but it's packed up and really don't have a place to keep it setup right now. I'm thinking of buying one of those Sky Shed domes.  Thanks for any input!

Bobby

[Craney]

I used to have one.    It had sharp optics and was a very well made instrument.   In terms of objects though,  I tended to use it for the Moon, planets, double stars or conjunctions like you say.

It has quite a high focal ratio (f13 -f14)  and so anything other than a very bright object will be dim unless you have properly dark skies.   By the way, it makes a very good wildlife lens for a DSLR.

If you do consider Astrophotography .... which will enhance the 'seeing' power of the standard eyeball, and you will need to track with a good equatorial mount to tease out any detail in a DSO. 

 I supose with modern CMOS cameras,  wide FOV, incredibly sensitive as well, you might be able to do better than I did 10 years ago with a Canon 600D.

I think  your CPC800  with a focal reducer would be a better bet.

Here are a couple of pictures from the  2017 eclipse using the C90.

Regds, Sean.

[bsshog40]

Cool eclipse pic. Yea I should get my Sky-watcher AZ-GTe mount in this week. Looking forward to mounting the C90 on it. My avatar is a pic I took with my canon T4i with the C90 a couple weeks ago. The tripod I have right now is not very steady and is not fluid head so it's hard to work with it. 

 

[Alien 13]

I have the C90 and find it very versatile, extremely good on Lunar as well as being truly grab and go...I also use it for daytime shots and it would make an very effective white light solar scope (with the appropriate front mounted solar filter).

This is one of mine taken with a Canon 650D, single shot with a play in Photoshop.

 

Alan

[Louis D]

I looked at the C90, but decided to pick up a second hand 127 Mak for about the same money as a C90 new.  It's actually about 118mm of clear aperture, so only a bit bigger than the C90 in the big scheme of things in both aperture and physical dimensions.

I've found it to be good for solar system views and planetary nebula as well as the Orion nebula and Trapezium.  Pretty much, it excels at small, high contrast objects.  It does best paired with a short focal length ED refractor or 50mm or larger finder scope given the Mak's super narrow field of view.

Edited January 6, 2021 by Louis D

[bsshog40]

20 minutes ago, Alien 13 said:

I have the C90 and find it very versatile, extremely good on Lunar as well as being truly grab and go...I also use it for daytime shots and it would make an very effective white light solar scope (with the appropriate front mounted solar filter).

This is one of mine taken with a Canon 650D, single shot with a play in Photoshop.

 

Alan

Very nice pic! I think the 600 series of Canons were more designed for astrophotography. The pic I took is on my tripod that really can't handle the weight of the scope and camera. Hoping the new mount will help. Yea, it was 2 reasons that I bought the C90. One was for a quick look at the moon and such and the other was for a spotting scope at the gun range. 

[bsshog40]

2 minutes ago, Louis D said:

I looked at the C90, but decided to pick up a second hand 127 Mak for about the same money as a C90 new.  It's actually about 118mm of clear aperture, so only a bit bigger than the C90 in the big scheme of things in both aperture and physical dimensions.

I've found it to be good for solar system views and planetary nebula as well as the Orion nebula and Trapezium.  Pretty much, it excels at small, high contrast objects.  It does best paired with a short focal length ED refractor or 50mm or larger finder scope given the Mak's super narrow field of view.

Nice setup. I was able to get my like new C90 for $120. Couldn't pass that up. 

[Alien 13]

Just now, bsshog40 said:

Very nice pic! I think the 600 series of Canons were more designed for astrophotography. The pic I took is on my tripod that really can't handle the weight of the scope and camera. Hoping the new mount will help. Yea, it was 2 reasons that I bought the C90. One was for a quick look at the moon and such and the other was for a spotting scope at the gun range. 

The tripod is critical to good Lunar images as is remote shutter release and mirror lock up if you have it.. The sky conditions have a big impact too, some days it will be impossible to get a good image. 

I would also always use live view X10 for final focus adjustment even though it can be tricky hitting the sweet spot.

Alan

[Gazereths]

I have the C90 on a Omegon mini Dobsonian mount, it's great for windowsill observing in the warmth/comfort of my own bedroom. I've not had a great deal of time with it yet but have managed to seperate Castor into two stars using a 8mm BST eyepiece. Also had a great view of the moon with the 8mm and 2x barlow (around 300x magnification I believe) though it was a little hazy I could make out really small craters. Not sure if the below picture was just the 8mm or with the barlow. Also not perfectly focused and my sensor on my A6000 Sony definitely needs cleaning (see the black spots). Also this was just taken though the eyepiece (I have a adapter now but haven't tried it yet)

 

 

I think Deep Space stuff depends on how dark your shies are though I'm FAAR from an expert. In a truly dark sky I imagine you'd see loads, in an urban area it will struggle.

Edited January 6, 2021 by Gazereths

[theropod]

I have C90 and have owned it almost 5 years. I built a long dew/light shield and flocked the inside. I added the blacked wet/dry sandpaper to the focus tube. With my 2X Barlow and 12 mm EP I can make the Cassini split on a good night. With my 32mm EP Andromeda almost fits in the FOV, and becomes a living monster made of stars. A couple times under great conditions I’ve managed the ring and lagoon nebula. M42 is an evening killer as it’s hard to look away once my C90 has it framed. For the aperture and cost I cannot imagine a better deal. I wonder if two would make uber binoculars?

[Gazereths]

33 minutes ago, theropod said:

I have C90 and have owned it almost 5 years. I built a long dew/light shield and flocked the inside. I added the blacked wet/dry sandpaper to the focus tube. With my 2X Barlow and 12 mm EP I can make the Cassini split on a good night. With my 32mm EP Andromeda almost fits in the FOV, and becomes a living monster made of stars. A couple times under great conditions I’ve managed the ring and lagoon nebula. M42 is an evening killer as it’s hard to look away once my C90 has it framed. For the aperture and cost I cannot imagine a better deal. I wonder if two would make uber binoculars?

Sorry to hijack the thread, but do you have any pictures of the mods you've made and how you did them? I'm all about modding stuff to get the best possible performance out of anything.

[Alien 13]

9 hours ago, Gazereths said:

Sorry to hijack the thread, but do you have any pictures of the mods you've made and how you did them? I'm all about modding stuff to get the best possible performance out of anything.

I think the newer versions of the Celestron C90 have (mine has) a matt black focus tube as standard rather than the shiny plastic one on the Skywatcher version so modification is unlikely to show major improvements.  Flocking the main tube should help especially if you can get hold of some "vanta black" or similar material/paint that is available now.

Alan

Edited January 7, 2021 by Alien 13

[bsshog40]

3 hours ago, Alien 13 said:

I think the newer versions of the Celestron C90 have (mine has) a matt black focus tube as standard rather than the shiny plastic one on the Skywatcher version so modification is unlikely to show major improvements.  Flocking the main tube should help especially if you can get hold of some "vanta black" or similar material/paint that is available now.

Alan

You are correct. Mine is matte black inside the tube. 

[theropod]

Bsshog40,

Lucky you! Inserting a precision cut hunk of sandpaper into that tube for both length and circumference, and getting it to lay flat, isn’t a breeze. It took me half a day, but I have stubby inarticulate fingers. I ended up coiling the paper around an arrow shaft tacked with some “snot” glue from junk mail. I slowly uncoiled the paper using the arrow shaft to press the paper to the plastic tube wall. No adhesive holds the paper anywhere, and “springiness” in the paper acts to mechanically hold itself. Eventually the paper ends joined, lay flat against the tube wall and turned the “light at the end of the tunnel” into either inky black or a star field. Used to be that I could get close to Jupiter and use the glare to home in. Now my finder matters, and is one more reason why I just bought, modified and attached a RACI 50x9 dual crosshair illuminating finder to my C90. The narrow FOV and terrible straight through finder with seriously coarse crosshairs was inadequate for the job. I’m thinking of mounting the old C90 finder to my little DIY refractor, although the new scope has a FOV so large a finder isn’t a big concern. Maybe I should buy a mounting wedge for the 60mm DIY scope, and leave the C90 off my mount. Hmmm I bet goto would be easier to get going right.