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C11 XLT A SCT defaults questions

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#1 ttorkelson

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Posted 24 July 2021 - 09:17 PM

So hi, first post.

I've been researching by life away for the last week because I'm finally serious about buying a nice rig. I've always wanted to but, only now have the resources.

I've came to this decision:

https://www.bhphotov...cassegrain.html

I think for both a beginner observer and a possible future AP, it's a good choice. I'd like to start out by observing the first year, getting used to the finders and tech/software, as well as the eye peices and filters, etc. Seems like the mount will be great repurposed for AP next year or later (and a new refractor).


One of my only issues with the scope is that I don't think I'll be able to use 2" eye peices I'd like to use to get 100 degree FOV... I MIGHT be mistaken here but the scope looks like it just maxes out at 1.25", but that may be my inexperience. I want to think a SCT would have standard SCT fittings/connectors for eye peices and diagonals, but I'm far too scared of being presumptuous.

I read another post asking a similar question. It seemed to me that they were saying there is a reducer of some kind, bringing it from 3.25" to 2"? It's hard to read exactly and the site doesn't explain the "visual back" well. Still not exactly sure what that is, just sounds le some kind of reducer. Is it 3.25" to 2" or 3.25" to 1.25"? I also saw a highpoint scientific product that the same post I read earlier recommended that would change the reduction. So, I'm just confused.

I'm currently on mobile and tab switching is a pain but I'll circle back with the post/item I'm referring to.

Thanks for any help!
-Trent

#2 ttorkelson

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Posted 24 July 2021 - 09:27 PM

I was referring to this post before: https://www.cloudyni...l-adapter-help/

#3 slepage

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Posted 24 July 2021 - 09:41 PM

No issues using 2 inch eyepieces with this scope.  You will need a 2 inch diagonal.  You can get them with an SCT thread or you can get an adapter such as this one: https://www.highpoin...706a3b40a47a718 and then any std. 2 inch diagonal.

 

Steve


Edited by slepage, 24 July 2021 - 09:42 PM.


#4 macdonjh

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Posted 24 July 2021 - 10:49 PM

No issues using 2 inch eyepieces with this scope.  You will need a 2 inch diagonal.  You can get them with an SCT thread or you can get an adapter such as this one: https://www.highpoin...706a3b40a47a718 and then any std. 2 inch diagonal.

 

Steve

+1

 

Welcome to Cloudy Nights, ttorkelson.  When you're ready to try astrophotography, remember, the much given advice here is to start with a small, short focal length refractor, rather than an 11" SCT.  While you're observing over the next year, you'll see lots of posts here explaining why, so I won't spoil the surprise. smile.gif



#5 ttorkelson

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Posted 24 July 2021 - 10:55 PM

Yes, C11 is definitely only for practice and observation. I've heard about large aperture AP and it sounds like a very unpractical way to start. I've heard it pays to start off with a not so outrageous retractor for AP. Thanks!

#6 ttorkelson

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Posted 24 July 2021 - 10:57 PM

And thanks slepage! If all that's required is a 25 dollar part on top of the 2" diagonal, I'm in good shape.

#7 Starman1

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Posted 25 July 2021 - 09:02 AM

And once you have the 2" diagonal, a nice eyepiece set could be:

40-41mm in 68° (maximum field size in the scope)

20-21mm in 80-100°

13-14mm in 80-100°

9-10mm in 80-100°

Could you use eyepieces with narrower fields?  Sure.

Could you use more eyepieces in your set?  Sure.

Could you use less expensive eyepieces in your set?  Sure.

Experience in the field is the biggest teacher of what you want.

 

Maximum field in the scope is narrow due to the long focal length--0.94° (56.6')

but that will cover 99% of the objects you ever look at.

 

It's a large and heavy instrument, and I would have started with something smaller, but certainly if it gets used a lot, an 11" is a powerful light gatherer.

 

You'll also need some other accessories other than eyepieces:

--Dew Shield-these extend the tube forward and prevent the formation of dew on the front lens of a Refractor or Catadioptric telescope (like a Schmidt-Cassegrain or a Maksutov-Cassegrain) by slowing the cooling of the front lens as it radiates its heat into space.

--Power Pack-portable batteries to give you power for your telescope and its accessories when you are in the field, far from a source of plug-in power. Car batteries are not designed to be discharged, so this is a better idea than hooking up to your car's battery.

--Barlow Lens-Doubling, Tripling, or more, the power of your eyepiece when used in the telescope right in front of the eyepiece, this can provide the extra power you need without costing as much as a lot of eyepieces.

--Planetary filters-these enhance the view of details on the planets

--Nebula Filters-these enhance your ability to see, and see details in, nebulae

--Solar Filters-These make solar viewing possible and exciting.

--Upgrade Star Diagonal-For the refractor or catadioptric telescope user, this can improve the quality of Images and expand the maximum field of view at the same time.  You're already thinking of this.

--Cleaning kit-All you need to clean any optical surface safely except the mirrors. Mirrors require their own cleaning methods.

--Observer's chair-Standing up is, well, uncomfortable. Plus, it's a lot harder to hold your head steady to look through the eyepiece when you're standing. These adjust to any necessary height and make viewing comfortable.

--Planisphere-Everyone should have one of these. Not only can you teach yourself the constellations by using one, it will also tell you at a glance what will be above the horizon any time of night any night of the year.

--Star Atlas-A map of the sky showing where all those pretty objects are, this is an essential part of an astronomers gear. These range from beginner to advanced.

--Accessories case-These come in all sizes. You need one to carry your eyepieces and your stuff.

--Telescope Case-Usually a bag or hard case for the tube assembly, they can make transport safe and worry free, or simply keep dust off when the telescope is not in use.

--Vibration Suppression Pads-Designed to go under the feet of a tripod, these can cut the shimmy from the mount in half, and allow easier focusing at high powers by damping vibrations from wind, motion of the scope, or even the beating of your own heart from your hand on the focuser.

--Focal Reducer-A useful tool for the photographer seeking to put the whole field of his telescope on a camera chip, or for the visual observer seeking the widest field possible in his telescope. For the catadioptric telescope user only.

--Digital Camera Adapter or cell phone adapter-this allows you to attach any digital camera to a telescope to take pictures right through the eyepiece. Makes Lunar and Planetary photos easy.

--RA finder-Your neck tired of twisting to look through that Straight-Through finder on your telescope? Try a Right Angle finder, and quit bending. Some of these even have the option of upright images.

--Binoviewer-They say using two eyes improves contrast by 40%. Whether that's true or not, it's certainly more comfortable to use 2 eyes to observe. This device allows you to view with both eyes. It's only drawback? It requires you have two of every eyepiece.

--Camera Adapters-Depending on your camera and intended target, these allow the camera to be mounted to a telescope.

--Red LED flashlight-Red light will not damage your night vision. A white light flashlight can destroy your night vision for up to 45 minutes. This is essential at a star party, where consideration for others is paramount. Use of a white light at a Star Party might get you kicked out.

--Piggyback camera adapter-these allow a camera to be mounted to the back of a telescope, so that wide-field photography of the sky can be done through the camera's standard lens.

--Folding hand truck-this is a small, portable, dolly that allows you to move your telescope and its equipment easily.


Edited by Starman1, 25 July 2021 - 09:04 AM.

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#8 Bill Barlow

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Posted 25 July 2021 - 11:17 AM

I think you scared him away, Don.  He is probably now looking for a 80mm f/6 refractor.  A CPC11 is an awfully big scope to start out with.  But to each his/her own.

 

Bill


Edited by Bill Barlow, 25 July 2021 - 11:17 AM.


#9 ttorkelson

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Posted 25 July 2021 - 01:00 PM

Not scared, just mildly intimidated by the sheer amount of accessories needed (thanks for all those suggestions starman1! I was aware of most but these are great for confirming and adding to my list.)

Eventually, I will be going with something along the lines of this OTA once I get into AP (I think). Sounds like it would work for DSO or planetary:

 

https://www.bhphotov...ntent=B&H Photo

 

I'm curious. If I have all the best in goto/aligning, why should a large SCT be intimidating for just observation? On the mount that comes with the C11 I'm looking at (CGEM II) along with starsense/GPS/skyportal Wifi, it should be fairly easy to find what I'm looking for, given decent viewing conditions.



#10 Starman1

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Posted 25 July 2021 - 01:16 PM

Finding objects won't be the problem.

Transporting and setting up will be.

So long as you are prepared for the transport and setup issues, the 11" won't be an issue.

The individual pieces are heavy and large, however.

 

You first set up the tripod, then place the mount on the tripod and add counterwieght(s), then add the scope to the mount and balance the ensemble.

Then you use a compass to initially polar align (at night, just use Polaris in the finder scope).  That's good enough for visual use.

You can use the StarSense device, but it's just as accurate (maybe better) to use a 3-star alignment.

 

Prior to getting the scope, you should learn some of the major constellations and at least 20 first magnitude star names, and not rely on the electronics to 

do your alignment for you. Once you learn some constellations, you'll never be lost under the stars again.


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#11 Paul Skee

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Posted 25 July 2021 - 10:34 PM

I can attest it's a good setup for visual. I bought the 11" when Celestron ran a promotion sale with the AVX mount. I already had the CGEM II but I wanted the AVX to mount a lighter OTA. I put the 11" on the CGEM II and am pleased with the performance (I do no AP). It's kind of a beast compared to the AVX, but if you're willing to go the extra effort, I think it's worth it.

As far as 2" stuff, I put a Baader Click-Lock to hold an Explore Scientific 2" diagonal. Absolutely recommend this set up.

I have used Masuyama 85 deg., Nagler 20mm (82 deg). My next outing with it will try a Brandon 48mm.

With good sky conditions, planetary detail is amazing. I use 1.25" Fujiyama ortho's for these targets.


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