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CAT Essentials

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#1 snufus

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Posted 13 September 2005 - 11:02 PM

Hi All,

I am about to be become the proud owner of my first CAT; a C11. Because this is my first catadioptric I feel like, and know I am, a complete newb when it comes to knowing what essentials are needed to protect it and to maintain it. Because I am new to the world of CATs I have no idea what is best and worst other than looking at reviews. So if any of you out there would like to lend me some of your CAT expertise on essentials I would be at your attention. :)

I know some items I need will be:

Dew Shield
Lens Brush - for cleaning dust off corrector
Collimation Device - which is best for CATs?
Kendrick Heater?
Upgraded Focuser - Not an essential I know but if you all think the stock one on the C11 could be better let me know.

Other than that I am open to whatever other essentials anyone mentions, I could use some advice on what the best brands are for the above items as well.

Thank you all!

#2 matt

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Posted 14 September 2005 - 01:56 AM

Avoid touching that corrector, just like any optical surface anyway.
Have a heater, and perhaps a blowdryer to make sure there is no moisture on the lens when you put the cap back on - dewdrops leave unpretty marks (the impact on viewing is subject to debate, but the ugliness of the marks really get under your skin) and attract dust.

- Get one of those 2" diagonals Astronomics has a special on while it's still time, even if you don't have 2" eyepieces

- get an orion fine focus adapter (it requires a 2" thread, hence the diagonal), it's a very cheap alternative to electric focusers, etc, and works very well.

- one of those 2", 32mm wide field kellners which can be had for a song and are awful in fast newtonians work quite well on f/10 cats, though not as well as a 35mm panoptic worth 10 times the cost.

#3 Donnie

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Posted 14 September 2005 - 07:28 AM

Depending on the humidity where you live, you will definitely want to go with some active dew prevention. I live in the Ohio Valley, humid most of the summer. A dewshield only delays the onset of the dew where I live. Even in the winter, the dewpoint around here is such that frost often forms on the corrector without dew protection. I dont have an SCT at the moment, but when I would set mine out to cool, I would go ahead and turn on the dew heater on low. If you wait for it to form, it is harder to combat.

As far as collimation goes, the best bet I found with the SCT's I have owned is just the star test under high power. Although F10, SCT's have a very fast primary. At around F2, collimation is critical to your best performance, especially high power work. I think this is one of the leading contributors to "mushy" images that SCT's are known for. That, and with 11" of aperture, seeing conditions often play a role. Especially where I live.

Matt pointed out one of the great advantages of SCT's. Even cheaper eyepieces work quite well at F10. The GSO series of widefield eyepieces work great in SCT's. With a faster scope you will need to have premium eyepieces at some point. Actually, I guess "need" is a strong word. Regardless, I was always satisfied with my SCT's and even middle of the road eyepieces.

Congratulations with your new instrument. I hope it gives you many good years of service and most of all many good memories.

#4 southmike

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Posted 14 September 2005 - 10:05 AM

kendrick heaters have had mixed reviews..the controlers are good the strips have burned out early for some people..you might want to look at dewnot dew strips with a kendrick heater. though i would still get a dew shield it helps for stray light and allows you to run heater at a lower setting.



the focusers are nice especially if you get one that is an eyeopener sct type..(mainly for meades but there is one for celestrons as well)it opens up the full field of view for a 2" eyepiece and adds the micro focusing part.

I also recomend buying a good 2" diagonal with coatings like the WO.

in fact buy only quality anything things like a cheap barlow will really hurt the performance. now some things still work pretty well and are inexpensive but are not cheap if you know what i mean..so do a little research and ask questions.

#5 LivingNDixie

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Posted 14 September 2005 - 12:06 PM

This is essential reading link

#6 Mike B

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Posted 14 September 2005 - 12:21 PM

Hi Daniel-

Congrats on the new scope... & welcome to CN, too! :grin:

My list of "must have" suggestions would go like this:
1. Flexible Dewshield, dewheater too if you've got humidity... i don't ;)
2. Vibe pads. Yup... makes a difference! Fer cheap.
3. portable battery or "powertank"... get out of the AA battery business, like fast!
4. CAT cooler, to get your optics to ambient temp... can run off #3 above while you set up :grin:
5. comfortable observing seat... with emphasis on the comfortable part ;)

Next would be my list of recommended upgrades:
6. full 2" visual back & "refractor" type mirror-diagonal
7. 2" wide-angle eyepiece, to max your FOV
8. Telrad finder (if you're a "star-hopper")
9. if your focuser has a lot of slop, you can upgrade to a "crayford" type tailpiece focuser, or try repairing the existing focuser "guts" with a "Peterson" kit
10. the ultimate upgrade... a binoviewer! :evillaugh: :woot: :yay:

Much of the above is covered at length in the CATs forum... try running a search therein. Here's one recent thread that covered much of what will likely get re-mentioned in this new thread...

Enjoy that new scope!
:cool: mike b

#7 jrford

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Posted 14 September 2005 - 12:53 PM

What about a screw on filter for the BACK of the SCT. This would seal the tube. I was told this would keep the dust and moths out. Not sure if this would affect cool down?

#8 southmike

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Posted 14 September 2005 - 01:14 PM

i use the 4 mm eyepice from my celestron kit, in the visual back usually..

or the lpr/uhc/broadband sct cell filter or
even the 6.3 reducer.

but the rear covers are probably a good thing..I just didn't like the 25~35 pricetag..when you can get a lpr filter used pretty cheap.

#9 Mike B

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Posted 14 September 2005 - 02:03 PM

jrford-

It would limit cooldown to that which occurs only thru radiating... which might be tolerable in stable climates (ie. 80*F day, 75*F night ;)), but would hamper most folks' efforts to get any kind of pleasing images at any kind of magnification, any time soon.

The CAT-coolers work so effectively by pumping exterior air directly, gently ;), and filtered into the tube to help the primary mirror achieve *ambient* temperature more quickly. But other than a brief episode of "up-periscope", my CAT is plugged during use with a star-diagonal & BV, or while stored with a plastic stopper with dessicant package attached.

I've had this CAT for 9 years now, & dust/moths have not been an issue whatsoever. Just the occasional hairball. JK.
:cool: mike b

#10 snufus

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Posted 14 September 2005 - 10:52 PM

Wow!

Thanks all for the great suggestions. I will definetly get the following:

Dew Shield
Dew Heater
CAT Cooler
Bobs Knobs
WO SCT Diagonal
Orion Fine Focus Adapter
Battery Pack
Vibration Pads (on my list already because of the mount)

The only question I have is regarding the dew heater. If I have the CAT cooler going I imagine it would be ok to have the dew heater going at the same time on low right? I do live in a place with a lot of humidity so I will need to use a heater. I just am wondering the best way to use it effectively in the warm climate I am in.

Thank you all once again for the great advice!

#11 southmike

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Posted 14 September 2005 - 10:53 PM

you do have an adjustable height observers chair right?
That was the best thing i have bought as an add-on

#12 matt

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Posted 15 September 2005 - 04:54 AM

To answer your last question Daniel, it is unlikely you will need the heater before the cooler is off: if the scope is warmer than the outside air (the reason you need that cooler for in the first place), dew cannot form on it. It can only form when the scope (ergo the corrector) gets cooler than the outside air.

The cooler is only necessary if it's much cooler outside than inside (let's say 10° or more). The environment friendly :smirk: alternative being to put the scope outside an hour or two before observing. If you observe from home it's the simplest way.

#13 Syzygy

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Posted 15 September 2005 - 05:56 AM

Daniel,

I live in jungle humidity in the summer. I run my CAT cooler for about 20 minutes while I set up the rest of the gear. It does a good job of jump starting the cooldown, but it usually takes a little while longer for the scope to cool completely down, depending on the temperature difference.

I'll turn my dew strips on low after I get everything set up. It's easier to keep the dew from forming than it is to use high power on the strips to burn off the dew. While you're buying dew strips, you might consider a strip for the EP. It's nice to have a dew free EP to look through. :grin:

#14 Rusty

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Posted 15 September 2005 - 08:32 PM

Daniel,

I'll turn my dew strips on low after I get everything set up. It's easier to keep the dew from forming than it is to use high power on the strips to burn off the dew. While you're buying dew strips, you might consider a strip for the EP. It's nice to have a dew free EP to look through. :grin:


And dew strips for the finder, and the Telrad. I DO live in a jungle...

#15 Syzygy

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Posted 16 September 2005 - 12:07 PM

Rusty,

I didn't want to scare Daniel away and I was exercising restraint. :grin:

I'm a dew heater fanatic, heating my corrector, Telrad, piggyback ST80 objective, ST80 EP, and both bino EP's. I have a strip for my finder objective when I choose to mount it.

If it's humid, heat it or lose it............

#16 Rusty

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Posted 16 September 2005 - 09:45 PM

Restraint is unacceptable behavior for N11 folks. :grin:

I only mentioned the other heaters so Daniel wouldn't engage in the same mistakes I did - our club dark sky site isn't called The Swamp for nothing....(complete with alligator, BTW)

#17 snufus

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Posted 16 September 2005 - 10:48 PM

I cannot thank you all enough for the great suggestions. My goal is to keep this scope looking and operating like new and I do not want either to suffer as a result of my 'newbieness'.

Ok, so heaters all around!:) I cannot wait to see people's reaction when they know I am heating my equipment (in the heat of Texas). Even at night the heat is almost unbearable, and being originally from Ohio I never thought I would sweat while observing! But if thats what it takes to keep everything dry then I will 'dew' it!

It was funny today as I went to place the order here at our local astronomy shop the owner was trying to tell me the Meade LXD75 SN-10 would be better for me. He said it costs less and I can upgrade it out for less then I would spend for this package. Trying to talk me out of it, oh well it did not work though. I have placed the order and got many of the accessories I need. Only ones left are the extra heaters and the WO Diagonal.

Thanks again all! I cannot wait for my new baby to arrive.

#18 Larry F

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Posted 17 September 2005 - 09:59 AM

I'm a big fan of using an artificial star for collimating. I have the Digitec. It allows you to collimate with the tube level, which really makes it easy. The new PicoStar version is $139.

#19 southmike

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Posted 17 September 2005 - 10:18 AM

look for dewnot strips ..very good inexpensive alternative to kendrick...some people say they last longer.

#20 Guest_**DONOTDELETE**_*

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Posted 19 September 2005 - 10:05 AM

Don't forget to check out the Denkmeier page. If you plan on upgrading the diagonal to a 2", you might as well do the Power X diagonal so you can then move right in to bino viewing with multiple powers. Mine should be here today! Will be putting it on my LX90 tonight.

#21 southmike

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Posted 19 September 2005 - 06:20 PM

sounds like a great addition..

#22 snufus

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Posted 19 September 2005 - 10:54 PM

Thanks to everyone! Off to purchase some accessories! :)

I will let you all know how it compares to LXD75 SN-10AT once it arrives. :)

By the way, after purchasing all the upgrades\accessories for the LXD75 and now the C-11 I will officially be poor again.. LOL! :)


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