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nmoushon

Bought my first SCT! - Need some Advice

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Long story short I have switch to visual astronomy from DSO Imaging after 4 years and so bought my first scope that didnt have an imaging purpose in mind. So with 4+ years of imaging I have good amount of experience under my belt in that category but have very little in visual observing. 


 


I got a used C9.25 EdgeHD last night and I am super excited to get it out on a clear night and use it but....I am leaving on a 2 week trip tomorrow so my anticipation is going to be cruelly dragged out until I return and if the cloud gods are nice to me. So since I can't actually take it out and use it and try to learn through trial and error, which I usually prefer as a way to learn versus just reading the manual, I'm going to be reading plenty of threads on this forum and others on observing and handling a SCT. 


 


I would like to ask all you observers out there if you wouldn't mind sharing any help tips you have come across over the years that you might typically find in books or articles that you found really helped you. Same with SCT owners. Are there any tips or tricks or suggestions that as a new SCT owner I would find helpful? Really any advice or suggestions would be greatly appreciated. Even though being in astronomy for a while now I feel that switching over to observing is like starting over from scratch.


 


I have only ever owned a small ED80 (for imaging mainly) and have actually never looked through anything larger. I've moved A LOT over the last 5 years so I have never really gotten the chance or opportunity to go to any star parties or join any clubs. But I've finally settled down and bought a house so this is why I have bought this scope and hopefully soon to join a club and go to some star parties. This is also a reason why I'm really looking forward to first light as the jump from an ED80 to a C9.25 is going to be pretty awesome!


 


PS: I couldn't make up my mind whether to put it here or in the observing section so if a mod needs to move it go right ahead.


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The second-best thing that you can do with a SCT is to get a decent Crayford focuser for the rear. Focusing with the standard knob is a pain, especially if you are imaging.

The best thing is a dewshield (a £10 camping mat works fine). The corrector plate is a dew magnet and will fog up in no time without one.

After that, some Bob's Knobs for collimation. Yes, you can save a few quid (literally, just a few quid) if you mess about with off-the-shelf thumbscrews which could potentially damage things if they are the wrong length. But BK is a great supplier, they'll be with you in a week and they will work well.

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as said a crayford focuser, i had the baader on my 9.25 worked a treat. also a dew heater is a must

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1. Manage cooldown

2. Manage dew prevention

3. Collimate it to within an inch of it's life :smiley:

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Bit of a FOV culture shock after the ED80, use Stellarium to simulate view to pick targets.

Dave

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What I would add to Zakalwe's good advice is to let the optics reach thermal equilibrium before trying to do any high power observation. The light passes three time through the tube and a disturbed lightpath plays havoc with the images. A great telescope which will not disappoint you.  :smiley:

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Sorry I should have added that I did pick up a heated dew shield with it. I also have a barlow and a 8mm and 20mm 1.5" EP that can with my ED80. I can't edit the OP for some reason so hopefully other will read this :grin: . 

I eventually do plan on getting a crayford focuser but I first got to recoup my funds. I will dabble a bit with DSLR imaging and use my guide cam for video imaging as well but that will be down the road as I want to really get into to visual astronomy and see what it has to offer.

Edited by nmoushon

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I have the same scope and the answers given pretty much cover it.

The crayford was the first thing i did. Then the dew shield first unheated, then heated makes life so much easier. The dew was a nightmare even with the unheated dew shield. Mine is in an observatory so cool down is not a problem, but if your is indoors then its well worth it. The "Bobs knobs" also make colimation very easy, but i guess they are not essential.

I remeber my 1st view of M42 through it simply WOW! Enjoy your new scope. :grin:

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+1 for the comments above... (though I don't have a Crayford focuser on my C6/SCT).

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I have Bobs Knobs, Feathertouch Focuser, heated dew shield and you won't regret having them. I also use a Baader SCT click lock adapter and can highly recommend that.

Peter

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An f6.3 reducer/corrector is a commonly used accessory (i have one) to get wider FOVs. With your eyepiece selection of 8mm and 20mm it would prove useful i think. They are not expensive and easy to find used.

Enjoy your scope, I have had mine for 15 years and love it!

Rob

Edited by RobertI

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Thanks for all the suggestions everyone. I am a bit worried about collimating as I've never done it before. I will have to do some reading up on that one once I get it. They guy I bought it from really took care of his stuff and hopefully it held collimation well enough that I dont have to mess with it much.

I have heard getting the scope to temp can be a pain at times. Is there anyway to help it out at all? Or do I just have to make sure I give it plenty of cool down time?

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32mm plossl or 40mm plossl - just for the field of view.

Something like the Celestron X-Cel at 25mm or the Astro-Tech Paradigm will deliver a similar field as the plossls.

The focal length of the SCT causes the field to be somewhat limited and you could well want to get back as much as possible, at least when simply locating things.

I moved from a nice little refractor to a MAK, screamed and went and bought a 40mm plossl :grin:  didn't really care about how good it was I just wanted things in view.

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The Edge HD needs special reducers.....

+1 for the Feathertouch 10:1 micro focuser. I like it much more than the heavy Crayford option.

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Don't be scared of collimating your SCT. I use a laser and it takes about 60 seconds. This links to the Hotech Laser Collimator, but I use an Orion and a 2" to 1.25" adapter. Very simple:

http://www.hotechusa.com/v/vspfiles/assets/images/manual%20-%20sct-v2.pdf

Other than that, I use a Astrozap Flexible dew-shield on my 12" Meade LX90:

http://www.astrozap.com/scripts/prodView.asp?idproduct=162

Much easier to balance than an aluminium type.

Enjoy the scope! I've heard rave reviews all over about them.

'ta,

Dave

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My main visual scope is the c9.25.  Stuff that is really useful:

Get rid of the 6x30 finderscope.  It's small, confusing and generally hard work.  Replace with a Red Dot Finder - so easy to use.  Does not invert image, no magnification, and you can use it with both eyes open (one looking through finder, other looking at open sky :) )  Cheap too.   http://hawksphotovideo.co.uk/ostara-finderscope-telescope-337495-p-61034.html

Heated dew sheild - switch it on (lowest power setting) as soon as you set up, even in summer.  You'll be surprised how quickly SCTs dew up

For aligning your goto mount, illuminated crosshair eyepieces are very useful.  However, the best solution is the Celestron Skysense module.  2 minute auotmated alignment :)

Eyepieces - you're likely to buy a few over the next few months.  First is a big focal length one.  42mm, or 50mm if you can find it.  42mm Revelation is amazingly cheap and worth having.  I also love my 30mm Moonfish.  Get 2" Eyepieces for all these long focal lengths!!  You'll need a new 2" visual back.  Well worth it - otherwise you won't get the full field of view.

Edited by Commanderfish

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Don't be scared of collimating your SCT. I use a laser and it takes about 60 seconds. This links to the Hotech Laser Collimator, but I use an Orion and a 2" to 1.25" adapter. Very simple:

http://www.hotechusa.com/v/vspfiles/assets/images/manual%20-%20sct-v2.pdf

Other than that, I use a Astrozap Flexible dew-shield on my 12" Meade LX90:

http://www.astrozap.com/scripts/prodView.asp?idproduct=162

Much easier to balance than an aluminium type.

Enjoy the scope! I've heard rave reviews all over about them.

'ta,

Dave

What are the highest magnifications you view at? I am wondering about the effectiveness of that laser collimator on an SCT. I collimate in focus at 700x in my C11 SCT.

One thing about heated dew shields - if you get one then you won't be able to collimate visually without the corrector fogging over on dewy nights, because you would have to remove the shield to get to the adjustment screws. I got a Dew-Not heater strap and use a separate dew shield so I can use the anti-dew and collimate at the same time!

Regards,

Alistair G.

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Separate dew strap and shield. If the strap goes kaput on a combined version you will need to replace the whole lot. Baader click lock visual back. BINOVIEWERS, BINOVIEWERS, BINOVIEWERS!! Nice big wide field EP like an ES 82 deg 30 mm. Baader prism diagonal. Bobs Knobs. I also have access to a Hotech Advanced Laser Collimator through my astro club. A few suggestions to be getting on with.

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Thanks for all the suggestions everyone. I am a bit worried about collimating as I've never done it before. I will have to do some reading up on that one once I get it. They guy I bought it from really took care of his stuff and hopefully it held collimation well enough that I dont have to mess with it much.

I have heard getting the scope to temp can be a pain at times. Is there anyway to help it out at all? Or do I just have to make sure I give it plenty of cool down time?

Collimating an SCT is surprisingly easy once you get the hang of it.

https://youtu.be/hqRVIDj4aZA

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Another thread for visual observing is double stars, and from the reseach I have done a good starting point would be a small refractor - eg the ED80. As I have an ED80 for astro photography and a Meade LX90 8" SCT for general DSO observing I plan to press my ED80 into service for double stars. So in essence you have got a good base with your ED80 and 9.25 SCT for a wide range of visual type observations. Good luck and happy observing.

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to aid tube equalisation with outside try flexible ice packs tied around the ota .speeds it up. also ive just bought a bader hyperion 111 zoom with 2.25 barlow as a deal together. absolutely superb. who needs separate eyepieces ? this comes close to all expensive ep's. as said by others as well a feathertouch 10:1 focuser is a must and a f6.3 corrector.

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For visual I'd forget the 6.3 reducer. I'd just go for a 2 inch back and a widefield 2 in EP. If you have a 2 inch back and suitable EP you can reach the maximum field of the SCT without the reducer and get better views.

Olly

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I have heard getting the scope to temp can be a pain at times. Is there anyway to help it out at all? Or do I just have to make sure I give it plenty of cool down time?

Whatever you do DON'T buy one of those SCT cooler rods! They are fine for standard SCT's but the Edge varients have a corrector inside the tube, if you used a cooling rod it would be game over as soon as it smashes through the nternal corrector.

The Edge scopes do have micro vents to aid cooling, my now sold C8 edge was obsy based so I'm not sure how well these actually work?

Other advice would be to use 2" Ep's rather than a reducer, a 40mm ish super wide eyepiece will serve you well, and it doesn't need to be an expensive one, F10 scopes are very kind on eyepieces. On the flip side fast scopes like big Dobs need good eyepieces to stand any chance of being sharp to the edge.

Collimation is simple on an SCT, its just the secondary mirror to adjust with 3 screws :)

Check this out but be very careful about putting a screw driver near the corrector plate like this guy, I'd rather fit Bob's knobs. There are arguments against Bob's knobs saying that the plastic tips mean that collimation doesn't hold, I haven't found this to be true at all. Generally speaking SCT's hold collimation very well.

Enjoy your new scope, it's a great choice, lots of aperture in a compact design :)

Edited by Chris Lock

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Don't fit Bob's Knobs. They may make collimating easier, but with their little squishy plastic tips, collimation will be required much more often - They're a self fulfilling prophecy.

+1 on a focal reducer. I'm pretty sure the Antares 0.6x will work, as it doesn't correct for coma. The Edge HD and Meade ACFs are coma corrected anyway. The massively expensive Celestron item [may] only really have an advantage when imaging in terms of field curvature at the focal plane or some such. PM me because I have a spare Antares you can have for postage to have a look see. :)

Use the scope before looking into Crayfords. From the few SCTs I've used, mirror shift can vary from being a real pain in the butt (moving a subject from one edge of the FoV in a 20mm EP) to barely noticeable as it is with my LX200R.

Finally, store it pointing upward. The primary mirror slides on a grease covered tube. You don't want a lump of that falling on your secondary because it got a bit warm one day.

Russell

Sent from my iPad using Tapatalk HD

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